[6 Gun]

Getting ready,to gap my piston rings and I have cylinder's with a taper bore here's the question for all the gear heads the O/H manual says to gap .045 to .055,at 4" from bottom then it says min. gap at top of travel .0075 now if I gap ring .045 at 4" the taper closes the ring .017 at top so that leaves a gap of .028 a long way from .0075 min. at top.Also on second ring should it gap a little losser to help control flutter of top ring and gap in manual says .020 to .040 on oil control the ring on all cylinders tapered or straight.I'm installing new Combustion Technology pistons of 8.7. to 1 going from a higher compression to this piston but I still have a need for Speed. What say you.
Bob

 

[jrs14855]

Gap

Something is not right. Are you sure you are correctly measuring the top ring position at top of piston travel? A little error in the point where you measure the minimum gap will make a difference. On factory Lycoming cylinders my gap at the top was a few thousands under the .0075.
Measurement at the bottom is WITHIN 4" of bottom of barrel.

 

[6 Gun]

mearsurement

Top mearsurement was at 6.5 from bottom of barrel .
Engine is angle valve io-360
Bob