Rod Bearing Wear pattern (1975 280z)

[corbenB]

Hey guys, im currently in the middle of taking out my rod bearings after finding some non-magnetic metal shavings in my oil (i believe them to be copper). I have pulled 2 rod caps, and the bearings both looked like this. This looks like particulate wear to me, and the shavings I saw i feel were much to big to be from these bearings. i havent pulled all of them yet, but i figured i would just ask what you guys thought. I had no rod knock or anything, but my instinct told me it must be bearings. Was I wrong? I have attached a picture of the bearing, as well as two pictures of the shavings. Thanks in advance!

[Patcon]

That bearing looks fine to me

What do the timing chain guides look like?

What is that draining out of the oil filter?

[Captain Obvious]

Yeah, I agree with that. If someone told me my rod bearings looked like that, I would not even take the caps off.

[corbenB]

51 minutes ago, Patcon said:

That bearing looks fine to me

What do the timing chain guides look like?

What is that draining out of the oil filter?

the stuff draining out of the filter was just oil, that is an older picture. After finding those bits I changed the oil and filter and drove it some more for roughly a week to see if it was just like a one time thing, but when i changed it again, i still found some more flakes. And i havent looked at the timing chain yet because i have been doing all of this with the engine stil in the car due to limited space. 

[Patcon]

I suspect the debris could be coming off the chain guides. I don't know what else could shed like that inside the engine unless its been rebuilt in the past

[kickstand80]

Looks like brass/copper and aluminum. Pull the thrust bearing main cap and check it. It should be the 4th main cap counting from the front. I can't think of anything else that has brass or copper inside the engine.

You  can see the thrust bearing circled in blue in this photo

 

 

[jonbill]

The yellow stuff might be the stuff used to bond the baffle into the cam cover. what does the inside of the cam cover look like?

 

[Racer X]

What about the oil pump/distributor drive spindle? I've seen the teeth shear off before, and found bits of metal that size. There are bronze gears available, and the pieces do look a little like bronze.

 

Edited October 15, 2022 by Racer X

[corbenB]

20 hours ago, kickstand80 said:

Looks like brass/copper and aluminum. Pull the thrust bearing main cap and check it. It should be the 4th main cap counting from the front. I can't think of anything else that has brass or copper inside the engine.

You  can see the thrust bearing circled in blue in this photo

 

 

Thank you, I've actually just come down with some sort of flu/cold, but once I'm over it i will be sure to check that and update.

[ETI4K]

I guess I have a different take on the bearing.  I see that some foriegn material has been fed through the oiling hole that has scratched the surface of the bearing at its midline - not terribly, just notably.  The filter should have snagged that but either didn't get the chance or it occurred during a bypass event.

Also, it looks like the bearing has spent some time without an oil film between it and the crank, hence the polishing/removal of the bearing liner material.  Oddly though, only the bearing edges are worn - not the middle and the wear area seems narrow.  I would expect to see that wear pattern uniformly across the bearing surface and involve more of the circumferential area.

I like @Racer X's suggestion of either bronze gear failing. 

 

Edited October 17, 2022 by ETI4K
Typo repair

[corbenB]

On 10/15/2022 at 4:23 AM, Racer X said:

What about the oil pump/distributor drive spindle? I've seen the teeth shear off before, and found bits of metal that size. There are bronze gears available, and the pieces do look a little like bronze.

 

What do you think? looks fine to me personally. I was really hoping it was this to be honest, cause it seemed like an easy fix. 

[Zed Head]

What is the history of the engine?  It might just be old stuff from a PO.  It might not be from the engine.  Take a closeup look at the pieces.

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