Roller bearing in bottom of oil pan

[bretto]

I pulled the pan to replace the rear main seal and at the bottom of the pan was a single roller bearing. Its just over 3/4" long and 1/4" in diameter. Its not a magnet and it is hardened. I cant for the life of me think of where this would of come from. There aren't any roller bearings in the 4.0 are there? At least I cant think of any. There was not a trace of any thing else, just oil. Boggles my brain where it came from. I was thinking maybe some sort of alignment peg but I don't see anywhere that it would of come out of. This is a '96 that I've had for just under a year so its nothing I would know about. :dunno:
Any ideas? Engine runs great and strong. I'm not too alarmed, I'm going to button it up and continue to run it.
Brett

 

[Runnin'OnEmpty]

I too have a 96, and know of nothing like that inside the
engine. The description does sound like a roller bearing.

My best guess is that it's there from the factory; just a foreign
object that somehow found itself into the pan before assembly.

Might have been dropped into the distributor hole...???

 

[xcm]

Camshaft button is the only thing close to what you are describing, that I can think of!

 

[RCP Phx]

That's a really good call!

 

[Runnin'OnEmpty]

Holy cam pin Batman!

That does appear to be the alignment pin that fits in the
front of the cam to press against the timing cover.
There's also a spring behind it.

I'm not sure how critical that pin is, or if it's worthwhile to
remove the timing cover to check it...?

 

[Runnin'OnEmpty]

Best I can tell, it's a thrust pin and was switched to a thrust
plate in 97. The cam can 'walk' and rub against the timing cover
if the pin and spring aren't in place. Causes a knocking sound.

I'd replace it. Cloyes and Summit sells the bolt, spring, and pin
as a kit.

 

[bretto]

This one? It certainly looks like it could be that pin.

 

[bretto]

Maybe the timing chain was replaced at sometime and that pin went missing but was replaced. The engine runs great and no odd noise.

 

[xcm]

That’s not something I would want to find… good luck sleeping at night going forward now that you know what it is!

 

[bretto]

Well I suppose since the oil pan is off, I might as well continue on and pull the front timing cover off and take a look.
Would one be able to put some forward movement on the cam from the bottom end to see if it springs back rearward? Is there or would there be that much play that it could even be noticed? Worth a shot at least since I can see and get at the cam from underneath. IDK, I'll probably will end up pulling the cover.

 

[Runnin'OnEmpty]

.........Would one be able to put some forward movement on the cam from the bottom end to see if it springs back rearward? Is there or would there be that much play that it could even be noticed? Worth a shot at least since I can see and get at the cam from underneath........

That's a good idea and nothing to lose. You could perhaps use a screwdriver
as a pry bar and see if the cam does indeed move backward after pressure
is released. After all, that's what the pin/spring is designed to do.

That may or may not work, since the lifters are probably holding
pressure on the cam and resisting movement.....

 

[Anak]

If you are going to pull the timing cover you should also at least replace the snubber for the timing chain. It is a rubber block that fits into a couple of slots in the cover. At best you will find that it has turned into a very hard block, so hard you will find it hard to believe it was once a rubber piece. There is a good chance you will find it to be broken on account of brittleness. It would be a good part to have already on hand so that you don't find yourself scrambling to find something you didn't anticipate.