350 thrust bearing failure?

[gwhiz]

what would cause the thrust bearing to go out. the motor is a 91 one pc rear main,with 117,000 miles on it.the motor is strong and clean ,could still see slight crosshatch in the cylinders,and no ridge at top of cylinders.the main bearing side clearance is still good ,but the crankshaft endplay is out of spec.the thrust bearing is trashed ,looks like crank was wearing into the side of the bearing lip.so am i screwed and need to line bore block or could i just replace bearings and polish or have the crank turned?

 

[crotchss]

Had this happen to a buddy's engine too. I asked the machine shop about it and they said they see it happen more often with manual transmission engines, because the clutch pressure pressing against it wears it out more. We put a new crank and bearings in the engine after a good cleaning and he has been fine since. You can't machine the crank to fix it either since it chews up the crank too.

 

[gwhiz]

this was in a conversion van that only saw camping and only towed a maybe 17 foot boat.so if it chewed into the crank counter weight a little the crank has to be replaced ?

 

[hurst1979olds]

Your main bearing might be bad but it probably didny wear the block or crank. Bur I would throw a set of bearings in and measure your end play.....if you have an automatic car it could be your converter. It could be ballooning and pushing against your crank. That can be caused by a stock converter pushing its limits or a trans with too much pressure...more then likely a converter.

 

[DRIVEN]

On occasion a torque converter can balloon and force the crankshaft forward. I got a free 350 with World Products heads because of that. I put new bearings and a good used crank that I had in it. Ran it for 30K more miles before I sold it.

Edit: Mailbox beat me to it.

 

[hurst1979olds]

Edit: Mailbox beat me to it.

Don't want to change topic but I don't know if I should be offended or not?.....mailbox!?!?......seems fitting, I like it. 8)

 

[gwhiz]

Your main bearing might be bad but it probably didny wear the block or crank. Bur I would throw a set of bearings in and measure your end play.....if you have an automatic car it could be your converter. It could be ballooning and pushing against your crank. That can be caused by a stock converter pushing its limits or a trans with too much pressure...more then likely a converter.

I am hopeing to just throw aset of bearings and rings in it and get it back in action.it has a ton of power so i think it will be fun in my monte carlo.

 

[DRIVEN]

gwhiz, If it's worn enough to mark the main webbing in the block, your crank might be too worn. I know mine was. Toss in a new set of bearings and measure your end play. Depending on what you find, you may need to look for another crank. If it wasn't using oil or smoking you could probably get away with reusing the rings. It's up to you.

Edit: Mailbox beat me to it.

Don't want to change topic but I don't know if I should be offended or not?.....mailbox!?!?......seems fitting, I like it. 8)

None intended. Just the avatar association that my brain makes. Maybe I should change mine before someone refers to me as brown dog :? .