Freelance Inline Twin

[yogi]

Aha!!! A potato it is... 
I will do that next time Ian. 

[b.lindsey]

Still watching yogi, great looking parts and an inspirational project.

Bill

[Art K]

Yogi,
Just out of curiosity in post #93 you show the valve guides they look like steel. What did you use?
Art

[yogi]

Thank you guys for the compliments. 

Art, the valve guides are made from O-1 drill rod.

[90LX_Notch]

Still following with keen interest yogi.

-Bob

[kuhncw]

Yogi,

Very nice work on your inline twin.  I'm looking forward to hearing it run.

Chuck

[Brian Rupnow]

I was thinking of the method you used for the valves yesterday, as I machined the valves from solid for my own current project. Something I read, and I'm not sure if I believe it or not. A well respected engine builder has stated that he doesn't try to get too accurate a fit between the valve stem and the guides. His explanation was that if you have a real high precision fit between the valve stem and the guides, then it doesn't allow the valve to "self center" on the seat and can lead to a poor valve seal on compression. His theory absolutely makes sense, but I have always tried for a precision fit on the engines I build. I'm sure there must be a "middle ground" in this theory. If the fit between stem and guide is too tight, then the valves will stick open and not seat at all. If the fit is too loose, then the engine will suck air around the guides, causing problems at idle. I read everything I can about designing and building engines, and I find his theory very interesting.---Brian

[yogi]

Thank you guys for the kind comments. 

Brian, making valves like I did, requires accurate equipment. Any runout in the collet will transfer to the valve and cause the valve face to not be concentric to the stem. As you mention, play in the valve guide could be used to compensate for that. Right now, my valve guides are a very close tolerance, and I'm planing on keeping it that way. I do foresee to lap the valves, as there probably is, even minimal, a little bit of runout. We have to see when it's assembly time if what I did worked or not.

I'll keep you posted.

Yogi

[yogi]

Another part for the cylinder head is the bracket for the rockers.

First, I clamped a piece of stock vertical in the vise, to machine the contour and drill the the hole.



The work piece is laid horizontal to mill the bracket to finish width:



The bracket is cut off the remaining stock with the cold saw:



The last operation is to clean up the saw cut, milling the bracket to final thickness. Drilling the mounting holes, and tapping for a set screw that will hold the rocker shaft in place. The paper in the vise is to protect the finished surfaces from getting marked up.



The finished bracket:




Stay tuned...
Yogi

[toolznthings]

That came out real nice ! 

Brian

[Doc]

You are doing sme nice work. I just found this build and am glad I did. some very nice work!!
I noticed your cnc the Maho Man I did a lot of driving one of those the one we had was a tool room machine with a b axis. Wish I would have bought it when they sold it. It went for I think 4500. Anyway I'm climbing aboard for the ride on the build keep up the nice work!!

[yogi]

Thanks for the kind comments, Brian and Doc! It's very much appreciated! 

For the camshaft, I'm staying with the spirit of this engine, as it will be built up of multiple pieces. In post 14 of this thread is a CAD rendering of the camshaft.

I started with the cam blanks, turned and parted off. They are made from 1144 Stressproof.



The second side of the cam blanks are finished turned:



Drilled and tapped for a set screw:



The two cam blanks, ready for the cam profile:



To set up for the milling of the cam profile, I chucked up a piece of shaft in the collet block, and milled a flat for the set screw.



The collet block is set up vertical in the CNC mill and the cam blank secured with the set screw.



The profile is milled using a t-slot cutter, to cut both cams in the same program.





The process was then repeated for the second cam, except it is a mirrored version of the first one.

The two cams finished:



The shaft has two flats milled, which need to be indexed 180 degrees. The collet block makes quick works of the indexing.



With the shaft still in the collet block, I engraved a line on the end of the shaft. This will help me to time the camshaft.



The assembled camshaft:




to be continued...

[b.lindsey]

Great progress and pictures both Yogi. Beautiful looking parts too.

Bill

[toolznthings]

Nice with the t-slot cutter. Great thinking ! 

Brian

[gbritnell]

Very nice work on the camshaft Yogi.
gbritnell