sotodn1

So after much wait, I finally began building the 350 that will go into the 86 iroc. The only problem is when I started to install the pistons, then the rod caps, after I tighten them down I turned the crank to make sure everything spun freely. I checked the rod bearings and they had noticeable scratches on them. Funny thing is I didn't notice any noticeable scratches on the crank. What gives?

Tuned Performance

iTrader: (92)

The bearings are very soft. Unless alot of the bearing material comes off and stacks up there was little friction when you rotated it bye had not enough to scratch the crank.
You had assembly lube on the bearing after you checked the clearances ?

sotodn1

Yup had lubed it up pretty well. Used (and the exact name escapes me) but It is an assembly lube that I used from Lucas. Not sure if using a oil additive like lucas heavy oil stabilizer would help with those scratched surfaces and will allow me to rebuild.

Tuned Performance

iTrader: (92)

Not sure but you can scuff a bearing coating with your finger or a paper towel super soft outer layer.

sotodn1

Not sure I understood what you meant. I included a pic of the bearing.still unsure if i can press on and use an oil additive as a fail safe

Tuned Performance

iTrader: (92)

Its hard to tell in a picture. But we're the big end of the rods reconditioned and the crank turned or polished or checked for out of round ? if its just the coating thats rubbed through you might want to re assemble and check your clearance if nothing else plastigauge.

sotodn1

No the crank wasn't reground. I am using the stock parts that came out the motor, just cleaned up and new bearings. Weird because the old bearings dont look bad. As far as the scratch, it is enough that you can feel it in your fingernail but not enough to get your fingernail hung up.

TTOP350

iTrader: (8)

It looks like some plasti gauge was left on the crank then the motor rotated.

sofakingdom

iTrader: (1)

That's not particularly serious, by itself. Mostly just means you got some dirt or trash of some sort in there.

Not near as serious as re-using a worn crank.

Don't expect real great longevity out of that. If all you're looking to do is to sodomize somebody by doing that and selling it, then yeah; but if you, or someone you know, is going to be using it, then you'd be wise to refresh or replace the crank. Not much money, but money WELL spent. If you think you don't have the money for it now, then where do you think you're going to get the money from to do a COMPLETE rebuild in a few weeks when it fails, and takes all manner of other parts along with it?

sotodn1

Yeah to be safe I might just replace the crank

sotodn1

Just to update everyone I decided to buy a new crank. It wasn't a matter of money, just time, cast cranks aren't expensive.

zraffz

Don't forget to rebalance. Your fresh motor with assembly lube (I like lubriplate) should not show any bearing wear