iaremec
Guest
in 1981 ih introduced what they called the pressure balanced piston. the top compression ring has a gap of.025 , the second ring has a gap of .075. they done it to hold the ring against the shoulder of the lans. the wider gap creates more crankcase pressure. it is also the reason when turboed it has to have a top mounted breather instead of crankcase vent. it would pump oil out of the crankcase vent.