mitsuman

iTrader: (1)

Well i was looking at the piston to wall clearance and it looks kinda big. The shop foreman said it was ok, but its bugging me. These are 81.5mm cp's. . I figured it might be ok because it does not move at all front to back just side to side. Anyone?

I dont have a gauge to read diameter of cylinder. The guy took the reading at the shop and one cylinder showed up at 81.3~ bore up top. He said this was within spec.

Muckman

iTrader: (2)

The pistons are tapered slightly. Piston to wall clearance is measured near the bottom of the skirt.

V-SPEC 1

That's correct.

mighty137

Yup, it looks good!! My does the same thing on 81.5mm CP pistons!

blaze the chemi

Sounds about right...

I measured my piston-to-wall clearance by placing the piston upside down since I didn't have the extra long thickness gauges. Besides, doesn't CP have good repeatible pistons that are accurate to 0.0001"? I wish I knew about them when I rebuilt my engine.

Finest

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blaze the chemi &raquo;</TD></TR><TR><TD CLASS="quote"> Besides, doesn't CP have good repeatible pistons that are accurate to 0.0001"? </TD></TR></TABLE>

A wiseman (R.I.P.) once said that CP pistons are so accurate that he can hone the block and drop them in without even needing to measure the pistons.

mitsuman

iTrader: (1)

Thanks guys. I feel MUCH better.

96 GSR-T

dont worry about the movement, it is probably built a little loose for boost. We just pulled the head off my friends 85mm car and his pistons have side to side play also with his CP's.

SD_Lurker

iTrader: (4)

Have you installed all pistons yet? You might want to check and measure it yourself.

mitsuman

iTrader: (1)

all pistons were installed by a reputable local shop.

ninesecrx

CP pistons are built with the clearance built directly in them. This means that the pistons on a turbo app. actually come 3.5 thou. smaller then the desired bore size. So when you bore and hone a block for 81.5mm, the machine shops job would be to put the block right on 81.5mm and not even a hair larger. If it was, you would have too much clearance. The motor will run if it is larger, but that is when you start to hear noise.

V-SPEC 1

That's for sure

JDMorgan

y not measure the bore?

ej8

I always take the pistons when i take a block to get bored/honed at the machine shop, tell them what piston to cyl wall clearance I want and its done with, perfect everytime

HiProfile

It seems a tad loose to me, but I'm guessing you don't have them on the rods or rings installed either. I gave my wisecos ~0030" clearance, and I've yet to hear any piston slap on cold startup. I've also burned zero oil over the total of 2146 miles I have so far on them.

SPOOLINmatt

mmmm if CP pistons have the clearance built in, then why do they send instructions with them on figuring up your clearance?

ninesecrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SPOOLINmatt &raquo;</TD></TR><TR><TD CLASS="quote">mmmm if CP pistons have the clearance built in, then why do they send instructions with them on figuring up your clearance?</TD></TR></TABLE>

They do not give recommendations on figuring bore clearance, they give you recommendations on how to file fit rings on one sheet. Then they give you a sheet on piston specs. Last they give you a sheet on what grit to hone with and how to finish the hone aka plateau. They do not offer size as or clearance as that like I stated above is built directly into the piston