lots of play with my piston

[hungryjoseph]

i just installed my cp pistons for my stock bore and they move around a little bit inside the cylinder. is this normal?

[CSUPUEBLOTIM]

Ugh did you buy stock sized pistons and assume they would fit your stock size bore with no machine work?

[hungryjoseph]

yes, but i also understand that forged pistons expand more then the oem ones so i had assumed it needed that extra clearance. but its starting to worrry me now

[Sil80315]

Pistons are not suppose to be able to wiggle after you install it. Might have the wrong piston rings or didn't gap them right

[hungryjoseph]

Ugh did you buy stock sized pistons and assume they would fit your stock size bore with no machine work?

what kind of machine work is required? piston to wall clearance i'm assuming?

Might have the wrong piston rings or didn't gap them right

i dont think it would make a difference if i didn't gap them right with the pistons moving around because as long as the ends of the rings dont touch each other inside the cylinder then it will exert the same amount of force against the cylinder wall. but i think its safe to assume i have the correct rings and gapped them properly

[Sil80315]

actually it does make a difference gaping the rings because rings expand. Maybe try using CP rings if your not already?

[hungryjoseph]

yes the gap is for the expansion but i dont think it shold make a difference with the way the piston moves around. i'm using cp rings. before installation i noticed that the rings moved around in the grooves pretty freely, but as did the oem rings in the oem pistons so i didn't think too much of it. i think i'll call cp tomorow

[Sil80315]

yeah I would give them a shout and see what they say.. hell they could of sent you the wrong pistons in the right box.. s*** happens

[Justin35ll]

your pistons should not be moving freely in the cylinders lol def call them tomorrow

[hungryjoseph]

they don't really move that freely... you have to force it with your hand

[GoTRicEo0]

post a picture of it.

[slidestyle69]

if your put enuff force on the piston with your finger tips, then yes the piston will wiggle to an extent...if your not familiar with the resistance that should be there this then yes let some one take a look at it

[hungryjoseph]

ok i took measurements from up and down the cylinder and of the piston. the cylinders have a 3.386 everywhere up and down. I dont know if i should be believing this because this motor has been run hard for the 40k i've raced/dailyed it and i expected some wall tapering. the pistons come out to be a 3.382 to 3.384 on every piston, it's not accurate but i think i will get it honed our another .0005. I talked to the CP tech and thats basicaly what he told me to do. he also said that its normal for the pistons to tilt and move slightly inside of the bore. stock cast pistons won't do it as much because they have a much tighter clearance.

[slidestyle69]

well there ya go

[codyace]

I know it's been answered, but you are correct - they will wiggle a bit.

CP pistons are usually 'fatter' in the middle of them as well....and I'm sure you noticed that if you spin them around, you can dee a SLIGHT difference in size as well depending on which side you measured from.

This is normal, and is designed that way due to the sillica content in them. I've got over 20,000 miles of pure hell and abuse on my CP's, no issues yet. Quality product, top notch customer service, and good to deal with.

[hungryjoseph]

thanks for the responses guys