Flat head hit and miss engine???

[Jasonb]

Yes the follower is a roller on a pin that bears against the cam. I think most I have done have a slot in the middle of the arm that the roller fits in and pin hole either side

[Brian Rupnow]

Thank you Jason--You are helping this design along.---Brian

[Brian Rupnow]

I'm pooched!! Flywheel and hit and miss mechanism have been moved to other side of engine, and various changes made to get a working hit and miss mechanism. Top manifold block will undergo some redesign tomorrow to reposition the carburetor and exhaust to clear the flywheel. Again, thanks very much to Jason for helpful suggestions.

[Brian Rupnow]

After a good deal of moving things around and about, I'm pretty sure I've got all the components arranged so that the hit and miss mechanism will work. This involved redesign of the intake manifold block, repositioning of the exhaust pipe and carburetor, and changes to the flywheel to tuck it in close to the engine. The light brown colored piece pivots on the right hand end and has a hardened wheel riding on the cam. The cam is attached to the yellow gear and they both spin on a 3/8" shoulder bolt. There will be a hardened convex shaped piece on top of the the light brown pivoting piece which contacts the end of my exhaust valve. The passion pink governor lever will pivot on a shoulder bolt and a 0.125" diameter rod welded to one end rides in the groove on the governor spool. At speed, when the governor weights swing out, the governor spool will move along the crankshaft causing the passion pink governor arm to pivot, and slide underneath the end of the pivoting light brown piece, thus preventing the exhaust valve from closing.


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[Brian Rupnow]

This morning I had a change of heart about the flywheel location. The whole reason I went to such a large flywheel was to cool the cylinder and head. I had it blowing directly onto the manifold block, but that's no good.  I want it to blow directly onto the cylinder fins.  So---I stuck the ignition cam and points and the flywheel on the other side of the engine and decided to let the hit and miss mechanism just hang out in the wind.

[Admiral_dk]

You could argue that the hottest Point would be the Exhaust part of the Valveblock -> needing the most amount of cooling ....

Great to see what you are up to now Brian 

Per

[Jasonb]

And you could always cut some fins into the valve block

[Art K]

Brian,
Good to see progress! I had to wrap my head around that stuff to figure out how they worked.
Art

[Brian Rupnow]

And this, boys and girls, is what you get for $150 Canadian dollars. Aluminum 4" square for the crankcase, cast iron 3" diameter for the cylinder and head, 7 1/2" heavy wall tube for the flywheel outer rim, 5" diameter steel round for the flywheel center, and 1 1/2" x 1/8" cold rolled steel to make flywheel vanes. All other small bits and bobs will be made from material I have on hand in my shop.

[Brian Rupnow]

Admiral_dk  Yes, the manifold will get hot, but that doesn't do any harm. However, if the cylinder gets to hot, it just might expand enough to seize the piston. I haven't ever had that happen, but I am aware of it.---Brian

[Brian Rupnow]

I want to start with something interesting and easy. The flywheel qualifies as fairly simple. Probably this will be the first part I make.---and if you noticed that it has no set screws, I will add them and update the drawing.

[Zephyrin]

Wouldn't it be easier to drill holes at an angle of 30-40° in the flywheel web to get a fan effect ?

[Brian Rupnow]

Zephyrin--It might be. There are many ways to skin this cat.---Brian

[Brian Rupnow]

So, half a day and a ton of swarf later, I have the inner hub of the flywheel half machined. Thats a lot of passes on a lathe that isn't happy with more than 0.015" depth of cut!!!

[Brian Rupnow]

Now, if I just had 8 vanes in there, I'd have a finished flywheel/fan. I'm going to put the 8 slots into the center portion of the flywheel using a 1/8" slitting saw. I have to make a jig to hold things at 45 degrees for 8 successive cuts. There was probably more machining in this than there will be in the rest of the engine.