Mine really arent either. This is the first instance of trying to diagnose a bearing to predict a potential issue that i have encountered. The 7M Bearings were spun/wiped, and otherwise destroyed so it was easy to determine (along with knowing the oil line wasnt connected anymore) that it was starvation of oil.
Accelerated wear is possible but i feel that in the illustration on page 24 it shows nearly the entire surface of the bearing is worn. It is possible that ive had some accelerated wear. That crank wasnt polished or touched other then to have it cleaned as the motor came apart in running condition. It was also built to stock specs. I have read that good clearances for a performance engine below 1khp is .0025" for the rods and .002" for the mains witch is outside of the stsandard spec for a 2J but is within the "maximum" limits.
Im thinking that at my power level maybe things are starting to flex and move around in the thousands of a inch level that maybe more breathing room in the bearings may benefit.
Im going to my machine shop today and im going to discuss bearing clearances with him further.
Heres a picture of the ProEFI log from the run that bent the rod.
The lines from highest to lowest are as follows. Blue = TPS, Green= MAP, Pink = Fuel Pressure (variance is below 2PSI), Purple = RPM, White = Ignition timing.
You can see that boost spiked from 25 up to just over 27psi here
I removed the O2 multiplier and AFR feedback so you can see the other parameters clearly. O2 multiplier is the correction from the O2 feedback. It was always within 5 percent and actualy was more stable at the higher boost with only a smaller 2-3 percent correction. There was no signs of detonation in the log or on the piston/combustion chamber.
I think my plan moving forward with the new motor is to pull 1 degree of timing above 20psi to be on the safe side and later in the year go back to tune it up to around 30psi.
At that point i think ill blow up my TH350 and be down again.
