How would a Cummins drop a thrust bearing?

[rossvtaylor]

Hi gang,

A customer...the super cool family with the bus from Epic Skoolies that had the electrical meltdown...just dropped their oil pan during a gasket change on their 5.9 (not sure if it's a 12 or 24V). And they found what looks to be half of a thrust bearing (photo below). Is there any way this could come out with out the main cap coming off? The engine was recently rebuilt.

[fo4imtippin]

Looks like the factory new engines had a three piece. That can separate and then cause slop between the flywheel and crank pulley. Most rebuilds opt for a single piece bearing now. Do they still have warranty?


https://www.cumminsforum.com/threads...aring.1804913/

[fo4imtippin]

Here's a better thread on the how. Looks like pre 1995


https://www.cumminsforum.com/threads...my-pan.613266/

[rossvtaylor]

Originally Posted by fo4imtippin

Looks like the factory new engines had a three piece. That can separate and then cause slop between the flywheel and crank pulley. Most rebuilds opt for a single piece bearing now. Do they still have warranty?

Thanks! I don't know these engines, but in the ones I do know the tabs or a raised lip trap the thrust bearings with the cap. So, in these engines, the multi-piece thrust bearings can escape even if the main bearing cap is tight? Or is it likely the cap's loose?

[IDoMy0wnRacing]

It is possible for the thrust bearing portion was knocked loose from the main bearing during installation. The end play on the 5.9 is something like .004 - .017 inches.
If it has endplay, there is potential for the thrush bearing to fall free.

Have them place a breaker bar between the harmonic balancer and the block and see if there is more than .004 - .017 inches of travel. If the thrush bear did in fact fall out, it could have near a ¼ inch of movement. Unless of course, the other half of the bearing is still intact.

If the oil pan has been removed, it could be possible to see if the thrush bearing is missing on one side of the main bearing cap.

[Booyah45828]

Oh boy Ross, you might have opened a can of worms.

They were using 3 piece thrust bearings up until the 6.7 afaik. FWIW the 6bt/isb only had a 180° thrust bearing, so the cap won't have anything on it.

In normal operation there's no issue with the 3 piece bearing, with the crank in place and the bearing intact it will never fall out. But finding a piece in the pan is kind of alarming. I'd be sure to pull that cap off and look into the block to see if you can find the other thrust bearing. If you can't, it's likely worn to nothing and is why the front half got spit out.

Thoroughly inspect this, as with the bearing gone the crank and block might be damaged requiring a new engine. If it's not(I'd be very surprised) they sell the 1 piece thrust bearing individually. You can roll it in same way you would if you were doing an inframe on any other diesel engine.

I've never personally seen this, at least not on something that was taken care of. But I have read on forums about this. A lot of reasons for it, from using the clutch too much(dumb and not it IMO) to having the torque converter protrusion set wrong(very possible).

Did they have transmission work or done a swap on this?

[rossvtaylor]

Thanks, all of you, for the input. I didn't mean to open any worm cans!

I'll see what I can find out about other work which was done. They have no paperwork on the rebuild, so no warranty that they know of.

They are in Yuma AZ, by the way, and they found a mechanic who seems good. They're going to get an estimate on fixing that thrust bearing issue.

By the way, these are the bus owners I wish we encountered more often...willing to learn and dig in and get dirty, with the goal of being as self-sufficient as possible. Cool people.