Broke a piston on 17 lbs WHY!!!
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Teching In
Joined: Aug 2007
Posts: 47
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From: Greenville, South Carolina
Broke a piston on 17 lbs WHY!!! My 408 317 headed twin 76 blow thru was just sneeking up on running some good numbers went 5.06 140 then 5.05 140 .Then on the 3rd pass on 17lbs right in the lights made a noise went 5.10 136. Got it home took the head off and #2 has a hole on the side down to the first ring. piston is a Mahle powerpak which is forged alum.AFR was 6.6 on E85,timing was 21. Any ideas on this
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8 sec potential, 12 sec slip
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Joined: Apr 2002
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From: Savannah, GA
Ive heard the ringlands on the dished mahle pistons are pretty crappy to begin with. I ran flat top mahle's with -4cc valve reliefs on my LS6 with 72cc heads which got me about 9.4 scr and i had no problems whatsoever at 15+ psi and up to 20 deg of timing. However for my 370 im building up right now I needed a dished piston, so I went with wiseco pistons. They have a very thick ringland. I know none of this helps what happened, but maybe you can use this info for future, and others reading it can benefit from it as well hopefully... Good luck with it all man 
I was surprised to see so many posts until KP's about the powerpak pistons...
You have far surpassed the capability of that piston. Its a 4032 alloy that I wouldnt run over about 8-10 psi on (600 rwhp would be my recommended limit for a converter/auto or maybe closer to 700 rwhp on a stick car).
You need to go to a 2618 alloy custom piston /w lowered ring lands, upgraded hell-fire or stainless top ring and upgraded tool steel pins.
You have far surpassed the capability of that piston. Its a 4032 alloy that I wouldnt run over about 8-10 psi on (600 rwhp would be my recommended limit for a converter/auto or maybe closer to 700 rwhp on a stick car).
You need to go to a 2618 alloy custom piston /w lowered ring lands, upgraded hell-fire or stainless top ring and upgraded tool steel pins.
