Did i give machine shop wrong measurements?

mecevans

mecevans

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Jan 18, 2009
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M-bay, cali
I just sent my block to the machine shop and think i gave them outdated clearances.:aigo: I have a late GE block that i am going na-t with .20 oversized cast npr turbo pistons. Looking for 350-400hp. I have an older tsrm that does not include turbo models. It specifies 0.06-0.08mm piston to cylinder bore clearances. Those where the number i gave them.

The online version has 0.07-0.09 for turbo and 0.08-0.10mm for non turbo. which clearances should i use? I need these number ASAP. I will be calling my machine shop first thing tomorrow to delay any work on it. Thanks in advance!
 
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Devin LeBlanc

Devin LeBlanc

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Apr 7, 2010
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The reason the turbo has smaller clearances is due to the pistons probably expanding due to more heat because of boost.. Good machine shops you just bring them the pistons and block and they will do the work to within spec and what is right if they know what their doing.. I would just do it what is within spec
 
mecevans

mecevans

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Jan 18, 2009
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M-bay, cali
Another thing i have to take into consideration is that i have no oil squirters to cool the pistons.

---------- Post added at 09:33 AM ---------- Previous post was at 09:30 AM ----------
barkz;1637473 said:
just have them do it, and if its wrong bring it back and argue that you told them the other numbers. lol
Click to expand...

I gave them a copy of the older tsrm.
 
suprarich

suprarich

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Nov 9, 2005
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If the pistons do not have a suggested clearance, then .0010 to .0011 per inch of bore is what most machine shops will look for unless told something else. The TSRM is based on OEM specs and HP levels. Increase the piston size and you need to increase the clearance a little. Increase the power output and I would increase the clearance a little also.
 
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