Question about ring gap

[amdburner]

I have new rings for my Jonsered 920 and was wondering what the gap should be for a new set. When I work on larger engines I usually go with .0035 for every inch of bore. Not sure what to go with with such a small bore. I do know that one of the new rings almost completely buts. I would hate to destroy the piston and cylinder. Also, both of the original rings were identical while the new set has one ring with beveled top and bottom corners on the face. I assume this would go in the bottom groove, am I correct? Any help would be greatly appreciated.

 

[amdburner]

Bueler?

 

[amdburner]

Bueler? Anybody? Please?

 

[ShoerFast]

Air cooled cylinders are less critical then water-cooled, don't have a chiseled in stone spec, but you should be cool with the traditional .0035 - .004 per inch.

Air cooled cylinders by there nature expand more, or at a closer rate to the piston and ring then water cooled, the only reason for the spec is if there was ever a very rapid work load placed on a cold start engine, the ring would expand faster then the cylinder, butt together and brake,,,,, less of a chance with less thermal mass of an air-cooled jug. It could still happen, but a catch 22 that works for us here, a piston ring is cut to fit a new jug, running it in anything with ware, adds to the safety margin!

 

[amdburner]

Thanks Shoerfast. I went ahead and assembled using that spec before reading your reply. Now I have to figure out how to start this beast since it doesn't have a compression release!!!! The added compression with new rings is unreal. I now have to stand on it to pull it over. Hopefully tonight I will have a chance to fire it up.