Originally posted by ludeboom
on the h22 series engines the weak area for high rpm is in the head not the block.
supposedly the stock h22a crank is good for up to 8500 rpm's
the retainers/springs/etc. are in danger in this case
true to a point, but the rod/stroke ratio says you're incorrect about 8500rpm. the cranks are balanced to 10k rpm by Honda... but no one said the bearings will withstand all the lateral forces from rotation. constantly ramming into redline will reduce the life of the motor significantly as the motor is not designed to be revved that high. anyways, the H22 hits peak hp at 6800rpm... so no worries about ever having to reach 8500rpm without significant motor buildup anyways.
besides, redline is set to prevent valve float. that's a given. the peak hp in the H22A comes in at 6800 rpm... this is due to the cam profiles, as the head only breathes efficiently to 6800rpm. higher than that and you get a significant dropoff in power due to breathing difficulties.