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General Forums => The Mess Hall => Topic started by: JC93YJ on July 31, 2016, 04:48:02 AM
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I plan on rebuilding my 2.5 soon and two people bored out theirs enough to run forged Chevy flat top pistons. I was wondering how big I could safetly bore the block out, since some people say only .030, some say .060, but to fit 4 inch pistons, I need to bore the block .120 over, I believe. I plan to turbo it, which is why I want to run forged pistons. I'm not too sure if it makes a difference, but I believe it is a 1993 block (the Jeep is a bit of a Frankenstein from the PO). Thanks.
Joe
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Not sure about Chevy pistons anymore but there was some talk about uding them years ago. I forget what became of that thread. I don't think the block will support anything over .060.
There are these forged pistons:
https://www.summitracing.com/parts/uem-ic944-060/overview/make/jeep
https://www.summitracing.com/parts/uem-ic944-030/overview/make/jeep
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Thanks Jeffy. I was looking at those, but then I found out that the stroker guys used them because ICON moved the wrist pin location so they can get more displacement. I have to go through all the measurements and I'll probably just call ICON to see if these are a "stock" replacement. So safe over bore is .060, cool. Thanks again.
Joe
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Another question. It says the piston head volume is +21.000 cc. I'm assuming that's the dish cut into the head. Does anyone know if that is similar to the stock piston? I would like to keep the compression ratio as stock as possible, or possible a little lower to help with preventing detonation with the added boost. I was going to run hypereutectics, but I was told that they shatter when there is detonation under boost. I know everyone runs stock pistons when they turbo the 2.5, but I was hoping to prolong the life of this motor for as long as possible with forged pistons. Thanks.
Joe
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When I did my 2.5 I looked at the same thing, on my 94 block there was not enough meat to do it. the stock cylinder walls were too thin. Rebuilder said he'd have to sleeve the motor and it would be a wet sleeve which he said for my purposes would likely be not worth the money.