end gap is critical especially if it is too tight. The ends can butt up when it heats up, the gap is to allow for this expansion. Too big of a gap puts you back where you started a lot quicker (rings out of tolerance and compression losses) Some manufacturers have different specs due to use of different materials. most manufacturers call for .004″ for every inch of cylinder size so in this case (has to be converted to inches then back again)
76mm / 25.4 = 2.9921259 inches
2.9921259inches X .004 = .0112 inches (rounded up)
.012inches x 25.4 = .3048mm
BUT
if it is a CP piston set they call for .005″ per inch
76mm / 25.4 = 2.9921259 inches
2.9921259inches X .005 = .015 inches (rounded up)
.015inches x 25.4 = .381mm
check your instruction sheet or their website as some are different and they should also tell you how to adjust the end gap.
If unsure on doing it take your cylinder and ring to your local shop and give them the end gap spec you are after and they might do it for you cheaply as they should be set up to do the job and have a ring grinder.
Most manufacturers also say your cylinder should be torqued down when checking the end gap, but dont know many that actually do this and dont know how much of a difference it makes, maybe someone with more knowledge can tell us all
try here
cp install
😆