Z28FirefighterI1

iTrader: (16)

Well I took my new motor back to my engine builder to see whats been going on because the car was throwing a P0336 crank sensor performance code. The builder pull the oil pan and seen the thrust bearing was chewed up on the back side and the crank to. The engine builder said something was pushing on the crank, but what? When I put the motor and trans together I did it while they where out of the car and it bolted up great nice and smooth. The trans is a th400 with a TCI ultimate street fighter stall and TCI flexplate. What do you guys think? Now I'm spending more money rebuilding the motor again and I don't want to put it all back together to do it again.

y2khawk

iTrader: (5)

how much gap did you have between the converter and flexplate before you pulled the converter forward and bolted it down?

Have you put excessive heat into the converter, ballooning converter perhaps?

Z28FirefighterI1

iTrader: (16)

I had about 1/8" before I bolted the converter up, and the the motor and stall only have 20 miles on them they didn't get hot.

Sean Collins

Did someone Hammer the balancer onto the engine Vs using a balancer installer ?

Hype

Damn, this is the first time I've heard of crankwalk since my days researching DSM's. Good Luck sorting it out.

Z28FirefighterI1

iTrader: (16)

I used a longer bolt to start the balancer on. What does the balancer have to do with something pushing on the back of the crank?

Z28FirefighterI1

iTrader: (16)

Somebody said the rear main bearing could have been installed wrong causing the crank walk? I also talked to some tranny guys and they said that if there was a problem with the stall bring installed wrong it would of chewed up the splines on the trans and they look good and the trans felt good.

tuff

iTrader: (15)

This is weird that i seen this thread because my motor is out and im in the same boat with the thrust bearing chewed up on the back side.My engine bulider said the same thing about the convertor being to tight and pushing on the crank.Im going to have to put it together to double check the clearance but if it comes back that the clearance is good i don't know what to do.If i remember right mine was 1/8 inch but when i put the new motor in i might have forgot to check clearance.

Z28FirefighterI1

iTrader: (16)

I know when I put it together I had clearance I could still spin my convertor. I don't know what to do? I can't tell the engine build that he's wrong and he screwed up thats just not going to work. What ever happened to the motor I need to know so it doesn't happen again.

cantdrv65

iTrader: (3)

Yeah you should be able to easily spin the convertor by hand with the engine and trans bolted together and no convertor bolts...If the convertor clearance was the culprit it would likely destroy the trans pump pretty fast...

Z28FirefighterI1

iTrader: (16)

Thats what a few tranny guys had sad and the convertor was easy to spin by hand. What do you think caused my problem?

Mean Green z28

iTrader: (17)

Like Collins mentioned, if someone hammered the crank pulley on, that could have messed the bearing up in the first place and then it got progressively worst. The only other option is that the bottom end wasn't put together right, 'cos a convertor shouldn't do that without causing other catastrophig failiure of some other system.

Not trying to say anything about your engine builder either but we had a customer who's engine (that was built by someone else) started making a real bad knocking sound after a few track passes and the engine builder told him it's probably because he pulled the wheels on the final launch before the bottom end acted up ... he's fixing it for free though but that's a bunch of BS, all our cars should have bottom end problems if that's true! Not everybody would admit an honest mistake.

LSXNV

iTrader: (1)

dude, for the life of me i can't remember what other small issues can cause this from the tranny side of things. probably too drunk tonight. i would give TCI a call. they are an easy bunch to talk to. that, or the thrust clearance just wasn't right when the eninge was built.

Ferocity02

iTrader: (60)

If you know how the main bearings are crank go together, you'd see that a walking crank is pretty much impossible. For the crank to walk, the thrust bearing must be SERIOUSLY fugged up, or non-existant. With proper bearings and clearances, the crank thrust should be between .003" and .004". Mine came out to be .0035".

pist0lpete

iTrader: (3)

Did you buy a flex plate that was made for a TH400 on an LS1 therefore it didn't require the spacer? Also, if you did use a spacer is is possible you had one of the truck cranks that doesn't need the spacer and you used one anyways? Just brainstorming here man I hope you get it figured out.

LSXNV

iTrader: (1)

i dont know about LS1's but i have heard of people actually putting the thrust/main bearings on the wrong main saddle. all so common for chevy guys to do this on traditional pontiac engines.

Z28FirefighterI1

iTrader: (16)

The spec sheet on the motor said the crank end play was set to .005 and now its like .050. The flex plate was the one for the ls1 it came with a crank spacer and the motor did need it the crank was stock.

tahoe

You guys are not alone with this crank walking thing:

http://www.performancetrucks.net/for...hlight=bearing

It would be extremly valuble if the root cause for theese failures could be found.
Are there any common factors in the thre trust bearing faliures?

It is a bit scary......

Br//

Z28FirefighterI1

iTrader: (16)

Thanks for the link but I still don't know what caused it, they didn't know in the link but thats weird that theres that many that have this problem but knowbody knows how it happens.

Ferocity02

iTrader: (60)

Your thrust bearing must be toast. Has there been unusual amounts of metal in the oil?