Thrust bearing replacement

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supercuda

supercuda

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I had my 340 rebuilt last year and it has maybe 1500 miles on it. Transmission was rebuilt at the same time, its a 904. The other day I hear a noise and discover the torque converter bolts rubbing on the block. Put a dial indicator on the crank bolt and discovered I had .023" of crank walk indication thrust bearing wear. Ive been told I can just replace the bearing while its in the car, and ive also been told to pull the crank and have it inspected. What are others opinions on this?? Also opinions on the root cause? Everything Ive been finding is leading to torque converter ballooning. My transmission guy says he doesn't see that on mopars with the exception of race cars. Motor is stroked to 416 so it's a mild build. Transmission had a shift kit put in it and has a hughes 3000 stall. Any help is greatly appreciated.
 
If it were me, i would drop the pan and inspect the mains, caps, bearings and block. I had a 318 once that the thrust bearing went out and it actually destroyed the block. Pull everything, inspect and repair it. Maybe cought it early enough where it didnt cause and damage.
 
Ditto... Lever leave anything to chance. The most important thing about a part failure is finding the cause so it won't happen again. If the thrust clearance is that far out of specs...what else is ?
 
Pull the engine, take it apart, inspect crank and block, clean everything. Check the tranny/converter, make sure they didn't cause the problem ..................

Good luck
 
Check the torque converter snout and see if it was interfering with the end of the crank (ie too tight).
 
famous bob said:
more than likely u ruined the thrust surface on the crank, be lucky if u didn`t !
Click to expand...

Crank is probably "machined" and screwed. Disassemble and do this. Thank me later. J.Rob

Cheepythrust.jpg
 
Thanks for all the replies. Once I get some garage space to tear it apart ill know more.
 
If the wear is on the converter side there is a 99% chance the converter was installed incorrectly. Then there is a 1% chance the converter doesn't fit the crank.

If the assembly is wrong there isn't a feed hole in the world that will fix it.
 
yellow rose said:
If the wear is on the converter side there is a 99% chance the converter was installed incorrectly.
Click to expand...

Are you referring to the converter not being fully seated, and damaging the bearing on initial startup, or an incorrect airgap?
 
@RAMM tried to send you a msg, inbox is full.

Do you mind elaborating on the bearing modification, or do you have a thread where it’s discussed in-depth elsewhere?
 
yellow rose said:
Yes.
Click to expand...
The old Chrysler method they used to tech at the drag seminars was to file the oil grooves bigger in the sides of the thrust bearing, following the natural taper already in them, but leaving the outside the same, just creating a bigger oil pocket. We did it on the hemi we raced for 14 yrs after loosing a bearing and crank , due probably from misalignment to start with, but that's another story, which is very important to do right.
 
Convertor fitment/ clearance, ballooning, or to much line pressure in tranny.
The first is most likely if you aren't using a high line pressure t brake like a Griner, doesnt sound like you are.
Just a shift kit and taking out the thrust is most likely the convertor isnt where its supposed to be
 
JoeSBP said:
@RAMM tried to send you a msg, inbox is full.

Do you mind elaborating on the bearing modification, or do you have a thread where it’s discussed in-depth elsewhere?
Click to expand...

Cleared out.

It's just a 1/32nd hole intersecting the main and it works wonders. I do it all the time. Guess what? Never had a thrust failure in 15 years since I've been doing it. It was published in an issue of EngineMasters Mag by Steve Dulcich when he lost a thrust bearing in a 318 he had in his truck. J.Rob
 
I trashed a thrust bearing in my 318 magnum a while ago. Never found the culprit. Destroyed the crank and almost #5 piston. The **** chunks will fling up and lodge into the pistons oil return holes. A couple skirts and a few gouged lower cylinders. The aft lower portion of the thrust face took the beating. Behind was a 904, too. Pull the engine and inspect.

The engine guys blame the transmission guys and the transmission guys blame the engine guys. On the rebuild I filed the bearing how famous bob describes above.

You can read this about it, and thrust bearing failures, too.

Thrust bearing failures
 
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