The Craftmans Shop > Model Engineering

Side Valve i.c. engine from Bar stock

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Brian Rupnow:
I made up gaskets for the intake and exhaust flanges (I had forgotten to make them) and after a bit of tuning this morning, I got out my spanking new digital tachometer. This gave me pause, because at first it wouldn't work. Then I tested the batteries that came with it from the factory, and two of them were stone dead. After replacing two of the batteries and warming the engine up, I found that its lowest consistent idle was at about 800 rpm. It would idle lower, but then it faltered and threatened to stall. On the high speed end, it topped out at a whopping 1950 rpm. This is really about what I expected from the cam I designed. This is more of an "industrial" engine that likes a steady speed without wide rpm range fluctuations. It is really happy at about 1200 rpm, and would run all day at that speed without faltering. The heavy flywheel gives a good steady run, with a slow throttle response due to its mass. This engine is almost the exact opposite of the Canadian Cub (Malcolm Stride's Jaguar engine wearing Canadian clothes). I went to separate camshafts so I could set the cam timing of exhaust and intake totally independent of each other.--You simply can not do that with a one piece camshaft. On the question of cooling fans---I wanted a fan with a pitch which would push air over the cooling fins, rather than pull it, when rotated clockwise. (All of my engines are set up to turn clockwise). Unfortunately, the only fan I could find in the correct size range was designed to rotate counter-clockwise, thus the curvature (dished shape) of the blades. However---That doesn't mean they won't blow in the opposite direction if rotated clockwise. They just won't blow as efficiently. I don't need a whole lot of airflow---just enough to keep a steady flow of air over the cooling fins, to move the heat away. As for writing a book---I have had two of my engines published in "The Home Shop Machinist" magazine. I may see about publishing this one, because it is a very unique engine and seems to run very well.---Brian

Joules:
Zip file downloads fine, all looks OK Brian, big  :thumbup: for publishing the plans.

krv3000:
well dun

Brian Rupnow:
The engine runs well, but the gears are---ahh----noisy. I knew that they would be. They mesh well, and operate very smoothly now that I have an hours running on the engine. However, experience with other engines I have built sort of forewarned me that the open gearing would make a fairly noticeable "whirring" noise as the machine ran. That is why I made provision for an enclosure to go around the gears. An enclosure will cut down the noise quite a bit,  will act as a containment for grease around the gears, and will provide some measure of safety (although I doubt I would have stuck my fingers in there anyways.)

awemawson:
Harder to make, but helical gears would be the elegant solution if the straight gears cannot be given an oil bath?

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