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Old 11-05-2012, 04:23 PM   #1
fatblockvelle
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8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread!=)

OK ... Need some 8.1 help here. I am far from a guru and dont claim i know everything... but my number 5 cyl is down on compression.... =) number number one is broke and number 7 is cracked.... has anybody ever seen anything like this before?"?? have a bent pushrod in #5 but im sure has to do with vanishing piston trick. question to you guys is... im tossing another motor in this car and i dont want to have same issues... this motor was in a bread truck and was tmu. One more question... does anybody know if gm stamps the pistons from the factory like that" or someone rehash this thing???? ??? sorry for the ramble ... THANKS FOR ANY HELP!!!!
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Old 11-05-2012, 04:23 PM   #2
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Re: 8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread

Top rh of 2 other pistons are cracked.
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Old 11-05-2012, 04:24 PM   #3
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Re: 8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread

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Old 11-05-2012, 04:37 PM   #4
no moa
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Re: 8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread

wow, last one i saw like that the guy missed a gear and she saw 7k rpm then BANG! Are you stuffing another 8.1 in the car? The guys around here won't buy a truck with one in them, they hate them for some reason.

edit: I should clarify, its wasn't an LS motor that blew up, just was using it as a reference to the last one i saw blown up.
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Old 11-05-2012, 04:59 PM   #5
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Re: 8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread

Quote:
Originally Posted by no moa View Post
wow, last one i saw like that the guy missed a gear and she saw 7k rpm then BANG! Are you stuffing another 8.1 in the car? The guys around here won't buy a truck with one in them, they hate them for some reason.

edit: I should clarify, its wasn't an LS motor that blew up, just was using it as a reference to the last one i saw blown up.
car has been together for a couple years now ... she is fun... i only rev her 5100
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Old 11-05-2012, 09:19 PM   #6
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Re: 8.1 , broke piston , help , ideas??? Pics inside. This is not your average thread

Use Forged Pistons!
Looks like piston fatique, Not common on a N/A engine.
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