lmt0705

iTrader: (7)

I was at the track over the weekend and after the last couple of runs and on the ride home i noticed my oil pressure was lower than normal and when I cracked the throttle the pressure dropped. I changed the oil and cut the filter up and sure enough there were tons of copper shavings. I pulled the motor down and found that my thrust bearing and the one in front of it were fu--ing fried. the cap side of the bearing was actually cracked!! and they all looked like they were heated. the rod bearings looked decent and the motor dident make any noise. The line bore was out .001-.0015 I was playing around with crankcase ventalation at the track. and my oil was 5/30 with around 3000 on it. did I boost the crankcase and lift all the oil? maybe I twisted the mains? Im running arp studs and the berrings were clevite 77s. the shops I talked to were puzzled that I had this problem at my horsepower level.

Whistler

iTrader: (46)

Who built the engine? They could have failed to seat the thrust bearing properly when torquing the mains, resulting in no thrust clearance and bearing damage.

lmt0705

iTrader: (7)

the motor had over 6000 miles on it and around 40 pulls on the dyno with no problems

Shawn @ VA Speed

iTrader: (3)

3 things usually kill main bearings-not enough clearance,crank flex or detonation.

lmt0705

iTrader: (7)

pistons look great,ringlands look great. clarance was .0022-0025 crank is being checked out

redvictor

take a look to see if your converter has pushed (ballooned)against the crank.The rear main would have gone first,and the one next to it after.
I would have more clearance on the rear main..003" to .0035" is good....

lmt0705

iTrader: (7)

its a 6 speed car, why would I want more clearance on the rear main, or do you mean the thrust bearing? anyone else have any ideas on what happened?

ChiTownHustler

iTrader: (3)

Or a loose nut putting the whole thing together

redvictor

OK,assumed it was an auto.... more clearance on the rear main bearing.It sees more heat than any other.Thrust clearance should be std tolerance.
I like Brad Penn oil.It helped us a lot.We now use Castrol Edge 25w/50 with good success...