Main bearings after 50K of UR underdrive crank pulley

[turbohounds]

I took a couple pics of the main bearings out of my '92 AWD A/T with 98K miles (broke a timing belt, and getting rebuilt from that). I installed an Unorthodox pulley several years ago, right before the 50K mile mark. Car has run a 13.2 and was autocrossed regularly. I'm not interested in starting any good/bad arguments about the pulleys, but I've never heard or seen evidence from anyone but Buschur, so here it is. Take it for what it's worth. There is some wear, but doesn't seem out of line for the mileage. The main bearing next to #3 on the other hand, looks like it was scored. I'd be happy to take pics of anything in particular that someone wants to see better.

 

[turbohounds]

pic of the crankshaft

 

[Defiant]

Looks like just a smidge too much crush, and some kind of junk got flushed out of the crank on #2 and wound up in the bearing, but otherwise nothing hideous. #1 also shows more wear, the end that would benefit most from a dampener. How's the clearances?

However, in terms of the non-damped crank, the threat isn't supposed to be to the bearings, but to the crank itself. In some engine layouts, they'll be much more prone to snapping. I have no data on the veracity of this in relation to DSM bottom-ends.

What's your choice of oils? Any additives?

 

[tmizer]

Can you post a closeup shot of the lower half bearings #1, #2?

Per Defiant, post your rebuild clearances for all 5 if you have them.

 

[turbohounds]

I have always used Mobil 1, no additives, and changed every 3K.

There was no play in the crank that I could tell, but I've decided to build a stroker and won't be reusing this crank. I can mic the crank and post that if someone knows the stock specs.

The quote I've always heard from Buschur was they saw excessive bearing wear. This is a 6-bolt crank, so the results with a 7-bolt could be completely different. In the top photo, bearings are from timing belt to flywheel (1-4). Second, flywheel down to timing belt side (4-1).

Close up pic has the two bearings closest to the flywheel side (would be at top of pic).

 

[Defiant]

That bottom one is foreign material grinding; I suspect from the crush area being overloaded and some bearing backing being carried into the bearing from the oil passage opening on the crank (next time, chamfer those oiling holes), and the top one just might be from not having a dampener- it looks like excessive loading on that one quarter of the arc.

I'd like to hear what someone who's much more knowledgable about it than I am has to say about it.

 

[pianoman]

my cousin ran a unorthadox crank pully and just recently had bearing failure.... although i didn't think it was from his crank pully but the pics you posted makes me wonder. I orginally thought it was maby crank walk, even though it is a 90 6bolt. but he didn't have any signs of crank walk.....