Official S65 Rod Bearing Condition Example Thread

[Scharbag]

^^^

Wow - those look very uncool.

Good thing you did the swap! What you put back in there?

[rdoctor]

Tdott, Wow... those look terrible! All of them seemed to be gouged/scratched in a narrow track in the center and very elongated wear compared to most of the the other pictures that have been posted. #8 looks like it was way ahead of the others on the road to failure. You dodged a bullet!

[tdott]

Originally Posted by Scharbag

^^^
Wow - those look very uncool.
Good thing you did the swap! What you put back in there?

Originally Posted by rdoctor

Tdott, Wow... those look terrible! All of them seemed to be gouged/scratched in a narrow track in the center and very elongated wear compared to most of the the other pictures that have been posted. #8 looks like it was way ahead of the others on the road to failure. You dodged a bullet!

I agree, they are the worse of the newer bearings I've seen. The crank looked fine, both surfaces were smooth to the touch even the bearings aside from how bad it looked it doesn't look like it did any damage. These were replaced with BE/ARP stuff, owner said it now feels smoother than before.

[doogee]

Originally Posted by tdott

2011 with 55k I did a few weekends ago:

I really don't think you should of installed new bearings in that engine without having that crankshaft removed and checked. If the crank oil holes weren't chamfered correctly from the factory, this isn't something you can see or feel.

I still think something is very wrong and I'm willing to bet the new bearings are junk already.


I'd like deansbimmer to chime in on this.

[rantarM3]

Originally Posted by tdott

2011 with 55k I did a few weekends ago:

I’d be concerned that there’s some other issue with that engine and the condition of the main bearings. Those look just nuts!

[deansbimmer]

I think Doogee is on point with speculating oil hole chamfer causing that wear. It is very disconcerting. If he made 55k on the tight 702/703 bearings and replaced them with the extra clearance BE setup then I wouldn't hesitate to say he could at least get another 60k out of them without worry. As long as there were no defects to the surface of the crank I would say don't worry about it.

[strokemycocktus]

Here are mine. Replaced at 61k kms. They look pretty bad for the mileage imo. Torn motor mounts gave a lot of clunking and shifting problems. Some info about the car
Registered oil changes (BMW dealership):
1500 km Castrol TWS
20000 km Castrol TWS
27500 km Castrol TWS
38000 km BMW M TwinPower Turbo 10W60
47000 km BMW M TwinPower Turbo 10W60

52000 km Liqui Moly 10W60 (independent shop)

ESS VT2-625 kit between ~44000 km and 50500 km. After that the engine was back to stock.
As far as I know the car was not tracked. I bought it at 54000 km and took very good care since then, always proper warmup, no WOT until oil temp was around 100 C, etc. Added MoS2 at around 57000 km.

I noticed the difference immediately after having the new bearings installed. Not that something alarmed me before, but the the sound engine makes on startup is night and day. It is now so smooth I can't even describe it. Before I would get an unpleasant grind (?) for less than 1s after the startup, the engine was shaking on cold start and was noisier ovarall. The starter motor sound is completely different, high pitched clean tone, before it sounded like it was struggling much more.

Went with Castrol FST 10W60 and OEM bearings. Just to note why: any aftermarket bearings need to be imported form USA, which makes the price about 40% higher due to taxes and customs fees, not to mention the shipping cost. In my country, noone has even heard about any aftermarket bearings, and no reputable shop would install them for me. Besides, I believe these OEM will be good for at least 70-80k kms when maintained properly. That's about 7 years of my ownership, so no big deal if I need to replace them after that time. Assuming I will still own the car

[don't mind the scratches on bearings surface - they showed up due to throwing the bearings around after disassembly, transport, etc.]

[doogee]

Originally Posted by strokemycocktus

I noticed the difference immediately after having the new bearings installed. Not that something alarmed me before, but the the sound engine makes on startup is night and day. It is now so smooth I can't even describe it. Before I would get an unpleasant grind (?) for less than 1s after the startup, the engine was shaking on cold start and was noisier ovarall. The starter motor sound is completely different, high pitched clean tone, before it sounded like it was struggling much more.

The placebo effect is strong with you!

None of these improvements you speak of are possible with a rod bearing swap. Especially when yours were in pretty "decent" shape.

Perhaps you've never done an oil change and the motor was starting to seize?

[strokemycocktus]

Originally Posted by doogee

The placebo effect is strong with you!

None of these improvements you speak of are possible with a rod bearing swap. Especially when yours were in pretty "decent" shape.

Really these are decent for 61000 km? I was told this was close to engine failure
I really didn't expect any changes after the swap, but was shocked when I started the car. It was 2 days after I left it at the shop. 100% the startup sound is completely different and quieter now, and the engine is not shaking like it used to. But maybe that's due to other things replaced - oil, motor mounts :

[doogee]

Originally Posted by strokemycocktus

Really these are decent for 61000 km? I was told this was close to engine failure
I really didn't expect any changes after the swap, but was shocked when I started the car. It was 2 days after I left it at the shop. 100% the startup sound is completely different and quieter now, and the engine is not shaking like it used to. But maybe that's due to other things replaced - oil, motor mounts :

If your motor mounts were torn, new ones can definitely transform how the car feels

[Iyzmi]

Originally Posted by doogee

The placebo effect is strong with you!

None of these improvements you speak of are possible with a rod bearing swap. Especially when yours were in pretty "decent" shape.

Perhaps you've never done an oil change and the motor was starting to seize?

I'm always amused by people who think they can perceive a difference after changing the bearings.

Motor mounts on the other hand - sure.

[strokemycocktus]

Originally Posted by Iyzmi

I'm always amused by people who think they can perceive a difference after changing the bearings.

How come so many threads on rod knock then? Are all these fake assumptions?
I am no mechanic and didn't even know what a rod bearing was prior to owning S65 equipped car, all I can say I have noticed these things after changing parts mentioned above.

[330ciprem]

Originally Posted by deansbimmer

I think Doogee is on point with speculating oil hole chamfer causing that wear. It is very disconcerting. If he made 55k on the tight 702/703 bearings and replaced them with the extra clearance BE setup then I wouldn't hesitate to say he could at least get another 60k out of them without worry. As long as there were no defects to the surface of the crank I would say don't worry about it.

Ok, a bit confused here.

Do you mean another 60K from the old 702/703 bearings?

[Iyzmi]

Originally Posted by strokemycocktus

How come so many threads on rod knock then? Are all these fake assumptions?
I am no mechanic and didn't even know what a rod bearing was prior to owning S65 equipped car, all I can say I have noticed these things after changing parts mentioned above.

We have "so many" threads on rod knock because a lot of people have no idea what actual rod knock sounds like and freak out over the slightest noise due to the ever-present rod bearing hysteria. I guarantee you that if you actually had rod knock, you would know. And by the time you knew, it would most likely be too late to get away with just changing the bearings. Whatever improvement you can feel after this service can be attributed to motor mounts and/or placebo effect. Saying otherwise would be like claiming your AC blows colder after filling up with a different brand of gas - that's just not science .

I have actually read some people talk about Liqui Moly being a "noisy" oil. I don't know how true that is but that may be another factor if you switched back to Castrol or TwinPower with the new bearings.

[deansbimmer]

Originally Posted by 330ciprem

Ok, a bit confused here.

Do you mean another 60K from the old 702/703 bearings?

No. I mean if the original 702/703 bearings went 55k miles on a potentially "defective" crankshaft, then I don't see any reason why the new BE bearings wouldn't be able to go at least another 60k on the same "defective" crankshaft.

[330ciprem]

Originally Posted by deansbimmer

No. I mean if the original 702/703 bearings went 55k miles on a potentially "defective" crankshaft, then I don't see any reason why the new BE bearings wouldn't be able to go at least another 60k on the same "defective" crankshaft.

Aah ok! Makes sense.

And doogee - you are saying that the reason behind the wear and tear is the oil chamfer? What makes you say so - the extent of wear and tear?

Sorry if they sound stupid - just trying to gain some knowledge.

[doogee]

Originally Posted by 330ciprem

And doogee - you are saying that the reason behind the wear and tear is the oil chamfer? What makes you say so - the extent of wear and tear?

Yes the wear is not even across the bearing whatsoever. Only reason I can see this happening is from the oil passage itself. The problem with that particular motor is the crankshaft, in my opinion. We've never seen this before.

[tdott]

Originally Posted by doogee

Yes the wear is not even across the bearing whatsoever. Only reason I can see this happening is from the oil passage itself. The problem with that particular motor is the crankshaft, in my opinion. We've never seen this before.

So some new information, said car was in an accident, oil pan was damaged. Do you think it being starved for oil for a brief period before shutting it down, would cause wear like that?

Originally Posted by Iyzmi

that's just not science .

Actually it kinda is, the crankshalf is rotating on the bearings, perhaps the oil film isn't strong and is causing increase vibration or even contact. With the new bearings and the coating, it is possible that things are rotating more smoothly.

Now is it a bit far fetched? Yes, but I can say I sat in my car after the bearings were done and heard the same, I didn't believe it, I dismissed it, after a while I was sure it was, but it's still possible. A few other friends have said the same after we did the bearings and I didn't mention anything to them about how i felt,but they said felt basically the same about their engine after.

If I had the tools to measure it, maybe I'd try to quantify it if I had the chance to do another, but for now you guys can continue to call placebo, I don't care, but I know what I felt. It's minor and it's not a reason anyone should care about.

Even your bad example, while not directly related can be explained by science. After filling gas, the car could have cooled down, no longer heat soaked and running cooler, maybe the fan was stuck and only kicked on after restarting, or the temperature could have dropped also. Basically there are variables that may not be directly related to your poor attempt at an analogy, but could impact the situation of causing the AC to run cooler after filling gas.

Both can be hard to prove, but it's not outside the realm of possibilities.

Originally Posted by deansbimmer

I think Doogee is on point with speculating oil hole chamfer causing that wear. It is very disconcerting. If he made 55k on the tight 702/703 bearings and replaced them with the extra clearance BE setup then I wouldn't hesitate to say he could at least get another 60k out of them without worry. As long as there were no defects to the surface of the crank I would say don't worry about it.

Exactly, those were my thoughts exactly. While disconcerting, it's not like we were going to take the engine out and disassemble to check/polish the crank. If it was catastrophic, it would have failed by now. The new bearings have a better chance of lasting just as long, if not longer. Plus given that there was a accident and the oil pan was damaged, that could explain it or at-least add another variable to it.

[doogee]

Originally Posted by tdott

So some new information, said car was in an accident, oil pan was damaged. Do you think it being starved for oil for a brief period before shutting it down, would cause wear like that?

That's totally possible. I still find the wear strange but yeah it's possible.

Originally Posted by tdott

Actually it kinda is, the crankshalf is rotating on the bearings, perhaps the oil film isn't strong and is causing increase vibration or even contact. With the new bearings and the coating, it is possible that things are rotating more smoothly.

Even if that were true, the balancer would wash any of these "feelings" away.

[Iyzmi]

Originally Posted by tdott

Actually it kinda is, the crankshalf is rotating on the bearings, perhaps the oil film isn't strong and is causing increase vibration or even contact. With the new bearings and the coating, it is possible that things are rotating more smoothly.

Now is it a bit far fetched? Yes, but I can say I sat in my car after the bearings were done and heard the same, I didn't believe it, I dismissed it, after a while I was sure it was, but it's still possible. A few other friends have said the same after we did the bearings and I didn't mention anything to them about how i felt,but they said felt basically the same about their engine after.

If I had the tools to measure it, maybe I'd try to quantify it if I had the chance to do another, but for now you guys can continue to call placebo, I don't care, but I know what I felt. It's minor and it's not a reason anyone should care about.

Even your bad example, while not directly related can be explained by science. After filling gas, the car could have cooled down, no longer heat soaked and running cooler, maybe the fan was stuck and only kicked on after restarting, or the temperature could have dropped also. Basically there are variables that may not be directly related to your poor attempt at an analogy, but could impact the situation of causing the AC to run cooler after filling gas.

Both can be hard to prove, but it's not outside the realm of possibilities.

Yeah...sorry, that does nothing to convince me. As you said, that explanation is far fetched to say the least. I'll wait for one of the engineers or a trusted mechanic like deansbimmer to say otherwise before I buy into your pseudo-science explanation of how bearings make a perceivable noise. I'd be more likely to believe changing oil from Liqui Moly to OEM would have some tiny effect or there was some small amount of vibration from old motor mounts causing some noise. You are welcome to your own opinion though.

You really read into my analogy more than intended, and yet missed that I said changing to a different brand of gas, not filling up gas. The analogy was meant to point out that bearings have about as much relation to the sound of an engine as the brand of gas you use to the temperature of your AC (none). Is your next point going to be that BP makes your AC run cooler than Shell?

[tdott]

Iyzmi

If a bearing has no impact on how smooth an engine runs or the sound it makes, where do you think rod knock comes from?

[strokemycocktus]

Originally Posted by Malek@MRF

Non-stretch. OEM bolts are TTY (Torque to Yield) stretch.

I have 2 S65B40's sitting on stands here. The engine with the VAC+ARP hardware with heads removed easily turns over by hand. The engine with all stock hardware and bearings turns over with more difficulty by hand (heads removed). Both engines are just assembled with crank, rods and pistons. I know this is not a scientific way of measuring or coming to any sort of conclusion, it is simply an observation.

Both engines are at 39,xxx miles.

Of course this isn't a comparison between an engine with worn bearings and a one with new bearings, but I guess this find may be extrapolated to such case, resulting in some (very minor of course) changes in how engine starts up/operates.

Not trying to argue or prove my point, just want to understand how all this works.