So I have an issue with my 440 where it ate the thrust bearing and ground into the crank,not the journal but the rear side of the face of the crank. not exactly sure why but I plan the investigate.. what are my options here? can I have the crank repaired or should I replace? stock steel crank,rods and heavy trw slugs.I didn't build the thing so not sure what happened but I suspect it took a little while. engine runs great so far.could of been bad from the get go or alinement issues with the trans or converter but I didn't notice any problems bolting this together.
Thanks

A crank repair shop should be able to weld it, and re-machine it. Not sure how much it will cost?

If the crank is being used in a high rpm application get rid of it. Had the same thing happen with a 340 forged crank, engine builder said dump it.

Why?

Welding and regrinding steel cranks has been going for along time, even in high rpm race engines.

It may be as cheap to just buy aftermarket than to replace.

Assuming you can find a competent shop locally to fix yours.

Centrifugal force

You should try and find out why it ate the thrust surface first so it won't do it again
If it was assemble incorrectly, center main bound up against the thrust surface, it would cause that. If assemble correctly, it had between .004 to .010 thrust clearance. If it was assembled correctly you should have the converter checked to see if is damaged from ballooning, That is one of the major causes of the thrust surfaces being damage
I wouldn't, and don't , worry about having the thrust surface welded, usually it is spray welded on that surface and then ground down and polish to the proper width
Good luck on this, let us know what you decide and how it works out

Not rocket science. How do you think they made stroker cranks back in the day?

Back in the day I had a 340 crank that spun a bearing and was chewed up pretty good, had it welded up and was ground .030 under and held up for almost 20yrs as far as I know its still running in that car now, car ran 11:50 and spun it up to 7 grand quite often.

[spoiler][/spoiler]Out of curiousity...is this 440 crank in a 4 speed car?

Thanks Everyone for the advice,helps a bunch. I think the converter ballooned but I haven't torn it down yet. can you purchase a new aftermarket crank and just drop it in or will you need a rebalance? I rarely take the rpm's past 6000. easiest thing to do is have it repaired and pick up a new converter.

Any time you change any of the rotating parts in a decent motor you should have those parts check for weight and if they will be out of balance or not
I've seen a bunch of variances in stock parts on both weight and rod lengths

If it's cheap to get done in your area, there's no problem having it welded and re-machined. I've done it in the past and never had any issues w/ it.
Like said before...there are a whole lot of race engines running welded cranks.

If you buy a new crank, at the very least you'll have to have it balanced. Definitely not a drop it in and go type of deal. Depending on what crank you buy, it may or may not need some corrective machining to be useable. Not uncommon for the cheaper cranks to have to be turned .010"/.010" to make them useable after you buy them new.

As to why yours ate the thrust...could be a few things. Converter ballooned, not enough clearance b/t converter and flexplate to start with, thrust not "set" when built, an out of balance issue, etc.

Centrifugal force is a meaningless answer. The thrust surface is so close to the center of rotation that there is no meaningful effect.

Crank grinders used to do this all the time. The main problems are we're running out of crank grinders, and a crank grinding machine has no special way to grind the thrust after it is welded. They end up using the cheek of a grinding wheel and it's not built for that.

R.

Arent used steel cranks a dime a dozen now that there's so many new aftermarket cranks available.

If the converter ballooned and if that is the cause for the crank failure it's probably not the converter's fault, but a problem with a crimped cooler line, clogged cooler, excessive main line pressure, or another issue in the transmission.

IDK since I didn't build this engine but I have half a mind of ball honing it and sticking a stroker kit in it.