Need some help with thrust bearing issues, just got done for the 2nd time putting the motor back together after thrust bearing failure and it did it again, so the set up is the stock ls1 block in my 99 Z28, stock crank, stock rods with ARP bolts, forged Wiseco`s , line bored and ARP main studs, TEA CNC heads .045 head gaskets, Melling oil pump, SAC city barbell and oil pickup hold down, BTR new Stage 3 cam 231-244, .631-615 on a 112.5 cam, GM performance Caddy Lifters, Trunion upgrade, Fast 92 with Nick Williams 92, DW 42lb injectors, Hooker Blackheart 1-7/8" headers with the full Blackheart true duals exhausts, Katech manual tensioner, Mighty Mouse catch can, and 3:73 gears. I am sure there is more but i had the work done by 2 different shops with very good reputations, the first time i had .005 of thrust clearance, the second time i had .004, both times i used Clevite Tri Armor MS-2199HK-10 coated bearings, no issue with the mains or rod bearings just the thrust bearing, during the first rebuild i also had the trans done with upgraded parts by a good local trans shop with a 501 converter, 3600 stall, so after the first time i took it back to them to make sure there was not a issue with the trans causing the issue, they said it was fine and there was nothing wrong with the trans. Before i started this project the car had 52,000 miles on it and everything was fine no trans issues, when i tore the motor apart no thrust issues, this is not the first motor i have put together, been building motors for a long time, but what the hell am i missing. sorry this was so long, just wanted to give you as much details as i could, i am about broke after 2 rebuilds, thanks for the help.

 

Unbolt the torque converter from the flex plate. Slide it towards the transmission there should be 1/8 to 3/16 clearance. Between the flex plate and torque converter mounts. Make sure there are no shims. Only other thing I can think of is to much power causing ballooning. I’ve had good luck with FTI converters.

 

i have between 3/16" and 1/4" clearance between the converter and flywheel, i was even concerned with runout on the snout of the converter so i chucked it up in the lathe and put a dial indicator on it and ha about .0005 runout. and had 1-1/8' from the bell housing to the converter mounting pads with it pushed all the way in before i bolted it up.

 

sorry, i also forgot to mention the first time i got the gold flakes in the oil filter within a 100 miles, this time was 15 minutes when draining the break in oil and cutting open the filter.

 

Converter ballooning. Some aftermarket stall converters are worse than others. I set up my thrust on my automatic trans builds at .008-.010 minimum. I’ve seen guys go .015 without issue on auto builds. I’ll go .004-.006 on manual trans builds.

 

Did you check crankshaft endplay upon assembly? How much?

 

like i put in the first post i had .005 on the first build and .004 on the second build..

 

@Che70velle are you taking that clearance off of the crank or the bearing, thanks.

 

Bearings. Surface plate, 300 grit paper, and lots of oil. Circular motions, with even pressure left to right. You’ll spend a couple hours doing this, but it’s worth it.

 

Is the rear end and drive shaft original and or the d/s the proper length?

 

The drive shaft is original , and the stock 10 bolt is in it.

 

You didn’t mention which transmission?
What is a 501 Converter?

 

Stock 4L60E, 501 Converters is a local company in Cleveland, they have been around for a while, and seem to make a pretty good product.

 

Intteresting...GM LS Gen III / IV thrust bearing clearances are 0.0015- 0.0078 and doesn't address whether its for manual or auto. I'll take that as a tip from a pro!

Thanks again sir!

 

Thanks.

When you push the converter towards the flex plate all the way, do the converter pads contact the flex plate?
Its an issue if it doesn’t.
Are you using washers to get that clearance to 3/16?

If it started making metal that fast, I doubt it’s a ballooning issue.

Have you measured line pressure in the trans? Or cooler line pressure?
Excess pressure in the converter will push it forward. Common problem with T400’s, not sure about 4L60’s.

 

The pads hit the flexplate with no issue, did not measure the line pressure, but it did start making flakes after running it for 15 minutes, drained the break in oil and cut the filter open.

 

When you say running for 15 minutes. What kind of running? Idling, 4.5k launch off a 2 step? What's the situation?

 

Going to ask a question,,, but its a dumb one,, is there a front/rear top bottom for the main that has the thrust bearing? I've seen them get flipped 180 when final assembly started.. covers the oil hole. I dont recall what a LS one looks like .. been a while.

also once something sheds metal, even if it stops it going to be spitting the shrapnel out for a while..

 

I just checked.

The Clevite’s I have are H series.
They have 3 oil drain slots on the thrust (rear) side vs 2 on the front side.
Of course the block side has the oil groove. As well as locating tangs, so would not go in the wrong way.

If seeing more metal in the oil, its easy to check thrust clearance in the csr.

 

The Thrust Main can easily be "centered" when their attaching bolts are loose, only hand tight.
After the crankshaft is installed with the thrust main only hand tightened, tap the crankshaft fore/aft.
Now measure End Float, my "spec" is .008"-.012".