[Mk2] [Turbo] Forged piston shrinking??

[turbo_87]

Has anyone ever heard of such a thing?

I have JE pistons in forged engine which used to run 500 hp. So they were previously under quite extreme circumstances.

They are currently off at a machine shop to be fitted into a new block, however the engineer has told me this pistons are not perfect and have shrunk....???

Is he just being a nob because there is some visual det marks on a couple of the pistons???

[T.F.S.]

sounds like b0ll0cks to me

[sjm1984]

did he tell you what size they are now?

[djpkins]

didn't wash them on a hot setting did he?

[alanmr2turbo]

i have heard that forged pistons can make the bores slightly oval after 20+k miles but never heard of them shrinking

[turbo_87]

Well the bored aren't a problem as the block is being binned anyway and it was only run for under 2k miles.

He didn't give me an exact measurement no, he just said they were a fraction smaller than what they should be..

LOL maybe he did put them on a quick hot wash!!

Glad it sounds like bollucks as I would quite like to use them again.

[bobhatton]

No piston will be the correct size, each one has to be measured then the clearance worked out and each bore sized to the piston that is being fitted to it.
It does not sound like they know what they are doing, I would not be using them if I were you.
I hope you have new rings and the end gaps set correctly.

[T.F.S.]

whilst thats true for some pistons (like the JE ones) its not true for a lot of pistons because they drop into a stock bore and do not require additional overbore

its likely the engineer hasnt used a piston like that before, he may need this (je instructions for je pistons)

[turbo_87]

Thanks very much for the input guys!! Yes I do have new rings to go in.

They came recommended to me so they should be pretty good....from quite a few people too...

Thanks I will give them the instructions and see what they say, but sounds likely they have never used pistons like this before.

Again thanks for the help guys!!!