2stockrocketz

i bought some new srp pistons that are standard bore.....but i need to know how much they will expand so i know how much clearence to give...so anyone with personal experience with srp's please help!!!

MikeJ-2009

The pistons should have come with papers with the recommended specs on them. I believe stock piston to wall is around .03? I may have a decimal off, but for boost I would be at .035. Again, the decimal. :P

2stockrocketz

thanks stealthy

Ravage70

check the srp website
they have a pdf with all the info

BoostCraze

so you mean you cant just pop the pistons in if they are bore
?

boosted_hatch_216

no, they expand when they heat up. thats why you have to spec it out.

BoostCraze

what do u mean spec them out, you have to hone or bore or what the walls?

MikeJ-2009

You have to have a little bit bigger bore than the piston. This gives the piston room to expand under heat conditions. For example (and don't quote the numbers) if you have a 2.75 diameter piston, your bore will be 2.79 or whatever the case is. Different pistons expand at different rates depending on what they are made of. Most of the time the manufacturer will specify what the piston to wall clearance should be.

And then you have some pistons with this clearance built into them. If you buy an 84mm CP piston, than you bore your block to exactly 84mm, because the reality is the piston manufacturer makes that pistons actually 83mm (or whatever the measurement is). In this case, they've built the piston to wall clearance into the piston, and you just bore the block to 84mm.

Mindless

Just want to back up what stealth is saying. I'm using SRP's and the piston to wall clearance is supposed to be between 0.030" - 0.035".