Official S65 Rod Bearing Condition Example Thread

[Shredicus]

Originally Posted by Duk996

I don't think so.

From another thread:

Originally Posted by Green-Eggs

The BMW 702/703 bearings are made by Glyco, not King. If you can't see the logo in this picture, click on it for a closer look.



That's the same logo found here:


But here's the interesting part. This bearing is made from the Glyco Bimetal Aluminum. Here's what the Glyco catalog says about it:

Provides greater seizure resistance and surface hardness than tri-metal materials, while dramatically reducing or eliminating bearing wear in a wide range of automotive and truck engines. Bored inside diameters improve the bearing’s oil retention utilizing hundreds of micro-grooves to provide channels in which debris is flushed away.

So that confirms the measurements in this wiki that these bearings are indeed much harder than the original 088/089 bearings, and explains why we see those little grooves in the pictures of people who replace these bearings.

But here's the sad part. There are six different Glyco bearing compositions, from best to worst. This Bimetal Aluminum bearing is fourth in the pecking order. That tells me it might not be a very high quality part and may have been chosen for cost savings. The next one up their quality list is the Trimetal lead/copper bearing. YMMV

[Duk996]

Originally Posted by Shredicus

From another thread:

Very interesting, I have never heard of that before. Seems suspect what do I know.

[deansbimmer]

The pics of his damaged bearings are not the micro grooves that the Glyco catalog speaks of. I have not seen a set come through my shop with wear like that so I can't inspect or measure them to determine the cause, but I can confirm that the micro grooves in BMW bearings are not that large nor do they run perpendicular to the journal rotation. I think I have a set I can photo to show the micro grooves....

I might speculate that the appearance may be caused by inconsistent babbit or bonding layer thickness during manufacturing. I don't see how a 2" shaft could indent such small wear lines into a 2" journal. The load is too evenly dispersed on the surface when it makes contact.

Edit: I don't have any Glycos. Didn't find much online to show either since they're too small to pick up in a regular photo. This photo from Taiho Bearings shows what the circumferential micro grooves look like.

[Duk996]

Originally Posted by deansbimmer

The pics of his damaged bearings are not the micro grooves that the Glyco catalog speaks of. I have not seen a set come through my shop with wear like that so I can't inspect or measure them to determine the cause, but I can confirm that the micro grooves in BMW bearings are not that large nor do they run perpendicular to the journal rotation. I think I have a set I can photo to show the micro grooves....

I might speculate that the appearance may be caused by inconsistent babbit or bonding layer thickness during manufacturing. I don't see how a 2" shaft could indent such small wear lines into a 2" journal. The load is too evenly dispersed on the surface when it makes contact.

I looked quickly at a bearing failure chart and the closest thing seems to be improper seating; the frequency seems too high though. I suppose it could be some frequency thing with the way the engine is firing or some other dynamic vibration thing but man is it consistent, I wouldn't expect anything like to actually wear the bearing in that way. It's very interesting.

We are assuming the bearings were good too, I wouldn't be surprised if those are high spots from the manufacturing process or something.

[kyrix1st]

Originally Posted by doogee

Unfortunately that's the situation with these motors. While mine have been done, I still have the worry of the main bearings in the back of my head. I'll have to do them at some point.

Recently witnessing main bearing failures. What a way to end the year!

[Sneaky Pete]

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

[BMRLVR]

Originally Posted by Sneaky Pete

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

Why would they? There is virtually no loss in oil pressure with the increased clearance bearings.

[doogee]

Originally Posted by Sneaky Pete

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

Even if that were true, which it isn't, it wouldn't matter because the main bearings are junk anyway

[Shredicus]

Originally Posted by deansbimmer

The pics of his damaged bearings are not the micro grooves that the Glyco catalog speaks of. I have not seen a set come through my shop with wear like that so I can't inspect or measure them to determine the cause, but I can confirm that the micro grooves in BMW bearings are not that large nor do they run perpendicular to the journal rotation. I think I have a set I can photo to show the micro grooves....

I might speculate that the appearance may be caused by inconsistent babbit or bonding layer thickness during manufacturing. I don't see how a 2" shaft could indent such small wear lines into a 2" journal. The load is too evenly dispersed on the surface when it makes contact.

Edit: I don't have any Glycos. Didn't find much online to show either since they're too small to pick up in a regular photo. This photo from Taiho Bearings shows what the circumferential micro grooves look like.

Hmm, my mistake

Originally Posted by Sneaky Pete

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

Man you are like the plague...

[LVI]

Is BE planning to offer a main bearing solution in the future?

[Scharbag]

Originally Posted by Sneaky Pete

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

At least you are consistent...

[Bartledoo]

Originally Posted by Sneaky Pete

Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.

Well, it would make sense to see increased main bearing failure rate on those particular engines...all engines that have catastrophic rod bearing failure have avoided the possibility of main bearing failure. So, if you prevent rod bearing failure then you are now allowing the possibility for that engine to have main bearing failure. Damn I can't believe I'm feeding SP's nonsense!!

[CHE///MIST3]

Originally Posted by ksteckba

Well, it would make sense to see increased main bearing failure rate on those particular engines...all engines that have catastrophic rod bearing failure have avoided the possibility of main bearing failure. So, if you prevent rod bearing failure then you are now allowing the possibility for that engine to have main bearing failure. Damn I can't believe I'm feeding SP's nonsense!!

Ahhhh but suppose you swap the connecting rod AND main bearings as well.... Does the tree make a sound ?


GM

[sirploppy]

Originally Posted by Duk996

I looked quickly at a bearing failure chart and the closest thing seems to be improper seating; the frequency seems too high though. I suppose it could be some frequency thing with the way the engine is firing or some other dynamic vibration thing but man is it consistent, I wouldn't expect anything like to actually wear the bearing in that way. It's very interesting.

We are assuming the bearings were good too, I wouldn't be surprised if those are high spots from the manufacturing process or something.

That's the thing that confuses me. The stripes are perpendicular to the rotation of the rod bearings/crank. I'm in the same boat as you suspecting a vibration or engine firing pattern.

[Green-Eggs]

Originally Posted by lawrence1

Is BE planning to offer a main bearing solution in the future?

No. Making main bearings is much more complicated. With rod bearings, you only need to pay for one set of tooling. For main bearings, you need four. That would be about $100k investment for main bearings.

[deansbimmer]

Originally Posted by Green-Eggs

No. Making main bearings is much more complicated. With rod bearings, you only need to pay for one set of tooling. For main bearings, you need four. That would be about $100k investment for main bearings.

That's not so bad...I'm thinking group buy? We'd only need like what, at least 500 commitments? Maybe lets start a gofundme account??

[pbonsalb]

There are about 60,000 motors. But probably only 10% of the owners agree their motors could have bearing issues and maybe 10% of that 10% might be proactive enough to do mains. The rest of the jobs will be by mechanics or salvagers after the fact, but I bet those people will be seeing more and more seized engines as these cars age and go through multiple owners with sometimes questionable maintenance and driving.

[sirploppy]

Originally Posted by pbonsalb

There are about 60,000 motors. But probably only 10% of the owners agree their motors could have bearing issues and maybe 10% of that 10% might be proactive enough to do mains. The rest of the jobs will be by mechanics or salvagers after the fact, but I bet those people will be seeing more and more seized engines as these cars age and go through multiple owners with sometimes questionable maintenance and driving.

Yeah, and stating the obvious the labor to do mains compared to just the rod bearings is more intense ($$$). My understanding is the engine must be removed.

So my bearing maintenance fund has just doubled to $6k..

[Scharbag]

Originally Posted by deansbimmer

That's not so bad...I'm thinking group buy? We'd only need like what, at least 500 commitments? Maybe lets start a gofundme account??

Just to wrap my head around this: The issue is not the quality of the OEM bearings, but the clearance of the OEM installation, correct? If that is the case, replacing the bearings with available OEM bearings would work if proper crank machining were completed. If you have to take the engine out etc., the cost to turn the crank would not be a terrible additional expense.

Or am I way off base here?

[admranger]

Originally Posted by Scharbag

Just to wrap my head around this: The issue is not the quality of the OEM bearings, but the clearance of the OEM installation, correct? If that is the case, replacing the bearings with available OEM bearings would work if proper crank machining were completed. If you have to take the engine out etc., the cost to turn the crank would not be a terrible additional expense.

Or am I way off base here?

I don't think you're off base, but knowing "how much" to take off and then retreating the surfaces of the crank are the tough parts is my guess (I assume the bearing surfaces are 'hardened' in some way).

[Scharbag]

Originally Posted by admranger

I don't think you're off base, but knowing "how much" to take off and then retreating the surfaces of the crank are the tough parts is my guess (I assume the bearing surfaces are 'hardened' in some way).

Given I know zilch about the finer points of engine rebuilding, I will leave it to the experts if I ever need to deal with mains. I hope that it is many years before mains become and issue.

Cheers,

[deansbimmer]

The issue isn't the OEM bearing quality it's the clearances, correct. Although I'd rather have copper in my bearings if given a choice.

If you want to refresh and adjust clearances on the mains, depending on which bearing color/size they used originally you may just be able to go to the next larger bearing color and be OK. If not then yes you're cutting and refinishing the crank to whatever spec your builder specifies. On damaged journals, generally you polish/cut until the journal cleans up and then measure to see where you are. There may or may not be bearings available that would work with the new smaller journal size.
Sometimes the journal scoring may be so bad that you have to weld up the journal and rebuild it.