Should the main bearings look like this?

[SS_Sean]

I'd say you got screwed...but then I don't know the whole deal...
I bought a GN with a rebuilt motor with (supposedly) 13,000 miles on the clock. I've got some rod knock going on, and am pulling the motor after only 1,000 miles. I'm not going to blame anything on the guy I bought it from. Anything second party and not under warranty = mystery motor.

 

[Ed Valvo]

Did motor have steel caps? Might be line bore issue? #3 looked better than the rest. Typically, #2 and #3 get beat pretty good.

 

[gnxtc2]

Looks like the clearances were too tight or the bearings are too hard for the stock cast crank.

Billy T.
gnxtc2@aol.com

 

[hemi8]

Looks like the previous owner pounded the hell outta that engine with detonation, crankshaft flexed under the load, caps walked and there you have it. I would completely tear it down and check everything. You will need to inspect those main caps real close, did they fall off when you removed the main bolts, especially the center 2? If so, you will need to fit the block with new center caps. After the crank saw so much stress I woulnd'nt trust it.
Mike
86 GN