The Craftmans Shop > Model Engineering

Side Valve i.c. engine from Bar stock

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Brian Rupnow:
I still have some fin cutting and finessing to do, but this is getting quite exciting!!! I have to buy some material to make a fixture to mount this combustion chamber in the 3 jaw chuck on my rotary table to let me cut the cooling slot that runs around the perimeter. There is a lot of work in this part, but I am pleased with how it is turning out.

philf:
Brian,

It's looking good!

Are the valve seats just aluminium or is there a steel or iron insert?

I agree with Manxmodder's suggestion that you could chamfer the thicker webs to camouflage your error.

Cheers.

Phil.

Brian Rupnow:
If you look way back to post #30 you will see the answer to your question. I will be installing pressed in valve cages, made of brass. That way, if a valve seat goes funky, I don't have to replace the entire complex combustion chamber. I will post a drawing of the valve cages sometime in the next 2 or 3 days.---Brian

Brian Rupnow:
For those of you who wondered about the fixture I would make to cut the groove in the combustion chamber and to round the curved side of it, here is how I am going to do it. I found a suitable piece of 2" round aluminum and bored it for a hard press fit of a 3/4" crs shaft. I then set it up in the lath and turned a spigot on the face to be a precision fit into the 1" bore side of the combustion chamber. I then drilled and tapped five #5-40 holes in it and bolted the combustion chamber to it, using bolt holes which were already in the combustion chamber. The third picture shows it set up in my milling machine with a 0.093" slitting saw mounted in the spindle arbor. In order to take a quick picture, I put the slitting saw arbor in my 3 jaw chuck. In reality, it will be mounted in a collet held in the mill spindle by the drawbar.

Brian Rupnow:
I get a great sense of accomplishment (and sometimes astonishment) when everything actually bolts together, and all of those random lumps of steel and aluminum begin to look like an engine. Today I have reached that point. The combustion chamber turned out great, and my experience with the .093 slitting saw was a success. The two yellow pencils indicate where the valves and tappets are going to be.Although there are many different directions I could jump in right now, I am anxious to see what the "overall" engine is going to look like, so I think I will machine the cylinder head next.

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