Hey guys how freely should the pistons move while inside the cylinder..should you be able to move them by hand or should they be tight that only light blows can move them? if this doesnt make sence i understand.. im using diamond 3.905 pistons with diamonds rings and i was wondering if i have to file fit these at all or should i be good to go....

 

Shouldnt you always have to file fit rings? Put the ring in the bore and check the gap with a feeler gauge. I dont remember what the gap should be off the top of my head.

 

Rings should always be file fit.

 

As for how hard it should be to move, they shouldn't be super tough, but there should be a degree of resistance. You should be able to slide them by hand if you have the bore good and oiled

 

I'd pull a piston, remove the rings and check the ring gaps. Then fit the piston upside down in the bore and using a feeler guage see what the piston to bore clearance is. Diamond will tell you where the measurement should be taken from and how far down the bore you should hold the piston. I would have thought that the piston would rock in the bore with hand pressure but you really have to double check now because you have doubts and didn't check first. I'm assuming the bore is honed true.

 

if it's n/a i'd look for .016-.018 ring gap for power adders step up to .022-.026 depending on how much power youre running.

Nate