Engine Thrust Bearing Failure

[RCP]

I am in the process of tearing down a Cummins 5.9 diesel for a rebuild, I did not hear the engine run before I bought it and did not get much history on the engine. When I pulled the oil pan, the flange on the thrust bearing was laying in the oil pan. Upon further disassembly, I found no damage to the block or the crankshaft, but I did find the remainder of the thrust bearing in good shape except for the missing flange. This engine was mated to an automatic transmission. I also found some bent pushrods and I think there was water leaking into one of the cylinders.

Has anyone else seen this type of failure?

Any idea what would cause the failure?

What should I do to avoid a repeat failure?

Thanks
Rich

 

[Bob Bancroft]

What about the other half of the thrust bearing? Same? Worn, ground, or broken off? In your picture, it doesn't look like a multi piece thrust bearing?

I have seen thrust bearing failure, but only in an application where there was a double clutch, and a throw out bearing applying lots of pressure to the crankshaft for way too long [continuously].

Was this engine always mated to an automatic?

 

[RCP]

The other side of the thrust bearing shows no wear at all, FYI in this engine only the upper bearing has thrust shoes. I only know that the engine was most recently used with an automatic transmission, no way to know what the rest of the history might be. I can also say I do not think it has not been apart before, bearings are all standards, there is no added numbering on the rod caps and the killer dowel fix was never done.

Seems strange to me that the thrust shoe could have worn and broke off, but no apparent damage to the crank or the block, maybe just lucky?

 

[Dopp Creek]

What about the machining of the block in the are that supports that part of the thrust washer? If it doesnt have support behind it, or the radius of the bearing doesnt match the machining, it could stress enough to break. I know nothing of 5.9 blocks, but have machined a lot of aircraft crankcases with thrust bearings both integral to the bearing and insert style.

 

[RCP]

Good point, I didn't see anything the first time, but I will look again.

 

[Bob Bancroft]

I also have never been into a 5.9. No offense intended, but was the thrust bearing in the correct spot?

Interesting that you say there is only half of a thrust bearing. Are all 5.9's that way? They must not ever figure on much thrust load.

 

[matthies]

Torque converter ballooning, had it happen on a 400 sb chevy. And knew the old lady that drove it.

 

[used red MN]

Just doing a web search on your problem it sounds like the thrust bearing may be 3 pieces to start with. So the thrust piece that fell out may be a separate piece. I know some bigger diesels are made with the thrust pieces separate. I would suggest doing a web search on the thrust bearing failure on that motor and study the replies. I will attach a forum response that came up when I did a search. I am referring to the response by sicumminsde.
Example info

 

[RCP]

Yes they are all that way, when you look at listings for main bearings, the bottom shell has no thrust surface.

 

[RCP]

You are correct, there are lots of large industrial engines where the thrust load is taken by separate thrust washers, but the Cummins 5.9 is not one of them.

 

[RCP]

I wondered about a trans or converter failure, but could not find any comments like that during an internet search. I also do not believe in coincidences when it comes to engine failures, the bent pushrods are trying to tell me something.

 

[RCP]

I did a Google search as you suggested, it seems that in 1996 a change was made to the thrust bearing to make the thrust bearing more robust in the corner between the thrust shoe and the OD of the bearing. The explanation in the write up I found was not very detailed, so I am not sure what was changed.

 

[showcrop]

On another forum a poster told about his difficulty in getting the engine and transmission on his car to mate up. He had to apply a lot of pressure with screws and bolts to to close it the last 3/8 of an inch. It turned out that he had installed a new pilot bushing on top of the old one. These things can happen.

 

[Determined]

The side that is worn off was it facing the front or rear of the engine?

 

[INCase]

for an automatic it could be hard-bang shifts (bad transmission) and dropping them into gear (like if you were racing around)

i had one go bad. pretty sure it was the bad transmission doing a hard bang shift from 2nd to 3rd (car not truck) not a problem for a couple but over a lot of miles it would wear.


on a manual transmission riding the clutch will do that. and as others mentioned if there is too much axial pressure/load on the crank you could expect that.

see if Chrysler had any update kits or see if any diesel forums mention this.

good luck.

 

[Janicholson]

I have seen crankshafts with the thrust main ground incorrectly (wide) creating the option for hammering back and forth pounding the flange. Jim