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.

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 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.

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.

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  :)

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.

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.

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.

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

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.

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:

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.

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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.

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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.