received pistons today.. are they too big?

**AE101LEV** · 12-04-2006, 07:54 PM

received my ceramic coated pistons from toyota for my gze and they are 50 thou over. not 20 like i thought. is this going to be a problem cos now the bore isnt going to be as thick and being forced induction the cylinders may be more prone to warp? it says 0.50 on top of the piston so im guessing that means 50 thou, is that my last leg of the gze block after that :S

**crowncustom** · 12-04-2006, 08:04 PM

If it has 0.50 stamped on top that is in millimetres which when converted to the old school imperial it is .20thou oversize so they are by the sounds of it what you want.And yes most if not all new oversize pistons nowdays are in millimetres not inches.Companys like to try and confuse us old mechanics who are not up with the times

Cheers Brett.

**slide86** · 12-04-2006, 08:07 PM

well.....if the block is bored 20 thou over and the pistons are 50thou over then me thinks that you have a problem.

Is the GZE block able to be bored 50thou over with out going to close to water jackets and the like?

I would be taking the pistons down to your machine shop and saying "i need these round things to fit in that round hole...." and see what they say. you might be in trouble tho.

How come did you get 50 thou over pistons? or have they been ordered wrong?

EDIT: im an idiot and he is right.

**AE101LEV** · 12-04-2006, 08:09 PM

was told they were 20 thou hey! :S hope your right brett but good idea slide i was going down to machine shop tomorrow to hand them over so i will ask them.. i didnt get them to do anything until i had them

**mullett** · 12-04-2006, 08:21 PM

A machine shop would want to be keen to try and resize pistons...for a start, they're not round...But it will be in mm, everything jap is. So .50 is 20thou, or damn close. Your shop will match the bores to the pistons anyway. And if by some bizzare occurence they ARE 50thou over, it must be OK to bore that far or toyota wouldn't supply the pistons. What did they cost, out of curiousity? I might need some soon...

RM.

**oldcorollas** · 12-04-2006, 08:24 PM

Originally Posted by AE101LEV

was told they were 20 thou hey! :S hope your right brett but good idea slide i was going down to machine shop tomorrow to hand them over so i will ask them.. i didnt get them to do anything until i had them

brett is right. measure them

(below the rings

)

**30psi 4agte** · 12-04-2006, 09:54 PM

AE101lev
i want pics of old pistons!!!!!!!!!!!
If they are ok ill buy

**Big T** · 12-04-2006, 11:38 PM

Yeah dont worry about it. It's 0.50mm which is dead on 20 thou... i ordered exactly the same OS pistons and had my block overbored 20 thou.

Eddie.

**allencr** · 13-04-2006, 12:53 AM

Yes .5mm is VERY close to .020in.

No machine shop worth anything would ever even think of boring it without having the piston already in hand.
If they would have bored it on just your say so, it would have been done out of ignorance, or greed, or trying to teach you a lesson.
It's not just squirrel protection!