help with some main issues.

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06-21-2011, 12:21 AM
Lithium

help with some main issues.

hey guys, wanted to start a discussion about main bearing failures. I recently finished the break in period on my new motor and noticed some odd increase in knock count and lower then normal oil pressure. Finally got the heart to open the pan and look at the bottom mains. two of them were flattened and expanded outward. The shop that build the motor said it was caused by excessive amounts of boost and or detonation. I myself have never seen mains flatten out like this. I never pushed the motor past 15psi and the AFR was never more then 14ish during the break in period. Any advice or perspective would be appreciated.
06-21-2011, 02:02 AM
RealMcCoy

detonation will wipe the center mains every time...

Is the motor stock? What turbos? supporting mods? what method of tuning? What was the AFR under boost? were you logging the knock counts?
06-21-2011, 10:27 AM
Lithium

Quote:

Originally Posted by RealMcCoy

detonation will wipe the center mains every time...

Is the motor stock? What turbos? supporting mods? what method of tuning? What was the AFR under boost? were you logging the knock counts?

The turbos are blouch 16ts with supporting mods, tuning with SAFC2 and MAFT. Logging knock with HHH. AFR under throttle was around 11ish
06-21-2011, 10:37 AM
CoreyB

Is it possible your mechanical or ignition timing is wrong?
06-21-2011, 11:55 AM
UTRacerX9

It's also possible they just flat out used the wrong bearings.
06-21-2011, 08:20 PM
Lithium

Quote:

Originally Posted by CoreyB

Is it possible your mechanical or ignition timing is wrong?

The heads were milled but not enough that would make me worried about mechanical timing. I hope the Ignition timing would be right, Thats still up to the ECU at this point. I'm sending it off to get checked.
06-21-2011, 08:23 PM
Lithium

Quote:

Originally Posted by UTRacerX9

It's also possible they just flat out used the wrong bearings.

I'm not sure, this guy and his father have been building engines their entire life with many people backing their work. That being said, all the other mains had premature wear on them. It looked like someone took a hammer to the flywheel side mains. I guess the good news is the crank is fine but needs some work.