So... Long story short my trans had appearantly been pushing forward on my crank and wore down the thrust bearing. Would it be ok to replace just that one main bearing with a new one and leave the others alone? The engine only has 12k miles on a fresh rebuild. Thoughts?

 

yes, as long as nothing more than the trust bearing was wearing you'd be fine to replace just the one shell. Use your best judgment though, look over the trust surface on the crank and all the other bearings while you're down there.

 

if your already torn down that far why not replaced them all, yes i know its a bit more expensive, but why just replaced one when it could lead to problems later on? i would suggest doing all of them, a little extra money now may save you alot in the end.

 

Agreed. For the price of a bearing set, replace them all while you are in there. No sense in replacing just one.

 

Check endplay in crank
also might as well check bearing clearance while out and put a new set of main bearing in it perhaps clevitte h bearings

 

Good idea ;-) looks like I can't order just the single bearing anyway... Not that it matters much now bc this little setback just became a big pain in the ***! Looks like the crank IS worn where it was pushing against the bearing so now I have to adress that :-( can it be machined and fitted with an oversized thrust bearing or will I need a new crank? This all started with a tranny failure and snowballed in to much more lol. Thank you all for your help on this ;-) I want to get the damn thing running again before summers over!

 

have the crank turned .010 and buy the appropriate bearings.

 

If the thrust surface is worn on the crank then you do have issues. If this is a stock crank, I would suggest finding a good used one instead.

Shane

 

Is it an aftermarket crank if so could have a fillet radius if that is the case check to make sure bearing is chamfered.

 

You may have damaged the cranks thrust surface as well so that must be checked and / or addressed as well.

 

It's a stock crank that's been balanced to the rest of my rotating assembly so I wanted to repair it. I called a local machine shop yesterday and they said that it could be welded and re-ground so it looks like that's my best option. I hope this stupid thing is done surprising me lol

 

yes but after welded and being repaired it will not be balanced to that assembly.honestly for a correct repair like shane said a new crank might be needed. i would suggest pulling the engine and having it properly repaired, or you can chance it and end up costing yourself an engine.

 

good call. didn't even think about the crank thrust surface. brain

btw, you should have the trans rebuilt to address the excessive endplay. otherwise you'll be doing the same thing 12k from meow.

 

What trans are you running? The problem (at this point, regardless of where it started) lies in the trans AND the engine, it's not isolated to either one or the other.

 

I had the 4L60E that was in the car when I bought it (I have no idea if it was rebuilt or what but the car had 156k miles on it when I bought it, bone stock down to the paper filter) When I was 19 I spun a rod bearing in the stock motor and started saving for a rebuild. Got a 30k mile LS6 block, a 'new' crank (20k miles w/ no issues), new stock rods and pistons (hey, I'm poor lol) MS3 cam, stock heads, full bolt-ons, etc... I didn't have the money for a built trans at the time so I threw my Yank SS3600 on the stocker which turned out to be a mistake.

This all started in October when I was driving to school. I was slowing down at a stop sign (engine at about 2000 rpm-ish) when all of the sudden *clunk* engine dies, car rolls to a stop. There was no loss of oil pressure or anything of the sort so I tried turning it over again and nothing. Locked solid... or so I thought.

So I got the car towed home and started searching for the problem. Interestingly enough when I got a pry bar and turned the engine over by hand I found that I could spin it with no problem what so ever about 80 degrees each way before I 'locked' up again. So at this point I figured I dropped a valve or broke the timing chain... nope, both fine. It wasn't until I pulled the engine out of the car completely and fought with the trans that I found this:



It appears that something in the trans locked up and completely destroyed my stall. Nice. I mean, don't get me wrong, I knew the damn thing wasn't going to last long but I didn't expect it to do that kind of damage. I guess a stock trans behind that motor lasting 12k miles with my less-than-kind right foot abusing it.

Well, having found the problem I bought a new TCI stall (cheap) and a built trans. I started putting the balancer (which i had taken off when I removed the front cover thinking I broke the timing chain) back on and noticed that I had about 1/16 of an inch of endplay. Lovely. And of course this was after I had already put the motor back in the car.

So, out it came again... this time on the engine stand. Pulled the oil pan, windage tray, got the thrust bearing out without removing anything other than the main cap holding it in (hoping to be able to replace the bearing and nothing else) and then realized that it had worn the crank some. So here I am. At this point I don't have the money to blow on a new rebuild so I'm going to pull the crank with the heads/rods/pistons still on/attached, take it in to my machine shop, have it fixed, new bearings, and back in. What a headache lol.

Sidenote: When my tuner was tuning my car he mentioned something about my line pressure being high in my transmission but didn't act like it was a big deal. Apparently it was lol. I still don't know exactly what caused all of this, but I will be watching it very carefully when (if) i get it running again.

 

How much is fixing this engine going to cost you versus picking up an LQ4 at a junkyard and dropping it in without opening it up at all?...I'm not trying to be a jerk, but it seems like you've had some bad luck...and to be honest, I've seen other people go down similar paths before, and wind up with no money, and a car sitting in the driveway that could be cool, but instead it's either got a broken engine, or no engine.

When I was 18-19 and didn't have the money/tools/skill to repair a damaged engine, I swapped it with a $500 junkyard engine, and didn't so much as take the valvecovers off, I just put my cars accessories on (LT1 stuff, it was a Caprice) and drove it, and it ran fine until I decided to be a hot shot and rev it 1800 RPM higher with a different cam...and surprisingly enough it lasted like that for 10-15K miles too...then I blew it up and tried again with another junkyard engine, this time I replaced the oil pan gasket because it was SOAKING WET, didn't cam it, and it ran great for a couple years before I got rid of the car.

Again, not trying to be a dick, just trying to offer you some advice to get your car on the road and enjoyable rather than worrying about issues that you're really unsure of the direct cause, and wether or not they'll come back.

 

Nas,
Welding and regrinding the thrust has absolutely no effect on the crankshaft balance. It is a very viable repair if done properly.

That being said, all of the major bearing manufacturers offer main bearing sets with wider thrusts. Your crank grinder should know about this. Unless the crank is really worn badly this is the easiest way to fix it, have it reground for the wider thrust bearing.

 

i stand corrected, i had always been under the impression when ever any repair to a crankshaft is done it must be rebalanced as an asembly so that it does throw engine balance off.

 

Usually it is so minute, it doesn't make a difference.