Hit miss engine (with a story)

[Chris Hamel]

Several months ago I talked my brother ( racer57) into a building a hit miss engine based on David Kerzel's design. I must say it was a rather ambitious project for someone who was a relative newbie to machining. Nonetheless he completed it but couldn't get it to run. I brought it home to my shop about a month ago. After about 40 hours of work, I finally achieved success today. Let's see... I remade the carb, made a new piston and rebored the cylinder, made a new rod bearing, and made a new cam shaft. We also had problems with the ignition module. After all this, I could get it to run, but not reliably. And it was hard to start.
Finally I decided to remake the valves. My brother cut the seats with 60 degree countersink and made the valves to match. I remade the valves and seats cut to 45 degrees. Turned out that made a huge difference. Engine runs great now.
My brother tells me I'm the engine's adopted father.

Check out the video

 

[benmychree]

Without a video, it didn't happen ---

 

[Chris Hamel]

Try again. I fixed it

 

[benmychree]

It happened after all !!!

 

[rdean]

Good job Chris and I am sure Will likes it too.

Ray

 

[Racer57]

First, I really appreciate the work the Chris put in. I had pretty much decided that it was going to be a good door stop. The biggest lesson that I learned is that the valves are critical. The spring tension on the intake needs to be VERY light. I had a light spring but not a VERY light spring. I also learned that the chinese import ignition modules are very picky. The net result was that we tried lots of things to move the needle. Some didn't turn out to have much effect.

I was working 250 miles from my technical support and there were a few places where the feedback was "we don't do what the drawing says. We found a better way". This was after I had spent time hitting my head on the wall .

It will take a while before I so another. I am working on PM Research steam engine that should be running by the end of the week.

Will

 

[Chris Hamel]

After Will and have talked about his engine, we both agree that the valves were the main source of trouble with this engine. Almost all of the things I redid were done in a trial and error fashion to eliminate causes. Had I redone the valves first the engine probably would have run.