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How To Design & Build Centrifugal Fans For the Home Shop


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Build Your Own Metal Working Shop From Scrap



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Dave Gingery




Steve Cohen sent us photos of his Atkinson Cycle engine along with these comments. .

Carb fixed the problem.!   I still have a little more tweaking but I can get the engine very slow, steady idle...very sweet now.  I also increased the valve lash to shorten the cam action and need to adjust further to prevent reverse air/gas out the carb.

I did notice one unusual problem that's not related to your design.......the points were firing twice a few degrees apart.  I can see this when I hand crack the engine. I never noticed this before but I am now setting it so the second spark occurs ATC. I can't correlate with ohm meter or observation. Could be condenser I suppose but it's hard to imagine it being bad. 

Thanks for all your help. The double spark was solved by closing the gap. I found that starting was easier if I squirted some fuel in the exhaust and back stroked it into the cylinder. I also shut down the engine by closing off the fuel. This seems to help when I restart. I sent along a few pictures so you can see some of my adaptations of your design esp. the ignition, coil and flywheel location. Thanks again Steve

Thank you Steve for sharing these photos of your great looking engine! Vince

Steve Cohen Atkinson Engine

Steve Cohen Atkinson Cycle Engine

Steve Cohen Atkinson Cycle Engine