Model Engine Maker

Engines => Your Own Design => Topic started by: Roger B on February 11, 2018, 07:51:21 AM

Title: Two Cylinder Engine
Post by: Roger B on February 11, 2018, 07:51:21 AM
I decided to make an updated version of my vertical engine using the same design concept but increasing the capacity and making it as a twin. I did think about a 4 cylinder version but it would be too large for my machines. The original was 16mm bore and stroke, this will be 20mm bore and 19mm stroke. The crankcase will be the same 40mm square aluminium with the crank running in two ball bearings. The cylinder liner will be more conventionally fitted but I am still wavering between cast iron or brass.
I started with the crankshaft. This is a piece of 30mm diameter moderate carbon steel (ST50). The ends were faced and centre drilled using the fixed steady and then one end was rough turned to 16mm. This reduced end was held in the Keats and the two centres for the crank throws were drilled on the mill. The Keats was then mounted on the faceplate and the bar was centred. The V block part of the Keats was then moved across the required 9.5mm (towards the centre for better balance) and the centre was put in the appropriate centre hole.
I started cutting with a 1.5mm blade type parting tool at 500rpm and 0.1mm depth of cut. As expected there was significant chatter but not a problem as the finishing cuts will be made with conventional tools. A short way in I realised that it would be better to cut the throw furthest from the chuck first  ::) The shaft was loosened and turned 180°, the alignment being checked with a square on the side of the Keats and a square across the centre holes.
Title: Re: Two Cylinder Engine
Post by: crueby on February 11, 2018, 02:26:24 PM
Great start, will be following along...
Title: Re: Two Cylinder Engine
Post by: Roger B on February 11, 2018, 04:25:11 PM
Thank you Chris  :ThumbsUp:

I gradually turned the journal to round but there were various clearance problems which resulted in an ever greater overhang. The crankwebs were finished with LH and RH 8mm shank tools. I them moved on to finishing the journal with 6mm tools but there was too much overhang with the Hobbymat toolpost. The QCTP gave more support to the tool. The ridge in the middle was removed with an 8mm straight tool. Back to the other journal.
Title: Re: Two Cylinder Engine
Post by: Art K on February 11, 2018, 09:15:45 PM
Roger,
Count me in, I'll be following along.
Art
Title: Re: Two Cylinder Engine
Post by: stevehuckss396 on February 12, 2018, 12:05:25 AM
Nice start. Looking forward to your updates.
Title: Re: Two Cylinder Engine
Post by: gldavison on February 12, 2018, 12:48:15 AM
Me  too
Title: Re: Two Cylinder Engine
Post by: fumopuc on February 12, 2018, 04:32:58 AM
Hi Roger, great start with this crankshaft. Something I have to do for my OPT engine twice in the near future.
Any Idea how to block the already machined journal against bending during the machining of #2 ?
I have seen special made spacers, fixed with tape or ty-rapes. Mr. Kelley has recommended this fixation by soldering.
My prefered idea is some epoxy glue.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 12, 2018, 09:44:49 AM
Thank you all for your interest  :ThumbsUp:

Achim, one of the benefits of using the Keats angle plate is that it takes most of the bending moment. The tailstock centre only really absorbs the out of balance forces. On a couple of other engines I fixed a bridge across the webs using the fixing holes for the balance weights as in the picture from my diesel build.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 14, 2018, 07:25:42 PM
I turned the second journal with the same series of tools  and then mounted the 16mm end in a ER25 collet and started to turn down the  shaft. This was at 500rpm and 0.5mm depth of cut.

https://www.youtube.com/watch?v=Ja-FeB2Mgkc
Title: Re: Two Cylinder Engine
Post by: Roger B on February 17, 2018, 07:18:36 AM
I then moved on to finishing the shafts. The reduced end was held in an appropriate ER25 collet (hence roughing out to 16mm) and the bearing seat and shaft were turned. It was then turned round and held in a 6mm collet for finishing the other end. With the centre removed there was very little run out so the distortion from two 180° crankpins seemed to balance  :)
Title: Re: Two Cylinder Engine
Post by: Jo on February 17, 2018, 08:46:45 AM
That was a lot of metal that needed to come off that crank Roger I bet your pleased with the progress  :).

Seeing your crankshaft has reminded me that there is the beginnings of a crankshaft for a twin sitting in that box of castings sitting on the dining room table that Surus was exploring. But I don't think it is as big as your new crankshaft ;)

Jo
Title: Re: Two Cylinder Engine
Post by: Roger B on February 18, 2018, 07:55:41 AM
Thank you Jo, I am pleased with the way it went but still need to improve the way I turn the crankpins, maybe a slightly bigger parting tool  :headscratch: As both crankshafts are sitting on sheets of A4 paper I don't think there is much difference. What's the engine, it looks like a flat twin?

The next step was to prepare the blocks of Aluminium that make up the crankcase and cylinder block. This was made easier with the new bandsaw even though I can only use it on the floor  ::)

I made a quick check that my boring bar was in fact long enough and then started squaring and sizing the blocks with a flycutter. The two halves of the cam carrier need to be screwed together so I can flycut the face that joins to the cylinder block.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 18, 2018, 03:28:59 PM
The cam carrier was drilled, counter bored and tapped M3. When assembled the mounting face could be flycut. The rest of the pieces were set vertical in the vice and flycut to length.

Back to lathe mode. The crankcase was centered in the independent chuck (the piece of 3mm rod is to give some clearance to protect the chuck when boring) and drilled 2.5mm using one of the long drills I bought for drilling the oilways in the diesel crankshaft. The hole was then opened out to 13.5mm (my largest MK1 drill) ready for boring.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 18, 2018, 03:35:52 PM
I then set up the boring bar with a new APT aluminium tip and set a stop to protect the chuck at the end of the bore. Next I made sure there was enough clearance between the carriage and the tailstock (I can take the tailstock off but it's a pain :(  ).

Boring was OK so far at 500rpm and 0.08mm/rev. Initially it was difficult to clear the swarf but as the hole got bigger it was easier.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 22, 2018, 08:13:16 PM
The next step was to bore out the big end clearance in the middle of the crankcase. This required the boring bar to be set at an angle and the crankcase to be turned round to finish the second end. The bearing surfaces were then clocked concentric and finished to size.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on February 22, 2018, 10:07:51 PM
It's one of those stages in the build where a casual glance at the case make you think that the maker only use a few minutes on it so far  ;)

Looking forward to more.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 25, 2018, 08:04:02 AM
Thank you Per  :ThumbsUp: This stage involves a lot of swarf. I did consider using a hole saw to remove the bulk of the material but it's not easy to maintain the centre  on square work.

Next up was the hole through the cam carrier. I did consider setting the halves up in the mill and using a 3mm ball nose mill to cut a 'pilot' bore to stop things wandering but decided to try the easy way first. I set in up in the 4 jaw chuck and pilot drilled 2.5mm with a long series drill followed by 9.8mm and a 10mm reamer. The hole looked to be central at the far end  :)

I then made a centring plug for the next operations and went back to milling mode on the crankcase. This was clamped to the table and aligned with stops set on the X axis so I could work between the two bores. As the wall is quite thin at that point I ran the centre dill right through to act as a pilot. This was then opened out to 15.5mm (my largest MK2 drill) ready for boring.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 25, 2018, 08:25:19 AM
The two holes were then opened out to 23mm with the boring head using a brazed carbide tool at 560 rpm and 0.6mm depth of cut.

I then set up the cylinder block using two 6mm square tool blanks as parallels to allow through boring. This was pilot drilled 4mm (the smallest drill that was long enough) and opened out to 15.5mm. The mill was struggling a little at the lowest speed but got through. I was using the quill feed for boring and had to extend the sleeve on the drawbar to be able to use the full travel (quill stroke 50mm, cylinder block 48mm). Luckily I had a suitable sleeve from my governor experiments and didn't have to resurrect the minilathe to make one. I used the same speed and feed as before but with a longer boring tool. It seemed to chatter mid bore until I realised that that was the point where I changed my grip on the handle and must have changed the feed rate  ::) If I used both hands I could keep it steady.
Title: Re: Two Cylinder Engine
Post by: AlexS on February 25, 2018, 08:13:17 PM
Nice start on your new engine! I let you know that I am following your progress. And do you have plans to add a lubrication system on the engine?

Cheers, Alex
Title: Re: Two Cylinder Engine
Post by: Art K on February 25, 2018, 08:26:47 PM
Roger,
It is great to see more progress, looking great!
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on February 26, 2018, 06:49:54 PM
Thank you both  :ThumbsUp:  Alex, it is planned to be splash lubricated with a side oil reservoir like the single. This time the reservoir will be under the camshaft. There is space for an oil pump but I don't think it will be needed. I have used a pumped system on my diesel but the loads there will be higher.

I finished the other bore and then set up the rotary table to round off the ends of the cylinder block. I used a 14mm end mill at 560 rpm in 10mm steps with 0.5mm depth of cut. The finishing cut was 0.2mm deep. There are chatter marks but they can be removed with light filling.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 26, 2018, 07:56:05 PM
The next step was to flycut the sides of the cylinder block. A little bit of filling should remove the various machining marks.
Title: Re: Two Cylinder Engine
Post by: Craig DeShong on February 26, 2018, 11:12:54 PM
Nice project.  It’s going to be interesting watching you convert this lump of aluminum into an engine.  I’ll definitely be watching.  :popcorn:
Title: Re: Two Cylinder Engine
Post by: yogi on February 26, 2018, 11:31:56 PM
Coming along nicely Roger!  :ThumbsUp: :ThumbsUp: :ThumbsUp:

 :popcorn: :popcorn: :popcorn:
Title: Re: Two Cylinder Engine
Post by: Art K on February 27, 2018, 12:01:24 AM
Roger,
The cylinder looks good. Probably the only way to get rid of the chatter marks is unafordable. Having the stock to clean it up is great. A file and some sand paper and they won't even show.
Art
Title: Re: Two Cylinder Engine
Post by: Longboy on February 27, 2018, 12:22:09 AM
Be nice to hear the sounds of a 180 crank inline twin and see the ignition setup.  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on March 01, 2018, 07:52:14 PM
Thank you all for your interest  :ThumbsUp:  :ThumbsUp: I can afford the better machines, but not the space to install them  ::)

The next step was to drill and ream for the cam follower guides in the cam carrier. As this requires 10mm holes on 10mm centres there is not much left in the middle but it works  :) I then drilled the fixing holes for the cam carrier and cylinder block and spotted them through onto the crankcase. Problem  :( 6 of the holes lined up nicely, two were more than a mm out  :headscratch: They will have to be tapped out M5 plugged and redrilled  ::)
Title: Re: Two Cylinder Engine
Post by: Dave Otto on March 02, 2018, 01:11:33 AM
You are making good progress Roger, the cylinder assembly looks great!

Dave
Title: Re: Two Cylinder Engine
Post by: Roger B on March 04, 2018, 07:01:45 AM
Thank you Dave  :ThumbsUp:

The next step was to cut two connecting rod blanks from a piece of 60mm x 10mm aluminium bar (the new bandsaw is wonderful). The ends were marked out and the center holes as well as the big end fixings were drilled. The next steps require going back to lathe mode.

I then moved on to the timing gear cover. This was to be cut from a piece of scrap 15mm aluminium which unfortunately had an M5 hole in just the wrong place. I used a 6mm endmill to move it over slightly. The final size will be 10mm but I wanted to reduce the chance of the next operation being deflected. This was roughed out with the bandsaw (it's just possible to cut 115mm in a 105mm saw  :) ) along with the backplate. The edges were trued up and the two pieces were sandwiched together for drilling.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 04, 2018, 07:07:51 AM
The two outer 6mm holes do not go right through. The inner one was opened out further with a 8mm end mill to reduce the chance of deflection before drilling 9.8mm and reaming 10mm. I used a previously made 10mm dia. 6mm bore sleeve to align the two pieces and fitted one of the outer hole over the 6mm spigot in the RT. The fixing bolt went through the hole in the sleeve. I then started to round the first end in a similar way to the cylinder block.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 04, 2018, 12:19:00 PM
The second end of the timing cover was rounded off then it was set up on the mill using the two 6mm holes for alignment. I then started hollowing it out with the boring head. My cheap brazed carbide cutters were the wrong profile for a blind hole and I have no means of reshaping them other than a diamond hone so I tried my 8mm boring bar with an APT aluminium tip. This worked but was a bit chattery. Cutting it to half the length would certainly have helped, I may see if I can find some cheap holders and cut them to various lengths.

Clean up and back to lathe mode for the next steps.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 04, 2018, 06:52:46 PM
I mounted the big end in the 4 jaw independent chuck and turned the conrod shank initially to 8.5mm. Then using a profiling tool I shaped the ends and took it down to 8mm. Same procedure for the 2nd rod.
Title: Re: Two Cylinder Engine
Post by: Ramon Wilson on March 05, 2018, 08:56:08 AM
Hi Roger - Rather late on board, I must admit to having only just looked at your project for the first time.  :-[

That's some nice machining you've done there and a super photo coverage of the processes too. I've yet to do a (one piece) two throw crank - you've shown just how much work goes into such a component   :praise2:

Nice work all round  :ThumbsUp: keep it coming

Regards - Tug





Title: Re: Two Cylinder Engine
Post by: Roger B on March 10, 2018, 11:03:10 AM
Thank you Tug  :ThumbsUp:

I then cut the big end caps off using a 0.5mm wide slitting saw. The rods were held in my new Proxxon steel vice and cut off in the lathe. Next the holes for the big end bolts were opened out to 2mm and I started to tap the big end caps. Problem  :toilet_claw: The M2 tap broke! I was initially not sure why as I was using the tapping fixture and lubricant  :headscratch: When I looked at the pictures afterwards I realised that I had started with the second tap rather than the taper  :facepalm:
Hopefully I can get the broken bit out with Sal ammoniac.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 10, 2018, 03:34:47 PM
Did I mean Alum for removing broken taps  :headscratch: I'll to look it up and see what it is called here.

As the tapping had to stop I moved on to the spotfacing cutter for the big end bolts. This is a short piece of 4mm silver steel with some cutting edges formed with a junior hacksaw and a half round swiss file. It was hardened and fixed to a 2mm shaft with Loctite. The cutting was done by hand with the shaft held in a small drill chuck.

Next I started on the cylinder liners. The first is made from a ~25.5 mm dia core I cut out of the cylinder block for the horizontal engine. The second will be made from a piece of nominal 25mm cast iron bar.
Title: Re: Two Cylinder Engine
Post by: fumopuc on March 10, 2018, 07:55:20 PM

I have bought it here.
https://www.ebay.de/itm/9-78-kg-Alaun-Kalialaun-Kaliumaluminiumsulfat-Kristalle-Knete-Hortensien-900g/263538342180?hash=item3d5c1bf924:g:fj0AAOSwUUdaoPue
Title: Re: Two Cylinder Engine
Post by: crueby on March 10, 2018, 11:20:47 PM

I have bought it here.
https://www.ebay.de/itm/9-78-kg-Alaun-Kalialaun-Kaliumaluminiumsulfat-Kristalle-Knete-Hortensien-900g/263538342180?hash=item3d5c1bf924:g:fj0AAOSwUUdaoPue (https://www.ebay.de/itm/9-78-kg-Alaun-Kalialaun-Kaliumaluminiumsulfat-Kristalle-Knete-Hortensien-900g/263538342180?hash=item3d5c1bf924:g:fj0AAOSwUUdaoPue)
Yup, can just see it now, buy some from there for shipment over here, and just watch the look on the customs  guys face as he sees the big bag of white powder in the package....!  ;D
Title: Re: Two Cylinder Engine
Post by: Art K on March 11, 2018, 12:40:30 AM
Roger,
I saw Achim's post and didn't go to google translate. It must be one of these things that eat out taps. I'm just glad it was the end cap & not the rod, much easier to make a replacement & chalk it up to experience.
Art
Title: Re: Two Cylinder Engine
Post by: MJM460 on March 11, 2018, 08:05:25 AM
Hi Art, why not try buying some aluminium sulphate, with or without the extra "I", and try it for future reference.  It should not be very expensive.

It is normally a water clarifier but now I think of it, I have seen previous references to using it for this purpose.  Presumably the aluminium and iron exchange somehow to give a ferrous (or ferric) sulphate.  You would need a strong solution and probably some time.  Obviously no good on a steel component.

Continuing to enjoy your great build log, thank you.

MJM460
Title: Re: Two Cylinder Engine
Post by: Roger B on March 25, 2018, 08:13:45 AM
I managed to get a small quantity of Alum and the bearing cap is currently sitting in a strong solution. There are some signs of corrosion but I expect it will take a couple of weeks.

I bored out the liner until the lap would just go in and then chamfered the end to ease get the piston rings in. It was then parted of over length so it can be faced off when fixed into the block. It was interesting that after boring the outside was no longer quite round, but not a problem as I had left 0.2mm to skim off.
The second liner was made from a different piece of CI which showed a much better surface finish using the same tools.
Next I need to mount the cylinder block in the lathe and bore the recesses for the top of the liners and the water jacket spaces.
Title: Re: Two Cylinder Engine
Post by: fumopuc on March 25, 2018, 09:38:07 AM
I managed to get a small quantity of Alum and the bearing cap is currently sitting in a strong solution. There are some signs of corrosion but I expect it will take a couple of weeks.
....
Hi Roger, when I have done it last time in Aluminium, I have kept the solution under 70° to 80°C for nearly 30 hours. Every 4 hours some fresh Alum was added.
Title: Re: Two Cylinder Engine
Post by: Ian S C on March 25, 2018, 12:54:22 PM
Keep it warm(the alum solution), and every now and then poke a bit of wire down the flutes of the tap to get the gas bubbles out, it doesn't really take too long until you can wiggle the tap, after which it won't be long until it will come out.
Ian S C
Title: Re: Two Cylinder Engine
Post by: Roger B on March 25, 2018, 05:53:41 PM
Currently the part is in a little jar with fresh alum at the bottom which I shake every time I go past it, no real hurry I have plenty of other parts to make  ::)

As I was in lathe mode I tapped the out of position holes in the crankcase out to M5 and Loctited a couple of plugs in. I also tapped the other bearing cap in case it also needed and Alum bath  :facepalm: No problems  :)

I then fixed the centering plug onto a piece of 6mm silver steel held in an MK collet in the mandrel  and set up the cylinder block to start boring out the water space.
Title: Re: Two Cylinder Engine
Post by: Art K on March 25, 2018, 09:56:01 PM
Roger,
The twin is coming along nicely.
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on April 01, 2018, 01:25:02 PM
Thank you Art  :ThumbsUp:

I turned the cylinder block round so I could finish boring out the water space and cut the recesses for the top of the liners. The passage between the two water spaces was then opened out with a cutter in the Proxxon hand tool.

I then went back to the crankcase and cut off the plugs, filed them flat and re-centred and drilled. The drift was quite surprising  :headscratch:

Finally have received my new deep parting tool (2mm wide 19mm deep blade) I finished off the crankpins with a significantly better finish than before  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on April 01, 2018, 01:25:46 PM
And due to the 8 picture limit-
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on April 01, 2018, 10:28:48 PM
That finish looks really good on the crank  :ThumbsUp:

Do I see a few rust spots ...?... if so, you better keep the parts oiled until an eventually paint job  ;)
Title: Re: Two Cylinder Engine
Post by: Art K on April 01, 2018, 11:40:35 PM
Roger,
Everything looks great, good progress. Curious though, what is the second gear opposite the cam going to drive?
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on April 02, 2018, 08:34:02 AM
Thank you both  :ThumbsUp: The brownish marks on the crankshaft are the last traces of the paint that was on the bar end that I used. The other gear will drive the water pump and the distributor.
Title: Re: Two Cylinder Engine
Post by: Roger B on April 04, 2018, 05:36:38 PM
I found that the alum was working rather slowly on the broken tap and following suggestions from the Forum I warmed it up on one of my halogen work lamps. This produced a much more satisfactory stream of bubbles and after several heatings I was able to push the remaining part out and finish off the cap. The alum didn't affect the aluminium but cleaned off the marking out blue.

https://www.youtube.com/watch?v=V_DqGU7GGdw

I then started on the camshaft blank. I tried my new parting tool to make the gaps between the lobes, going in 0.5mm and then traversing. After the planned 4 steps the diameter was still 0.5mm oversize and it appears that the cutting force (as suggested elsewhere on the Forum) pushed the insert deeper in.

I now need to extend my milling jig to take the longer shaft. Hopefully I won't need to add a centre support.
Title: Re: Two Cylinder Engine
Post by: AlexS on April 05, 2018, 06:59:23 PM
Good progress on your twin Roger! May I ask you of what kind of material the camshaft are made from? And what kind of tooling you use for mill the cam profile?
Title: Re: Two Cylinder Engine
Post by: Roger B on April 05, 2018, 07:21:07 PM
Thank you Alex  :ThumbsUp: The camshafts are made from silver steel. I mill them in 6° steps, finish them with a fine file and then abrasive cloth. After this I harden and then polish them with abrasive cloth. The last picture (474) shows my camshaft milling set up.

I then set the conrods up on the mill and drilled and reamed the ends. They were then mounted on the RT to round them off.
Title: Re: Two Cylinder Engine
Post by: AlexS on April 05, 2018, 07:47:06 PM
Thanks Roger for your feedback. Currently I want to mill the profile of the cams for my engine. They also made of silversteel. Had to make some tools to fit a chuck on a index table and a countercenter. Before I had to much vibration when milling the cams, but the cutters (hss) did not like it. So hopefully I have this weekend some more time and try it again! If that does not work so well, I'll make a tool like yours;)
Title: Re: Two Cylinder Engine
Post by: zeeprogrammer on April 05, 2018, 08:53:33 PM
Jumping in to enjoy some  :popcorn:

Looking good.

P.S. Small quantities of alum can be bought at grocery store in spice aisle.
Title: Re: Two Cylinder Engine
Post by: Roger B on April 11, 2018, 11:49:40 AM
Thank you Zee  :ThumbsUp:  :ThumbsUp:  Now the weather has improved and I can reopen the R&D dept progress on this will slow while I get back to my fuel injection fun.
Title: Re: Two Cylinder Engine
Post by: Jo on April 11, 2018, 01:59:36 PM
Now the weather has improved and I can reopen the R&D dept

Looking forward to watching your progress Roger :)

Jo
Title: Re: Two Cylinder Engine
Post by: Roger B on May 20, 2018, 12:21:31 PM
I have being doing a few more bits on this one.
The little ends were rounded off using some filling buttons and the big ends were finished on the RT. I then started on the body of the water pump, this is now waiting until I next change to milling mode.
As I had been doing lots of tiny bits for fuel injectors I wanted something a bit bigger to do so decided to make the flywheel for this engine. I ordered one of the commercial taper clamps that Achim used but decided that it was a bit to bulky and will make my normal taperlock bush.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 20, 2018, 12:30:37 PM
The flywheel is a slice of 50mm diameter CI. It was faced, drilled out to 11.5mm and then bored with a 15° taper until the large end was 18mm. 15° is a bit steep but worked ok on the original 3cc engine . I have used 6° on the bigger engines. The bush is turned from a piece of 20mm free cutting steel. I cut a runout groove with a parting tool and turned the taper. The compound slide had not been moved since the flywheel was bored so the angles should be identical. The bush was drilled 9.8mm and reamed 10mm.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 20, 2018, 04:26:30 PM
I then used the Proxxon RT on the Proxxon drill to drill a set of 3mm hole 8mm deep at 120° intervals and a set of M3 holes 10mm deep on the other set of 120° intervals. The bush was then split with a slitting saw on the mill. The bush is then turned 60° and clamped with M3 grub screws in one set of holes and released by putting the screws in the other set of holes.
Title: Re: Two Cylinder Engine
Post by: Gas_mantle on May 20, 2018, 04:54:07 PM
Hi Roger, somehow I've missed this thread till now but it looks like a great engine in the making  :ThumbsUp:

It was interesting to see how you tackled the crankshaft.
Title: Re: Two Cylinder Engine
Post by: fumopuc on May 20, 2018, 07:25:26 PM
Hi Roger, I am still following along. I see also that your Proxxon tools are getting more and more. In my experience a good choice.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 29, 2018, 07:32:59 PM
Thank you both  :ThumbsUp:

A few more bits on this one.
I machined the oil reservoir in the bottom half of the cam carrier, on the first version this was a separate component on the other side of the crankcase. I initially made the design 11mm wide with 3mm radius corners but decided that a quick cut with a 10mm end mill would work fine.
I then started on the water pump which will also be the support for the ignition system. First I drilled the various holes for the fixings and inlet and outlet passages and then drilled and reamed the main bore that will be used to set out the bores for the gears.
Title: Re: Two Cylinder Engine
Post by: Roger B on June 25, 2018, 07:29:30 PM
Due to all sorts of life things the next stages have taken some time  :(

The water pump body was set up on the mill to drill the idler gear bore and to rough out the cavities with a 10mm end mill. The main bore was then centred on the faceplate and the cavity and bore were finished using a 6mm 2 flute end mill as a boring tool. The idler bore was centred the same way and the cavity was bored out to 14mm. Problem   :facepalm: I had drilled the side port too deep and there was very little material between the two ports  :(  Time to start again  ::)
Title: Re: Two Cylinder Engine
Post by: fumopuc on June 25, 2018, 08:11:00 PM
Hi Roger, I feel your pain.
But the new one will be better, nicer and you will get it faster.
Why do I know this ?
Title: Re: Two Cylinder Engine
Post by: Craig DeShong on June 26, 2018, 12:27:38 AM
Been there, done that.  What I DIDN'T mention in my last Lauson post is that it took TWO attempts to carve a carburetor body out of a block of aluminum; but if you don't tell anyone I won't either, and they'll never know. :mischief:

One of the great things about working with bar stock is that you can always cut another piece and have another go.  Not like begging a new casting from a supplier (yea, and I've done that too).
 
Title: Re: Two Cylinder Engine
Post by: zeeprogrammer on June 26, 2018, 12:40:31 AM
I hope this doesn't come across wrong...

It does us inexperienced, newbies good when the experienced have oopsies and tell us about it.

And it's just an oopsie.  ;D
Title: Re: Two Cylinder Engine
Post by: Roger B on July 11, 2018, 07:15:34 PM
Thank you for the comments and support  :ThumbsUp:  :ThumbsUp:

Finally back to the water pump. As Craig said its just a bit more 20mm square aluminium and a bit of time not a catastrophe. I made a few changes to the way I made the cavities. In the first version I drilled for both shafts for the gears and then opened out to 12mm with an end mill. This had two problems, first the 4mm hole for the idler gear had a good chance of drifting slightly and second the 12mm endmill broke through into both ports and in the middle. This time I drilled and reamed the main bore and opened out with a 10mm endmill. I then moved across 12mm plunged nearly to depth with a 6mm centre cutting endmill (the biggest I have) and opened out with the 10mm cutter.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 11, 2018, 07:24:30 PM
I then centre drilled and opened out the 4mm bore for the idler gear to minimised the chance of the drill wandering. After a quick check of the gear centres with some short lengths of silver steel I went back to lathe mode. This time I started with the idler side and using a 6mm endmill as the boring tool opened out the cavity to 14.2 mm diameter (to allow for expansion of the Delrin gears. I then centred the main bore and opened out that cavity with the depth stop at the same setting as for the idler cavity. Finally I bored out shaft hole to 9.8mm and reamed it out to 10mm.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 11, 2018, 07:25:09 PM
And due to the 8 picture limit.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 11, 2018, 09:29:44 PM
Looks like you succeeded at last Roger  :ThumbsUp:

What can I say - I done my share of goofs lately - just not on engines, but it still bugs me  :-\
But I got my stuff done in the end like you.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 30, 2018, 07:03:19 PM
Thank you Per, remember that they are trial pieces not mistakes  :cheers:

I didn't have any long 4mm bore Oilite bushes so I turned the flange off one to make up the length. The next step was to drill the water inlet in the cylinder block and see how it all went together. As expected the connecting pipe will be a little tortuous but possible. I noted that the top fixing hole was closer that I liked to the cylinder block fixing. I decided to redrill it lower down knowing that it would interfere with the inlet flange. With a little hindsight there is no real need to flange the water connections, the horizontal engine works fine with the pipe Araldited in place. This will also make the connection between the pump and the block easier.
I received a small contact breaker from TS today so now I can measure it up and design the mounting.
Title: Re: Two Cylinder Engine
Post by: Roger B on August 19, 2018, 03:20:26 PM
On with the contact breaker. The mounting is made from piece of 3mm thick aluminium. The profile was cut the easy way with hacksaw and file.
Title: Re: Two Cylinder Engine
Post by: Roger B on August 19, 2018, 03:30:32 PM
Next up is the ignition cam. As this has an opposed crank the lobes need to be at 90°. I could have gone for a wasted spark system but fancied a challenge. The same techniques could be used for four cylinder system so it is not really wasted effort. The required shape was turned from 16mm silver steel. This was then marked with two horizontal lines 90° apart and centered in the Keats angle plate. The angle plate was then offset 7.5mm and set vertical. The blank was then rotated until the first line was at 72.5mm (centre height + the offset). This was then turned down until the dimension across the cam was 14mm and the cross slide setting noted. The angle plate was set vertical again and the blank was rotated until the second line was at 72.5mm. The second cam was turned to the same setting as the first. The blank was then parted off and faced on a tapered mandrel.

https://www.youtube.com/watch?v=ABJeupbhyiI
Title: Re: Two Cylinder Engine
Post by: steam guy willy on August 19, 2018, 03:57:19 PM
Hi Roger , may i ask you how you get the text onto the photos that you post ?? Engine build looking good.. Cheers

Willy
Title: Re: Two Cylinder Engine
Post by: Roger B on August 19, 2018, 04:07:32 PM
Hi Willy, I use a photo editing programme to reduce the size of the pictures and when I am finished I go to 'Save As' rather than 'Save' and then type in the text. Some characters, like ? and . are not allowed so I always have to write 1 point 5 mm etc.
Title: Re: Two Cylinder Engine
Post by: steam guy willy on August 19, 2018, 11:25:33 PM
 hi Roger, ok Thanks, i shall endeavour to do that.........
Willy
Title: Re: Two Cylinder Engine
Post by: Roger B on August 26, 2018, 04:14:15 PM
Next up is the connecting rod bearings. Both are made from RG7 bronze bar. The big ends were split in the mill using a 0.8mm thick slitting saw and then soft soldered back together. This piece was then mounted in the 4 jaw independent chuck and adjusted so that the split was on centre. I drilled and ream the bore before turning down the outside to reduce the chance of it cracking open (found out the hard way  :( )
Title: Re: Two Cylinder Engine
Post by: Roger B on August 26, 2018, 04:18:09 PM
The finished bearings were melted apart with a electric soldering iron and the joint faces were cleaned up. It all fitted together  :) The little ends were drilled and reamed before turning to final size and were then pressed into the con rod. The reamer was put through again by hand to compensate for the interference fit.
Title: Re: Two Cylinder Engine
Post by: Kim on August 26, 2018, 05:24:03 PM
Great work on the bearings Roger.
And very nice pics!
Kim
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on August 26, 2018, 05:42:07 PM
Beautiful work Roger.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Roger B on September 06, 2018, 05:56:43 PM
Thank you both  :ThumbsUp:

I drilled and tapped a few more holes in the crankcase and then tried to assemble the crankshaft and conrods. Ooops I had forgotten to mill the clearance slots  :facepalm: On to the mill for a quick job with a 3mm end mill. It is now mostly ok but needs a little fettling as the design does not have much clearance.
The next problem to solve was the flywheel. When I first tried to install it the grub screws wouldn't hold. Checking again I found that I had used M3 instead of M4 and due to the two different materials, cast iron and free cutting steel, the holes had drifted inwards. I set it up on the RT and opened the clearance holes out with 4mm end mill and the tapped holes with a 3mm end mill. These were then opened out with a 3.2mm drill ready for tapping.
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on September 06, 2018, 06:05:41 PM
Hey again Roger,

Your project is coming along nicely.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: zeeprogrammer on September 06, 2018, 07:11:01 PM
Following along.  :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on September 17, 2018, 07:38:46 PM
Thank you both  :ThumbsUp:

The small holes were then tapped M4, the bush was turned 60° and the flywheel was fitted on a length of 10mm silver steel for a final skim. After a bit of fettling of the crankcase it was all fitted together and turns smoothly  :)

https://www.youtube.com/watch?v=0T2iuYGNzno
Title: Re: Two Cylinder Engine
Post by: crueby on September 17, 2018, 08:41:38 PM
Very nice!
 :popcorn: :popcorn: :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on September 30, 2018, 07:52:59 AM
Thank you Chris  :ThumbsUp:  :ThumbsUp:

The next step was to make a 20.15mm plug gauge for the cylinders ready for lapping. Both liners were lapped at the same time, the tighter one first. This was done as before with an Ezelap and (relatively) coarse diamond paste. When the plug gauge was a snug fit in both bores it all went into the ultrasonic bath for cleaning.

https://www.youtube.com/watch?v=i8Pz230FWx4

The top of the cylinder block was marked out, drilled and tapped for the cylinder head fixings and water ways. I had previously bought a set of stub drills from Proxxon which certainly helped with head room and reduced deflection.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 06, 2018, 10:30:37 AM
Next up was the pistons. These were turned from a length of 25mm aluminium. The outside was turned to 20.10mm, checked for fit in the liners and the recess was drilled and bored. Next the piston ring groove was cut, 0.9mm wide 1mm deep and the blank parted off.
To keep up the machining videos this was turning down the bar, 500 rpm, 1mm depth of cut with an aluminium insert from APT.

https://www.youtube.com/watch?v=ORm3tD_DF9E
Title: Re: Two Cylinder Engine
Post by: Roger B on October 06, 2018, 10:36:56 AM
The piston blank was then set up in a vice on the Hobbymat mill to drill and ream the gudgeon pin hole and then moved to the RT on the Proxxon mill to machine out the little end cavity. The chart on the mill suggested 20 000 rpm for a 3mm cutter in aluminium but I ran at 8 000rpm with a 2mm depth of cut. Lots of swarf in a small hole  ::)
Title: Re: Two Cylinder Engine
Post by: Roger B on October 06, 2018, 10:42:24 AM
There are a couple of design points still to think about:

1. Retaining the gudgeon (wrist) pin. I can use grub screws from below as before or I can fit brass/bronze end caps  :headscratch:

2. Retaining the liners. I could fix them in place with a Loctite product or fit an O ring at the bottom and assume I will be able to remove them later if I want to. I suspect that the cast iron and aluminium will corrode together so they will be as tightly held as if I had used Loctite  :headscratch:
Title: Re: Two Cylinder Engine
Post by: fumopuc on October 06, 2018, 06:03:14 PM
Hi Roger, I have used both ways to fix the wrist pins in the past. Now and in future I will prefer the brass pins. They can't get loose and block the crank drive.
And, good to have more than one mill.
Title: Re: Two Cylinder Engine
Post by: AlexS on October 06, 2018, 09:45:35 PM
Hi Roger. Great progress. What about to fix the wrist pin from below while bore though the pin and so in the piston again? Assemble the whole and then tap the holes (m3?), then use a set of adjusting screws? I did uses this method to fix my cams at the shaft (with some loctite 401 glue). greets
Title: Re: Two Cylinder Engine
Post by: Roger B on October 07, 2018, 05:00:09 PM
Thank you both  :ThumbsUp:  :ThumbsUp:

This time I decided to try brass plugs. The 18mm long gudgeon pins were made from 5mm silver steel (genuine Stubbs with the stamp on the end  :) ) drilled through 2mm and hardened. The 0.75 mm thick plugs were from 4mm brass rod and were cut just using a blade parting tool then pressed into the ends of the pins. Finally I smoothed of the corners of the plugs with a file in the lathe.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 10, 2018, 07:56:25 PM
I decided to fix the liners with Loctite 577 thread sealant. The water jacket on the diesel is fixed with 648 but that is fairly permeant. After assembly it all turned smoothly and there is probably enough compression to run without piston rings.

https://www.youtube.com/watch?v=qgw_2PmleE4

I then skimmed the top of the block and liners with a fly cutter.

https://www.youtube.com/watch?v=DGOabcLjTQU

Next step is to turn the pistons to the correct length to give 1mm depth.

Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on October 10, 2018, 09:06:48 PM
Hello Roger,

Looks great, anxious to see it running.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: fumopuc on October 11, 2018, 07:29:12 PM
Hi Roger, nice progress.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 16, 2018, 08:03:18 PM
Thank you both  :) As I was in milling mode I decided to make the blanks for the cylinder head and rocker support. I have kept the small step at the base of the rocker support from the original design although it is probably not really necessary to keep the alignment.

https://www.youtube.com/watch?v=MTKHEJdex6o

Lots off holes to drill and slots to cut (hopefully in the right places) ::)
Title: Re: Two Cylinder Engine
Post by: Roger B on November 03, 2018, 12:13:51 PM
The rocker support needed a long 3mm hole which I decided to drill in the lathe in hope of keeping it on axis. I started with a 2.5mm stub drill and worked up to one of the 2.5mm long series drills I had bought for crankshaft oilways. I had to ream from both ends due to the length of the reamer and hope that it followed the drilled hole. OK  :) a length of 3mm silver steel would go through.

Next up was drilling the many holes in the cylinder head. The 6mm reamed holes for the valves went ok but I obviously got confused with the head fixings and water ways  :( I could plug and redrill but decided to start again. This time I had to use a vice in vice to hold the stock in the band saw.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 05, 2018, 07:32:52 PM
The next attempt went rather better  :) In the same way as before I marked everything out first and then used the milling machine scales to confirm. All the holes seemed to coincide with the marks and the six fixing holes lined up  :wine1: I'm not sure what went wrong before  :headscratch: Possibly tired due to a major machine problem at work.
The next step was to drill the water passages which went without problems.
Now I have to work out the best way to machine the angled and siamesed ports. It looks like it is best to use the RT in the mill as I can set each 6mm valve bore over the 6mm mandrel in the RT and then set the angle. The ER11 chuck looks like it will have enough clearance as long as I lock the quill in the extended position. The ideal way would be with a 5mm long series centre cutting end mill, but I don't have one so it will have to be done in stages starting with a 4mm centre cutting end mill, then a 5mm end mill and finally a 5mm drill.
Title: Re: Two Cylinder Engine
Post by: AlexS on November 08, 2018, 04:44:04 PM
Great work! Like the cylinder head with port design. May I ask how do you want to connect the different waterways in the cylinder head?
Title: Re: Two Cylinder Engine
Post by: Roger B on November 08, 2018, 05:27:10 PM
Thank you Alex  :ThumbsUp: There is a horizontal waterway at the sparking plug side of the head and two waterways that pass between the valves. The open ends will be closed with aluminium plugs in the same way as I did on the single cylinder version.

Moment of truth  ::) I aligned the mandrel in the RT on centre and then clamped the cylinder head in place. The x axis was then aligned and I started out as planned with a 4mm centre cutting mill, no problems. I then followed with a 5mm end mill and 5mm drill again no problems  :) The head was reset for the other port and the process was repeated again without problems. Result a correctly aligned inlet port pair. I followed the same procedure for the two exhaust ports remembering to set 25° instead of 27°. Sometimes everything works as planned  :wine1:
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on November 08, 2018, 05:39:16 PM
Hello Roger,

That is some nice looking work and glad all went well.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Roger B on November 11, 2018, 09:23:07 AM
Thank you Thomas  :ThumbsUp:

The next steps were to mill out the slots for the rocker arms in the rocker support and bore out the combustion chambers in the head.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 11, 2018, 04:27:07 PM
Next up was the sparking plug recesses and threads. As these were to be a 45° I decided to use V blocks to support the head. For the first operation it was clamped using a short length of 4mm rod pushed into one of the water ways. First centre and then mill a small flat are to stop the drill being deflected. The 3mm pilot holes came out neatly on the corner (as I hoped  :) ). The head was then turned over as this step required some more significant milling it was clamped with a piece of 8mm rod bearing on three 3mm rods in the head fixing holes. The recesses were cut with a 14mm end mill in 1mm steps and the pilot hole was opened out to 5.5 mm for the 1/4-32 tap.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 11, 2018, 04:31:44 PM
The holes were then counterbored with a 10mm end mill and threaded. I tool the drive belt off and used the ER chuck tommy bar to rotate whilst keeping the feed neutral with the quill feed lever.

A quick deburr and ultrasonic clean and all looks good  :wine1: Next step some plugs for the waterways.
Title: Re: Two Cylinder Engine
Post by: Kim on November 11, 2018, 06:20:11 PM
Great work Roger!
Looks kinda like a block of swiss cheese, doesn't it?  :Lol:
Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on November 11, 2018, 06:36:43 PM
I think there are nearly 40 holes  :)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on November 11, 2018, 08:20:06 PM
Fantastic progress Roger - you are really moving forward now  :ThumbsUp:

And this is one of the more complicated components.
Title: Re: Two Cylinder Engine
Post by: Art K on November 12, 2018, 03:46:20 AM
Roger,
Great progress, on a very complicated part. Looking at the drawing under the head in one of the photos. Are you planning to radius the corners to match the cylinder?
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on November 12, 2018, 08:06:49 PM
Thank you both  :ThumbsUp:  :ThumbsUp:

Art,  I could radius the sparking plug side but the manifold side would have to remain flat (the ports have to be outside the push rods) I think I will keep to as much of the original design as possible.
Title: Re: Two Cylinder Engine
Post by: Gas_mantle on November 12, 2018, 08:17:57 PM
Looking great Roger, can't wait to see it running  :)
Title: Re: Two Cylinder Engine
Post by: Art K on November 13, 2018, 05:25:59 AM
Roger,
Sorry my bad, looking at the blueprint closer I realized it was just the oval shape of the cylinder.
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on November 16, 2018, 05:53:56 PM
Thank you all for your interest  :ThumbsUp:

I turned some 4.3mm plugs from aluminium rod, pressed them in and filed them flat. The four rockers were then cut from 6mm square silver steel and squared up with the Proxxon micro mill using a 3mm carbide cutter at 8000 rpm and 0.2mm cuts. As this will go as fast as I can turn the handle it didn't take long. The holes for the adjusting screws were drilled 3.2 mm (to be tapped M4) and the pivots were drilled 2.8mm and reamed 3mm. On the single I fitted thin brass bushes but I think silver steel on hardened silver steel should be OK. A quick alignment check on a 3mm rod suggested that the holes were in the right place.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 17, 2018, 04:00:29 PM
The adjuster screw holes were then aligned on a short length of 1/8" silver steel and the sides were milled using a 3mm end mill 8000rpm and 0.4mm depth of cut. The pivot holes were aligned again on the 3mm silver steel and the bottoms were milled. Next I got out the fixture I used to radius the tips for the vertical engine. I had to make a 3mm to 6mm mandrel to centre the RT using a 6mm filing button Loctited to 3mm silver steel. The radiuses were cut at 8000rpm with 0.2 mm depth of cut. I now need to tap the adjuster holes M4 and do a little fettling. I haven't decided whether to harden the tips or not  :headscratch:
Title: Re: Two Cylinder Engine
Post by: fumopuc on November 17, 2018, 04:04:33 PM
Hi Roger, nice progress.
Title: Re: Two Cylinder Engine
Post by: Kim on November 17, 2018, 05:45:10 PM
Nice looking rocker arms Roger.  Enjoying the show!  :popcorn:
Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on November 17, 2018, 07:34:33 PM
Thank you both  :ThumbsUp:  It's interesting using the Proxxon micro mill, the process window is a long way from what I am used to. Very high speeds, shallow cuts and feeds as fast as you can turn the the handles  ::)
Title: Re: Two Cylinder Engine
Post by: Art K on November 17, 2018, 08:41:49 PM
Roger,
That looks like a great way of using fixtures to do multiple steps at a time. Looking good.
Art
Title: Re: Two Cylinder Engine
Post by: zeeprogrammer on November 17, 2018, 09:48:54 PM
I haven't said much but I've been following along.

In the last picture with the rotary table...there's a clamp on the left that's using a bolt to lift the end of the clamp.
I hadn't seen that before.

Did you modify the clamp to take that bolt? And if so, what size is it?

I have a small rotary table and clamping has always been an issue. That looks like it could help.
Title: Re: Two Cylinder Engine
Post by: crueby on November 17, 2018, 09:52:48 PM
I haven't said much but I've been following along.

In the last picture with the rotary table...there's a clamp on the left that's using a bolt to lift the end of the clamp.
I hadn't seen that before.

Did you modify the clamp to take that bolt? And if so, what size is it?

I have a small rotary table and clamping has always been an issue. That looks like it could help.
Great work Roger!




Zee, I have clamps like that, Sherline has them, fits in spaces where a step block is too wide. Would be easy to make from some flat stock too.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 18, 2018, 09:16:08 AM
Thank you for your interest  :ThumbsUp:

Carl, I have two sizes of the clamps, both take M6 clamping bolts, the support bolts on the small ones are M4 and on the large ones M6. The small ones came with my RT and the large ones with my EMCO copy milling table, both from RC Machines in Luxembourg.
Title: Re: Two Cylinder Engine
Post by: Roger B on December 01, 2018, 02:47:08 PM
The adjuster holes in the tappets were tapped M4 and the sharp edges were removed. Next I milled some reliefs in the bottom of the rocker support to clear the cylinder head fixings and then moved on the camshaft area. The tappets run in Oilite bushes that are turned down versions of the tophat bushes that the shaft runs in.
Title: Re: Two Cylinder Engine
Post by: Roger B on December 01, 2018, 02:52:34 PM
The tappet bushes were pressed in in one operation as there is zero clearance between them.

I then needed to extend the base of my cam milling fixture to accept the longer camshaft. Finally I milled 2mm keyways in the crankshaft and camshaft. The single just uses grubscrews but I want to be more certain with this engine as there is also a water pump to drive and possibly fuel injection.
Title: Re: Two Cylinder Engine
Post by: Art K on December 01, 2018, 05:42:53 PM
Roger,
Looking good, moving right along.
Art
Title: Re: Two Cylinder Engine
Post by: Craig DeShong on December 06, 2018, 09:38:05 PM
Great progress Roger.   :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Roger B on December 19, 2018, 07:23:28 PM
Thank you both  :)

A little bit more on this one. I broached the keyways in the crankshaft timing gear and the camshaft milling jig adaptor. Next step is the valves. These are turned from M4 x 40mm A2 Stainless Steel caphead screws as before. The first step was to true the heads to the shanks ending up at 6.6mm diameter. For the next step I went back to the Hobbymat spring collet system with a 1/4 collet to hold the heads for center drilling and turning the shanks down to 2.5mm (also using the DTI on the cross slide). The blanks were then radiused under the head with a 3mm form tool. As you can see There are 6 valves to allow for some mistakes  :toilet_claw:
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on December 19, 2018, 08:27:11 PM
Hello Roger,

That is some pretty work.

Have a great holiday,
Thomas
Title: Re: Two Cylinder Engine
Post by: Roger B on December 27, 2018, 12:50:58 PM
Thank you Thomas  :ThumbsUp:

On with the valves. I cut of the remaining threads, cleaned up the end and then checked the fits with an offcut of brass drilled and reamed 2.5mm. The seats were then cut at 45° and the heads were thinned.

The valve guides were made from Cu Sn8 bronze rather than RG7 as I could get smaller diameter rods and less wastage (the smallest RG7 is 13mm). They were drilled 2.3mm and reamed 2.5mm. The outside was turned to 8mm and the guide to 6.05mm as a press fit in the head. This bronze seemed less 'snatchy' than the RG7 and produced annoyingly long curly swarf.
Title: Re: Two Cylinder Engine
Post by: steamer on December 27, 2018, 02:56:16 PM
Coming along nicely!

Dave
Title: Re: Two Cylinder Engine
Post by: Roger B on December 27, 2018, 04:17:34 PM
Than you Dave  :ThumbsUp:

The valve guides were held in the ER11 chuck to turn the spring seating to 4.75mm and were then pressed into the head one at a time with my bench vise.

I had been planning to use the seat cutter I had made for my vertical engine to cut the seats forgetting the ports and valves on this engine are slightly bigger otherwise I would have made the cutter at the same time as the valves. This time I tried to use the ER11 collet chuck to hold the head but even with the shorter collet it was not stable so I went back to the 1/4" spring collet.
Title: Re: Two Cylinder Engine
Post by: Florian Eberhard on December 27, 2018, 05:48:09 PM
Hey Roger

Well done, that is some nice work!
Just be careful with CuSn8. That is some nasty stuff to drills! It can (but doesn't have to) happen that the drill gets stuck pretty fast and then breaks immediately. A bit like stainless steel but with less signs what is going to happen.

Cheers Florian (just beginning to bring everything to my new shop :) )
Title: Re: Two Cylinder Engine
Post by: Roger B on December 27, 2018, 06:19:48 PM
Thank you Florian  :ThumbsUp: With the drills I have (normal as far as I know) it seemed easier than the RG7. I did use a cutting lubricant for drilling and reaming.

How long before the new shop is up and running?
Title: Re: Two Cylinder Engine
Post by: Florian Eberhard on December 27, 2018, 06:55:54 PM
Hi Roger

Well you had good luck with the drills then  :D

My shop? Aehm a bit difficult to say, I hope to have moved everything until the end of next week.
But I am planning to make a few improvemens (felt wipers for the guideways on my lathe and renew the ones of my milling machine and a bunch of small things like repositioning some lubrication cups which are hard to reach, swarf guard for the column of my milling machine etc.)

So the answer is it depends on how you define "up and running" ;)

-> I'm off to my new shop, painting the workbench for the second time (final pass)
I'll put a picture in the shoutbox when I get back up  ;)

Florian
Title: Re: Two Cylinder Engine
Post by: Roger B on December 28, 2018, 06:00:13 PM
I cut off the last of the thread and then cut the seat. There is no need to radius under the head of the seat cutter. The cutting edges were made with a half round swiss file and the seats were cut by hand using a T handle hex key.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on December 28, 2018, 08:01:56 PM
Hi Roger

I like your idea of using a Allan head bolt as the cutter - simple and clever  :ThumbsUp:

It looks like you got a nice result from cutting the first two - was it easy to control the cutter ?

Best wishes

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on December 29, 2018, 08:59:29 AM
Thank you Per  :ThumbsUp:

As there is no real clearance the cuts are very fine. The seats you can see probably had 10 turns of the cutter (20 half turns  ;) I don't have fully rotating wrists)
Title: Re: Two Cylinder Engine
Post by: Roger B on January 19, 2019, 07:52:25 AM
Back on this one. After some thought and a lot of checking I made up a spreadsheet for the cam profiles and set up to cut the lobes. This is one of the disadvantages of having a single machine, once there is a set up in place I can't do anything else until that set up is finished. Each lobe requires 60 cuts (6° steps) and each cut requires at least 30 turns of the cross slide handle  ::)
The cam followers are made from 6 mm silver steel drilled 5mm dia. 10mm deep. The camshaft and followers were cleaned up with a fine file and then fine abrasive cloth. They were all hardened, luckily without noticeable distortion, and now need a final polish.
Title: Re: Two Cylinder Engine
Post by: Kim on January 19, 2019, 05:44:37 PM
Very nice looking cams, Roger.  That is a LOT of twiddling there.  I'll bet you're glad to have that behind you!
Kim
Title: Re: Two Cylinder Engine
Post by: Craig DeShong on January 21, 2019, 12:51:41 AM
Lots of exacting work Roger.  Looks great!
Title: Re: Two Cylinder Engine
Post by: Art K on January 21, 2019, 01:12:42 AM
Roger,
Good work on the cam, I must admit I have never made a hardened cam. I have made a few cams that way using cam-calc works great.
Art
Title: Re: Two Cylinder Engine
Post by: steamer on January 21, 2019, 01:19:07 AM
Rodger    what material are you using for the cam?
Title: Re: Two Cylinder Engine
Post by: Roger B on January 21, 2019, 12:21:26 PM
Thank you all  :ThumbsUp:

Dave, the cam is made from 10mm diameter silver steel (drill rod).
Title: Re: Two Cylinder Engine
Post by: fumopuc on January 21, 2019, 08:24:22 PM
Hi Roger, nice job on the cam shaft.
Title: Re: Two Cylinder Engine
Post by: AlexS on January 23, 2019, 09:59:09 PM
Great job with cam and hardening. What are the specs of the cam, duration opening closing angles?
Title: Re: Two Cylinder Engine
Post by: michelko on January 24, 2019, 09:07:40 AM
Hi nice work, can you give some more Information About the calculation of the cuts?

Michael
Title: Re: Two Cylinder Engine
Post by: gbritnell on January 24, 2019, 12:45:20 PM
Roger,
I make all my cams like that with very good success. The difference is I use a rotary table on the mill.
gbritnell
Title: Re: Two Cylinder Engine
Post by: b.lindsey on January 24, 2019, 02:05:50 PM
Seems I have missed a few days of progress Roger. That cam came out very nicely!!

Bill
Title: Re: Two Cylinder Engine
Post by: Roger B on January 24, 2019, 03:24:02 PM
Thank you all  :ThumbsUp:

This cam design is copied from my 3cc vertical engine. It is the forth version I made for that engine, I haven’t gone back to try the previous 3 again to see how they work with the engine in it’s final form.

The designs were made using the cam calculation programme on the MEN website:
http://modelenginenews.org/
Go to the menu on the left and open up ‘Resources’ and then ‘Design Centre’. This is a Java programme so I don’t know how well it will work on modern browsers.

One of our members has produced a version based on Excel which has a similar interface but I have not used it.

The design was based on values given in various books on model petrol engines.

Valve lift is 1.5mm (based on ¼ of the valve diameter)

Theoretical opening period is 260°

The angle between the lobes is 114°

This gives a theoretical overlap of 32°

The output of the programme is a table of angles and lifts for one lobe. I put this in a spreadsheet and shift the angles by the angle between lobes and also invert the lift values due to the way my milling fixture is set up.

This design programme does not allow for any clearances so I have reduced the base circle by 0.1mm. The transition was worked out by plotting each cut in a cad package and extrapolating.

I have attached the spreadsheet I used as well as the base circle drawing. The green circle is the base circle used in the calculation. The next black circle is reduced by 0.1mm. The ‘cuts’ for half a lobe are shown, the red line being the last from the cam design. The blue lines are then another three cuts to reach the reduced base circle.

George, I made this fixture before I had a rotary table and have kept using it. I can see benefits in a RT especially when cutting the base circle  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on January 24, 2019, 08:20:23 PM
I am now moving onto assembly which is where I have to make all the little bits, studs, etc. First up was a thrust washer for the end of the camshaft. This was made using a spring collet so I could reverse it to face to other side. Next was the fixings for the timing gear cover, A few holes and some studs.
Title: Re: Two Cylinder Engine
Post by: Roger B on January 24, 2019, 08:27:22 PM
The water pump body needed finishing as the distributor is mounted on the end of it. There was a hole that was no longer needed due to a design change that was filled with a piece of 3mm aluminium Loctited in place. One of the fastenings is a little bit special as it is also the clamping screw for the timing adjustment. Finally I needed to shorten the oilite  bush for the waterpump to give space for the water seal. As these are quite soft it was held in a spring collet and supported with a piece of 6mm silver steel held in the tailstock chuck.
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on January 24, 2019, 10:29:32 PM
Hello Roger,

Looking good as it is coming together :ThumbsUp:

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Old Bill on January 25, 2019, 10:18:40 PM
The designs were made using the cam calculation programme on the MEN website:
http://modelenginenews.org/
Go to the menu on the left and open up ‘Resources’ and then ‘Design Centre’. This is a Java programme so I don’t know how well it will work on modern browsers.

One of our members has produced a version based on Excel which has a similar interface but I have not used it.

Nice job Roger. I really wanted to see it done before I have a go!

I want to mill my cams in the same way but, as you have predicted, the calculation software doesn't work in my browser! Might the Excel version be available to me please?

Keep up the good work!

Steve    :) 
Title: Re: Two Cylinder Engine
Post by: Roger B on January 26, 2019, 07:34:30 AM
Thank you both  :ThumbsUp:

The Excel file is to big to link so I will send it by PM/Email. I have asked on another thread to find the author (I have forgotten who it was  :( )
Title: Re: Two Cylinder Engine
Post by: Old Bill on January 26, 2019, 08:04:17 AM
Hi Roger.

Safely arrived for which many thanks. That will save me a lot of graft and head scratching! What a wonderful resource this forum is!

Kindest regards,

Steve   :ThumbsUp:   ;D
Title: Re: Two Cylinder Engine
Post by: tangler on January 26, 2019, 09:37:32 AM
Here's the link to the Excel file in my dropbox:

https://www.dropbox.com/s/i1h8fqc8h4ub4al/cam%20with%20draw.xls?dl=0

Cheers,
Rod
Title: Re: Two Cylinder Engine
Post by: Roger B on January 26, 2019, 07:34:41 PM
Thank you Rod  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: Two Cylinder Engine
Post by: Roger B on February 03, 2019, 06:49:35 PM
The shortened bush was pressed into place in the vice and then I moved onto the shaft. Unfortunately I used the piece of silver steel from cutting down the bush rather than the planned piece of stainless  steel to make the shaft  :facepalm: Start again. The keyways were cut with the Proxxon micro mill together with the shaft for the Junkers governor.

While trying the pieces I decided I could thin the  ignition cam from 12mm to 9mm which would simplify fixing it. I then started the fixing hole for the ignition rotor.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 03, 2019, 07:01:33 PM
I then used a 4mm end mill to cut a clearance for the screw head. A bit chattery in the Proxxon drill but it worked  :)

I then moved onto the valve spring caps. These started as 8mm aluminium bar. They were turned down to 6mm, drilled 2.4mm and reamed 2.5mm. The seats for the E clips were cut with a 5mm end mill and the rest was finished with a parting tool. I made five as I know that the swarf Gnomes like them  ::)  One from the horizontal engine is still missing  :(

The rocker shaft was made from 3mm silver steel and hardened by hanging from a magnet and heating until it fell of into the water bath.
Title: Re: Two Cylinder Engine
Post by: JC54 on February 03, 2019, 07:54:31 PM
Many thanks Roger for the tip with magnet. I have great trouble with the colours when trying to harden steel. :old: :DrinkPint: JC
Title: Re: Two Cylinder Engine
Post by: Roger B on February 06, 2019, 07:56:39 PM
Thank you for following along  :ThumbsUp: I find it useful for little pins etc that are difficult to hold. You probably don't get maximum hardness but it works for model engine parts in silver steel.

I cut the valve stems to length and then cut a groove for the E clips that retain the valve springs. Next up is the distributor cap and rotor. These are made from a length of 1" Delrin rod. This machines nicely but produces a mass of static charged swarf  ::)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on February 06, 2019, 09:22:29 PM
I see that you continue to make good progress  :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Brian Rupnow on February 06, 2019, 09:47:37 PM
Looking very good Roger. It won't be long now.---Brian
Title: Re: Two Cylinder Engine
Post by: fumopuc on February 07, 2019, 08:46:12 AM
Hi Roger, it seems that the re-opening of the RD department, due to the the European weather conditions and the status of you build will match perfectly in some days.
Center of Munich is still under snow, but from today onward we expect temperatures above 5°C.
 

Title: Re: Two Cylinder Engine
Post by: Roger B on February 10, 2019, 07:56:12 AM
Thank you all  :ThumbsUp: Achim, unfortunately we haven't seen much improvement in the weather yet  :(

The rotor was turned from the same piece of Delrin. To maximise the material between the shaft and the electrode the hole was finished flat with a 4mm end mill.

The cap was bored out to 16mm. Due to the size of the boring bar there is a slight pip in the middle but that shouldn't cause significant problems. It then moved to the RT in the Proxxon drill for drilling and tapping the holes for the leads then onto the mill to finish the fixing flange.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 10, 2019, 10:41:19 AM
The clearance angles and the slot for the contact breaker were cut on the same set up. A junior hacksaw was the quickest solution for the final cut. It all seems to fit together  :) Time for some fiddly brass pieces  ::)
Title: Re: Two Cylinder Engine
Post by: steamer on February 10, 2019, 01:32:31 PM
It's certainly getting closer Rodger!   

Dave
Title: Re: Two Cylinder Engine
Post by: Roger B on March 17, 2019, 08:18:26 AM
Thank you Dave  :ThumbsUp:

Next up were the various brass electrodes for the distributor. I did consider making the centre electrode from graphite but didn't have any suitable material. The output electrode were turned just using a parting tool. I made a spare as they look like something for the swarf Gnomes  ::) The rotor electrode was hand filed to shape and superglued in place. Finally I set the phasing between the cam and the rotor arm and drilled and tapped the fixing hole. The RT was used as it was already fitted and is a good way of holding round things.
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on March 17, 2019, 09:26:18 AM
Hello Roger,

Looking really good :ThumbsUp:

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Zephyrin on March 17, 2019, 10:23:30 AM
very interesting job on the distributor, thanks to share !
first class use of the small tooling you have, this mill looks quite accurate.
Title: Re: Two Cylinder Engine
Post by: Kim on March 17, 2019, 03:32:03 PM
Nice work on the distributor, Roger!  That's lots of shiny little bits you made  :)
Kim
Title: Re: Two Cylinder Engine
Post by: fumopuc on March 17, 2019, 05:45:04 PM
Hi Roger, always watching every progress.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 18, 2019, 06:00:59 PM
Thank you all for your support  :ThumbsUp: Zephyrin, I have found the small Proxxon drill and mill very useful. I have a very small workshop they will sit out of the way on a shelf when not in use. As my main machine is a combined Lathe and Mill I can do small milling jobs without having to convert from lathe to mill and back again. I am currently investigating the FD150/E micro lathe so I can make small bushes and adaptors whilst I am in mill mode.

Next up were the clamps for the distributor cap. These were made from 8mm aluminium bar drilled 3mm and then half milled away. I was quite impressed at the accuracy of the two parts  :) Two clearance flats were then milled on the same side. I then faced the water pump gears to size, giving about 0.1mm clearance to allow for thermal expansion (found the hard way on the horizontal engine  :( ) The key way was cut with the broach I made for the previous pump. Now I need to make a 2mm stainless steel key.
Title: Re: Two Cylinder Engine
Post by: yogi on March 18, 2019, 06:55:49 PM
Looking good Roger!  :ThumbsUp: :ThumbsUp: :ThumbsUp:
The engine is coming together nicely.  :popcorn: :popcorn: :popcorn:
Title: Re: Two Cylinder Engine
Post by: bent on March 20, 2019, 05:14:51 PM
Cheers from the popcorn gallery, it's looking good Roger! :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on March 31, 2019, 10:10:32 AM
Thank you for your interest  :ThumbsUp:

Finally a bit of workshop time on this. The water pump drive key was milled from a length of 3mm stainless steel and the ends were rounded by filling. When I assembled the gears they didn't turn smoothly and on close inspection the force of cutting the keyway had stretched between two teeth  :( I tried again this time with the gear held in a 14mm collet as I did for my horizontal engine, all ok  :)

I had decided I didn't really need to flange the water inlet as things were a little tight so I Loctited a stub of brass pipe in place. Finally I used my new toy to put cones in the end of some 4mm grub screws for the tappet adjusters starting with a centre drill and following with a 3mm drill.
Title: Re: Two Cylinder Engine
Post by: yogi on April 03, 2019, 11:24:46 PM
Coming together nicely Roger!
I like your new toy!  :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on May 19, 2019, 04:58:52 PM
Thank you  :)

I have done a few little bits on this one. The distributor connection have been soldered onto the HT wires and I have started making the punch template for the head gasket. This is two pieces of 3mm thick aluminium with a couple of 4mm dowels for location and two M3 screws to clamp it together. The 3mm holes for the head fixing bolts were marked in red to reduce the chance of mistakes and together with the 4mm holes for the water passages were drilled and reamed on the bench drill. The two cylinder holes were made on the mill, starting 6mm drill then 15.5mm drill and boring to 20.6mm. The actual bores are 20.15mm after lapping. Next I need to make the punch for the bores. I already have 3 and 4mm ones from other engines.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 25, 2019, 08:09:36 AM
The punch was turned from a short piece of 22mm mild steel with a chamfered cutting edge. This will then be case hardened which needs to done outside.

The next step was to set up the timing and cut the keyways in the two 40T gears. Problem  :( I couldn't turn the camshaft  :headscratch: I dismantled the cam assembly and found the camshaft had bent 0.2-0.3mm, I guess due to residual stress from hardening. I could have annealed it, straightened it and then re hardened but the same problem would probably occur  :thinking: I decided to take the high risk route and try and straighten it while hard. The pressure was applied using the cross slide so I could increase the deflection in small controlled stages. As expected it broke  :toilet_claw:  I will make a new one from 10mm mild steel and case harden the lobes rather than using silver steel and hardening it through.

The gaps between the lobes were cut using a replaceable tip parting tool I purchased for making crankshafts which worked well without chatter. There was one small calculation error but this won't matter as I will reduce all the lobe below 10mm to give clearance in the housing.
Title: Re: Two Cylinder Engine
Post by: Florian Eberhard on May 25, 2019, 08:48:20 AM
Hi Roger

Straightening of hardened steel seems to work only a very short period of time after hardening.
What can work is if you temper the workpiece under preload into the direction you want it to go. I have already successfully done that. In my case to a light straw color - and in the oven, using a thermometer to make sure the oven wasn't getting too hot.

Florian
Title: Re: Two Cylinder Engine
Post by: Art K on May 25, 2019, 04:19:37 PM
Roger,
I have to admit to never having hardened a camshaft. I think I have used stainless steel in both my engines. Sorry to hear about the broken cam, maybe a grinder on oversized shafts would work. That is if you have a grinder.
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on June 18, 2019, 06:51:39 PM
Thank you both  :ThumbsUp: The problem was that the tip of the cams were almost the full 10mm diameter of the tunnel that the cam fits in so 0.2mm deflection caused everything to jam up. I decided to reduce the diameter by 0.4mm for the next version to give some clearance. This kept the base circle still larger than the 6mm shaft. Time has been very limited in the last month or so but I have finally machined the blank read for hardening.
Title: Re: Two Cylinder Engine
Post by: Roger B on June 20, 2019, 08:04:05 PM
Another problem  :( I case hardened the camshaft together with a couple of head gasket punches. Whilst I was polishing the camshaft with emery cloth in the lathe it snapped off  :facepalm:

The broken face had the same even grey finish as first time so my piece of free cutting MS was obviously not what I thought it was  :toilet_claw:

I took a selection of pieces of 10 - 12mm diameter steel and parted off 1mm thick discs. The first two I heated to dull red and then quenched. They were clamped to half diameter in the vice and bent. Both failed with brittle fractures. The next sample machined nicely and I tried it first without heat treatment. It bent but cracked, after heat treatment the result was similar. The last sample was not so nice to machine but bent without cracking.

I obviously need to keep my material stock under better control  :headscratch: and learn how to analyse the grinding sparks  :thinking:
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on June 20, 2019, 08:31:22 PM
Hello Roger,

Sure hate to see that happen to you, it can be frustrating when you get faulty material or mislabeled material.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Roger B on June 24, 2019, 06:47:35 PM
Thank you Thomas  :ThumbsUp:

Better luck this time  :) I selected a piece of free cutting MS which had a noticeably better finish after milling the cams, very little polishing was required.  After case hardening a little finger pressure was required to reduce the runout to less than 0.05mm and it assembled and turned freely  :whoohoo:
Now I can set the timing and make the pushrods  :)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on June 24, 2019, 09:51:45 PM
Nice to see that you have progress again  :cheers:  all the more important as this engine hass to earn it's keep.

That said - I truly know the feeling ; Yeah I finally moved forward - only to realize that this has to be followed by two (or more) steps backward  :???:

Best wishes

Per
Title: Re: Two Cylinder Engine
Post by: fumopuc on June 26, 2019, 09:32:12 PM
Hi Roger, finally a perfect result. Congratulations. I have to learn these cam lobes milling to.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 07, 2019, 07:49:25 PM
Thank you both  :ThumbsUp:

A little bit more workshop time. I made a head gasket so I could confirm the length of the push rods. They were then cut from 2mm music wire (with side cutters) and then rounded on the bench grinder. The cam timing and sequence was checked and the keyways were cut in the two 40T gears. I put the spark plugs in and was happy to find reasonable compression on no 2 cylinder considering that there are no piston rings and the valves have not been lapped yet  :)

The next step is the inlet and exhaust manifolds. The exhaust need a couple of bends so I tried bending some 6 x 5.1 brass tube with my old Girling former. This was annealed first and then bent by hand around the former. The bends were somewhat flat so I carefully squeezed them back to shape using some aluminium jaws in the vice. Not perfect but should work  ::)
Title: Re: Two Cylinder Engine
Post by: Kim on July 08, 2019, 05:26:46 AM
Lots of nice progress there, Roger!
2mm seems really small for a push rod - any danger of it bending rather than pushing?

The bends in your brass tube look great!  It can be hard to get those done with the tube coming out anywhere near round, and yours look quite good to me.

Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on July 11, 2019, 06:23:20 PM
Thank you Kim  :)

The push rods (and most of the valve gear) are copied from my single cylinder vertical engine which will rev to around 10 000rpm so no problem.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 19, 2019, 08:08:03 PM
A little bit more on this one. I started some flanges for the plumbing and then found the jig I had made for the single cylinder engine was incorrect. The milling centre was set at 13mm rather than the radius so I had to make a new one.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 19, 2019, 08:11:26 PM
The exhaust bends were then cut to length and the joint was shaped with a selection of round files. After silver soldering it doesn't look too bad. Next step silver solder the flanges.
Title: Re: Two Cylinder Engine
Post by: Kim on July 20, 2019, 12:08:26 AM
Nice looking flanges & piping work, Roger!
Kim
Title: Re: Two Cylinder Engine
Post by: Craig DeShong on July 27, 2019, 10:05:13 PM
Following along Roger with all the “ups and downs”.  Still lots of progress.  Look’in good!   :popcorn: :popcorn: :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on July 28, 2019, 09:54:04 AM
Thank you both  :ThumbsUp:  :ThumbsUp:

I positioned the various flanges and silver soldered them in place. Luckily the exhaust still fitted  :) Next up was the starter coupling using a 6mm bore sprag clutch like on the single. Rather then using an edge finder to centre the grub screw hole I just used a 150mm ruler balanced on top.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 28, 2019, 10:08:21 AM
The carburettor adaptor was next. This is turned offset to give a little more material for the grub screw. The one for the horizontal engine was carefully set up in the 4 jaw independent chuck. This time as I found the same stub of 12mm brass I tried a quick and dirty version with a 2mm shim in the 3 jaw sc chuck. Close enough  :) The engine end was turned and drilled, then the blank was parted off and the hole for the carb was drilled. The finished piece was soft soldered onto on of the previously made pieces.
Title: Re: Two Cylinder Engine
Post by: Roger B on August 26, 2019, 07:02:59 PM
Back to a bit on this one. As the first runs are in sight I made a pair of engine bearer from 10mm square aluminium bar, similar to those on the single. Then as I was lapping the plunger on the injector test pump it was a good opportunity to lap in the valves and then put it all in the ultrasonic bath together.
The valves were marked with small dot punches on the head and were lapped with 20 micron diamond paste using a  small drill chuck as a handle. The seal was checked by fixing a pipe stub to each port and sucking. A leak is generally obvious. As the inlets are siamised they both had to be checked together.
Title: Re: Two Cylinder Engine
Post by: Roger B on August 30, 2019, 08:04:04 PM
The valves and head went in the ultrasonic bath together with the injection test pump components. I managed to reassemble the valves and springs without donating any parts to the swarf gnomes. There seems to be quite good compression without piston rings  :) I then started to make some spark plug connectors from some 0.3mm phosphor bronze sheet. The core diameter was difficult to measure, but I got a reasonable chance with two 0.5 mm drills. 2.5mm was the result so I drilled 2.3 mm and then opened out with a Swiss file. The wire connection was drilled 2mm and the connection was opened out with tin snips along with a 4mm deep cut down the middle. Another step done  :)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on August 30, 2019, 09:15:57 PM
Looks like you are moving nicely forward - how much is still to come / has to be made ?
Title: Re: Two Cylinder Engine
Post by: Roger B on September 01, 2019, 07:18:12 AM
Thank you Per, it just needs piston rings and the seals for the water pump.

The next step was to make a base plate, not as elegant as Old Bill's or Vixen's, but will work. The engine, 6V coil and fuel tank (borrowed from the single) were mounted and connected. I checked that the sparks came at approximately the right moment and decided to give it a try as even without rings the compression was quite good.

I initially got a few short bursts of firing and then nothing  :headscratch: Finally I noticed that the fuel was not being sucked up the fuel pipe to the carb and kept flowing back to the tank. I opened the tank cover to check that there really was enough fuel and got a pop. I hadn't removed the block from the tank breather and had built up a vacuum in the tank  :facepalm: I tried again and got a few pops plus some oil from the exhaust. Finally the rollers fell out of the sprag clutch  :(

Back into the workshop to assess what had gone on. The plugs were very oily, only one showed any real carbon traces. The combustion chambers were full of oil too. I guess that all the choking trying to get fuel into the carb also sucked oil passed the pistons which there was no combustion to burn off. I removed the distributor cap to see what had gone on there. There was a slight (0.5mm?) lack of clearance and the rotor had been rubbing on the outer electrodes spreading brass shavings around. I then removed the cylinder block to check the pistons and the bottom end. All looks ok with no signs of pick up, just a lot of oil.

I will have to make a new housing for the sprag clutch as the original was fitted with Loctite 648.
Title: Re: Two Cylinder Engine
Post by: fumopuc on September 15, 2019, 06:52:12 AM
Hi Roger, good to the see the R&D department busy again.
Waiting for the next attempt to get it running.
First pops seems to show that the basics are fine so far.


 
Title: Re: Two Cylinder Engine
Post by: Roger B on September 21, 2019, 08:25:35 AM
Thank you Achim  :)

I made a new sprag clutch housing and skimmed 0.5mm off the end of the rotor arm to give some clearance. I also found that turning the engine backwards when checking the sparks is not a good idea. As the rotor is not near a plug contact when the contact breaker opens there is a vicious spark down the side of the rotor arm to the cam  :zap:
Next up is some piston rings. Although there is currently only one groove per piston I have space to add a second ring if required and so to allow for breakages I need to make at least 8. The rings are planned to be 0.9mm square. First up I made the setting ring for the skimming jig. This is bored to 0.05mm over the bore size so 2.20mm which was checked using the plug gauge I made for the bores together with a feeler gauge. I then roughed out the piece of cast iron to make the rings and let it relax for a while.
Title: Re: Two Cylinder Engine
Post by: Roger B on September 22, 2019, 08:16:03 AM
The blank was then bored out to 18mm and the inner surface was polished to reduce the risk of the rings breaking on installation. The outer diameter was finished to 20.15mm and the rings were parted off. The first one was checked in the piston groove and the same feed was used to cut the rest. The faces were polished on some 400 abrasive cloth to remove the flash from parting and the internal corners were smoothed with an abrasive rod. The rings were then split using piano wire rated wire cutters.
Next up is the heat treatment jig and heat treatment. The centre of the jig was turned to 19mm which seemed to give a suitable gap.
Title: Re: Two Cylinder Engine
Post by: Roger B on September 22, 2019, 02:55:29 PM
Five rings were clamped in the fixture and heated to dull red. After cooling down naturally they were removed and the second five were heat treated. They had grown a little but would still fit in the setting ring as it is 0.05mm oversize.
I then needed to make the skimming fixture. This can be done in one operation in the 3 jaw SC chuck but if I have to use it again it has to be carefully centred in the 4 jaw independent chuck. The body has two steps, one 0.05mm over size and one 0.05mm undersize. The rings a loaded into the setting ring which is centred over the larger diameter. They are then clamped in place and the setting ring is removed. This allows them to be skimmed to the bore diameter.
Title: Re: Two Cylinder Engine
Post by: Roger B on September 22, 2019, 05:25:07 PM
My initial attempt with 5 rings was a little optimistic, two of them broke away  :( I was able to finish the remaining three from that batch without problems and then did the others as a three and a two.
The gaps on two rings were set in the bores to around 0.05mm and were fitted onto the pistons without problems. Now I need to put it back together and give it a try  :)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on September 22, 2019, 09:22:29 PM
Looks like you had some productive in the shop and a satisfactory result - even if a few went into the bin  :ThumbsUp:    :popcorn:
Title: Re: Two Cylinder Engine
Post by: Art K on September 22, 2019, 11:23:00 PM
Roger
Getting the rings installed without breaking them is always a good thing. :ThumbsUp:
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on September 23, 2019, 05:44:34 PM
Thank you both  :)

I put it back together, took it outside and it's a runner  :whoohoo: It fired up on the first choking and after a couple of tweaks of the needle I got this:

https://www.youtube.com/watch?v=CY_AMjFN1F4




Title: Re: Two Cylinder Engine
Post by: crueby on September 23, 2019, 06:27:56 PM
Terrific!!
Title: Re: Two Cylinder Engine
Post by: fumopuc on September 23, 2019, 07:12:24 PM
Roger, it is running like hell. Congratulations.
Title: Re: Two Cylinder Engine
Post by: Jo on September 23, 2019, 08:22:48 PM
Nice runner  :)

I was a bit worried about it bouncing around on the top of the narrow wall in case it fell off  :paranoia:

Jo
Title: Re: Two Cylinder Engine
Post by: bent on September 23, 2019, 10:03:53 PM
Woo hoo!  Nice runner, Roger!
Title: Re: Two Cylinder Engine
Post by: MJM460 on September 23, 2019, 10:07:40 PM
Hi Roger, an excellent result to have it running so smoothly.

You must be all smiles after all the hard work.

MJM460

Title: Re: Two Cylinder Engine
Post by: Admiral_dk on September 23, 2019, 10:39:45 PM
Yeah it is a runner - easy starting and it sounds very even too - what more can you ask for  :ThumbsUp:  :cheers:
Title: Re: Two Cylinder Engine
Post by: Kim on September 24, 2019, 05:00:05 PM
Runs great Roger!  And it started quite well, too!
Kim
Title: Re: Two Cylinder Engine
Post by: Art K on September 25, 2019, 03:03:29 AM
Roger,
That's great, it started right up. I suppose next up is a cooling system. :ThumbsUp:
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on September 26, 2019, 09:57:26 AM
Thank you for all the support  :ThumbsUp:  :ThumbsUp:

I have given it a few more short runs and took a couple of rpm measurements. The idle is around 2000 rpm (this was just how the carb was set from it's previous duty as a throttle for my fuel injection trials) and the top end is around 9000 rpm.

As Art says the next step is to set up the cooling system. I need to make a couple more flanges and fit the seals in the water pump (once they are in the engine has to run wet or they will burn out). I have a rather large computer cooling radiator to try although I might make a dedicated one for this engine.

I will strip it down at the same time to remove the gunge from the initial runs, cast iron liners and rings are messy at the start, and put some Hymolar on the critical parts.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 04, 2019, 05:22:15 PM
So I made up the required flanges and then started stripping the engine down for inspection and cleaning. A couple of the rockers were somewhat stiff and there is still not enough clearance in the distributor.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 04, 2019, 05:28:47 PM
Removing the head everything looks ok. The exhaust valves have been warmed up. Plenty of gunk in the bores from the cast iron. The water pump looked alright so I pressed the seals in place. The camshaft and followers were also ok but as I got deeper in the gunk levels increased. There were some unexpected water droplets in the big ends and crankcase and I found I had forgotten to drill the lubrication holes in the bottom of the big ends  ::)
Overall not too bad. Clean it all up and reassemble.
Title: Re: Two Cylinder Engine
Post by: Zephyrin on October 05, 2019, 08:05:00 AM
very nice pictures on the innards of your engine, highly informative.
Title: Re: Two Cylinder Engine
Post by: Brian Rupnow on October 05, 2019, 01:44:53 PM
Great results. I'm glad it started right off, because if they don't there is always a bit of heartache trying to figure out whey they didn't. I see from your pictures that it doesn't appear that you used a ring spacer before heat treat.  Is there a name for that method of making  your rings?---Brian
Title: Re: Two Cylinder Engine
Post by: Roger B on October 06, 2019, 07:42:44 AM
Thank you both  :ThumbsUp:  :ThumbsUp:

Brian, I'm not quite sure where my ring making method comes from. The final skimming to size comes from Tubal Cain's 'Model Engineers Handbook' but I think that it is originally from Professor Chaddock. Setting the gap by the diameter of the mandrel of the heat treating fixture may also have been copied or it may have been the easiest way to keep 0.8mm square rings under control  :headscratch: I have added a picture of the rings for a different (16mm bore) engine on the mandrel showing how the gap is formed.

On with rebuilding the engine. I drilled the missing holes in the big end bearing caps although I'm not sure if they are really a benefit. The slots that the rockers fit in were opened out slightly with a fine file to stop the binding. I machined another 0.3mm off the end of the rotor arm before I realised that it was being stopped by the end of the shaft  :facepalm: Deepen the bore by 0.5mm instead. The timing was set before I put the cylinder head back on and then with it all assembled I started looking at the water cooling piping. The pipe between the water pump and the block tended to collapse when I used the clear plastic pipe so a piece of braided neoprene was used instead. The radiator (computer cooler) looks rather large. I will have to find something smaller.
Title: Re: Two Cylinder Engine
Post by: Brian Rupnow on October 06, 2019, 01:36:06 PM
Thank you Roger. I will try and find out more about the Chaddock method of ring making.---Brian
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on October 06, 2019, 08:17:27 PM
Nice to see continued progress Roger  :ThumbsUp:
I hope that you don't end up with more water in the crankcase after the next runs - though I'm not even sure that you had the cooling system connected last time  :noidea:

I'm sure that the current cooler is a lot bigger than needed - unless you increase the power output and load quite a bit.

Some engines do not like to work under a certain temperature and others are the other way around  :headscratch:  All (I only had 3) Moto-X bikes of my youth, were converted road mopeds and all of them had their max power output exactly when they where started from cold. As they were bump-started, I really could feel the power and acceleration when they fired - and power slowly decreased as the temperature rose. I do not know for sure, if this is the explanation, but my racers and the first road going bikes I had where all two-stroke, air-cooled, and they all shared the max power at cold (maybe the MZ150 where an exception - not much pull anywhere) and all my later four-stroke worked best when heated to at least 60 degree C .... but here the air-cooled lost some above 120 degree C (and the liquid cooled do not go up there).
Title: Re: Two Cylinder Engine
Post by: Art K on October 07, 2019, 12:47:45 AM
Roger,
It is good to see progress, even if it's a step back then two forward the R&D department is open for business. It ran very well so I have no doubts about it doing the same soon.
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on October 07, 2019, 12:36:15 PM
Thank you  :) :)

Per, As it had no cooling system I only ran the engine for short intervals. I think that this may have resulted in condensation in the crankcase without enough heat to evaporate it away.

I will probably move that cooler over to the horizontal engine ready for some load tests with variants of the petrol injection system.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on October 07, 2019, 06:23:27 PM
Condensation sounds like a likely explanation. So it is a question about how long you can run it then - neighbors etc.
Title: Re: Two Cylinder Engine
Post by: AlexS on October 15, 2019, 05:18:50 PM
Great first run! That 180 deg twin runs like a Swiss clockwork.
I see that you are removing the pc radiator to the other engine.
Maybe a idea (electrical sub project) to use the radiator with a switch between engine-pump-radiator for warm temperature and a switch to engine-pump-engine. Like a thermostat but electrical controlled with solenoid valves controlled by a arduino and temperature measured by a PT100. So you could 'control' temperature of coolant.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 25, 2019, 06:04:27 PM
The smaller PC radiators still haven't arrived  :( The were ordered from an Amazon site in Germany but seem to be on the slow boat from China. As it was a nice evening when I got home I decided to give the engine a try with the big radiator. All went well, the circulation was visible and there was enough cooling without a fan with the engine off load.

https://www.youtube.com/watch?v=VhkSLBta9WE
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on October 25, 2019, 08:40:12 PM
Hello Roger,

Very well done, sounds and runs great. It is a really nice looking engine.  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on October 26, 2019, 09:00:12 PM
You really should be happy with the result so far (I expect that you aren't finished yet)  :ThumbsUp:  :cheers:
Title: Re: Two Cylinder Engine
Post by: Brian Rupnow on October 27, 2019, 01:54:46 AM
Good stuff Roger. Congratulations on a nice running engine.---Brian
Title: Re: Two Cylinder Engine
Post by: Art K on October 27, 2019, 01:58:28 AM
Roger,
Once again good results from the R&D department. Your twin runs great, sounds great as well. :ThumbsUp:
Art
Title: Re: Two Cylinder Engine
Post by: Chipmaster on October 27, 2019, 05:16:33 PM
Excellent Roger, could we have a longer video please.

Andy
Title: Re: Two Cylinder Engine
Post by: Roger B on October 28, 2019, 10:57:09 AM
Thank you all for your support  :)

As Per says this is only the begining, the next stages are:

- Fit the correct radiator and cooling fan.

- Couple to a generator and carry out load tests.

- Make a 360° crankshaft and camshaft and repeat the load tests to see if there is any difference.

- Install petrol injection and load test again. (This is only practical with the 360° crankshaft due to the siamesed inlet port.)

- Select the best option and install in a small tractor (possibly to be interchangable with the diesel if it ever runs to my satisfaction ::) )

There will be plenty more videos during this process  :wine1:
Title: Re: Two Cylinder Engine
Post by: AlexS on October 28, 2019, 11:40:19 AM
Great ideas in mind to upgrade the engine.
Also plans to test different exhaust/ intake mods camshaft specs under load?
I would follow along to see more progress!
Title: Re: Two Cylinder Engine
Post by: Roger B on November 09, 2019, 03:00:40 PM
Thank you Alex  :ThumbsUp: I am not sure about changing the camshaft design yet, I will have to see how it runs. I am also not sure that my camshaft cutting technique is accurate enough to show small differences.

I borrowed the generator from the vertical engine and set up a drive using a bellows coupling. The coupling is rated at 3 000 rpm and will be running at least twice that  ::) As the correct radiator has been lost in transit I am waiting for it's replacement. The weather wasn't too bad today so I decided to have a test run.

https://www.youtube.com/watch?v=7LbKKnjhT9w


The test went quite well but I will need to move the fuel tank and make a lever for the throttle before further runs as well as adding a cooling fan. The best result I got was around 38W but I ran out of hands when trying to adjust the needle and had no chance of adjusting the timing. The voltmeter is hopefully readable and the ammeter is 15A full scale.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 23, 2019, 03:52:46 PM
I made a throttle control lever and added a fan to the radiator. This is a 12V fan running on 6V so it is just a gentle breeze. Optimising the timing and needle I reached a maximum of 45W, 4.5A at 10V. It has quits a crackle at 9000 rpm so I will have to think about a silencer, the microphone on the camera was overloading.

https://www.youtube.com/watch?v=-KhXAJvILiU

After several runs the was an oil spray trail on the non exhaust side of the flywheel from oil passing the rear main bearing. The exhaust side was clean. A quick check of the plugs showed some oil on number one, number two looked good. I had hoped for 60W so will have to see what else I can change/optimise.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 24, 2019, 10:31:08 AM
After I refitted the spark plugs the compression seemed very low so looking at the various oil traces I decided to remove the cylinder block and check the pistons and rings. All looked ok even though number one which had the oily plug seemed clean and number two which looked good had an oily piston top.

I then made a quick check of the valves by blowing down the manifolds with one length of plastic tube whilst listening in the cylinders with another length of tube as a stethoscope. Number one exhaust was definitely leaking and number two possibly although this was somewhat masked by the large leak on number one. The inlet valves seemed ok.

I removed and stripped down the head. Both exhaust valves (A4 stainless steel) were quite pitted as were the seats. The exhaust valve seats were re cut using the original cutter and the valves were cleaned up in the Proxxon lathe (the Hobbymat is occupied) using an abrasive stone. Next step lap in the valves.

I don't know if the seats were not adequately lapped first time round or if I have reached the power limit for this design  :headscratch:
Title: Re: Two Cylinder Engine
Post by: AlexS on November 24, 2019, 01:38:41 PM
Are the seats like a edge made in the aluminium cylinder head with a seat cutter?
Title: Re: Two Cylinder Engine
Post by: Roger B on November 24, 2019, 06:45:15 PM
Yes Alex the seats are cut in the aluminium cylinder head. There has been a lot of previous discussion between seats in the head, seat inserts and combined valve cages and valve guides. At the moment I think that the seat inserts and cages cause more problems  but I am willing to learn (as ever)  :thinking:  :headscratch:  :wine1:
Title: Re: Two Cylinder Engine
Post by: AlexS on November 27, 2019, 06:58:32 PM
You would expect that the valve will shape/fit the seat easier due to the softer aluminum. Definitely worth trying further. I myself also had problems with sealing the exhaust valve. I have finished this by placing the valve seat with cylinder head in the lathe. I'm afraid this is possible for your cylinder head?

Something that comes to mind. To determine the degree of leaking valve, I have to color the valve seat with a water-resistant marker. Then the valve seat lapped. I also had the exhaust channel filled with water and pressurized with compressed air. Maybe this helps.
Title: Re: Two Cylinder Engine
Post by: AlexS on November 27, 2019, 07:40:47 PM
Maybe a crazy idea. But what about this.

If I am correct, the valve guide was tailor-made to 2.5 mm.
Mount an axle with the same diameter in the valve guide. Just looked that this may be available in silver steel material.
You could possibly mount a valve cutter on this shaft that has the same fit as the shaft. The valve cutter could possibly be clamped in a column drill. And possibly have high speed cut (hoping for few vibrations). With the aim of no rotating movement in the valve guide and possibly better concentric of the valve cutter.

Greets Alex
Title: Re: Two Cylinder Engine
Post by: Roger B on November 28, 2019, 05:32:28 PM
Thank you Alex  :) The seat cutter was made from the same cap head screws as the valves. I didn't cut the hex off and made some cutting edges with a fine file. It is hand operated to minimise chatter/vibration. After lapping the valves, cleaning and reassembling I checked the seating using air pressure from the manifold side. They all withstood 4 Bar (60psi) from a tyre pump.

There could be many reasons for this failure. The seatings may have been too narrow. Quite a lot of heat is dissipated through the seatings. The valve clearance may have been too small and closed up when the engine was hot so the valves didn't seat. There may have been residual stresses that caused the valve heads to distort slightly  :thinking: I will have to wait for the next opening of the R+D department. Maybe I should keep the revs to 6000-7000?

As I have spent too much time playing with fiddly little pieces I decided to start on the alternative 360° crankshaft for this engine. ( I am also planning a 25mm bore 25mm stroke version in case I can't reach my desired output). I didn't have any more 30mm ST50 (~EN8) so started with some 35mm bar. Plenty of swarf  :)
Title: Re: Two Cylinder Engine
Post by: doubletop on November 29, 2019, 09:43:39 AM
Roger

A very nice engine and I like the idea of the PC radiators. My Bobcat was built for water cooling and I just conected it to the tap. I'll be ordering a radiator as soon as I finish typing here

Pete
Title: Re: Two Cylinder Engine
Post by: Roger B on December 07, 2019, 07:52:06 AM
Thank you Pete  :)

The last section was turned down to 30mm leaving a barely detectable line. I clamped the crankshaft blank in the quick set Keats angle plate and used the mill to set out the crankpin centre drilling then back to the lathe to turn the crankpins. This time I remembered to start with the one nearest the tailstock  ::) The cut was quite chattery with the interrupted cut but settled down once the pin was round. I found it best to increase the depth of cut whilst traversing the parting tool so I was only loading the corner not the full width. Doing this I could increase the cut 0.1mm per traverse. When I got down to 8.5mm I faced the webs with a 8mm tool.
Title: Re: Two Cylinder Engine
Post by: Roger B on December 07, 2019, 07:57:24 AM
Finally I set the parting tool square and finished the journals 8mm diameter ready for a final polish. As expected when I released the tailstock centre the end of the crank moved about 0.5mm due to the unbalanced stresses. I will finish the rest of the machining and then carefully straighten it. The 180° crank didn't have this problem as the stresses were fairly well balanced.
Title: Re: Two Cylinder Engine
Post by: Kim on December 07, 2019, 06:49:32 PM
Very nice, Roger!  Regarding the warping, I'm unfamiliar with the European naming for the steel. You said you're using EN8, but is that 'stress proof'?  Like the 1144 Stressproof steel we can get in the US?  Or is it just standard steel?

Also, what's the clearance problem you're referring to in image "645 Clearance problem.JPG"?   is it the clearance between the workpiece and the SHCS clamping the compound slide?  Or something else?

Thanks,
Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on December 08, 2019, 08:09:56 AM
Thank you Kim  :) I'm not really sure of the equivalence. ST50 is a medium carbon construction steel, nothing special may be similar to 1040. It is cold rolled so tends to have built in stresses and it will warp if the metal removal is not balanced. You are correct there was a clearance problem with the cap head screws so I had to increase the tool overhang even more.

The next stage was to finish the ends of the shaft. This was done in a series of steps to try and keep everything as rigid as possible. Luckily the tailstock centre kept it true so I didn't need to put spacers between the webs. It even ended up looking like the drawing  :)

I now need to decide how to balance it. I may just remove material from the centre web and leave the two ends round  :thinking:
Title: Re: Two Cylinder Engine
Post by: Brian Rupnow on December 08, 2019, 11:57:48 AM
Roger--That's a great looking crankshaft. 1144 stress proof is only available in round bars in Canada. I always mill away two sides so that I have a piece of "flat-bar" to work with, which is  a lot of extra work. I think by doing it the way you have is going to leave far too much "counterweight".  Let us know please, Brian.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on December 08, 2019, 04:44:07 PM
Nice looking crank Roger  :ThumbsUp:

Brian - there is no counterweight right now ...!!... for that to happen, Roger will have to remove weight from the same side as the crank "pins" ...!
Title: Re: Two Cylinder Engine
Post by: Roger B on December 08, 2019, 06:40:39 PM
Brian, Per is right there. The 180° crank that is currently in the engine is made the same way but that is inherently statically balanced. For this one I need to remove enough metal around the crankpins to compensate for the mass of the crankpins, big ends and some percentage (always a discussion point) of the mass of the conrods and pistons. Leaving the crankshaft round will increase the total mass of the engine but unless you are intending to fly it does it really matter. It certainly reduces the machining.

I am sorting out a few other bits and pieces. I feel that this engine needs a silencer to avoid problems with the neighbours and have started building one based on the one on the horizontal engine. Following the advice on various threads I decided to purchase some 3mm spotting drills to use rather than the centre drills. They seem to work  :)  Silver soldering the baffles in place was fun but ended up ok. I am waiting for a length of 7mm brass pipe to finish this off. I also wondered if the limited output was due to a mismatch of the generator and engine and purchased another motor to use as a generator. This is the same frame size as the one I am using on the horizontal engine but has a different winding. The 'model' couplings in this size all seemed expensive but I found a small Fenner coupling with 6mm pilot bores that would suit and is good for 17 000 rpm  ::) The motor end was opened out with a previously made 1/4" reamer. The engine end was drilled out 9mm and then bored to 10mm to avoid the deflection caused by the grub screw hole. When assembled the motor is quite capable of cranking the engine with a 12V battery  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on December 09, 2019, 05:58:19 PM
I finally received the smaller radiators but they didn't have a place for a filler/vent. I carefully drilled a 3mm hole in the end of the header tank and opened it out with a taper reamer until I could start an M8x1 tap. A small adaptor was turned up and threaded to suit. This was then screwed in place with the aid of some two component epoxy putty that is rated for 120°C (I have already been caught out by the low temperature rating of Rapid Araldite  ::) )

The piece of 7mm brass tube arrived so I could finish the silencer. I had a brief test run (too dark for photos or videos  :( ). The silencer significantly reduces the crackle and I got about 80W (9A at 9V)  :whoohoo:
Title: Re: Two Cylinder Engine
Post by: AlexS on December 10, 2019, 06:42:52 PM
Nicely done. Great job, done alot :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Ye-Ole Steam Dude on December 10, 2019, 08:17:25 PM
Hello Roger,

Super nice radiator that will look great with your setup.

Have a great day,
Thomas
Title: Re: Two Cylinder Engine
Post by: 90LX_Notch on December 13, 2019, 01:47:16 AM
I've quietly following along Roger.  Great build.

-Bob
Title: Re: Two Cylinder Engine
Post by: Roger B on December 28, 2019, 05:14:59 PM
Thank you all  :)

I made a support bracket for the radiator (my first adventure with aluminium solder) and connected up the system ready for some trials.

https://www.youtube.com/watch?v=WmOeDPbYabg

https://www.youtube.com/watch?v=sMYScoC5MjQ

It idles quite nicely around 2000 rpm and picks up the load well to a point where it suddenly struggles. It will stop firing and adjusting the needle doesn't seem to help. If I wind it up to maximum rpm and then add the load it is ok but accelerating with the load is a problem. It seems to me as if it is (from my motor sport days) coming off the cam. The silencer also fell off a few times so I need to make a clamp for the pipe. I reckon it at least halves the noise level  :)

This is the end of  experiments for the moment as we are having to move apartments and although I have a slightly larger cellar for the workshop I need to find a new R&D department.
Title: Re: Two Cylinder Engine
Post by: Art K on December 29, 2019, 04:11:00 AM
Roger,
Your twin runs good, I couldn't read what the meter's read to determine what sort of load you had. When I last went to the "local" model engine club he had a pony break set up so that anyone who wanted could set up their engine & check how much power it made. My Val engine put out 1/3 horsepower at 6100 rpm. Then it promptly stalled multiple times.
Art
Title: Re: Two Cylinder Engine
Post by: Roger B on February 19, 2020, 08:07:03 PM
Thank you Art  :)  I got to about 80W (9V at 9A) but the carb is not optimum. Depending on the efficiency of the generator that puts the actual output at a bit under 1/4 hp.

Finally back to some engine making. I put together an electrical system in the same style I used for the other petrol engines and then made a clamp for the silencer from a 5mm x 0.5mm strip of phosphor bronze. I put some cooking alcohol in the tank and started it briefly to make sure the wiring was correct (I have used a 7806 regulator to reduce the voltage for the 6V ignition coil and have had problems before).

I now need to look at a new carb design to improve the response to loading if the engine is going to power a tractor  :headscratch:
Title: Re: Two Cylinder Engine
Post by: Roger B on July 15, 2020, 07:46:45 PM
The plans for this engine require a fuel pump for the SU type carb trial and then a fuel injection pump with the 360° crank. I have been thinking about how to install these for a while and have come up with several designs for eccentrics and cams that would work but could not be assembled  ::) I finally had the inspirational moment and realised that if I turned the gears round it would be easy to fit the pieces over the gear bosses. The ignition side was easy as both keyways were vertical, the camshaft side is a little advanced but probably not enough to cause a problem.
Title: Re: Two Cylinder Engine
Post by: Kim on July 16, 2020, 05:25:15 AM
Seems like a pretty good inspiration!  :ThumbsUp: :popcorn:
Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on August 31, 2020, 08:22:25 PM
When I started the next trials with the SU type carb it did not run well and I could feel fuel blowing back out of the carb intake  :( This usually means cam timing problems. I printed out a degree wheel and stuck it onto a piece of 4mm plywood. A check with a DTI showed that the exhaust valve was closing around 15° BTDC and the inlet valve was open at around the same point. Firstly obviously too advanced by around one tooth and secondly where has the overlap gone  :headscratch: I moved the timing back by one tooth of the 40T gear (18°) which was somewhat more sensible.
The ignition timing was 36° BTDC which I reduced to 20°.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on August 31, 2020, 09:52:30 PM
While very annoying ... at least you now got an idea about where to look for the reason.

I must admit that I can't remember how you did your camshaft - is it one solid piece or are the cams "loose" units assembled onto it ?
Title: Re: Two Cylinder Engine
Post by: AlexS on August 31, 2020, 10:33:15 PM
It looks pretty familiar to me. my engine block has similar values of valvelap vs timing. Theoretically you assume a valve overlap of about 20+ degrees and practically it is a number of degrees like your engine. Option was to reduce lobe separation, but affects opening of the outlet and closing of the inlet.

I see your camshaft is made in one piece. only thing i can think of is the geometry between the size of the cams (base circle) and the valve lobes could possibly be changed. For my one cylinder I used rollers and I think, maybe the diameter of these are to large in comparison to the size of the cams (especially the smaller exhaust one).
Title: Re: Two Cylinder Engine
Post by: Roger B on September 26, 2020, 03:30:28 PM
After some thought I decided to check the valve clearances. They were 0.2-0.3mm instead of 0.1mm (the base circle undercut). There is subjective amount of overlap now but I haven't measured it yet. I assume a fairly major stripdown will be required to fix the water leak (carb thread) so I will recheck the timing afterwards.
Title: Re: Two Cylinder Engine
Post by: Zephyrin on September 27, 2020, 11:50:19 AM
I also spend a lot of time adjusting the timing of the cams according to my diagram, and clearances carefully set, just like you do...
It's a never-ending job for me with unhardened cams and pushrods, the hammering of the valves means that ultimately the clearance is such that the diagram is never respected, not to mention inertia on rockers with fast runner, but surprisingly, the engines run...
Title: Re: Two Cylinder Engine
Post by: Roger B on September 27, 2020, 05:52:47 PM
Most of my components are hardened but I guess there must be some bedding in.

The water leak was due to a bit of a bodged connection with some PVC pipe and an oversize pipe clip. I originally planned an elbow at the water pump inlet which I need to do. It will also give a better pipe run. I made up a small filter PCB for the cooling fan with a 220uF electrolytic and a 0.1uF ceramic which seems to have resolve the fan stopping problem. Finally I made the proper pivot pins for the fuel pump to replace the bolts.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 04, 2020, 10:41:15 AM
Whilst waiting for some 6mm elbows to arrive from Germany (Drop it Hide it Lose it have taken 4 days from Krefeld to Speyer. I think I could walk faster) I decided to start a new camshaft for the 360° version.

Based on my last experience I tested a couple of pieces of 10mm bar to make sure they wouldn't harden. The first one shattered but the second was ok. It didn't give a good finish with a steel tip but was ok with an aluminium one. The lobes were cut with a 2.2m tipped parting tool.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 05, 2020, 08:02:16 PM
Next I milled the keyways in the 360° crankshaft and the new camshaft using the little Proxxon mill. Alex S had very kindly made some balance calculations/designs in a 3D CAD programme for the 360° crankshaft so I had to work out how the make this with the equipment I have. Using my middle size drill vice and the degree wheel from my camshaft milling jig I came up with a solution. I was a little nervous about the vibration loosening the drill vice but it seems to work  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on October 05, 2020, 08:07:45 PM
I worked my way around the 4 flats. The fine details will be easier with a file than trying to do a milling set up.

I also received the 6mm elbows. I have Loctited one onto the water pump inlet and think I may use them on the other water connections to get better hose runs.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on October 05, 2020, 09:41:00 PM
That ought to improve the running quite a bit - I hope it is the here case too  :cheers:

Balancing an engine can be done to very good results, but will always be a compromise. You have now done the first important step forward. Adding a counter rotating balance axle is the next level, adding yet another (sometimes at double the RPM) is yet a step - BUT it's kind of the Law of Diminishing Returns along that road, and that's most likely the reason I never saw an engine with three balancing axles.
Title: Re: Two Cylinder Engine
Post by: steamer on October 05, 2020, 09:47:26 PM
I like it a lot Roger!

Dave
Title: Re: Two Cylinder Engine
Post by: Roger B on October 06, 2020, 08:09:27 PM
Thank you both  :) Somewhere near balanced will be fine for me. I will finish up the rough edges and put a radius in the corner by the balance weights with a selection of files.
Title: Re: Two Cylinder Engine
Post by: AlexS on October 06, 2020, 08:22:52 PM
Great work, that looks nice! :ThumbsUp:

It would be fun to see an model engine with one or two primary balancing to compensate the forces of the accelerating piston. But indeed no need for light weight piston and connecting rods!
It is possible to test the balancing, mount the crank in  the lathe with fitting the connecting rod and bearings. And connected the rods with an elastic at a fixed place, for example a wall. And supports it with a counter center.
Title: Re: Two Cylinder Engine
Post by: Roger B on October 07, 2020, 08:06:46 PM
Thank you Alex  :ThumbsUp:

I added some more elbows to the cooling system and neatened up the pipework. The feed to the block now goes over the flywheel end to make space for an injection pump. The connections also are ready for when/if this gets installed in a tractor and the radiator moves to the front.
Title: Re: Two Cylinder Engine
Post by: Roger B on November 22, 2020, 07:52:49 AM
Whilst thinking about the next steps with the diesel I continued with the 360° camshaft for this engine.

First step was to make a thrust washer for the fixture as I had found that the shaft would slide along on the deeper cuts unless the clamp bolt was very tight. The rest was much as before, spread over several evenings to reduce the chance of me losing concentration and having to start again.

The new cooling system is better but on the limit at full load.

https://www.youtube.com/watch?v=aLP3_FKovd4
Title: Re: Two Cylinder Engine
Post by: Roger B on January 09, 2021, 05:39:19 PM
As the intention is to compare the 360° and 180° versions I needed to take some reference measurements for the 180° Version. At 2500rpm it delivered 4.2V at 2.5A, about 10W. At 5500 rpm I got 8v at 8A, 64W and at 7000rpm 9.5V at 11A, 105W. The full speed figure was slightly better that with the barrel type carb I used initially.
I then tried some on and off load testing at around 90W and 50W which it took without a stutter. Finally I tried revving it into a load, again without problems. On with the rebuild  :)

Low speed run 2500rpm

https://www.youtube.com/watch?v=onotmaoX6W8

Load dump 90W

https://www.youtube.com/watch?v=lzYmMhobIgU

Load dump 50W

https://www.youtube.com/watch?v=kV_tjLb6o-g

Revving under load

https://www.youtube.com/watch?v=k3TUprVcAas



Title: Re: Two Cylinder Engine
Post by: Admiral_dk on January 09, 2021, 08:37:57 PM
I've just finished a book about the Kawasaki Racing effort in the USA by Randy Hall.
In the end of the first book in the series, he mentions that the KR250/350 started out as a 180 degree (remember this was a two cylinder tandem engine). Since it was a mere question of how you assembled it if it was a 180 or 360 degree firing interval - they tried both.
Initially they got exactly the same power, but with the counter rotating cranks the 360 degree version had much fewer vibrations and this meant that they could increase the RPM's quite easily .... mind you - almost all motorcycle racing two-strokes have a top RPM around 12,000 RPM .... yes you could go higher but at no gain.

The modern Four-stroke period has also experimented quite a bit on the phasing of the crank throws and firing order. They never got any power increase, but it has a big impact on tyre life and how likely the bike is to throw the rider off the bike ...!... and how well it behaves round corners etc.
Title: Re: Two Cylinder Engine
Post by: Roger B on January 11, 2021, 06:22:49 PM
Thank you Per  :ThumbsUp:  I am interested in seeing the effect on mixture distribution with the siamesed inlet port  :headscratch: If I have equal firing angles I can use a single fuel injector driven at crankshaft speed.

I case hardened the cam and luckily it didn't distort much (straightened by thumb pressure)  :) It was easier to remove the engine from the base for the rebuild. First I stripped down the distributor to check the cam dimensions so I could make 180° version (I wasn't sure that the drawing was correct). There was a lot of oily goo inside the cap but it didn't seem to affect the operation.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on January 11, 2021, 10:56:56 PM
Oh yes - I forgot about your inlet arrangement - on racing engines it's usually individual mixers - but on your engine it should make some difference and I understand your desire to see about a single injector solution, as it potentially could reduce the requirements of the construction ....
Title: Re: Two Cylinder Engine
Post by: Roger B on January 16, 2021, 03:01:47 PM
The contact breaker cam is made from an offcut of 20mm mild steel. The original doesn't seem to show much wear so I probably won't case harden it. The design is such that the centre of the flank curve is on the circumference of the cam making it very easy to set up with the Keats angle plate. After turning the first flank the blank was rotated 180° using the scribed line for alignment to turn the second flank. The blank was then parted off and faced to length on a tapered mandrel. Finally the rotor fixing screw hole was drilled 2mm and carefully relieved with a 4mm end mill to clear the head.
Title: Re: Two Cylinder Engine
Post by: Roger B on January 16, 2021, 03:02:57 PM
The fixing grub screw was then drilled and tapped M2.
Title: Re: Two Cylinder Engine
Post by: Kim on January 16, 2021, 04:56:58 PM
Hi Roger,
I continue to follow along, though I don't have any experience in IC, I find it fascinating and try to understand what's going on. And initially, I couldn't initially understand why you moved to the keats setup, but I figured it out eventually. That is a pretty neat setup :)

So, did you leave the transitions between the different radiuses sharp? Or did you round them off a bit?  Just curious.

Kim
Title: Re: Two Cylinder Engine
Post by: AlexS on January 17, 2021, 02:30:43 PM
I thought I had seen a video on this forum with the engine running (360 deg version)? On high rpm
Title: Re: Two Cylinder Engine
Post by: Roger B on January 18, 2021, 10:25:35 AM
Thank you Kim  :ThumbsUp: 

I find the Keats useful for all sorts of setups. The transitions were just smoothed off with a fine file. As there is just a light plastic follower I don't think it needs anything more.

Alex, There are quite a few videos on here with the engine running in 180° form. However there seems to be some form of security problem and a lots of people are unable to see them. There is just a blank space in the post.

https://www.modelenginemaker.com/index.php/topic,10150.0.html
Title: Re: Two Cylinder Engine
Post by: Roger B on January 19, 2021, 05:17:52 PM
The videos seem to be fixed now  :)

The distributor cap was fixed to a 16mm mandrel to make the seating for the 180° position. This was made as before. Luckily I could unscrew the existing connection and reuse it. I had made a spare brass nipple but it wasn't needed. I then continued stripping the engine down. The pistons and rings look fine but there was a bit of fibrous debris in no. 1 combustion chamber. The existing crankshaft looks good but I guess it has had less than 10 hours total run time. The new cfank fitted nad turned easily but is about 1mm too long  :( I need to check the dimensions  :headscratch:
Title: Re: Two Cylinder Engine
Post by: AlexS on January 19, 2021, 07:55:50 PM
Thank for letting me know about the security problems, but it seen that they are been fixed!

+- 10 hour total run time!  :o Did you measured the dimensions of the piston rings before and after?
Title: Re: Two Cylinder Engine
Post by: Roger B on January 21, 2021, 05:39:08 PM
Hi Alex, the most it has run is 10 hrs. I suspect it is more like 5 or 6. The last load trial series was maybe 1/2 hour total.

I checked the crankshaft against the drawing and by a build up of tolerances the outer webs were too thick so I skimmed them back to the correct overall length. Both con rods fitted and turned freely but are a little tighter than on the 180° crankshaft. Next step was to change the camshaft which fitted without problems. The 180° one showed no signs of distress. Now I have to finish rebuilding the engine.
Title: Re: Two Cylinder Engine
Post by: Vixen on January 21, 2021, 07:04:05 PM
Still watching and enjoying what I see. :ThumbsUp: :ThumbsUp: :ThumbsUp:

Mike
Title: Re: Two Cylinder Engine
Post by: Roger B on January 23, 2021, 04:09:16 PM
Thank you Mike  :)

The block and head were refitted as a unit and everything still seems to go round, although it is a little tighter than before. I got confused on the new ignition cam and drilled the rotor fixing hole 90° out of position  :facepalm: It was easier to re-drill and tap the rotor. I continued refitting the fuel pump and then mounted it back on the base ready for a trial. It started up and ran with the same carb settings as before. The fuel pump output needs reducing as the chamber is tending to flood and I need t  check the valve timings and set the ignition timing (it was just done by eye  ::) )

https://www.youtube.com/watch?v=IPNMn-ufsRk

Title: Re: Two Cylinder Engine
Post by: Roger B on January 26, 2021, 05:45:26 PM
The cam timing was correct as I hoped having cut the lobes in relation to the keyway. The ignition timing was also close to 20° BTDC so it makes sense that the engine ran well. It needs it a bit more bedding in and then I can run some quantifiable trials.

As I have reached this point I now need to see about fitting fuel injection for the third phase. There is generally enough space but I will need to modify the back of the timing case to be able to mount the pump on the base of the cylinder block.
Title: Re: Two Cylinder Engine
Post by: Roger B on January 31, 2021, 03:38:49 PM
I took the engine off to the welding bay for some load tests. Overall I think that it is similar or maybe slightly more powerful than before but there wer two problems:

1) My aging analogue meter seems to have problems and is not reading correctly. As the full load bank is 1 ohm current should equal voltage which it didn't (and I realise that it didn't in the last test with the 180° crank). I borrowed another meter from the workshop and got the expected result  ::) For the last trials I will have to recalculate just using the voltage value.

2) The vibration from the 360° version is causing frothing in the fuel reservoir so fuel is spraying out of the vent and the carb is being starved. If I can get to a non resonant rpm it runs quite well but at critical points it is surging and spraying fuel over the exhaust (yes I know where the fire extinguisher is). A bigger fuel reservoir and possibly a flexible mounting may help  :headscratch:

As I have a set of 180° parts maybe I should make another engine to go around them  ;D

https://www.youtube.com/watch?v=KaZ4AVgVmps


Title: Re: Two Cylinder Engine
Post by: Admiral_dk on January 31, 2021, 07:45:32 PM
When I have obviously wrong measurements, I usually end up discovering why - it's a lot worse when you believe the results and much later discover that your wires / probes are faulty and wonder how many wrong values you have used / recorded before you notice.

A common wire to the meter that is starting to deteriorate, might still give the right voltage when used to measure voltage. The same wire will have an increased value when you measure for continuity and be way off the scales when used to measure Ampere ....  :rant:   :zap:   :cussing:

And it's not much better with Scope Probes not up to specs any more  :Mad:

So the fact that you got a problem, means that you can measure the equipment to figure the reason - yes it's annoying that today's results are more or less useless - but at least you know not to trust them for future reference ....

I notice that you use Fluke Meters - are they the True RMS versions ?  If so, it might be interesting to measure AC as well - just to see if there is a lot of fast variation in the DC values you get.
Since you do this at work - any change off 'borrowing'  a good deep memory Scope, with high a quality Voltage and Current Probes ?  If so, try to use the Math Function, as this should give you Voltage, Current and Power. You obviously still need to be sure the measurements represent the true values.

I hope I am giving you useful ideas and doesn't sound like I'm telling you something you know much more about than me ....

Best wishes

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on February 01, 2021, 02:26:19 PM
Hi Per,

The problem appears to be quite basic, mechanical failure of the movment of my ~40year old analogue meter. I have been using this as it has a 15A range wheras my other meters only go to 10A. A quick check showed that the zero setting is not consistent, sometimes it will return to ~1A sometimes it will be offscale -ve so sometimes it will under read and sometimes over read.

With this engine and generator set up I am only reaching around 9A so no problem. The horizontal engine gets up to around 12V at 12A so I will need another meter for this.
Title: Re: Two Cylinder Engine
Post by: AlexS on February 01, 2021, 08:29:39 PM
Hi Roger,

Maybe this could help you out for quick measurement of volt, current and power?

https://nl.aliexpress.com/item/4000206861390.html?spm=a2g0o.productlist.0.0.42bf38ceOkYZ5Q&algo_pvid=105b1b23-c4b3-4559-b265-9b396e85663a&algo_expid=105b1b23-c4b3-4559-b265-9b396e85663a-0&btsid=2100bde316122106286337560e53d8&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

I think it does not have the accuracy level and quality of Fluxe meters. But maybe I tell old things and have you already consider of this meter.

And for the vibrations of the 360 deg, how is the engine running on lower rpm's? Good progress! ( for my self I started on working on a ac -> dc dyno)
Title: Re: Two Cylinder Engine
Post by: Roger B on February 02, 2021, 07:08:53 PM
Hi Alex,

Measurement systems are not a problem if I look at my work resources, I just have to look deeper if I need more that 10A DC ( AC clamp meters take me to a few thousand amps). For the 180° series I just didn't see the obvious problem at the time, I was concentrated on how the engine was running.

As expected the 360° version is not so well balanced as the 180° version. This is a short clip of it wandering around the bench at lower speed. I am not sure how to reduce the vibration in the fuel reservoir  :headscratch: The next step is fuel injection which won't be affected.

https://www.youtube.com/watch?v=SLvOzfd8gpY
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on February 02, 2021, 07:51:51 PM
Place the fuel tank at some distance (or in that nice heavy Vice) and run a thin rubber hose (made for the right fuel) to the engine.

On a full size engine you usually use a balance axle nowadays .... and rubber mounting of the engine is nothing new either (just look inside the engine bay of your car).
Title: Re: Two Cylinder Engine
Post by: Roger B on February 03, 2021, 07:18:11 PM
Hi Per,

This engine is intended to be used in a model tractor so it has to survive on it's own. The 180° crank version with the CD carb worked and maybe a fuel injected 360° crank version will be better  :headscratch: A few more months work may tell  ::)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on February 04, 2021, 11:08:20 AM
OK - how about rubber suspension of the tank then - normal on motorcycles (though that is normally not because of fuel, but comfort and longevity).

I don't know about two cylinder European tractors, but the John Deere of Old had a 180 degree crank ....
Title: Re: Two Cylinder Engine
Post by: Roger B on February 23, 2021, 07:43:37 PM
Due to the vibration problems with the 360° crankshaft and the CD carb I have started on the fuel injection system. The pump module and the injector will be based on the diesel ones. The pump will be mounted above the timing case and will be driven with an excentric from the crankshaft to give an injection per revolution. The pump will be fixed using the fixings for the timing case backplate.

A bit of milling has produced the support bracket and then I will go back to lathe mode to produce the pump element and the body.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 27, 2021, 07:36:07 AM
The bulk of the adjustment slots was removed with a 2.5mm drill ready to be cleaned up later with a 3mm end mill. The M3 fixings to join the body to the bracket were drilled and tapped and then the body was set up in the 4 jaw independent chuck to bore out for the pump element.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 03, 2021, 07:56:24 PM
The bore for the pump element was started with a 7.5mm drill and finished with an 8mm end mill. The clearance for the spring was then opened out with a 10mm end mill. This showed a problem  ::) I hadn't moved the fixing holes over when I moved the pump centre over so it broke through into the fixing holes  :facepalm: As this would still work I opted to continue. I will have to remake the bracket and the pump body, but maybe I will need to do that anyway later due to some other unknown problem. Finally the delivery valve end was reamed out to 6mm and a lead in for the pump element O rings was cut using a large centre drill.

The pump element is made from 8mm silver steel as for the diesel. The spring end and the O ring groves were machined and the blank was parted off. The bore was then drilled 1.85 mm and reamed 1.95mm. Finally the delivery valve seat was cut with a 4mm end mill and the thread for the delivery valve was cut M5 x 0.5.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 03, 2021, 08:08:48 PM
Next the inlet port was drilled and the location flat was milled, same vice different machines. I then checked the bore. The 1.96mm pin gauge just passed through and the 1.97 gauge would not enter from either end, much as before. Finally I drilled and tapped the locating screw hole and the inlet union holes in the body.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 04, 2021, 11:49:36 AM
You are getting rather good at hitting the same small diameter hole every time Roger  :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Roger B on March 06, 2021, 05:34:46 PM
Thank you Per  :ThumbsUp: It took me a long time to learn how to ream properly  ::)

A quick sanity check to make sure it will fit before I start all the fiddley bits.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 07, 2021, 05:34:59 PM
On with some of the little bits. First was the bronze bush for the pump tappet turned to 6.05mm, reamed 5mm pressed in and reamed again. Next up was slitting the end or a piece of 5mm silver steel as the start of the pump tappet. This was done with a 1.2mm wide saw in 3 cuts to get a 2mm slot. Finally turning the piece that goes on the end of the pump plunger before going over to milling  mode.
First in milling mode was to cut a 10° angle on a piece of 4mm square silver steel for the stroke adjustment wedge.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 09, 2021, 05:42:32 PM
The wedge was then used to set the angle for the tappet using a piece of 2mm brass in the slot to ensure it was vertical. Next up while in milling mode the 4mm slot for the adjustment wedge was milled in the bracket and the body. It seems to align well enough. The pivot hole in the wedge was then drilled 1.8mm and reamed 2mm.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 10, 2021, 07:25:13 PM
The tappet was then set up to drill and ream the pivot hole. All the silver steel parts were then hardened. The bore of the pump element shrunk so that a 1.95mm pin gauge no longer entered. It was then lapped out to 1.97mm using an Acro needle lap and 1 micron diamond paste.
Title: Re: Two Cylinder Engine
Post by: fumopuc on March 12, 2021, 08:40:18 AM
Hi Roger, always a pleasure again and again to follow your "Swiss Clockwork" model engineering.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 13, 2021, 12:36:15 PM
Thank you Achim  :ThumbsUp: Progress is a bit slow at the moment as there is various work and family things going on. My daughter's first book was published last week and she has two more underway. My employer is building a factory extension here which includes a new ebeam facility. As the accelerator is being supplied by an American firm all communication is by email and teams which is far less efficient than sitting a conference room surrounded by drawings.

Next up I confirmed the required plunger length by putting a 1mm drill in the inlet port and measuring the spacing to the end of the body. The end of a 1.97mm pin gauge was annealed and threaded M2 for the tappet/spring seating. Finally the pin gauge was cut to the calculated length using a thin abrasive disc. It all seemed to fit together and the tappet was flush with the body with a 1mm drill in the inlet. That a gives 1mm stroke to close the inlet port and a maximum of 2mm pumping stroke.

When I have lapped the needle of the diesel injector (on the fuel injection thread) the pieces can all go in the ultrasonic bath. I have been trying to overlap this and the new injector to minimise the number of set up changes.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 13, 2021, 06:37:54 PM
Still following your progress Roger  :ThumbsUp:

Yes - we do not always plan our own time / other projects take the priority ....

Did I just read between the lines that you work @ Cern ?
Title: Re: Two Cylinder Engine
Post by: Roger B on March 15, 2021, 12:32:42 PM
Thank you Per,

I'm not at CERN, I work for a manufacturer of high performance wire and cable at the other end of Switzerland:

https://literature.hubersuhner.com/Technologies/Lowfrequency/EbeamCrosslinking/?gotofirstsearchresult=white%20paper&page=1

Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 15, 2021, 09:52:40 PM
OK - but interesting none the less ....

I had not heard of electric cabling made with voltages between 500KV and 3MV before - definitely NOT a place to FOOL around in the wrong places  :zap:   :o   :insane:

That said - I expect that this is confined to certain areas or even inside equipment + of cause the "Lab Facilities" of the R&D Department.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 18, 2021, 05:45:14 PM
The connections are M5 x 0.5 unions from Regner, the inlet is standard, the delivery valve is modified. The excentric strap is cut from a 25mm wide 2mm brass strip. The hole was bored to 19mm in the lathe and used to check the diameter of the excentric itself. I did not allow enough clearance in the fuel pump excentic and it seized  ::)
Title: Re: Two Cylinder Engine
Post by: Roger B on March 18, 2021, 05:46:17 PM
Due to the 8 picture limit
Title: Re: Two Cylinder Engine
Post by: Roger B on March 25, 2021, 08:27:05 PM
The necessary holes were drilled in the excentric strap and the excentric was drilled and tapped M2 for a grub screw. The rest of the strap was finished with hacksawing and filling. I could have made some complicated set ups with the RT but this seemed quicker  :)

Ready for a trial assembly of the pump. I still need to make an injection inlet manifold.
Title: Re: Two Cylinder Engine
Post by: Roger B on March 29, 2021, 07:43:55 PM
The excentric fitted and aligned with the pump. It all seemed to work together when turned with starter  :)  Next step was to mill a cut out in the timing gear cover.

https://www.youtube.com/watch?v=M9jwPD-DGMI
Title: Re: Two Cylinder Engine
Post by: Roger B on April 04, 2021, 01:05:36 PM
Next up is the induction pipe and slide throttle. The slide throttle is a reduced size version of the one on the horizontal engine and the induction pipe is made in a similar way. The angled pipe was supported with a piece of 5mm rod to stop it collapsing in the vice. Rather than use a flange to hold the injector I decided to make clamp based on the design George Britnell used for his pipe clamps. The initial boss was made of stainless steel in the hope of having a stronger thread but it wouldn't wet with the silver solder so I made a replacement from 3mm brass rod. As before I used a centre drill to open up the hole into the main bore to avoid it cutting into the side of the tube. The bush was then split with a razor saw.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on April 04, 2021, 08:49:13 PM
If it wasn't for the "missing throttle valve" - I would say that you have moved your inlet + injector design forward a few decades - but as usual, it might just be me missing a few pointers  ;D
Title: Re: Two Cylinder Engine
Post by: Roger B on April 05, 2021, 04:45:16 PM
Thank you Per  :) I am learning a lot through all these fuel injection experiments. Nothing actually broke on  the diesel in the last trials  ::)

On with missing throttle. The various parts of the body were milled to size and the slide was taken down to a fairly precise 8.0mm. The slot was then cut in the body with an 8mm endmill to 2.05mm deep giving an easy running fit. The port (is that the right word??) was drilled 5mm and recessed 6mm for the induction pipe.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on April 05, 2021, 09:25:03 PM
That should do it.

On my big bike I see a few mm. from the throttle valve to the injector. I think that is done, so you get the maximum amount off turbulence to help mix the fuel and air ....
The injector is located closest to where the biggest amount of air pases the throttle when not fully open.

Notice the closeness and the four Laser drilled holes in the pic.
Title: Re: Two Cylinder Engine
Post by: Roger B on April 07, 2021, 07:29:07 PM
Fuel injector and throttle positions are completely variable. Older F1 injected into the trumpet before the throttle. Road cars will inject onto the inlet valve after the throttle. Too many things to learn  :thinking:  ::)

Lots more holes to drill and tap, but unfortunately the hole in the end of the slide drifted and the slide had to be remade  :( All looks ok now just the full throttle stop to turn up.

Dave just needs to make 12 for the 917 engine  :stir:  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on April 10, 2021, 03:41:46 PM
The full throttle stop rod was turned from 1.5mm silver steel and threaded M1.4 at both ends. I turned up some more M1.4 nuts from 2mm brass hex. The idling stop is an M1.4 cap head.

The manifold assembly was then fitted to the engine to sort out the linkages. I will initially need separate controls for the throttle and pump stoke so I can work out a suitable relationship for different speeds and loads.
Title: Re: Two Cylinder Engine
Post by: Roger B on April 17, 2021, 03:12:33 PM
I started with a bracket for the throttle control lever. It is designed to allow a face cam to be fitted to adjust the pump stroke as well if required. The levers were then cut from 3mm aluminium.
Title: Re: Two Cylinder Engine
Post by: Roger B on April 17, 2021, 03:17:08 PM
I didn't have suitable die holder to thread the pivot shafts M3 so I concocted one from an Apex die holder and one of the adaptors from my big tailstock die holder. I do need to design something better for the Proxxon.

The throttle lever spindle is held in the bracket with a grub screw, but the bracket is intended to be used as a bearing in the final system.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 01, 2021, 11:16:52 AM
On with the linkages. The stroke adjuster link is tapped one end to allow for the offset connection to the adjuster wedge. The throttle linkage is two shortened M2 model aircraft joints.

Next up clean it all up and assemble. Just a couple of pipes to make  :)
Title: Re: Two Cylinder Engine
Post by: Roger B on May 02, 2021, 03:54:55 PM
I tried the stroke adjustment linkage with the starter. I will need more friction to keep the position and at minimum stroke the wedge 'toggles' out and jams. I will have to make a support so the link cannot drop too far.

https://www.youtube.com/watch?v=ye9QWGaT25E

The piping was finished and installed. The injector pipe is soft soldered as the pressures should be somewhat lower.

The timing cover hit the injection pump excentric pivot so it will need to be milled out a little more.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 09, 2021, 07:59:50 AM
I milled a cutout in the timing cover and assembled it ready for a quick trial. Not very successful  :( there was a fuel leak from around the delivery valve. I removed the valve and the end was crushed so the ball was trapped. I had obviously got something wrong.

I checked the measurements in the top of the pump element and made a new delivery valve, increasing the parallel section from 0.5mm to 1.5mm. I then made a support for the end of the stroke wedge from 0.3mm phosphor bronze.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 09, 2021, 08:04:44 AM
Time for another unsuccessful trial  ::)

It started raced away and the wedge flipped out upwards  ::) This control system was fine with a horizontal pump where gravity kept the wedge in place but it needs some more work in this configuration  :headscratch:

There was also still a fuel puddle on top of the pump but I think this is coming round the pump element. I need to check the O rings are undamaged and are suitable for Alkylate fuel (they are not suitable for alcohol but are fine with diesel).
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on May 09, 2021, 09:58:18 PM
I'm still impressed with your persistence - can we increase the scale / grade  :thinking:
.... but there is probably only one result that will satisfy you - and that won't be medals etc.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 24, 2021, 02:09:06 PM
Thank you Per  :ThumbsUp:

I dismantled the injection pump and the top O ring had a little bit cut out by a sharp edge on the inlet port in the body  ::) I have tried to smooth it with a rifler file but access is not easy. I now need to work out a suitable guide for the metering wedge  :thinking:
Title: Re: Two Cylinder Engine
Post by: Roger B on May 27, 2021, 07:41:14 PM
A little bit more playing. The support for the wedge that I tried is obviously not the answer  :( I think a couple of solid pins will be better. I also soaked an O ring in alkylate fuel for 30mins and saw no swelling or shrinkage so I think that the leakage was due to the damage.

https://www.youtube.com/watch?v=6CPan6h29WM

https://www.youtube.com/watch?v=zmzB46wCW9Q


Title: Re: Two Cylinder Engine
Post by: Roger B on June 03, 2021, 05:29:42 PM
I am trying a new design of restraint with stop pins above and below the arm. The 10mm square blank was faced off in the ER25 chuck as that was on the lathe at the time.

It seems to work so now I need to tighten everything and fit some locknuts ready for the next trial  :)

https://www.youtube.com/watch?v=29vGQnIjIII

Title: Re: Two Cylinder Engine
Post by: 90LX_Notch on June 04, 2021, 01:50:10 AM
I’m still following along Roger. Great stuff, keep going.

-Bob
Title: Re: Two Cylinder Engine
Post by: Roger B on June 04, 2021, 06:32:27 PM
Thank you Bob  :) I often feel like I am the strange kid doing his own thing in the corner, but in a way that is my life  ::)

The delivery valve is leaking under fuel pump pressure which I think may be a problem of the hardened pump element, there seem to be similar problems with the diesel. Maybe I will try an unhardened silver steel version. The earlier mild steel pumps did not have this problem  :thinking:

I gave it a try anyway. It did run but the stroke control system is still not good, more thinking required  :headscratch: In all the excitement I didn't notice that it was running out of (leaking out) fuel when I went to rev it up  :facepalm:

https://www.youtube.com/watch?v=hqURL3ND1FM

https://www.youtube.com/watch?v=Y9HwO-Sr8q0



Title: Re: Two Cylinder Engine
Post by: Admiral_dk on June 04, 2021, 09:51:01 PM
I'm not completely sure that you are the strange one out in the corner Roger - but I will admit that you have taken on one of the hardest projects in the model world, and as you have mentioned before -these are prototypes to get a working concept -> the appearance do not matter .... and most other people would have given up long time ago  :praise2:
Title: Re: Two Cylinder Engine
Post by: Nobby Sideways on June 07, 2021, 05:40:02 PM
What an incredible build, it's taken me a while to get up to date!
Title: Re: Two Cylinder Engine
Post by: Don1966 on June 08, 2021, 04:56:09 AM
 :Love:……


 :drinking-41:
Don
Title: Re: Two Cylinder Engine
Post by: Roger B on June 08, 2021, 05:14:43 PM
Thank you all for your interest and support  :ThumbsUp:  :wine1:

I have been looking at the various problems and have some more things to try:

The leak past the pump element is due to the inlet port in the body being ~1mm too high and too deep so that the cone on the end of the tapping drill has broken through. This makes a fine O ring slicing cutting edge and also exposes the O ring. Solution; make a new body.

The leaking delivery valve can hopefully be fixed by lapping the flat part of the seating.

I think that the inertia of the long brass stroke adjuster rod is part of the problem. I will try a new linkage with a short light arm as on the horizontal engine.

As this is general fuel injection stuff I will post it on the fuel injection thread:

https://www.modelenginemaker.com/index.php/topic,4906.315.html

Title: Re: Two Cylinder Engine
Post by: Roger B on June 29, 2021, 06:59:26 PM
Some of the injection problems were, hopefully, solved on the fuel injection thread. The new injection pump body was fitted and I started on the new stroke adjuster linkage. The short link was roughed out on my Proxxon  circular saw. Roughed out is not quite appropriate, one end was 4.01mm the other end was 4.06mm. The other pieces were cut with the band saw and filed to size.

There was a fuel leak from the supply pump so I dismantled it to check the membrane. It seemed ok so I tightened the clamp plates a little.

Finally a trial assembly to confirm the sizes for the pins and spacers.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 02, 2021, 06:53:32 PM
The forces from the wedge are quite high so I added an additional friction disc to the control arm. As the Hobbymat was in lathe mode I turned the new pivot pin for the wedge on it. Not as easy as on the little Proxxon  :(  I assembled the linkage and had a short trial run. Although I was running out of hands it seems that the stroke wedge has to be almost totally withdrawn to get a sensible mixture  :headscratch: I think I will need to reduce the excentric stroke from 3 to 2 mm and possibly raise the pump a little to get a sensible working range.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 03, 2021, 05:26:26 PM
A bit more playing/thinking about this one  :thinking:  The 25cc horizontal engine ran with an injection pump stroke around 0.5mm. As this is 6cc per cylinder it will require a stroke of around 0.12mm. This is consistent with the position of the wedge, it also means that a 10° wedge is far to coarse, less than 1mm of movement of the wedge will adjust by more than the total stroke. This results in it being rather touchy to get to run. I now have a new task list:

-Make new shorter stroke excentrics for the feed pump and injection pump.

-Resolve the fuel leak around the pull rod of the feed pump. The bigger version had no problems but I scaled the clamping pieces.

-Make a shallower angle adjusting wedge, maybe 4°

I also noted that the injection pump excentric strap is already ~0.2mm oval  ::)

The first video clip shows what happens if the tripod leg is in contact with the engine bench, quite surreal  :)

https://www.youtube.com/watch?v=tTEcvJ87pdo

https://www.youtube.com/watch?v=tJECoGtBc6c
Title: Re: Two Cylinder Engine
Post by: Roger B on July 07, 2021, 07:56:40 PM
The excentrics were offset in the 4 jaw chuck and turned to size. I then moved to milling mode to cut the 4° wedge. The excentrics and the wedge were then drilled, tapped and reamed as appropriate.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 07, 2021, 08:03:01 PM
Next up was the tappet. This was slotted 2mm in three passes with a 1.2mm slitting saw. The pivot hole was drilled and reamed in the same setup to ensure it was perpendicular to the slot. It was then set to 4° using the wedge as a guide, milled to length, hardened and polished along with the wedge.

Next step was to refit the feed pump, minimising the stroke to minimise the stretch on the diaphragm.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 28, 2021, 06:59:39 PM
The fuel feed pump still leaked so I made some new 5mm clamping nuts instead of the 4mm hex ones. The inner one was fixed to the rod with Loctite and I drilled a couple of 1mm holes in the outer one so it could be tightened with my circlip pliers. I also decided to make a new diaphragm as the original was showing some signs of distortion and damage.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 28, 2021, 07:06:49 PM
The pump was reassembled and reinstalled. The next trial was much better, no fuel leaks and fairly consistent running (it would also be easier with three hands  ::) )  :) I need to move the injection pump up a little as the wedge is right at the end of it's travel. More measurements suggest the working stroke is less than 0.2mm which matches the theory. Maybe I need to look at a 1.5mm bore injection pump   :headscratch: Overall Happy with this  :wine1:

https://www.youtube.com/watch?v=nWIY3J_x7Wk
Title: Re: Two Cylinder Engine
Post by: propforward on July 28, 2021, 08:35:49 PM
Looks like a great result to me Roger. Great work all round.

I quite enjoyed the video where the tripod leg was touching the bench. Felt like I was going into a time warp or something.
Title: Re: Two Cylinder Engine
Post by: Dave Otto on July 28, 2021, 10:06:06 PM
Nice! Sounds great and nice throttle response too.  :ThumbsUp:

Dave
Title: Re: Two Cylinder Engine
Post by: MJM460 on July 29, 2021, 12:41:17 PM
Congratulations Roger.  A great result for your patience.  Really amazing work. 

Would it be better to make a wider wedge than lift the pump?

MJM460.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 30, 2021, 08:36:23 PM
Thank you both  :ThumbsUp:

MJM, the pump is mounted on slotted holes so moving it is no problem. As I found with the horizontal engine once you get all the air out of the system the pump stroke is reduced.

Further analysis showed that:

1 The rod ends I was using to operate the slide throttle were limiting the movement.

2 The idle stop screw had fallen out and the nuts on the opening stop had also come loose.

I trimmed a little off the rod ends and got a lower idling speed but there is more to be done  ::)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 31, 2021, 06:43:20 PM
Great to see it running again and with a nice throttle response  :cheers:
Title: Re: Two Cylinder Engine
Post by: Vixen on July 31, 2021, 06:47:30 PM
Nice work Roger  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Mike
Title: Re: Two Cylinder Engine
Post by: Roger B on August 02, 2021, 05:34:14 PM
Thank you both  :)

It is interesting that this engine seems to respond much the same as the 25cc horizontal in that there is very little need to adjust the injection pump stroke. Maybe load tests will require more  :headscratch:
Title: Re: Two Cylinder Engine
Post by: Roger B on August 19, 2021, 06:57:05 PM
Having played a bit more I will probably have to move the stroke adjuster less than 1 mm between idle and full load. I have an idea about using a sector cam for this, however to get everything to fit I needed to shorten the inlet manifold. The throttle lever an the cam will be on a cross shaft so the phasing can be altered for fine tuning.
Title: Re: Two Cylinder Engine
Post by: Kim on August 19, 2021, 10:54:22 PM
I just have to say that looks amazingly cool, Roger.
I can't say as I understand any of the intricacies that you're working through, but it looks quite the business!

Kim
Title: Re: Two Cylinder Engine
Post by: bent on August 20, 2021, 06:13:11 PM
Sounds like it is running great Roger.  As for fine tuning the pump stroke, any thoughts about trying to measure exhaust temperatures or other methods to confirm mixture at different throttle positions?
Title: Re: Two Cylinder Engine
Post by: Roger B on August 21, 2021, 07:32:15 PM
Thank you Kim and bent  :ThumbsUp:  :ThumbsUp: I don't think my accuracy of mixture control will support that  ::) I will try and work with the power output from my motor/generator. At the beginning of this experiment I had no idea how much stroke I needed on the fuel pump. I could do some calculations but the losses/leakages were unknown. lots to learn  :thinking:
Title: Re: Two Cylinder Engine
Post by: bent on August 23, 2021, 04:58:28 PM
I can see the difficulty in miniaturizing the diagnostics for a miniature engine, LOL.  A power map (via a linked dc generator?) sounds like a good approach I think.   :popcorn:
Title: Re: Two Cylinder Engine
Post by: Roger B on August 27, 2021, 07:41:53 PM
Slowly continuing with the injection pump control. This is not the final solution but I have to be able to learn the control range required before a final design can be made.

The parts for the metering sector were cut out using my little Proxxon saw. it can cope with 3mm brass or aluminium and around 1mm steel. I spent some time wondering how to keep the bushes and the arms concentric when silver soldering them together  :headscratch: I remembered someone (Crubey, Kim ??) using brass pins to keep things in place as they would just melt into the join and realised that if I put a short length of 3mm brass tubing in the holes and the soldered them together I could bore back out to 3mm and all would be good  :)

The ends were rounded off with filling buttons, often quicker than setting up the RT  ;)
Title: Re: Two Cylinder Engine
Post by: Roger B on August 27, 2021, 07:48:57 PM
The sector for the stroke adjusting sector is soft soldered in place as I am assuming it will be replaced as I learn more  ::) The curves were cut using the small Proxxon RT being turned by hand. This was on the limit of practical and the next version will be done clamped to the bigger geared RT on the Hobbymat. You can see where the cutter was pulling the sector out of the chuck  :(  :toilet_claw: It will work for the trials but is not how it should be.
Title: Re: Two Cylinder Engine
Post by: Roger B on August 29, 2021, 03:21:26 PM
After looking at a few possible milling setups I decided to file the ramp on the sector. The system was assembled and seemed to work as planned although the slope of the ramp will have to be determined by trials.

I then tried to have a quick running trial  :toilet_claw:  I couldn't get the injection system to prime properly, sometimes I would get a brief burst and then nothing  ::) After some playing I decided to go right through the system checking everything. I had reduced the stroke of both pumps so that was a first thing to check. The output of the fuel feed pump was healthy and of sufficient pressure. It would hold over 1 bar for at least a minute. The pressure needs to be at least 0.8 bar to stop the fuel vaporising on the suction stroke of the injection pump.
Next I stripped down the injection pump. The plunger was still 1.97mm. A 1.97mm plug gauge would go through a 1.98mm gauge would barely enter so no obvious problems there. I put it all back together and had a major fuel leak from the bottom of the injection pump  :(  :(
It was difficult to determine if the leak was past the plunger (why? it measured ok) or past the element O ring (no sign of damage)  :headscratch: I put the 1.97mm plug gauge in the bore and angled the body downwards, the idea being that if the leakage was from the bore it would flow down the plug gauge  and if it was past the O ring it would flow out of the body.
It was past the O ring so I stripped the pump down again and replaced both O rings although I couldn't see any difference between the new and the old  :thinking:  Memo to self: always replace the O rings  :facepalm2:

This time I also checked the plunger height for start of injection and used this to readjust the pump height.

It runs again  :cartwheel:  Now I can start trying to adjust the position and possibly the ramp on the sector.
Title: Re: Two Cylinder Engine
Post by: Kim on August 29, 2021, 05:00:12 PM
Sorry you had all that trouble, Roger.  But that was sure a good bit of detective work to figure out where the problem was.  Glad you finally got it sorted!  Now you can move forward.

Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on August 29, 2021, 06:34:20 PM
Thank you Kim  :)

This engine is stretching me even farther. The injection pump stroke is between 0.1 and 0.2mm (4 to 8 thou). I think I need to look at a smaller plunger, 1.5mm should be possible. The vibration from the 360° (parallel) twin is also a problem  ::) It caused excessive fuel surge in the CD carb and as you can see in this video the battery is wandering around and the camera is having focus problems (I made sure the tripod was clear of the engine bench this time) :(

So far I think that the 180° version with the CD carb was/is the best.

https://www.youtube.com/watch?v=veUohJi7GjA
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on August 29, 2021, 10:33:56 PM
It's getting much closer now  :ThumbsUp:
And the vibration problem is obvious - like old British Parallel Twins  ;)

The biggest contributor is usually the weight of the piston, followed by the Rod.
If you look at the pistons in modern IC engines - they are usually just a small percentage of the weight from our youth and the same goes for the Rods ....
Title: Re: Two Cylinder Engine
Post by: Roger B on August 30, 2021, 06:59:24 PM
Thank you Per  :)

It is still proving difficult. It stopped and wouldn't start again, the cause this time being that the soft soldered joint on the union above the injection pump had cracked, probably due to the vibration. I resoldered it and then had the fun of trying to prime the system again  ::) The 25cc horizontal is relatively easy to prime as there is more than 4 times the pump stroke/volume available  :thinking: I am also not sure about the inertia effects of the stroke adjusting wedge, maybe it's a dead end  :headscratch:

I see two ways to go:

1) Make a smaller bore injection pump. I already have reamers and laps for 1.5mm, but M1.5 is not a standard thread for the end fixing. 1.4mm will halve the area and double the stroke. I have M1.4 taps and dies and I think that I have a 1.4mm reamer for the mushroom injectors but would have to get some suitable sized pin gauges for the plungers.

2) Go to a helix plunger design. All the commercial mechanical petrol injection systems seemed to have taken this route. Variable stroke seem to be only used in low speed hot bulb engines. I am fairly happy with grinding the helix in a 2mm plunger. Maybe I could do it in a 1.4mm plunger.

As ever lots more to learn  :D  :wine1:
Title: Re: Two Cylinder Engine
Post by: Roger B on September 01, 2021, 06:47:06 PM
I had a couple of more goes with the twin. It will run well then just stops. I captured a picture of an air bubble in the fuel feed pipe. That is bigger than the volume of fuel injected so if it gets into the injection pump it all stops and has to be bled again  :(  :(

I was beginning to doubt some of this fuel injection stuff and took the 25cc engine of the shelf to confirm it would still run (I think it last ran for the virtual model engine show last year  :headscratch:) It took a few minutes to prime the system, one of the longest parts was getting the injector clamp nuts back on  ::)

Once it was primed it started and ran like before. It would happily idle at 1000-1200 rpm without altering the injection pump stroke from last time and would rev up without problems. There are two significant differences;

-It is four times the size of the twin.

-The feed pump runs continuously and there is a pressure relief valve which may help to keep air bubbles out of the system.

https://www.youtube.com/watch?v=BqgAJj7HfOQ

Title: Re: Two Cylinder Engine
Post by: Roger B on October 31, 2021, 05:29:05 PM
I improved the delivery valve seating and the injector needle and had some more successful runs. The pump stroke-throttle linkage needs further development. As you can see from the bubbles in the fuel lines I let it run out of fuel again  ::)

https://www.youtube.com/watch?v=tYhOF7OrTD4

Title: Re: Two Cylinder Engine
Post by: Admiral_dk on October 31, 2021, 09:58:30 PM
It sounds like it's running very evenly + nice throttle control  :ThumbsUp:

Any idea what the idle and max. RPM's are ?
Title: Re: Two Cylinder Engine
Post by: Roger B on November 02, 2021, 05:32:57 PM
Thank you Per  :)

I would guess 2000-6000 rpm but it ran out of fuel before I checked. I think I need to redesign the fuel pump with helix/rack control to reduce the inertia and may need to reduce the plunger from 2mm to 1.5mm but that requires several other re designs of the rest of the system  ::)
Title: Re: Two Cylinder Engine
Post by: Roger B on January 30, 2022, 08:26:00 PM
I have nearly finished the new injection pump on the injection thread:

https://www.modelenginemaker.com/index.php/topic,10603.0.html

So I now need to make a new bracket to fit it to the engine. When I started to remove the existing pump I found that the excentric strap had worn away almost 1 mm in at most 20 mins running  :headscratch: the similar strap on the horizontal engine has run far longer with no significant wear. Thinking back this may be due to the fuel leaks from the injection pump (mostly the O rings) washing all the oil from the excentric  ::) the excentric itself is unworn.
 
The new bracket is made from an offcut of 20mm square aluminium. The blank was milled to size and then the bulk was removed by drilling and sawing (much quicker that milling  :) ) next I need to cut the adjustment slots using the little Proxxon mill .
Title: Re: Two Cylinder Engine
Post by: Roger B on February 05, 2022, 07:49:42 AM
The slots were milled in the bracket and then the fit was checked on the engine. The corners need to be radiused to clear the timing gears.
A new eccentric strap was roughed out of 2mm brass using the table saw and the pivot pin was drilled and reamed 2mm. It will be finished when the Hobbymat is back in lathe mode.
Next up are the pump tappets. A length of 5mm silver steel was faced on both ends in the Proxxon lathe (having a second lathe is always good  :)  ) and mounted in the mill. One end was slotted 2mm for the eccentric strap and the other end was opened out to 2.5mm for the diesel pump tappet roller. The pivot holes were drilled and reamed in the same set up to ensure they are perpendicular to the slots.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 08, 2022, 05:45:17 PM
Back in lathe mode the eccentric strap was centred in the 4 jaw chuck and bored out to 19mm. It was then mounted on the Proxxon RT and the outside was milled to 25mm diameter. Feeding clockwise for the cut was fine but the last part of the return tended to snatch as it was climb milling  ::)

The pump bracket was rounded off with some filing buttons and then trial assembled to confirm the length of the tappet.
Title: Re: Two Cylinder Engine
Post by: Roger B on February 15, 2022, 05:13:16 PM
Some success and some problems  ::) The delivery valve was finished as before with the hole for the 3mm ball increased to 3.2mm. The tappet was hardened together with the tappets from the diesel and the pump parts were cleaned in the ultrasonic bath.

The system was assembled and after a lot of problems with fuel leaks from the pump element O rings I got a brief but good run. There is still significant fuel dripping from the pump  :(

https://www.youtube.com/watch?v=59L-XjprMic

I stripped the pump down yet again and noted the running position of the helix for reassembly. Why won't the O rings seal properly? The pressure is around 1 Bar, the clearances are according to the guidelines with a 1mm O ring compressed to 0.7 mm. Viton should be OK with petrol (not with alcohol  ::) ). Maybe the surface finish of the grooves in the element is not good enough after hardening  :headscratch:
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on February 15, 2022, 10:52:51 PM
Very nice run - smooth and even  :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Minh Thanh on February 16, 2022, 11:18:53 AM
 Hi Roger !
Your engine had run
Congratulation !
I haven't made a piston  and pump like yours so I can't say anything
I hope you will find a way to make the pump better.
Title: Re: Two Cylinder Engine
Post by: RReid on February 16, 2022, 03:05:50 PM
Quote
Maybe the surface finish of the grooves in the element is not good enough after hardening  :headscratch:
Can you get into those o-ring grooves with a small Dremel style rotary brush? Perhaps some scale or other gunge got left behind after heating that the ultrasonic failed to dislodge?
Title: Re: Two Cylinder Engine
Post by: Roger B on March 05, 2022, 06:44:55 AM
Thank you for your support and interest  :)

I have tried a few more things still without success. The first step was to mill a piece of brass to the width of the O ring groove and then use some 5 micron diamond paste to lap/polish the base and sides of the groove.
Next I purchased some nitrile (NBR) O rings to try instead of the Viton ones both in the planned size of 6 x 1mm and also 6.5 x 1mm. None of this was successful and although the engine would run there was still a major fuel leak :(

I took the helix plunger out of the pump and replaced it with a 1.97mm pin gauge to block the inlet port. I could then pressurise the input with compressed air and also with fuel. Sometimes there was an obvious air leak and sometimes it would hold 4 bar air pressure. There was also still a tendency to leak fuel, although much less.

The recommended groove depth for a 1mm O ring is 0.7 mm so the ring should be compressed by 0.3mm.  A piece of 8mm silver steel had detectable play in the pump body so I made some simple plug gauges from M5 cap head screws. The 8.20 and 8.15 mm ones would not enter. The 8.10 mm just started so I filed the sides down to make a proper ‘no go’ gauge. I would judge the bore in the body to be a little under 8.10 mm but I will make another plug gauge to confirm this. Although it was reamed 8 mm h7 the 8 mm endmill used to flatten the end of the bore may have removed a little from the bore.

Title: Re: Two Cylinder Engine
Post by: Roger B on March 05, 2022, 06:54:28 AM
I then tried to determine the diameter over the O rings. I judge the one at the delivery valve end to be 8.25 mm and the one at the rack end to be 8.20 mm. This gives a compression of the O ring of less than 0.1 mm instead of the recommended 0.3 mm  ::) I think that under constant pressure the O rings could build up a seal as shown by holding 4 bar but under the fluctuating pressure in normal operation they had no chance to seal.

The next step, make a new element with shallower grooves. The original had a diameter of 6.4 mm for the O ring seat. I decided to increase this to 6.7 mm. The grooves were cut with my new Aplitec parting/grooving tool. Before I did too much work on the bore I fitted some O rings and tried it in the body. The 6.5 x 1 mm rings had some slivers shaved off and it looks like the inlet port nibbled a bit from a 6.0 x 1 mm. I need to look at smoothing some of the transitions.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 05, 2022, 12:25:12 PM
That will be a bit of a challenge .... figuring a way to make a very small radius on those port openings ....
The R&D Department might have to make a number of test subjects, to find the sweet spot between not enough to protect the o-rings and not too much disruption of timing  :thinking:

Still following with interest and admiration  :cheers:

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on March 05, 2022, 03:24:47 PM
Hi Per, it's not so much of a problem. I only need to smooth the transitions in the pump body where the diameter reduces from 10mm to 8mm and where the 2mm fuel inlet hole feeds through to the pump element. The diameter reduction is chamfered 45° using a large centre drill (hand held) so some work with a couple of rifler files radiused it enough. The fuel inlet was harder to access and impossible to see but I can now assemble the pump body and element without obvious damage to the O rings  :)

The rest of the pump element was finished much as before, drill 1.85mm, ream 1.95mm and check that a 1.96mm pin gauge goes and a 1.97mm pin gauge does not go. The delivery valve end is finished with a 4.5mm end mill and then taped M5 x 0.5. Unfortunately I broke a 0.8mm centre drill off in the hole when starting to drill the inlet port but could just turn the element 180° and start again. The locating flat was cut using my homemade fine feed for the drill rather than moving the set up to the mill.

The element was then hardened and after some external cleaning and polishing is ready for lapping the bore and delivery valve seat.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 05, 2022, 05:08:48 PM
Quote
I can now assemble the pump body and element without obvious damage to the O rings  :)

Great that you got past that one so easily  :)  and nice to see more parts made  :ThumbsUp:

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on March 06, 2022, 10:27:46 AM
The bore and delivery valve seat were lapped as before starting the bore with 5 micron diamond paste and finishing with 1 micron paste so a 1.97 mm pin gauge just passes through. After a clean up the pump was re assembled and fitted to the engine. There is no fuel leak from the top of the pump and a few drops from the bottom which I think are what is leaking past the plunger. I do have some ideas for additional seals if required. I am quite sure that the plunger on the horizontal engine also leaks a little but the fuel doesn't go anywhere that causes a problem.

I can now do some trials to relate the rack position to fuel output to set the 'no fuel' position for the rack. With the spark plugs removed the motor generator turns the engine at around 3500 rpm which is a sensible speed for tests.
Title: Re: Two Cylinder Engine
Post by: RReid on March 06, 2022, 03:09:16 PM
Glad you were able to track down and fix the main source of the leak. Maddening as they are, your (outwardly) calm step-wise approach is the only way to deal with leaks, isn't it?  :wine1:
Title: Re: Two Cylinder Engine
Post by: Roger B on March 07, 2022, 05:50:41 PM
Thank you Ron  :ThumbsUp:

I made a series of output tests with different rack positions. The output was fairly linear but I could not reach the no fuel position so I had to step the rack along 1 tooth.

I then had a trial run. It responded well but there was still enough fuel leaking to wash the lubricant away from the excentric. The gunge in the picture war after the ~30second run below  ::) a mixture of brass and oil.

https://www.youtube.com/watch?v=b6ak_3CKurg
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on March 07, 2022, 07:03:03 PM
That is a shame, as the Engine is running very well and sounds as if you got the mixture close to perfection.

I can't tell from the video nor the picture where exactly the source for the metal nor the oil is - but it looks almost like it's the gears that throws the pattern ....

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on March 08, 2022, 08:05:53 PM
Hi Per,

As far as I can tell the fuel leaking past the pump plunger is flowing past the tappet and then onto the pump excentric which is washing the lubricant away and abrading the brass excentric strap. The resultant slurry is then spread around by the timing gears. The excentric strap with the previous wedge stroke adjustment pump had worn by nearly 1 mm probably due to fuel leakage that I had not noticed in all the other excitement of trying to keep the engine running.

If the horizontal injection pump on the horizontal engine leaks it doesn't drip on anything important so I probable haven't noticed  ::)

I am going to move the fuel injection problems and thoughts back to the fuel injection thread for a while. The metering concept works, but there are a lot of details to resolve  :thinking:
Title: Re: Two Cylinder Engine
Post by: Roger B on April 04, 2022, 05:24:48 PM
Having resolved the fuel pump leakage problems and achieved this run (same video clip as the fuel injection thread) I can now look at a suitable control linkage for the fuel rack. Total movement required seems to be around 2mm. First I opened out the clearance for the fuel pump in the timing gear cover to avoid feeding bits of my fingers into the gears.

https://www.youtube.com/watch?v=I96e8rIJkbs


Title: Re: Two Cylinder Engine
Post by: Rick Doane on April 04, 2022, 10:51:37 PM
That sounded like a pretty good throttle response here in Tennessee!  Good job :praise2:
Title: Re: Two Cylinder Engine
Post by: Roger B on May 01, 2022, 09:22:22 AM
Thank you Rick  :)

The injection system on the horizontal engine seems to have found the sweet spot where the speed related leakage past the plunger compensates for the required fuel increase with speed/load.

This engine requires some form of mixture control. The leakage past the helix plunger at idling speed means the rack needs to be set to deliver more fuel at low speed than at high speed. I am hoping I can compensate for this with a suitable shaped sector cam controlled by the throttle position. If this doesn't work I either need to look at some form of electronic control with speed and throttle position sensors or a different design of stroke controlled pump where the leakage path is much longer.

The sector is cut from a piece of 2mm brass. The 8mm boss is silver soldered in place and the metering sector is soft soldered so I can replace it if necessary. Some fairly dodgy setups were used to turn the radiuses but with sharp tools and light cuts all went well. The sector profile will be filed with the shape being found by experiment.
Title: Re: Two Cylinder Engine
Post by: RReid on May 01, 2022, 02:59:28 PM
Quote
Some fairly dodgy setups were used to turn the radiuses but with sharp tools and light cuts all went well.
That's a really interesting set-up using the 3-jaw. Are there any shims between the part and the chuck face for support? As long as it's recognized as dodgy and the weaknesses are considered and accounted for, I'm all for whatever it takes to get the job done. The result speaks for itself. :ThumbsUp: :cheers:
Title: Re: Two Cylinder Engine
Post by: Roger B on May 02, 2022, 11:16:54 AM
Hi Ron,

I made a similar sector for a different design of injection pump and tried to mill the profile on a Rotary Table. The thrust due to the helix of the mill made it difficult to hold.
In this case the outside was turned just holding the 8mm boss in the three jaw chuck. It was pushed against the chuck jaws as they were tightened.
The inside (photo 1051) was turned with the sector held on a tapered mandrel. Again it was pushed against the chuck jaws.
Both were turned at around 1000rpm and 0.1mm Depth of cut.
Title: Re: Two Cylinder Engine
Post by: RReid on May 02, 2022, 02:56:41 PM
Thanks for the explanation, Roger. I had the mistaken impression that the sector itself was clamped by the jaws in an unusual way.
Title: Re: Two Cylinder Engine
Post by: Roger B on May 08, 2022, 05:54:38 PM
It's getting there  :)

I had to drill and tap a new grub screw hole in the sector as the original was inaccessible. Some trials suggested a suitable profile which I filed on the sector and then added a return spring to the rack. The first trials were good so I set up a quick load trial. The load is a resistance back with a maximum load of 1 ohm. This means I just need to measure the current and square it to get the output in Watts. The meter has a full scale of 15A. I was able to run up to 9A so 81W and could both accelerate under load and add and remove the load without stalling  :) The video is a bit messy but hopefully you can see what is going on  ::)

https://www.youtube.com/watch?v=7RVp_fwLo0o
Title: Re: Two Cylinder Engine
Post by: Kim on May 08, 2022, 08:54:57 PM
That is very cool, Roger!  :ThumbsUp: :popcorn: :popcorn:

81W seems pretty respectable for a little fuel-injected engine! :)

Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on May 10, 2022, 08:12:26 PM
Thank you  :) I think the real output is somewhat higher but I can't measure it at this time  :headscratch:
Title: Re: Two Cylinder Engine
Post by: Roger B on June 05, 2022, 05:33:22 PM
As the MFA motor was not capable of fully loading the engine I found another motor in my 'rescue' collection that will hopefully have a more suitable characteristic. Some quick trials showed that this was not quite capable of starting the engine on 12V and due to the larger diameter I decided to mount it on the end of the existing MFA motor and hanging off the end of the baseboard. The coupling I have has a 1/4" bore both ends which suits the MFA motor. The new motor has a 6mm shaft so I needed to bore and sleeve the coupling. With some thought I bored and reamed it out to 11.5 mm as I had a suitable reamer and I can then turn a piece of 12mm stock to suit. I drilled the grub screw hole in the sleeve to 6mm as clearance so both parts would be held by one grub screw and I didn't need Loctite (experience says this will be changed more than once  ::) ). I now see why Jason choose 24mm bore as he can use 25mm stock for the pistons rather than turning 30mm down to 25mm.
The mounting plate was clamped to the face plate ( Dodgy Set Ups are Us) drilled 13.5 mm and then bored 28mm to suit the motor.
Title: Re: Two Cylinder Engine
Post by: Kim on June 05, 2022, 07:53:33 PM
Silly question, but what does MFA mean here?

Thanks,
Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on June 05, 2022, 08:39:39 PM
Kim, not a silly question, just a European one. MFA is a supplier of model drills, motors, gearboxes, etc.

https://www.mfacomo.com/index.html

I have tried to use available motors as my loads rather than random things I have in my rescue box so others can hopefully follow/copy.
Title: Re: Two Cylinder Engine
Post by: Kim on June 05, 2022, 08:54:24 PM
Ah, Thanks Roger!  That clears it up for me. :)

Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on June 12, 2022, 01:48:41 PM
The fixing holes were drilled in the plate and the support arms were drilled and tapped M5. It was all then assembled and set up for a quick test.  The characteristics of this motor/generator are completely different. I was getting around 60V at full speed without a load and around 30V at 3A on load but then the engine started spluttering and stalling, it would idle but not rev. I tried adjusting the fuel rack setting but without success  ::) Removing the timing gear cover showed the problem, lots of brass/oil emulsion and a completely worn excentric strap  :toilet_claw:
Title: Re: Two Cylinder Engine
Post by: Roger B on June 12, 2022, 02:02:50 PM
Brass was obviously not a suitable strap material for the speed/load requirements of this injection pump. The excentric on the horizontal engine injection pump shows no signs of wear after significant running, but it barely reaches 2000 rpm whereas this one will exceed 8000 rpm.
I decided to try a case hardened steel version together with case hardening the excentric. This was roughed out of 2mm strip with a hacksaw, rounded on the Proxxon mill and cleaned up with some filling. It was bored directly from 6mm by taking shallow radial cuts. I was doubtful about opening it out with a 12mm drill first due to the risk of snatching. I am using the 4 jaw SC chuck as that was on the lathe at the time.
After hardening and cleaning up it seemed to run freely so I reassembled the engine and gave a quick trial. It runs again  :) however I need to readjust the rack/throttle relationship.
Title: Re: Two Cylinder Engine
Post by: crueby on June 12, 2022, 03:47:35 PM
Hi Roger,
Are the two pieces different types of steel? If the same, is there a risk of the two galling together, or does the hardening prevent that issue?
 :popcorn: :popcorn: :popcorn:
Chris
Title: Re: Two Cylinder Engine
Post by: john mills on June 13, 2022, 12:12:27 PM
Hi
I worked in industry on metal working machines as apprentices we were told you don't run similar metals together but wire bending machines were all driven by cam rollers and pins same hardened and ground some nitrided slides were lined with ground stock hardened and ground all sliding faces only one had a free loading bush of aluminium bronze as long as lubrication kept working gave good service if lubrication failed then turning blue and wearing away when they stopped turning.
John
Title: Re: Two Cylinder Engine
Post by: Roger B on June 14, 2022, 09:02:28 AM
I believe that both hardened steel and cast iron don't tend to gall when run together.
The highest loading in a conventional IC engine is the camshaft - cam follower interface. These are almost always surface hardened steels however without adequate lubrication they will rapidly fail. A number of the additives in 'High Performance' motor oils are to help this interface.
Title: Re: Two Cylinder Engine
Post by: Roger B on July 03, 2022, 02:40:32 PM
I'm still battling with this one  ::)  ::) It ran very well and smoothly as can be seen in the various video clips but then started giving all sorts of problems. At first I thought it was the wear in the injection excentric but after having fixed that it still kept misfiring and stopping. I could hear little ticking noises just before it stopped and realised it was tracking in the distributor cap.

I removed the cap and found it full of gunge so I cleaned it and reassembled it. It still wouldn't run well and was sparking in various odd places  :headscratch:

This engine has a 6V coil (because that's what I had) fed via a 7806 6V regulator from the 12V battery. This worked ok on the horizontal engine although I also had problems with the regulator there. I checked the voltage on the coil, 12V with the points open 2.6V with the points closed. The regulator had obviously failed  :(

I replaced the regulator and it seemed to run better but with an odd 'note'. This was due to a crack in the exhaust manifold cause by the vibration  ::) I silver soldered across the crack which hopefully also anneals that area of the manifold.

Finally I was ready to try it powering a little electric car I had made for my children many years ago. The traction batteries were disconnected and the controller was connected to the output of the generator. The engine was started and I cautiously pressed the accelerator. It would move slowly under engine power  :) but the running of the engine became worse and worse. As the lighting in our underground garage is fairly dim I could see the fireworks in the distributor cap so assuming the regulator had failed again I gave up for the moment.

https://www.youtube.com/watch?v=y4ZTvBWlS4s

Back in the workshop a quick measurement showed 12V on the coil again so this time I will do it properly and buy a 12V motorbike coil like I am using on the horizontal engine now.


Title: Re: Two Cylinder Engine
Post by: Kim on July 03, 2022, 03:59:08 PM
Good detective work, Roger.

Bummer about the regulator though... Wonder if the 7806 is getting high-frequency current spikes or something and causing it to fail?  Would the 12V coil help that?  Bigger inductor to filter out the high-frequency spikes maybe?  (he says making it up as he goes along.)

I'm sure you'll get it figured out but it's a struggle, nevertheless.

Kim
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 03, 2022, 06:47:01 PM
I don't really see many standard Regulators that can survive in this application .... (not even all Lab Supplies can).

Serveral reasons (and Kim mentioned some of them) - The Ignition Coils often requires more Current than the god old 7806 (and it's siblings) can supply, they are not happy with high voltages or reverse polarity - some of this can be 'Rectified' with Diodes and Condensators ....

None the Less - Great that you found the reason  :ThumbsUp:   :cheers:

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on July 05, 2022, 11:42:50 AM
Thank you both  :)

The 7806 has been in use for some time on a couple of engines. It has the two small ceramic capacitors between the input to ground and the output to ground as well as a 2200 microfarad 25V electrolytic across the output. This is sufficient to maintain the voltage when the engine is running although it goes into current limit if the engine is stopped with the points closed. Maybe the new ones I have are of lower quality.

I have ordered a 12V coil with the same small 44mm diameter. These are not so easy to find as there was a small window between when motorbikes moved from 6V to 12V before they went for ignition systems without the traditional style coil in a metal can.

The 12V coil can be connected directly to the battery with no need for a regulator  :)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 05, 2022, 10:25:04 PM
Do you have a diode across from the Output to the Input ?
If not, you will damage the 7806 (when you turn Power Off), as it do not like a higher Output Voltage than Input Voltage ...  :zap:
So Anode to Output and Cathode to Input.

I hope you will have a long life with your new Ignition  :cheers:

Per
Title: Re: Two Cylinder Engine
Post by: Brendon M on July 08, 2022, 01:06:23 PM
Roger, will you eventually convert the kid's car to diesel electric? :D
Title: Re: Two Cylinder Engine
Post by: Roger B on July 16, 2022, 05:52:20 PM
Hi Brendon, only as an experiment to confirm that the engine power is sufficient  ;)

Still having fun with this one  ::) You get a few excellent runs with a model engine and then they go off song for a bit while you check and improve everything  :headscratch:

I received a 12V motorbike coil from a German bike spares company. Unfortunately it was 44mm diameter rather than 40mm so I had to make a new fixing ring. I kept the original circuit board and just moved the coil connection to the input as it was used as a junction board for various supplies. This seemed to run better but there was still some arcing in the distributor so I took the cap off and cleaned it again.

There was still significant misfiring, although no obvious arcing, so I checked the plug gaps, 15 thou, and the valve clearances, 6 thou.

https://www.youtube.com/watch?v=XWqidUQrSKw

I then wondered about the fuel system and if the plunger/rack could be sticking as there was no way to lubricate then, not a problem when there are just short runs followed by dismantling for modifications. I decided to drill a 45° 3mm oil hole in the side of the body so I could lubricate the rack gear and plunger.

This required removing the pump body and then the gear and plunger, carefully recording their positions. The hole was started with a 3mm end mill and then finished with a drill. It was all carefully cleaned, reassembled and lubricated. Priming the pump, as ever was a bit of an effort due to the very small volumes compared to the pipe size.

It runs better but still it hasn't got the crispness of earlier trials.

https://www.youtube.com/watch?v=xUeGdfnsgUU
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 16, 2022, 08:00:10 PM
I can't say that this is what is required here (and remeber that it can be Detrimental) .... But in my youth I got a lot faster Throttle respons by adjusting the Ignition Adwance to about 5 degrees earlier than stock  ;D
 But it also makes the Engine run hotter + more load on the Pistons, Conrods and Crank + Bearings ...!!!

Per
Title: Re: Two Cylinder Engine
Post by: Kim on July 16, 2022, 08:34:56 PM
Wow, Roger!  It sounds really good to me!
However, I do hope you get it running to YOUR satisfaction soon. :)

Kim
Title: Re: Two Cylinder Engine
Post by: Roger B on July 18, 2022, 12:51:38 PM
Hi Kim, I just want to get it back to how it was in May.

https://www.youtube.com/watch?v=7RVp_fwLo0o

It was running how I wanted it to and then the performance just dropped away and it wouldn’t rev.

My first diagnosis was wear in the brass injector eccentric so I made a case hardened steel version. With hindsight this could be a problem as the pump plunger would be operating in a different part of the stroke.

Next I found that the 6V regulator feeding the coil had failed and the spark voltage was much to high. Fixing this removed the symptoms of arcing in the distributor but didn’t really improve the running.

I don’t, as yet think that it is a problem with the engine mechanics, both cylinders have compression and grounding either spark plug brings equally bad running.

I need to check the various aspects of the fuel injection system:

Is it injecting on the induction stroke?

Is the fuel delivery pump under pressure when the injection pump  inlet port is open?
 
Is the inlet port fully opening?

At what point in the stroke does the inlet port close and injection commences?  Maybe it is important that the plunger is moving with maximum velocity at this point.

Plenty to think about, but I will play with the diesel for a bit now.
Title: Re: Two Cylinder Engine
Post by: RReid on July 18, 2022, 02:45:00 PM
One thing I'm learning in my own twin build is that vs. a single the population of potential gremlins seems to increase not linearly but exponentially. ;D :shrug:
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 18, 2022, 08:44:49 PM
Earlier this year I learned that some very succesful Fuel Induction Systems, actually don't Inject the Fuel during Induction, but for instance during Combustion, so the cool Fuel hits the Hot Valve. This helps with Cooling the Valve and increases the Fuel Evaporation ...! Others have more than one Fuel Injection Period, during the 720 degrees.
This is of cause an very easy experiment, when you just change som values in a piece of Firmware and quite a bit more complicated in your System ....

I can only agree on your other Considerations, having an Influence on the result.

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on July 21, 2022, 07:18:51 PM
As the next step I decided to raise the injection pump a little to match the wear on the original brass excentric. The slots needed to be milled away to give enough additional movement. This seems to be promising  :) I can move the pump up till the engine barely runs (which is what I think happened in May as the excentric wore away) I can then lower it which improves the running considerably. As I lower it further operation then becomes worse again somewhere is the 'sweet spot'

https://www.youtube.com/watch?v=BaKZGobENqc

I need to try and understand what is happening, but it maybe an additional dwell time for the pump cylinder to refill with fuel  :thinking:  :headscratch:  ::) The plunger is limited in it's travel so the inlet port is just fully open. If I lower the tappet the port remains open for longer and the tappet is travelling faster when it meets the plunger.
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on July 21, 2022, 09:58:11 PM
Even if you can't explain the exact reason, why it made the difference it did - it still sounds and runs better now  :ThumbsUp:  :ThumbsUp:

Per
Title: Re: Two Cylinder Engine
Post by: Roger B on August 06, 2022, 05:29:10 PM
Thank you Per  :)

Another known problem is that there is a tendency for air/fuel vapour to collect at the outlet from the fuel tank. If the air bubble stays there no problem, if it gets to the injection pump the engine will stop and I will have to bleed the system again  :( This could be due to the lower pressure where the fuel is sucked to the top of the tank or could be due to an air leak  :headscratch: I searched for another style tank with a bottom outlet. This has a floating sintered filter but the outlet is around the fuel level.
The first attempt was not successful  ::) The pipe to the sintered filter was not compatible with Alkylate fuel and swelled enormously  :toilet_claw: I replaced it with a piece of my petrol/gasoline compatible pipe, bled the system and all seems ok so far  :)
Maybe time for some more load trials  :thinking:
Title: Re: Two Cylinder Engine
Post by: Roger B on April 09, 2023, 02:33:14 PM
I finally got around to another load trial. This was rather more successful although the generator characteristics are not really suitable. I could drive it with a belt reduction or find another generator with a lower voltage output but at least I have proved the principle.

https://www.youtube.com/watch?v=FGwGoNfH2zk
Title: Re: Two Cylinder Engine
Post by: RReid on April 09, 2023, 02:56:22 PM
Now That's a fun test! Well done, Roger! :ThumbsUp: :ThumbsUp:
Title: Re: Two Cylinder Engine
Post by: Kim on April 09, 2023, 04:58:58 PM
Very cool, Roger!  8)   :popcorn:

Kim
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on April 09, 2023, 05:41:12 PM
OK - that is a new and different take on testing the Engine performance Roger  :ThumbsUp: - but is that fast enough for the Olde Racing driver (You)  ;D  :Lol:

Per        :cheers:
Title: Re: Two Cylinder Engine
Post by: Zephyrin on April 10, 2023, 01:41:19 PM
that's a very sympathetic way of gauging power of your engine, Roger, lot of fun with this test...and impressive results !
Title: Re: Two Cylinder Engine
Post by: Roger B on April 14, 2023, 05:10:35 PM
Thank you all for your interest  :ThumbsUp:  :ThumbsUp:  :wine1:

I knew from steady state measurements that the engine delivered enough power but I didn't now if it was enough to start more that 100kg of me and car moving or if the engine was flexible enough not to just stall. The revs dropped from around 8000 rpm to around 5-6000 (by ear) but it kept going  :)

Per, it was quite fast enough, keeping an eye on the engine, looking where I was going, holding the camera and trying not to rest my elbow on the sparking plug connectors  ::)
Title: Re: Two Cylinder Engine
Post by: Admiral_dk on April 14, 2023, 08:18:08 PM
Quote
Per, it was quite fast enough, keeping an eye on the engine, looking where I was going, holding the camera and trying not to rest my elbow on the sparking plug connectors  ::)

 :lolb:   :lolb:    OK - I didn't think about all those factors .... and they DO add up (especially with age) !

Per          :cheers:
SimplePortal 2.3.5 © 2008-2012, SimplePortal