Consensus on rod bearings?

[thingsontoast]

Originally Posted by Scharbag

I do not feel you are being a dick at all - I like good discussions. All good.

As for the variables you mentioned:

Break-in - bearings do not break in. Also, some professionals suggest engine break-in should be done quickly under load. I have raced a lot of Honda products and every one of my re-built junk yard B16 and B18 engines have been broken in on the track. They all ran strong and lived life bouncing off the limiter. Hell, our latest B18 has 4 24 hour races (~9,000KM) under its belt with 170TKM on the junk yard engine with new rings and bearings (did not touch the head at all).

Maintenance - I agree, proper maintenance is important to every reciprocating engine. That said, if maintenance is such a big deal, then every high revving engine should share the S65/S85 penchant for bearing wear. Unless BMW M owners are just bad at maintenance - which does not seem to be the case typically as we are neurotic car freaks. And the typical issues that I have seen from LCI is sludge buildup in the heads, not bearing damage.

Climate/conditions - Engine oils today can run 250F+ no problems. Also, modern synthetics can still be pumped when very cold. That said, -40 and 10W60 freaks me out (never did that to my M). Why do we not see similar issues with Audi, Porsche, Honda etc.?

Operation - All reciprocating engines share certain fundamentals. Audi, Porsche, Honda, Ferrari, Lamborghini, Bugatti etc. all have to follow the same rules of physics. If high RPM use is detrimental to all high HP NA engines, then we should see similar rod bearing failure rates in other brands with similar HP/L NA engines. (This statement assumes that the engine is not abused, which is different than being driven at high RPM.)

Fuel - this has almost nothing to do with rod bearing failure. Yes, detonation can cause excessive loads - but - this raises the question: do only S65 and S85 owners use crappy fuel in their high performance engines? Also, the MSS60 would throw some codes if the detonation was really that bad.

Oil - Any good 0W40 or thicker synthetic has been shown to work just fine in the S65 (not sure how the S85 VANOS reacts to thinner oils). Modern synthetic oils are all very very stout and we all typically change the oil WAY more often than needed.

Mods - The S65 can easily run 600+HP and 400+ftlb of torque with a blower. Yes, too much load will eventually break something - but the S65 is pretty stout. Most E9x M3s are not boosted. Given the S65 can accept boost without immediate blowup, this leads me to posit that there exists no NA mods for the S65 that will cause undue stress on the rotating assembly.

Anywhoo, each owner can make their own choice. I am happy I changed mine even though I got lucky and seemed to have adequate clearances.

Happy motoring and keep the revs up. I know I do. Perhaps that is why I average 11MPG... :P

Hey man, he said to PM to keep going. But to be fair, I work with get lit and we rebuild engines fairly regularly and he's been doing the rod bearing discussions since the class action lawsuit that fell through. I bought his e90 and did bearings at 115k, I really could have gone another 115k. WPC Coated OEM bearings is what I went with only for piece of mind. I fully believe it is the owners fault for failure at the end of the day for premature failure. It doesn't happen for no reason. Let it warm up, use only TWS (I use BMWs oil) , and change it frequently depending on how you run the car. Use anything other than TWS, you'll end up with failure. It's happened again and again but people still argue until they're blue in the face with 10k worth of engine repair to worry about because they probably shouldn't have bought this car and not trusted the engineers behind it.

[DRLane]

Originally Posted by thingsontoast

Hey man, he said to PM to keep going. But to be fair, I work with get lit and we rebuild engines fairly regularly and he's been doing the rod bearing discussions since the class action lawsuit that fell through. I bought his e90 and did bearings at 115k, I really could have gone another 115k. WPC Coated OEM bearings is what I went with only for piece of mind. I fully believe it is the owners fault for failure at the end of the day for premature failure. It doesn't happen for no reason. Let it warm up, use only TWS (I use BMWs oil) , and change it frequently depending on how you run the car. Use anything other than TWS, you'll end up with failure. It's happened again and again but people still argue until they're blue in the face with 10k worth of engine repair to worry about because they probably shouldn't have bought this car and not trusted the engineers behind it.

More nonsense... These threads just never end.

[Cyberdemon]

Rod bearings are like religion; Either you believe or you don't. Nobody adopts a stance of believing god exists with only 30% certainty. You just hope you don't meet your maker. ��

[Scharbag]

Originally Posted by Cyberdemon

Rod bearings are like religion; Either you believe or you don't. Nobody adopts a stance of believing god exists with only 30% certainty. You just hope you don't meet your maker. ��

I wish you were not so damn correct...

It is a shame that, in this modern world, belief can easily outweigh logic and reason in so many topics.

Let us hope that gravity is not questioned with such voracity. The consequences could be messy.

Good times...

[Scharbag]

Originally Posted by thingsontoast

Hey man, he said to PM to keep going. But to be fair, I work with get lit and we rebuild engines fairly regularly and he's been doing the rod bearing discussions since the class action lawsuit that fell through. I bought his e90 and did bearings at 115k, I really could have gone another 115k. WPC Coated OEM bearings is what I went with only for piece of mind. I fully believe it is the owners fault for failure at the end of the day for premature failure. It doesn't happen for no reason. Let it warm up, use only TWS (I use BMWs oil) , and change it frequently depending on how you run the car. Use anything other than TWS, you'll end up with failure. It's happened again and again but people still argue until they're blue in the face with 10k worth of engine repair to worry about because they probably shouldn't have bought this car and not trusted the engineers behind it.

This is a public forum. I am not interested in side discussions. Plus my inbox is damn near full.

It is disappointing to me that we cannot have an open discussion about data without people forming teams. I am 100% open to every thesis as to why the S65 suffers failure. But, a thesis is followed up by data, interpretation and finally a conclusion that is supported by that data. Science is not (or should not be...) a belief. I do not have to believe in gravity for it to be real. I do not have to believe in the speed of light for it to be true. I do not have to believe that water is made of hydrogen and oxygen for it to be true.

NASCAR, Indy and Grand-Am race winning engine builders shared data (and their collection methods) that supports their thesis that BMW did not follow industry best practice for rod bearing clearance on the S65. They also shared data that shows BMW further exacerbate the issue by not adequately controlling tolerance stacking. We are all able to re-create their data following their methods if we choose.

If you disagree with the rod bearing clearance and tolerance stack thesis, then scientific method demands that you provide data and/or analysis that supports your position. Simply saying you disagree is not science. Simply stating an opinion without data is not science. Simple belief is not science.

I am always interested in learning. These forums have taught me so much about the M3. This would not be the case if all these posts were private conversations between individuals.

Cheers,

[RedScytheM3]

Originally Posted by thingsontoast

Hey man, he said to PM to keep going. But to be fair, I work with get lit and we rebuild engines fairly regularly and he's been doing the rod bearing discussions since the class action lawsuit that fell through. I bought his e90 and did bearings at 115k, I really could have gone another 115k. WPC Coated OEM bearings is what I went with only for piece of mind. I fully believe it is the owners fault for failure at the end of the day for premature failure. It doesn't happen for no reason. Let it warm up, use only TWS (I use BMWs oil) , and change it frequently depending on how you run the car. Use anything other than TWS, you'll end up with failure. It's happened again and again but people still argue until they're blue in the face with 10k worth of engine repair to worry about because they probably shouldn't have bought this car and not trusted the engineers behind it.

Who are you? You have one post in your history and it's this one to chime in to defend yoursel... er... your buddy. And honestly, just because you know how to change bearings doesn't mean you know anything about mechanical engineering, so your qualification of authority (and low post count) don't mean anything. You think it's owner fault based on?

[tdott]

Originally Posted by Scharbag

If you disagree with the rod bearing clearance and tolerance stack thesis, then scientific method demands that you provide data and/or analysis that supports your position. Simply saying you disagree is not science. Simply stating an opinion without data is not science. Simple belief is not science.

Amen.

[SAMM3Y]

OP see what you did!!! You deserve nothing short of a public flogging for posing such a question!! Shame!! Shame!!! Shame!! Law how is this thread not locked? Get in here you slacker!!

Remember brothers, rod bearing questions is Outside influencers trying to meddle, infiltrate and divide us.. stay strong. 😂

[bstone801]

Originally Posted by GotV8?

here we go again!!! lol

I just had mine done as a preventative @94,000 miles and I hang around 8,500 rpm many times after proper warm up thanks to BPM tune!!! when the old ones came out!!! they still look great and I change my oil every 5k miles religiously !!

Dang! The few the proud.

[kyrix1st]

I will explain a little from an engineer's perspective:

Auto engineers: Hey we need a stable oil strong enough to withstand x loads at y points for z duration while retaining all the trivial engine oil properties to satisfy eurob6tch regulations.
Chemical engineers: Could you detail us on where these x loads take place?
Auto engineers: Yeah these are the parameters we are working with, we also need to keep the oil flow at alpha so we can evenly distribute loads and stabilize engine temperature.
Chemical engineers: In that case, would you like to proceed with SAE 10w60 with ACEA A3/B4 specifications?
Auto engineers: Oh we don't know, just do whatever you need to get these parameters in check.
Chemical engineers: (consults with bean counters) In that case we shall proceed with off- the-shelf product and make a few *cough* adjustments to it.
couple of years later
auto engineers: what the hell, you said these oils would protect our engines!
chemical engineers: well, nobody told us that there would be such manufacturing variances potentially changing the parameters, so how can you blame us?
auto engineer:

So the notion that 'nobody knows better than BMW engineers' is really not accurate. It's rather 'BMW auto engineers only know so much' and 'Cxxxxl engineers only know so much'(maybe a little more ). It is rarely a case that someone has complete understanding of both fields.