Vacuum Rotor

[oldtinkerer]

I was just given a Vacuum Rotor flame licker to restore. It's missing the piston and con rod. Can someone supply the dimensions for these items?
Thankyou in advance.
Ken the oldtinkerer

 

[minh-thanh]

I don't know your engine
Do you indicate piston stroke - based on crankshaft and cylinder length ?

 

[rickhann]

Ken, any flame licker engine needs to have the piston fitted/lapped to a very close fit, so giving dimensions to machine a piston that would work would be difficult. I have built 2 operational flame lickers. What I would do is measure the bore of the engine, lap the bore to insure that the bore is absolutely parallel. I would then measure the bore, machine the piston to a very tight fit in the bore and then lap the piston to fit the bore to within .0005". The piston should slide through the bore without lubrication and not slide through with one end sealed off (vacuum tight). As for the other dimensions, when the piston is TDC it should be just even with the back of the slot to allow the flame to be drawn in when the piston reverses direction. You can calculate the other dimensions. R

 

[oldtinkerer]

Thanks for the information. I have built one flame licker that ran very well after a little preheating.

 

[oldtinkerer]

Would cast iron be the material of choice for the piston or would aluminum be acceptable?

 

[CaneSelvatico]

Aluminium would only be trouble as the expansion rate is very different than the cast iron of the cylinder, making it wery hard to run.

 

[portlandron]

Graphite is a good material for pistons for this type of engine.
Easy to get a good fit, no problem with expansion from heat and self lubricating.