Author Topic: 80CC OHC V8  (Read 17147 times)

Offline Coopertje

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80CC OHC V8
« on: December 03, 2014, 11:46:31 AM »
Inspired by builds on this site (I follow most of them quietly, sorry for that) I have started to put together a V8 in Solid works. It will be

based on the Schillings plans (I have bought them many years ago at www.vth.de), although I do not like the square box looks of that engine. I

will try to get a more detailed and realistic look on this engine, change the water flow through the cylinder block, different valve covers,

electric starter etc. Do not know if this will make the engine “my design”, on the other hand when it is finished it will be a unique one. If

the moderators think it is more appropriate in the “from plans” section please let me know.

My main goals with this project are:

1)   Build a working V8 with a combination of manual as well as CNC machines
2)   Learn to draw and design with Solid Works
3)   Generate G-code of the 3D Solid Works parts with SprutCam V9 CAM software
4)   Make the missing tools / accessories for my machines (have a long to do list here) needed to build this engine

I plan to only use the CNC machines where it is required due to part shape or when I have to make multiple items of the same. The crank will

be a build-up style and all the rotating parts will have ball/needle bearings. Initially it will be a glow-plug engine, in this way I

eliminate the distributer and ignition timing. When it is running well on glow plugs I might convert it to sparkplug and even fuel injection.

Since this is my first multiple cylinder engine I prefer to take things step by step....

Below some pictures of the design as it is today, guess I have about 70% – 80% finished.










The very nice thing about 3D CAD software is that you can really tackle design issues in a very early stage. If you look to the section view

below you will see a collision between conrod and cylinder block. Normally I would see this at assembly time, now it becomes clear before the

first piece of material is cut saving lots of time and frustration in a later stage. There is another error visible in this picture, the left

cylinder bore was off by 0.25mm (see the connection between combustion chamber and cylinder bore).



I had a last opportunity to buy material against trade prices (got it over a friend and the department he is working is sold...). I bought

some lengths of 3mtrs of free cutting steel, aluminium, C45 steel and Stainless steel tubing, all in different sizes.






From the scrap yard I collected some aluminium blocks, one piece of 7075 and some pieces unknown but they have milling marks so it should be

ok for machining. The 7075 will be for the cylinder block.





Although the design is not finished yet, I am eager to start making some chips! It will be a very long project and most likely parallel to

others since I cannot focus on a single project for more then 3 to 4 months.... Hope that positing the build here will help me keeping

motivated to bring this project to a proper end....

Suggestions / design idea's etc are more then welcome!

Regards Jeroen


Online steamer

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Re: 80CC OHC V8
« Reply #1 on: December 03, 2014, 01:23:44 PM »
That's exactly the type of crank I want to do on the V12 I sketched out a while back!    NICE! :popcorn:

Dave
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Damned ijjit!

Offline fumopuc

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Re: 80CC OHC V8
« Reply #2 on: December 03, 2014, 01:38:57 PM »
Hi Jeroen, the plans,the book and also Mr Schillings single/two cylinder plans are under my pillow since 3 years now. Everythink in my entire current projects is to get the kwnollage to build this engine. So I will follow your build with very big interest.
Kind Regards
Achim

Offline Coopertje

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Re: 80CC OHC V8
« Reply #3 on: December 03, 2014, 02:33:13 PM »
Thank you for checking in Dave and Achim. I believe that this type of crank construction is the most simple and straight forward way of making a multi cylinder crank. For sure it does not have the looks like the master pieces from for example George Britnell or Keith5700, but I am quite sure it will work. 

I have a doubt about the lubrication on the needle bearing though. Would they need lubrication when the engine is running? I am thinking on adding an oil pump and some piping that will feed the oil in the direction and hopefully will reach the bottom of the pistons. This would cool the pistons and at the same time all the needle bearing would get some lubrication by the mess caused. If possible some guidance / advice on this would be much appreciated.

Regards Jeroen

Offline Roger B

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Re: 80CC OHC V8
« Reply #4 on: December 03, 2014, 07:39:28 PM »
That's an excellent challenge you have set yourself  :ThumbsUp:  :ThumbsUp: I will be following along  :popcorn:  :DrinkPint:

Like Achim I am trying to improve my skills with the current builds to move onto the 'dreams' (I will collate and post them one day).
Best regards

Roger

Offline Coopertje

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Re: 80CC OHC V8
« Reply #5 on: December 04, 2014, 07:45:43 AM »
Isn’t funny how the grass always looks greener on the other side! My skills are fur sure not better then yours Roger or Achim’s. When I look at the work of both of you I always think to my self that I still have a lot to learn. In my opinion it is better to have a project that has your true interest to improve your skills then to do “simple” things only. More complicated projects pushes you over your own limits and then you really improve your skills. And if it goes wrong, think, ask and learn and redo the part. Sometimes with Solid works I spend evenings to figure out how to draw that one thing I have in my mind. Great feeling of victory when it is finally achieved. Same with machining, I finally have reached a point that I can get my parts to good tolerances, but I have to work really slow and concentrated. As soon as I speed up it goes wrong.....
My piece of advice, just start to build your dream engine, your skills will develop along the way!

Offline gbritnell

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Re: 80CC OHC V8
« Reply #6 on: December 04, 2014, 01:30:31 PM »
Hi Jeroen,
I know the engine is in the preliminary stages but here's few things you might consider.
1. The wrist pins don't get enough radial movement to require a bearing so you could eliminate that.
2. Even though the engine is spinning on bearings they will need some type of lubrication. For a bearing engine a splash type would be more than adequate. You only need a pressure pump if you're going to be sending oil to the heads or elsewhere.
3. You will need at least 2 rings per piston and possibly 3. The third one being some type of oil control ring. (holes drilled to return the oil from the cylinder walls)
4. Although some engines (full sized) don't have the piston coming to the head deck it's common practice to to do this. This way the shape of the combustion chamber in the head can be designed to facilitate the burning of the fuel efficiently.
5. Just looking at your drawing it seems like the compression ratio will be very low. (total area of piston recess and combustion chamber shape) versus the stroke length.
gbritnell
Talent unshared is talent wasted.

Offline Coopertje

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Re: 80CC OHC V8
« Reply #7 on: December 04, 2014, 08:06:15 PM »
Hi George,
Thank you for your input and suggestions, they are appreciated. Related to your input:
 
1)      I could make them from bronze, I am just afraid that they will wear out because they do not get a pressurized lubrication. I have already bought the bearings so for the moment I will stick with them, I do not believe they will hurt.
2)      I have considered a splash lubrication by mounting small blades on the conrods. The disadvantage I see here is that the oil level in the engine should reach let say up to half the crank. I am afraid to have leakage at the crankshaft ends when the engine sits for a while. If I add an oil pump and guide the oil flow by piping I can keep the oil level below the crankshaft end bearings and prevent leakage. 
3)      In my other engine I made the piston 0.005mm smaller then the cylinder bore. It has a lot of compression even without piston rings. I would have expected that it would get stuck quickly when the engine is running due to the different expansion coefficients (cast iron liner and aluminium piston) but to my surprise it doesn’t, keeps running without a problem. My idea is to run the engine without rings, only cut the grove in the pistons just incase I need to add piston rings.
4)      This I do not understand, do you mean that the top of the piston should be at the same level as the top of the liner when the piston is in TDC?
5)      I did not calculate the compression ratio, I took the shapes and volumes from the Schillings plans. The engine should run with this, it is a proven design. I think you are right that it is not optimal, if I look at the engines from Luther (google on “luther model engines”) I see that he has made pistons with a “head” to increase the compression ratio. Since building this engine on its own is already a very big challenge for me, I will stick to the plans for this part. If the engine is running  it is not so much work to make another set of pistons and start to experiment.
 
Thank you again for thinking with me and preventing me for my beginners mistakes
 
Regards Jeroen

Offline Roger B

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Re: 80CC OHC V8
« Reply #8 on: December 04, 2014, 08:17:42 PM »
Hi Jeroen,

My projects are all things that I want to make, it's just that I realise that if I start with the simpler ones the mistakes cost less. Either of the next two will push me, a version of the 1898 Saurer opposed piston engine with paraffin (kerosene) injection or a horizontal two stroke diesel (Field Marshall style) to operate as a true diesel with high pressure fuel injection using pump diesel. The one to follow will be a Hulsebos-Hesselman (maybe you know this one?) 5 cylinder wobble plate semi diesel. There is also the possibility of a Junkers/CLM opposed piston diesel.
Best regards

Roger

Offline Coopertje

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Re: 80CC OHC V8
« Reply #9 on: December 04, 2014, 09:04:55 PM »
Hi Roger,

Most of the mistakes normally can be rescued, it is more the mental damage then the waste of materials  :facepalm2:

Those are indeed some challenging engines you mention there. Do not know any of them, did some google on them and I like the wobble plate design! Not an easy one but should be do-able in a home shop. Do you have experience with CAD?

Regards Jeroen

Offline dieselpilot

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Re: 80CC OHC V8
« Reply #10 on: December 04, 2014, 09:15:33 PM »
Another Solidworks driver! Save as --> .jpeg makes for easy screenshots. Otherwise, the snapshot button copies the screen to the clipboard which you can paste into a new file in your photo editor. That looks nice.

What does Schillings suggest for lubrication? I assume the typical model airplane glow fuel with 15-20%oil in the fuel. It seems that sump oil and splash lubrication would require an oil level high enough to put the crank bearings in oil which would cause a substantial load. The little rod end with rollers doesn't need much oil at all. Many utility two strokes use a bushing here with 50:1 oil. Most RC four stroke engines get by on just what oil gets past the single ring and bronze bushings in the rods. I don't think piston cooling is much of a concern, unless the engine is making a lot of power and run at high load.

Combustion efficiency and fuel consumption are not a concern in model engines. A deck height of zero is OK, but production model four stroke engine's pistons are usually around 1mm below the top of the liner. This has no adverse effects. The main reason for a small deck height is to allow more control of the squish band design.

Schillings compression ratio is high enough to work well with glow plug ignition and fuel so that must be in the region of 6-7:1.

The truth is that all of this stuff has been done so many different ways that for a display engine that occasionally runs almost anything that's square and straight works. It's when you try to run at peak power/rpm for hundreds of hours and sell it for a reasonable price that the smallest details matter.

Those crank roller bearings look like they run directly on the crank journals. How hard will the journals be? Typically they ask for <57 HRC in real applications. What's more amazing is that it was used at some point in full size engines, by Tatra according to the interwebs.


Offline Coopertje

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Re: 80CC OHC V8
« Reply #11 on: December 05, 2014, 11:36:16 AM »
Hi Greg,

Yeps and I must say that I like Solid works a lot. Most of the things are really intuitive, the only thing I keep fighting with is the reference planes, when you want to have them in a specific angle and position it is not so easy. Thanks for the tip to save as jpg, I had found this already but was lazy and took some quick pictures with my mobile phone to send to a friend (my hobby PC is not connected to internet).

I looked in the book of Schillings and he is speaking about lubrication caused by the mess in the crankshaft housing. So he uses a higher oil level and splash lubrication. I will see what I will do, took the basics from his plans and I like to work out the rest of the engine to my own ideas.

The crank disk will be made of C45 steel not hardened. This because the rollers in the needle bearing are already hardened, and as far as I know hard on hard does not work well. 

You are right about the fact that these engines do not need to perform and last 200.000km, so keep things realistic in material usage and optimal compression ratios etc. However it would be fun to experiment a little when the engine is running, at least that is if I have any motivation left at that time.

Nice picture of that Tatra crank!

Now it is not wise but this weekend I will start on machining the cylinder block and lower block, had enough of working behind the PC. I will leave enough stock left for detailed outside shape finishing, did not bother about that yet.

Regards Jeroen

Offline Roger B

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Re: 80CC OHC V8
« Reply #12 on: December 05, 2014, 12:14:38 PM »
Hi Jeroen,

I have limited CAD abilities I use 2D DraftSight as a sort of electronic sketch pad but have never tried any 3D systems.

Maybach made a series of tunnel crankshaft petrol and diesel engines that were used in tanks and locomotives. There are a couple of pictures of a crankcase about 1/3 of the way down this page:

http://sp9010.ncry.org/mechanical1.htm

Best regards

Roger

Offline dieselpilot

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Re: 80CC OHC V8
« Reply #13 on: December 05, 2014, 02:11:27 PM »
I'm surprised, that he uses splash lubrication with all those bearings inside. The point of rolling element bearings is to reduce the oil requirement. I've had his book on my list for a long time, but still haven't purchased it. If you do splash lube then I would follow George's suggestion about oil rings.

Rolling bearings need a hard surface to run on. There the hardness difference between rolling elements is too great, problems arise. Take a look at the engineering manual for the bearings you've selected. The manufacturers recommend using their race components if the running surface can't be produced to the required hardness and surface finish.

Roger, I saw mention of the Maybach but didn't see any photos. More recently, Timken proposed a needle bearing crank with normal proportions for the main journals for truck engines.

You have to start cutting metal sooner or later, or you'll end up like me tweaking a design for years. Though it did save me from making parts for an engine that I couldn't assemble, even after many checks for assembly procedure. I mostly modify RC four stroke engines for now.

This is a section of an OS FS-30.



Offline Roger B

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Re: 80CC OHC V8
« Reply #14 on: December 05, 2014, 03:00:02 PM »
This link has better pictures of the Maybach engine:

http://sp9010.ncry.org/Maybach.htm

And this is a small cutaway drawing
Best regards

Roger

Offline Art K

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Re: 80CC OHC V8
« Reply #15 on: December 06, 2014, 02:41:35 AM »
Jeroen,
This engine sounds like a very interesting project, and I will be following along. As far as oil level in a splash oil system I think the rod needs to dip in it but not much more The oil will cover the insides well. I don't know how that will work with needle bearings. I have my Upshur vertical single and early on I was sorting out oil level and crankcase ventilation. At one point in time I had to much oil and not enough ventilation and the oil was coming out everywhere, messy.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Coopertje

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Re: 80CC OHC V8
« Reply #16 on: December 06, 2014, 07:16:37 PM »
Roger, I can only advice you to have a try with for example Solid works. It is really not that difficult and it is fun to see your design growing step by step. Especially with the engines you want to make in the future I believe it is true added value to have them in CAD first. It helps you to get a better feeling of the parts to be made.

Greg, the book is nice, a little vague at some points though, like on the lubrication. He also talks about some oil pumps, unfortunately the plans he refers to are not displayed in his book. What he does mention is that the HK3512 needle bearings should run on C45 not hardened. Who am I to doubt his knowledge, the man has build more engines then I will be able to build.

Stopping a design in Solid works is indeed quite difficult, it is never good enough and it has alway room for improvements. I believe that the block, crank, liners etc are quite save to produce already, they are not likely to be changed. Need to spend time to add a little bling to the outside to the engine to get rid of the square block looks.

Nice work on the OS engine, you seem to know your way around in Solid works!

Thanks for sharing your experience Art, did not think about ventilation yet….. I guess an easy way of oil level check is to drill a hole in the side of the block such that the bottom of the hole corresponds with the top of the oil level. This can then be used to fill up the oil until it comes out. Below a section view of the V8 block



There is plenty of space for splash lubrication. The end bearings are well above the required oil level needed to have the rods touching it, so I do not have to be afraid that it starts leaking when the engine sits for a while. Splash lubrication it will be, thank you all for your help!

Did some work in the shop, mostly squaring up the raw material for block and under block. Will do more tomorrow, will post some pictures later.

Enjoy the weekend, regards Jeroen

Offline dieselpilot

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Re: 80CC OHC V8
« Reply #17 on: December 07, 2014, 06:21:11 PM »
Jeroen, I've been running Solidworks on and off for work since version 98+. I'm currently using 2013. The hard part about CAD and machining is thinking in terms of what you can actually cut with your equipment or the time you're willing to spend cutting. George, for instance, does what I call manual CAM/CNC work. He does on paper ( spreadsheet) what CAM software does and translates all of this to turning the handles by hand. I will be the first to say that I'm too lazy for that (maybe if I had DRO) and his work and persistence is incredible.

The dynamic load rating for the HK3512 is 13,100N (2940Lb) and there are five on that crank! Possibly, with such a low load on each individual needle the surface hardness is of little importance. Does he spec a tolerance on those journals INA says the matching inner race is 35 h6. I think more in terms of production and working loads, so sometimes I over do things even though I know a lower standard will usually be acceptable.

Offline Coopertje

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Re: 80CC OHC V8
« Reply #18 on: December 09, 2014, 11:40:32 AM »
Hi Greg,

So you are some years ahead with Solid works, I just started beginning this year. Use 2013 too. I believe it proves how open the software is, I could not imagine to draw up a V8 with so little problems without experience.... I believe the hobbyist are in advantage here, we do the design but also the manufacturing of the parts. When I draw up a part I always think of the machining, will it fit my machines, can I make the set-ups, is it possible to mill / turn these kind of shapes. I have heard a lot of complaints by manufacturing companies that get design from people that never drilled a hole in their live and there designs are impossible to produce....

I believe I am ok with the non hardened C45 journals. And there is no problem with your way, better 10 times too strong then just too weak! I put the 3512 bearing over a 35mm bar and the fit was very sloppy! Had a lot of radial play, way out of acceptable for me. I took a piece of 40mm steel, reduced it to 35.2mm and start to cut it down with very small steps of 0,02mm. After each cut tried the bearing and found that with 35.10mm I had a tied fit and the bearing was running freely. So never trust the datasheets and I am very glad that I did this test before making the crank. Will test the fit again when the bearings are in place in the block and decide on the final diameter for the journals. My plans is to finish the assembled crank on the lathe with 0.1mm oversize and finish it to size on my Tachella grinder. With turning I never had a nice surface finish with C45 steel.....

The work did so far on the block is not much, I took a lot of time to make sure that all was within 0.01 to 0,02mm tolerances. These initial cuts form the foundation (reference) of all further machining steps, time spend in this stage will pay back double in a later moment. I started with trimming my mill so that all axis are below 0.01mm over there complete travelling range.

Squared up the under block, this will be bolted to the cylinder block. Aluminium type is unknown, got it from the scrap yard but it had milling marks so it should machine well.



Drilled the holes 4.2mm and milled 2 slots at the side of 2mm deep





Flipped the block and faced the upper side of the under block and countersunk the 4.2mm holes



The cylinder block will be made of 7075 aluminium. Dimensions of the block below are 167mm long, 150mm wide and 75mm height.



My vise is too small to eat this piece of material. Used a “wood clamp” to tighten the vise, tested it with a rubber hammer and the aluminium block didn’t move at all



Faced the top and cut a slot in the middle 2.02mm deep to make sure that the bottom block will sit on its shoulders.



Test fit between cylinder and under block, I am happy with the fit, need to tap it lightly with a hammer in and out of place



Drilled and tapped the holes in the cylinder block M4, 15mm deep



And the 2 parts bolted together



Used the under block side to check if it was straight in the vise before facing the sides



And faced both sides of the assembly





Surface finish on the 7075 aluminium of very nice



Initially I planned to make the central bearing bore with a between the centres boring bar in the lathe. However on the Harrison lathe there a very limited possibilities to mount clamps, it does not have T-slots in the cross slide and I refuse to drill additional holes in the machine. Alternately I could make the boring in the mill with a boring bar, I just have enough height in the Z to make the set-up



I will go this way, the mill is rigid enough to make this boring. Advantage is that I can pre-drill the hole with a 32mm drill, the biggest one I have, and the set-up on the milling table is much more easy then to set it exactly on centre height on the lathe.

(sorry for the wrong orientation of some pictures, I really don't understand Photobucket sometimes  :Mad: )

Regards Jeroen





Offline Ian S C

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Re: 80CC OHC V8
« Reply #19 on: December 09, 2014, 12:00:12 PM »
Fitting needle roller bearings; each size of bearing has a specific size of hole that is required for the bearing to be pressed in so that it contracts to fit the shaft.
From what I'v read, quite a number of model locomotives run needle roller bearings on unhardened axles.
                                              Ian S C

Offline Coopertje

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Re: 80CC OHC V8
« Reply #20 on: December 09, 2014, 08:21:10 PM »
Hello Ian, thanks for your input. Will check a good datasheet to see how it should be mounted. On the other hand, in the end it doesnt matter if you or sqeeze the baring or increase the shaft diameter....

Regards Jeroen

Offline Coopertje

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Re: 80CC OHC V8
« Reply #21 on: December 11, 2014, 11:42:39 AM »
I managed to make the 42mm boring. Set the block on a parallel set and clamped it to the table. Took my time to check the set-up so that I was sure if was perpendicular to the milling table







Predrilled the bore with a 32mm drill, the biggest drill I have. It’s a Chinese quality drill and it made quite some noise so I switched on the coolant. It has been sitting for some years without use and it looked like it was sucked from the local swamp, all dirty and brown..... Time to clean the coolant reservoir and change the coolant. For now it helped to reduce the noise during drilling.



Mounted the boring head and start rough cutting until I reached 41mm. Then in 5 steps of 0.2mm I finished the bore to 42.00mm.



Next I drilled the 8mm holes for the water cooling channels. The need to be more then 150mm deep, I will drill them to final depth with a hand drill later, too much work on the mill where my Pinole has a travel of 50mm only.



To check the parallelism between bottom and cylinder block I made a small dial indicator holder from a piece of brass. It worked quite well, from front to back and left to right the reading are within 0.01mm.





Regards Jeroen





Offline metalmad

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Re: 80CC OHC V8
« Reply #22 on: December 11, 2014, 01:17:40 PM »
Hi Jeroen
Love the Build so far, will be following along for sure  :ThumbsUp:
Pete
A little bit every day, sometimes the same little bit

Offline fumopuc

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Re: 80CC OHC V8
« Reply #23 on: December 11, 2014, 02:38:11 PM »
Hi Jeroen, looking good so far. If I look at your first posting http://www.modelenginemaker.com/index.php?topic=4398.0, there is some machining visable in the middel of the Vee of the your engine block. I am afraid, this will cause some deformation due to the internel stress of the material. This could have an effect on your crank shaft bore.
Kind Regards
Achim

Offline Coopertje

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Re: 80CC OHC V8
« Reply #24 on: December 11, 2014, 03:44:19 PM »
Thank you Pete, how’s your V8 coming along?

I am not quite sure what you mean Achim. I have chosen to make the boring first to not have interrupted cuts during the boring. Due to the flex of the relatively thin boring bar (16mm) I was afraid for that. If you have a in-between-the-centres boring bar of 30 to 35mm flexing is less an issue. They are 2 quite big pieces of aluminium, I do not expect them to deform when milling some pockets and hole drilling. I normally take several light cuts instead of few deep cuts. If I am missing your point let me know please.

Regards Jeroen

Offline fumopuc

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Re: 80CC OHC V8
« Reply #25 on: December 11, 2014, 07:35:18 PM »

....... They are 2 quite big pieces of aluminium, I do not expect them to deform when milling some pockets and hole drilling. I normally take several light cuts instead of few deep cuts. If I am missing your point let me know please.

Regards Jeroen

Hi Jeroen, in your CAD model is a big pocket in the Vee of your engine block. This machining process could have an influence to the main bearing bore , but if you do it as mentioned above,  with several light cuts it could be without any effect to the bore.
I have learned, that some times these aluminum blocks are doing strange things after cutting big holes in it.
Kind Regards
Achim

Offline metalmad

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Re: 80CC OHC V8
« Reply #26 on: December 11, 2014, 09:20:28 PM »
Hi Jerorn
I am intending to have 2 weeks off over Christmas and really hope to get the Con rods poured, so with any luck there will be some progress soon.
I did however fit the Tacho and Temp gauge into the base the other day  :cheers:
Pete
« Last Edit: December 11, 2014, 11:44:13 PM by metalmad »
A little bit every day, sometimes the same little bit

Offline mikemill

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Re: 80CC OHC V8
« Reply #27 on: December 12, 2014, 12:41:07 PM »
Jerorn

That’s a very useful looking jig borer/ mill you are using, what make is it and do you know if they are still made?

Thanks

Mike

Offline Coopertje

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Re: 80CC OHC V8
« Reply #28 on: December 12, 2014, 07:38:48 PM »
Ok Achim, get the picture now. The V will be milled with the CNC mill, 1mm deep cuts, no heat generation at all. But thanks for the warning, nice to have some one looking over your sholder and tap my fingers when needed.  :ThumbsUp:

Wow Pete, that is some engine you have there  :praise2:  Seem to have missed some progress on your build, did not see the blower yet. I hope to make a furnice in not to far away future, must be very nice to make your own castings! Good luck with the conrods.

Mike, the milling machine is a German Thiel140, 1979. It came from a sort of school andit is practically new. Power feed on all axis, hydraulic locking, SK40. As far as I know Thiel was bought by Deckel and after Deckel. The boringhead is a eastern European make but simular to a Wolhaupter. It has the possibility of auto feed to make pockets etc. New very pricy, best to look for a good used one. Most of my tools I get second hand.

Regards Jeroen

Offline Roger B

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Re: 80CC OHC V8
« Reply #29 on: December 12, 2014, 08:24:03 PM »
I do agree with Achim, there can be a lot of stress in a piece of bar stock. I have just made a couple of long cuts in a length of extruded aluminium as the start of a connecting rod and the after a ~100mm long cut the end opened up more than 1mm.
Best regards

Roger

Offline Coopertje

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Re: 80CC OHC V8
« Reply #30 on: December 14, 2014, 03:29:39 PM »
Thanks for the warnings, up to now I never experienced this with aluminum, I will try to remember it for the future to keep the part cool during machining. But most likely I need to hit my own nose before it stuck into my brain…. like with children, you can tell them 100 times that they should not that, one they will do it anyway and hit their nose. Then the lesson is learned. Did make quite a progress this weekend, do not have time to put a post together now, will do that beginning this week. I found also a mishap, the hole made by the boring bar is not round but oval  :rant: The diameter where the 2 pieces of aluminum are connected is exactly 42.00mm (this is the dimension I have check during boring). 90 degrees further its 42.07mm, so 0.07mm oversized! The only explanation I have is that there are 2 different types of aluminum, so most likely the boring bar had a different flexing in the both blocks. It can be fixed though, I will skim of a little of the blocks so the hole becomes undersized again and when all the machining is finished I will clean it up on the lathe with a between the centers boring bar.

Regards Jeroen

Offline Coopertje

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Re: 80CC OHC V8
« Reply #31 on: December 15, 2014, 11:35:53 AM »
Had quite a productive weekend (at least for me it was). I started with turning 2 disks having 42mm and 48mm diameter. When I mounted these in the 42mm hole I had bored for the main bearings I noticed that the boring was not round. At the line where the lower and upper block join it is the required 42.00mm, but 90 degrees rotated it is about 0.07mm oversized. It must be the result of using 2 different grades of aluminium causing the boring bar to flex differently....Lesson 1 learned.



Set-up the angle plate and put the block on a set of parallels. I wanted to clean up the outside of the block related to the boring, if it would have wandered off a little it would be corrected by this operation.







Next I drilled the 8mm water passage holes to the required depth of 154mm (they were pre-drilled 60mm deep). I used the hand drill for this, much easier  to retract and clean the drill.



Then I milled out the pockets in the bottom of the block. Started with drilling the corners and then with a 8mm end mill the pockets. This would take ages, so I swapped to a bigger end mill to remove most of the material. Later finished the pockets with the 8mm mill.









Drilled and tapped the M4 holes using my recently acquired tapping head. What a nice toy this is, torque limitation and auto reversing mechanism, such a joy to use! These M4 holes will be used to mount a bracket securing the main bearing position (should not be necessary, but just to be sure it will not hurt),


 
Tested the fit of the bearings, they can be mounted but I noticed that they would become oval due to the weak outer ring...



Then late in the evening I took the stupid decision to cut away a little material inside the boring to prevent it from being squeezed oval. The reason I did this was because on side of the bore is too big and I never managed to make a hole smaller.... During the night I woke up and realized I made a big mistake. The diameter can be reduced by skimming 0.1mm of the under or upper block and re-bore it to the correct size, but this time with a between the centers boring bar in the lathe. I will fill out the removed material in the boring with JB weld and save the new boring as last operation after the warnings about the behaviour of the aluminium during machining. Lesson 2 learned, never take such drastic decisions without taking a good night of sleep first (I knew this one already, but I seem to forget it now and then...)

Since I have a new CAM software I would like to test the code before attacking the real material. I took some piece of “flower foam”, it cuts really nice, to test the CNC code. It did exactly what I expected to do, nice to get some trust in the generated code. Roughing pass 6mm end mill, finish pass 6mm ball nose mill.







Full of confidence (I know this is the point when it is about to go wrong) I mounted the lower block and started the CNC program. Quickly after it started to make noise and I hit the stop button. The End mill came out of the collets and caused quite some damage to the part. The collets used in the speed increaser suck, they need to be tightened extremely hard to hold a mill. I will not use this anymore until I make a new ER-11 collet holder for it....





Mounted a normal tool holder and restarted the program. All went ok from here, just a little slower because the reduced feed speeds. Below some pictures of the process, rough milling, ball nose finish, Dremel, file and sand. Need to play a little but more with the CAM settings to find a optimum between finish and machining time (Rough and finish pass took about 1:30 hours).


 












Last the part had a visit to the sandblast cabinet, I must admit I like the looks. It removes  the small filing and sanding marks and gives it a casting look.





That’s it for now, regards Jeroen
 

Offline MMan

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Re: 80CC OHC V8
« Reply #32 on: December 15, 2014, 01:59:40 PM »
Hi Jeroen,

Which CAM program are you using now? I am just comparing HSMxpress (free) against CamBam (popular) and AutoDesk Fusion 360, trying to find something good for a good price.

All the best,

Mman.

Offline Roger B

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Re: 80CC OHC V8
« Reply #33 on: December 15, 2014, 02:46:58 PM »
Very nicely finished piece  :praise2:  :praise2: I'm glad you have managed to find work arounds for your problems.

I would wait until all the other machining has been done before line boring the crankcase. There may be some more movement/distortion when you shape the cylinder block and bore the holes for the cylinders.
Best regards

Roger

Offline Coopertje

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Re: 80CC OHC V8
« Reply #34 on: December 16, 2014, 08:02:35 AM »
Hello Mman. I am currently using Sprutcam V9. We used this software for an article in a model magazine and it is not perfect (does that software exists?) but it can do 4-axis milling, 3D waterline operations and has milling and turning. Sometimes it does things that I do not expect it to do, then I have to reload the part and set the operations again and it works. Do not claim this is a bug in the software, it might as well be my inexperience. I have tried other software’s (mastercam, solidcam etc) and the entrance step was just to big. I spend many evenings and never got reasonable code of the other software’s. With SprutCam I was able to have a 3D part carved out the first evening, intuitivety is very important to me because there can easily be 6 or more months between my CNC milling projects and then most what you learned is already again forgotten. I believe Sprutcam is also offered together with a Tormach milling machine. They have some nice tutorials on their website.

Thank you Roger. The part is not to bad in the end but is far from perfect. There are just to much little mistakes in it, I hope one day I can get rid of those. If you move your mill only 0.02mm too far in a pocket it already shows, as you can see clearly if you look in more detail to the part I have made. But for the moment this is the best I can do, guess that is a fact of live when you put a account manager with an electronic background behind a milling machine  :facepalm2: But as long as I am having fun and step by step improve I am happy!
What you suggested is exactly what I will do, save the line boring until the other operations are finished.

Regards Jeroen

Offline Coopertje

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Re: 80CC OHC V8
« Reply #35 on: January 06, 2015, 11:39:44 AM »
First of all a very happy new year to you all! That it may bring a lot of shop time and successful projects.

Time for an update, made some progress (and more mishaps) on the V8 block. Got a little slowed down, got myself a nice Deckel SON tool grinder and that needed to be refurbished. All parts of the Deckel are now in the ground layer of painting waiting to dry well and then receive their final finish painting.

Created the G-code to mill out the bottom of the cylinder block to a V-shape. The block is too big for my vice on the small PC mill so I had to make me a set of bed clamps first. Next I could not reach the outer edges to indicate the block in the milling machine so I mounted the lower block in order to be to indicate the part in the machine



Roughed out the pockets with a 8mm end mill and ran the finish pass with a 6mm ball nose



After cleaning up with files and emery paper, sandblasted the pockets. Below the result





While the CNC was busy I started to turn the crank disks from C45 steel. I cannot get a good finish on this material, no matter what I try. The disks are well oversized, 36mm in diameter, final diameter will be around 35.1mm.





Next I brought the height of the block to its final dimension. It needed to be reduced more them 10mm so I tried to use the bandsaw to cut off most of the material.



Bandsaw is too small (or block too big....) so off to the mill and take of the material. Paid attention to the temperature, cooled the block with air in-between the cuts.



Unbelievable how much swarf is created....



With the block at its correct height the next operation was to mill a V-shaped pocked in the top of the block with the PCMILL. The nice thing about CNC machine is that they do exactly what you tell them to do. The bad thing about CNC machines is that they do exactly what you tell them to do!
I had a soft limit warning because I loaded the G-code and did not indicated the part yet in the machine so it was out of range. After indicating the part I still had the message, so I reloaded the code and the message was gone. All good so far. Hit the start button and the 8mm end mill went in 3mm deep and started to make some serious cuts. W.t.f. @#^. Before I realized what happened and hit the stop button it already cutted a nice pocked. When reloading the G-Code I selected the program for the bottom instead of the top of the block :Doh: Loaded the correct program and milled the pocked. When the engine is assembled this part will not be visible, so in the end its only my emotional damage and the knowledge that this is quite a stable machine and that I program it way below its mechanical limits. 


 


Good that we have JBWeld available (Did they invent this especially for me? My first name is Jeroen, last name is Broek, in short JB).



Off to the bandsaw again and cut away most of the material to get the 90 degree flats. Had to cut from both directions. Set-up was weak but good enough to have the material removed.







To mill the flats I could not use the swivel table of the mill, this is limited to 30 degrees. Luckily I have a very large travel in the Z-axis and bought a angle sub table some time ago over internet. It became quite a tower but it worked out fine





In the same set-up I milled the side of the block to size. The angle came out to exactly 90 degrees, finally a operation that went without any mistakes!



That’s it for now, next is to drill the holes for the cylinder liners.

Regards Jeroen
 

Offline Roger B

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Re: 80CC OHC V8
« Reply #36 on: January 06, 2015, 11:52:33 AM »
Good progress  :ThumbsUp:  :ThumbsUp: That's a lot of metal to remove  ::)  I think that Jason B already has the rights to JB weld  :mischief:
Best regards

Roger

Offline vcutajar

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Re: 80CC OHC V8
« Reply #37 on: January 06, 2015, 12:55:29 PM »
That is a lot of progress there Jeroen.  Keep it up.

Vince

Offline fumopuc

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Re: 80CC OHC V8
« Reply #38 on: January 06, 2015, 01:03:15 PM »
Hi Jeroen, a lot of swarf to feed the work shop gnomes. A big step you have done there in the meantime. Still following along.
Kind Regards
Achim

Offline Coopertje

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Re: 80CC OHC V8
« Reply #39 on: January 07, 2015, 11:38:01 AM »
Thank you for checking in Roger, Vince and Achim!

Regards Jeroen

Offline gbritnell

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Re: 80CC OHC V8
« Reply #40 on: January 07, 2015, 12:04:02 PM »
Hi Jeroen,
Even though your setup looks like it wouldn't be that rigid with everything stacked up the cut on the head deck sure looks nice and smooth.
gbritnell
Talent unshared is talent wasted.

Offline Coopertje

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Re: 80CC OHC V8
« Reply #41 on: January 08, 2015, 11:44:58 AM »
Hi George,

Thanks for passing by. Guess you are right, it might look instable on the picture but it was in fact rock solid. The sub table is a heavy one, it weights about 30kg. Its well designed and accurate made. All adjustable parts are locked with big M10 bolds. Glad I have it, easy to mill a part under a specific angle without having to tramp the milling table to zero afterwards.

Regards Jeroen

Offline metalmad

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Re: 80CC OHC V8
« Reply #42 on: January 10, 2015, 10:25:43 PM »
Hi Jeroen
That Block is really starting to come up nice  :ThumbsUp:
Pete
A little bit every day, sometimes the same little bit