Art's Val

[Art K]

Hi,
I thought I would get a little head start and then post, so that I can keep the gaps to a minimum. Also when I've had enough in the shop I can go inside sit back relax and have a cold one while I tell what I've been doing.
A little info if you are not familiar with Val. It is an engine designed by Brian Fairey, and is featured in Model Engine Builder magazine. It is 1 cubic inch, 1.124" bore X 1.1" stroke. It has overhead valves and is setup like an RC airplane engine, with a flywheel instead of a prop.
I talked with Mike Rehmus about this engine and some modifications I intended to make. I am in the camp that doesn't like built crankshafts, I minimized the amount of pieces from 4 to 2(not including gears). As George Brittnel would advise using 1144, that is what I used. This is actually take two on the crank, I scraped the first one on the threads, then broke down and bought a die. I figured the fuel line I used to protect the finished throw flexed enough to go down the middle, won't do that again. I did recycle it as the cam driver side of the crank.
Art

 

[stevehuckss396]

Looking forward to seeing your progress. My last crankshaft took 3 tries so keep at it.

 

[Art K]

Steve,
I'm happy to say the crank is done and fitted to the bearings and crankcase!
Oh but I get ahead of myself.
Art

 

[Art K]

After finishing the turning portion of the crank I set it up in the mill on the rotary table zeroing the disc of the crank then offsetting the crank throw .55 and dialed it in on the crank throw to machine out the web for the counter weight. Ending up with this.
Art

 

[Art K]

After finishing the offset half of the crankshaft I turned the ruined part down using the throw stub as a driver. I then machined the driver slots in the disc and ended up with this.

 

[Art K]

I next started on the crankcase. I had an over sized chunk of aluminum set it up in the vise cleaned up the top then with an end mill, cleaned up the sides set the center from that and machined it to size. to do the 45 degree cuts on the corner I used a 90 degree chamfering tool so I could cut the whole top side in one setup. Flipped it over and did the bottom side. I had decided to turn it in the lathe but didn't want to use the 4 jaw so I indicated it vertical, used the edgefinder to pick up the center and used the boring bar to turn a stub I could use to chuck it up in the 3 jaw.
Unfortunately I am not in the mind to carry the camera around the shop, so I have to remember oh yeah I need to take some pictures, troop into the house, wash hands grab camera, click. So thus you get one like this where I have already finished this stage of the part. then I flipped it indicated the previously mentioned nub faced it to length and bored it to size, and proceeded to forget to take a picture of the finished part.
Art

 

[stevehuckss396]

I'm guilty of the same thing. I'm better than half done with something before I realize the camera is in the house.

 

[Art K]

Steve it occurred to me that I could set the part up put in the right tool and take the photo but it never happened, and when you get to far along in the process well....
Next I set it up in the mill and did a circular pocket and bolt hole circle for the cylinder/head mounting holes.
After that I set it up on end indicated the ID of the crankcase then drilled and tapped the back cover mounting holes. Last year at the NAMES show I spent $80 on an Interapid indicator that reads .0001" best eighty dollars I've ever spent.

 

[Art K]

Next I went about installing bearings, polishing shafts to fit the bearings to a slight press fit. Upon installing the crankshaft I discovered some discrepancies. The large main bearing is .035-.05 of an inch to deep.I looked for a washer .04 thick and put it together between the crank and the bearing. Then thinking better took an old chunk of free machining turned the OD to just fit inside the bore, and the inside so it shielded the bearings seal but didn't touch the inner bearing race. I then used the height gauge to calculate how much shim I would need to give me .005" preload on the bearings. Then using some smaller stock I turned and bored it and cut off several slices in different thicknesses.

The first photo is the two halves of the crank and the completed crankcase.

The second is with the large main bearing installed for the first time. If you look close you can see how far past the inner surface of the crankcase the bearing is.

The third shows the small outer bearing installed.
After finishing up the shims I assembled all the parts with an arbor press and I am happy with the results.
Thanks for everyone who has commented. It's great to have the feedback!
Art

 

[stevehuckss396]

very nice work. Is this going to be a 4 stroke or just 2?

 

[Art K]

Steve,
Four stroke, I don't think I'm up for a two stroke.
Art

 

[Art K]

Ok I must admit it's been a rough week. Had lots of other things keeping me preoccupied and away from the project. One thing that held me back is knowing that in Sprutcam I should be able to follow a 2D line to fly cut the surface. I did it as an MDI move, if someone knows how to do that in Sprutcam 7 please help me for future reference. Tried it as an engrave but obviously didn't choose my 2D line as I thought. Thanks for the offer Steve but by the time I read your email I had the part done.
Here is the finished part. Ive yet to mount the back half of the crank but after cutting my test backcover oversized on the bearing and undersized on the OD size I adjusted my program and it seemed to come out good. I'm thinking I'll move on to the flywheel next. I've decided to do a square cylinder with a pressed in cast iron liner so I now have to design the aluminum portion of the cylinder soon.
Art