ChillOutWayne

Ok so i pulled apart a buddes 99Si and found i some cylinder damage and its time for a bore and hone. Now, he wants to bump compression some so i ordered some .25 oversize P30 JDM Sir2 pistons and was just wondering a few things.

First off the stock bore is 81.00MM, so with the oversized pistons it will jump it to 81.25MM, now heres the questions. Whats the piston to wall clearance supposed to be and when i take it to the machine shop, do i count that in, or jus tell him what the piston size is? I just want to make sure i get these clearances right considering it has to go to the machine shop tomorrow and i wont have the pistons till the end of the week.

Thanks guys.
Dan

ChillOutWayne

bump

ChillOutWayne

Maybe i should ask how much horsepower ill get with an intake or what kind of header to get.

Come on guys i need help on this one.

eXcelonTypeR

http://www.c-speedracing.com/h...c.php just go there and put in the bore size on the "Block" section of the calulator.

EDIT: its goes from 1587cc to 1597cc & compression goes to 10.4 from 10.2. And that is all according to the calculator on the link I provided

ChillOutWayne

Thanks for the response but that doesnt answer the question. I know the piston size will be 81.25, but i need to know piston to wall clearances so i can give the machine shop total bore size, meaning clearance plus piston size.

I think i found it on AllData:
Oversized Piston Diameter:
0.25: 81.23-81.24 mm (3.1980-3.1984 inch)
Piston-To-Cylinder Clearance:
Standard (New): 0.010-0.040 mm (0.0004-0.0016 inch)
Service Limit 0.05 mm (0.002 inch)

eXcelonTypeR

sorry for not reading the whole thing, i was really tired when i read it. But i can't answer that. I'd search around the all motor forum, im sure theres all kinds of post related to this.

Luserkid

Tell the machine shop what the piston size is and theyll take care of the rest. Even better though is if you could give them a piston with the rings on then theyll match the cylinders.

ChillOutWayne

The clearance is what i was concerned with, he would make the clearances set to american V8 clearances, which would make my pistons slap like crazy. I needed to get the spec sheet, which i got, thanks.

DAn