Author Topic: 80CC OHC V8  (Read 17145 times)

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