Engine Teardown Analysis and Questions (pics)
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Engine Teardown Analysis and Questions (pics)
Hey all,
For years my car has suffered from some smoking under deceleration. In an effort to fix this I was replacing the valve stem seals when I noticed that the #7 cylinder was not holding pressure. I pulled the motor and found this:
This is a stock shortblock with AFR heads, around 10:1 SCR. Never revs past 6800. My tuner set up the car for reliability as I run at the track often. What I'm wondering is what the most likely cause is for cracking a piston like this. I'm taking delivery of a Katech 427 next month and I want to make sure this doesn't happen again.
Thanks in advance to any helpful replies!
-ch
For years my car has suffered from some smoking under deceleration. In an effort to fix this I was replacing the valve stem seals when I noticed that the #7 cylinder was not holding pressure. I pulled the motor and found this:
This is a stock shortblock with AFR heads, around 10:1 SCR. Never revs past 6800. My tuner set up the car for reliability as I run at the track often. What I'm wondering is what the most likely cause is for cracking a piston like this. I'm taking delivery of a Katech 427 next month and I want to make sure this doesn't happen again.
Thanks in advance to any helpful replies!
-ch
Last edited by hyperion; 03-30-2009 at 03:09 PM.
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That is somewhat common, and almost always #7. Don't know why though. One thing I have read that makes some sense is the possibility that the intake manifold flows slightly more air to #7, which would make this cylinder run leaner than the rest.
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Thanks for the replies! No power adders, and runs on CA 91 octane pump fuel. But it's somewhat comforting (I guess) that #7 is the common failure.
Is this type of failure usually due to heat or detonation?
-ch
Is this type of failure usually due to heat or detonation?
-ch