manxaru
03-07-2008, 02:33 PM
I have a few minor pits on the cylinder wall of a used EJ257 shortblock I just picked up.
If I stay with the stock pistons and rings, how much can I safely hone from the bore? .001 or .002" , or is that even too much?
If I remember correctly, the first oversize piston that Subaru sells is .010 over, if that tell us anything.
Thanks!
Valerie@TopSpeed
03-07-2008, 04:06 PM
You can safely go .020 over.
manxaru
03-07-2008, 07:48 PM
You can safely go .020 over.
Thanks for the reply. I should probably rephrase my question....
If I want to use my original stock rings and pistons, how much can I hone the cylinders before the stock pistons and rings will be "too loose" in the bore?
Thanks!
hauntedwrx
03-07-2008, 07:53 PM
.003" is probably max if I remember correctly.
Red_Wrx
03-07-2008, 08:27 PM
i would just get new piston heads (concave) so you can increase boost on them (what im working my project 2.5) however crosshatching isnt bad. some pits ( and i cant remember the wording) are ok and some are bad. i think there called cohesive where its ok to have pits in it cause there cohesive, then there the otherones i cant remember there called. but just so you know not all the pits on a piston wall are terrible.
wish i had a better memory but im know im close.
good luck
KitoAutoSport
03-07-2008, 09:20 PM
It totally depends on where it's puts your piston to wall clearance. there is a range of acceptable values and knowing where you are starting from is the key.
Nobody can give you a set value. It depends on your existing clearance. If you are already at a piston to wall clearance of say 0.003" then you don't have any room and you are out of spec. If you are at 0.001" then you have about 0.0002" to go by factory specs. Factory P/W clearance is 0.0004-0.0012" on a EJ257.
-Dominic
manxaru
03-07-2008, 09:27 PM
It totally depends on where it's puts your piston to wall clearance. there is a range of acceptable values and knowing where you are starting from is the key.
Nobody can give you a set value. It depends on your existing clearance. If you are already at a piston to wall clearance of say 0.003" then you don't have any room and you are out of spec. If you are at 0.001" then you have about 0.0002" to go by factory specs. Factory P/W clearance is 0.0004-0.0012" on a EJ257.
-Dominic
Thank you sir...
Can you remind me if piston wall clearance is measured "per side" or total?
Thanks again!