Timing a vacuum engine... flame eater

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rlukens

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I'm still stewing over which type valve arrangement to design into a flame eater.
Regardless, common to all is valve timing. Is there a consensus on timing and duration? I assume a crank provides adequate "ramp" vs. a complex cam?
Tia
Russ
 
Rlukens--This is the cam used on the Senft "Poppin" engine. It is connected directly to the crankshaft. When the roller is riding "up" on the cam, the valve is closed. When it isn't up on the cam, the valve is open. There is a spring which keeps the roller in contact with the cam. The instructions say to set it up so that the valve closes completely when the crankshaft is 45 degrees before bottom dead center for clockwise rotation.---Brian
Dr7Et2.jpg
 
Thanks Brian. That's exactly the info I was looking for. I still wonder if a crank provides the save performance. It would be interesting to see the lift of a simple crank compared to the profile of the cam. That look like something a guy with your computer skills could show with an overlay ... hint, hint.
Russ
 
Thanks Brian. That's exactly the info I was looking for. I still wonder if a crank provides the save performance. It would be interesting to see the lift of a simple crank compared to the profile of the cam. That look like something a guy with your computer skills could show with an overlay ... hint, hint.
Russ
I'll do it but I'm not exactly sure what you mean. The large radius minus the small radius gives you the lift. If you can explain what you want better or put up a sketch, I'll do it.---Brian
 

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