Cyberman

It almost looks like it could be part of a piston.

allnmstkn313

Not a crank bearing.

I'd take a peek at your timing chain and guides.

abecedarian

you can see how hard it would be for piece of a bearing, particularly as large as those pieces to slip out of the crank or connecting rod.
They'd have to make a 90 turn to get out past the web or throw:

also, none of the bearings have a 'lip' like the first photo.
I'm kinda in agreement that it looks more like piston pieces, or something left after some previous work.

sh0kk86

could just be a messed up timing chain guide that got chewed up and bent(would have been originally straight...)

iamsuperbleeder

I hate to quote myself, but...

but the OEMs are plastic...

er nylon...

er whatever...

it would have to be an upgraded metal guide set

91Toyota

looks like a piece off of your timing cover. That would be my only guess.

thook

Highly, highly unlikely that's a piece of bearing. If it were, the motor would be destroyed to point of an entire rebuild or all together a new motor. I mean you'd actually have to have blown a counter weight on the crankshaft. In which case, I can't see anyone logically leaving a piece of bearing in the pan. Doesn't make any sense.

What's more likely is that being a piece of the timing cover, as suggested. There is crescent form on the cover right around/below the crank sprocket for the chain that often gets shattered when a chain goes. I've seen it with my own motor as well as others on this forum that have shared their pics of destruction.

thook

Well, what you really need to do to make absolutely certain is scratch the concave side of the shrapnel. If it is a bearing, there will be a copper tone to it underneath the apparent surface. Unless someone had aluminum bearings in it, OEM bearings are tri-metal with a lead babbit surface over a copper layer. I forget what the backing material is, though.

YotaJunky

I've got time to work on the engine today. I'll poke around with a flashlight and check the piston skirts. After having read the posts thus far, I'm now more inclined to guess that it's either a piece from the timing cover or piston skirt. The only reason why I thought it might have been a bearing was how the curvature of the broken piece matched up perfectly with a new main bearing.

The PO's only put on 200,000 km (that's only about 125k miles). Other than a high idle, the engine sounded fine. I only pulled the pan, because I already had the diff out and the oil pan had a leak.

I pulled the timing cover when I replaced the head earlier this year, but I don't recall seeing anything out of the ordinary. I'll pull the cover again and take a closer look for any missing chunks.

This has certainly been another learning experience. I guess there's always more to learn.

Stay tuned...

thook

LIke I said, scratch the concave surface and look for the copper. That will help in determining.

YotaJunky

Mystery solved after inspecting old timing cover that was removed earlier this year. Everyone pretty much called it right by saying that it couldn't have been a bearing. Give yourself a big pat on the back...





Here's a shot of the new cover and a look at the clearance between the chain and protruding lip in the TC.

abecedarian

that's why the guides and tensioner are so important and why you should change them periodically.
congrats on figuring it out and finding it wasn't as serious as it could've been.

YotaJunky

I couldn't agree with you more. Yes, I'm relieved that it didn't turn out to be a full rebuild.