enginjoe

iTrader: (11)

Went to the track and ran a 12.058 @120.3mph w/2.0 60ft.

After the run I noticed a clattering noise at certain rpms and loads. There was no detonation and I think it was almost impossible due to the following: T67 @8psi, 50/50 mix 91/100 octane, 100% meth injection turning on at 6psi with about 10.2 afr. It sounds deep in the engine more than up top. I took off the valve covers and everything is ok up there (I up graded springs, ti ret's and chromoly pushrods when I did the cam). I pulled the oil filter and cut it open and it is filled with small metal flakes (oil was 2 days old). So, I'm thinking spun rod bearing from the sound and from my searches on the forum here. Anyway, my question is, would it be worth it to rebuild, using the stock crank(if useable) but use forged pistions and rods this time or just go for the whole enchilada. My plans are to go ~8.5 to 1 compression w/good heads and max out the T67 using an intercooler then eventually get to 15 psi with a T76.

edit --> Oil pressure is good: 40psi at idle

gametech

iTrader: (1)

Sounds like an excuse for a stroker crank. I mean hell, the motor will already be out, right?

navymitch12

iTrader: (1)

sorry to tell you but sounds like you spun a bearing.....

i spun one like 4 mths ago and it did the exact same thing you are describing

enginjoe

iTrader: (11)

Yeah, motor's coming out. It's gonna take me awhile because of work and stuff. Then I've got to save up some dollars...

I was just wondering what I could do for a little bit less money.

99.9percenter

iTrader: (2)

Spun bearing may not of hurt the crank. Clean off the burnt bearing material, check everything out.