Lang Racing on the S54 Rod Bearing problems

[bigjae1976]

Originally Posted by regular guy

IMO, technology from 30 years ago: no; technology from today: yes. I think 200k miles on today's technology with an engine that is properly clearanced and properly maintained is what one should expect.

I'm thinking that BMW is not thinking the same thing which is unfortunate. I have no dreams of my E90 M3 running flawlessly for 200k. I'm looking at anything past 100k as a gift. DCT, engine, and all of the rubber stuff will need to be addressed. If the trend with past M3s holds true then M Lock unit will be on borrowed time past 100k. Those will usually start to clunk.

I know the diff in my E46 M3 track car with 103k miles is probably getting near the end of its life.

Originally Posted by Top_Gear

Let me say something upfront. I appreciate the good info from you, BLMVR, and all the other well-meaning and more experienced folks that are contributing to this topic. However, I am still trying to assess the magnitude of this problem before I take any action. In all honesty and at this point in time I am still not fully convinced I need to take any action let alone what type of action to take. The problem for me is a little complicated because I do want to add a bit more power in the next year.

I think the whole disagreement is on the question of what to do. I plan on starting to do an oil analysis on my E90 M3 once I get up to 80k miles.

[Top_Gear]

Originally Posted by bigjae1976

I think the whole disagreement is on the question of what to do. I plan on starting to do an oil analysis on my E90 M3 once I get up to 80k miles.

This is the only thing that has everyone in agreement. I am sending my first sample in for analysis with my next oil change and will be watching for excess lead content. But I am not waiting to do this until my car hits 80K miles.

[aus]

Originally Posted by kawasaki00

The oem 5-30 is really the same as the German 0-30, the specs on it are so close that many are under the assumption that all they do is rebrand it to the bmw label.

Thank you!!!
Would either mix well with BMW 10W60? Maybe 50/50??
Would it be ok to run either oil instead of the 0W40 you recommend if we do oil changes more frequently?

Thanks again for any info.

.

[Yellow Snow]

I get the point about thin oil getting around the journals quicker, but when the engine is stopped and a couple of crank pins come to rest against compression, what happens to the oil on the top of the bearing?

It drains away easier leaving the journal in contact with the top bearing half. Then when it's started from cold, the pin wears the top bearing from it's initial metal to metal contact.

That's the reason to stick with 10w60

[BMRLVR]

Originally Posted by Yellow Snow

I get the point about thin oil getting around the journals quicker, but when the engine is stopped and a couple of crank pins come to rest against compression, what happens to the oil on the top of the bearing?

It drains away easier leaving the journal in contact with the top bearing half. Then when it's started from cold, the pin wears the top bearing from it's initial metal to metal contact.

That's the reason to stick with 10w60

At this point it doesn't matter, the journal needs a pressurized feed for it to have a proper lubricating effect! The difference between 10W60 and 0W40 in this instance is negligible even if the 10W60 provided any more protection on initial startup due to the oil retained in the bearings it would be more than made up for with the quicker flow of oil to bearings on cold start not to mention the much, much better lubrication it will provide between cold start and operating temp.

BMW picked the 10W60 for it's stability at high temps and not the better protection to bearings on startup. The 0W40 is going to do a much better job on initial startup due to increased flow, and, it is plenty robust and stable to provide adequate protection at higher temps. The 0W40's spec sheet and VOA's show that it is more than up to the task of providing protection up to 150 C (300 degrees Fahrenheit). Since the S65 will go into limp mode before this you should be just fine with the 0W40 in all conditions!

[kawasaki00]

Originally Posted by Yellow Snow

I get the point about thin oil getting around the journals quicker, but when the engine is stopped and a couple of crank pins come to rest against compression, what happens to the oil on the top of the bearing?

It drains away easier leaving the journal in contact with the top bearing half. Then when it's started from cold, the pin wears the top bearing from it's initial metal to metal contact.

That's the reason to stick with 10w60

That is a incorrect statement. Engines running for a couple seconds with no oil pressure will not create damage. Even the lightest of oils are still sufficient at providing the layer of protection needed at idle speeds. At less than 1k rpm this engine is no different than any other engine on the street, many cars run 0-20 now for oil and they live a long long life.

[Malek@MRF]

As BMRLVR has posted, there are quite a few shops here in Southern California that are trust worthy in working on the crank assembly to set proper clearances for the engine. This engine is not any different with respect to machine work on the crank in comparison to other engines. The two shops listed below is who I have used time and time again for this type of work without fault. They have the tooling, experience and know how to properly do this type of work and stand behind it. The engine assembly portion of the work has always been done on my own.

-Van Dyne Engineering
-Pfaff Engines

For engine overhaul and assembly, as mentioned before, this should be left in the hands of experienced engine assemblers with the proper tooling and FACTORY literature for assembly and fastener data. Even changing the rod bearings should be done with extreme care. Can't count how many times I have seen DIY jobs on S54 engines gone bad with respect to rod bearings, even a couple of them didn't last more than 10 miles after rod bearing replacement.

Feel free to PM me if any additional information is needed.

[Yellow Snow]

Originally Posted by BMRLVR

At this point it doesn't matter, the journal needs a pressurized feed for it to have a proper lubricating effect! The difference between 10W60 and 0W40 in this instance is negligible even if the 10W60 provided any more protection on initial startup due to the oil retained in the bearings it would be more than made up for with the quicker flow of oil to bearings on cold start not to mention the much, much better lubrication it will provide between cold start and operating temp.

BMW picked the 10W60 for it's stability at high temps and not the better protection to bearings on startup. The 0W40 is going to do a much better job on initial startup due to increased flow, and, it is plenty robust and stable to provide adequate protection at higher temps. The 0W40's spec sheet and VOA's show that it is more than up to the task of providing protection up to 150 C (300 degrees Fahrenheit). Since the S65 will go into limp mode before this you should be just fine with the 0W40 in all conditions!

I'm talking about the initial metal to metal contact on the top shell.

When the journal is sitting against the bearing on compression for a day or two whilst parked the oil drains out of the bearing. This means there is metal to metal contact for the first revolution of the engine when the start button is pushed.

It doesn't matter how quick the pump takes to pressurise, a layer of 0w40 won't protect as well as 10w60 on the first revolution.

There is more damage done on the first rev than driving 1000 miles down the freeway with a warm engine and clean oil.

[G80indy]

So.... Redline 10w-60 then.

[BMRLVR]

Originally Posted by Yellow Snow

I'm talking about the initial metal to metal contact on the top shell.

When the journal is sitting against the bearing on compression for a day or two whilst parked the oil drains out of the bearing. This means there is metal to metal contact for the first revolution of the engine when the start button is pushed.

It doesn't matter how quick the pump takes to pressurise, a layer of 0w40 won't protect as well as 10w60 on the first revolution.

There is more damage done on the first rev than driving 1000 miles down the freeway with a warm engine and clean oil.

The first revolution is insignificant. you are obviously grasping at straws! Do you want an oil that protects better for the warm up period (inarguably the point where most wear occurs) or do you want an oil that protects you for one revolution! Anyway, a journal bearing has little to no lubrication from the residual oil in the shell, a journal bearing in an engine works on pressurized oil feed to keep the bearings pressurized/full of oil, then the hydrodynamic principles take over due to the eccentric shape of the bearing shell compared to the journal creating a wedge of oil that keeps the two separated. In order for hydrodynamic lubrication to stay developed, the oil pressure and flow to the bearing has to be maintained to ensure the bearing is "full".

Just for your information, some of the engines I work on have prelube pumps and others don't. The prelube pumps pressurize the lubrication system in the engines to roughly 5-8PSI before it will crank. The difference in bearing condition between the engines with and without prelube pumps are negligible. Engine heaters have a bigger effect on wear than prelube pumps in my experience! This disproved your theory of thicker oil protecting better on initial start-up or "first revolution" as you put it.

[Yellow Snow]

Originally Posted by BMRLVR

The first revolution is insignificant. you are obviously grasping at straws! Do you want an oil that protects better for the warm up period (inarguably the point where most wear occurs) or do you want an oil that protects you for one revolution! Anyway, a journal bearing has little to no lubrication from the residual oil in the shell, a journal bearing in an engine works on pressurized oil feed to keep the bearings pressurized/full of oil, then the hydrodynamic principles take over due to the eccentric shape of the bearing shell compared to the journal creating a wedge of oil that keeps the two separated. In order for hydrodynamic lubrication to stay developed, the oil pressure and flow to the bearing has to be maintained to ensure the bearing is "full".

Just for your information, some of the engines I work on have prelube pumps and others don't. The prelube pumps pressurize the lubrication system in the engines to roughly 5-8PSI before it will crank. The difference in bearing condition between the engines with and without prelube pumps are negligible. Engine heaters have a bigger effect on wear than prelube pumps in my experience! This disproved your theory of thicker oil protecting better on initial start-up or "first revolution" as you put it.

So you are stating that the first revolution from metal to metal on the top bearing shell is insignificant?

[BMRLVR]

Originally Posted by Yellow Snow

So you are stating that the first revolution from metal to metal on the top bearing shell is insignificant?

Yes I am! Compared to the amount of wear that occurs during the warm-up process where the oil is way it is insignificant! During the first revolution the engine is turning probably 400-600RPM so bearing load is very low plus the rod bearings are not dealing with combustion forces from the rod. If what you were saying was true we would see excessive bearing wear on all engines running lighter oils but this is usually the opposite. In the Fleet I work on we changed to 5W40 from our regular 15W40 and noticed no measurable increase in bearing wear.

[Yellow Snow]

Originally Posted by BMRLVR

Yes I am! Compared to the amount of wear that occurs during the warm-up process where the oil is way it is insignificant! During the first revolution the engine is turning probably 400-600RPM so bearing load is very low plus the rod bearings are not dealing with combustion forces from the rod. If what you were saying was true we would see excessive bearing wear on all engines running lighter oils but this is usually the opposite. In the Fleet I work on we changed to 5W40 from our regular 15W40 and noticed no measurable increase in bearing wear.

I'm not talking about cold start RPM, I'm talking about the first revolution from a dead stop, when the journal is touching the bearing metal to metal.

[Malek@MRF]

Originally Posted by Yellow Snow

I'm not talking about cold start RPM, I'm talking about the first revolution from a dead stop, when the journal is touching the bearing metal to metal.

This phenomenon is not rectified with 10W-60 either with the criteria you are referring to where the car sits for a day or two. Either oil will have drained and trickled down. The initial revolutions until the engine fires and runs are not loaded revolutions as combustion is not occurring yet. That initial contact you speak of is not really consequential with respect to the time it takes for the engine and oil reaching operating temperature.

[Yellow Snow]

Originally Posted by Malek@MRF

This phenomenon is not rectified with 10W-60 either with the criteria you are referring to where the car sits for a day or two. Either oil will have drained and trickled down. The initial revolutions until the engine fires and runs are not loaded revolutions as combustion is not occurring yet. That initial contact you speak of is not really consequential with respect to the time it takes for the engine and oil reaching operating temperature.

I am not talking about the initial revolutions. I am talking about the first portion of the first rotation of the crank. The rod that lands near tdc will scrape the top bearing as it gets moving. A thicker oil will give better protection than a thin oil in this scenario. A tighter clearance will also give more surface area for the oil to cushion.

Where are you suggesting the wear takes place? Once everything is revolving and the hydrodynamic oil film takes place the bearing won't wear. Why is the top bearing wearing more than the bottom?

Clear is clear. Nothing is wearing even if the clearance is only .03mm.

BMW designed this engine with some serious R&D facilities and knowledge. (Especially after the S54 problems)

Clean 10w60 TWS every 7k miles and careful start procedure are key here. Talk of removing the crank to get a thou ground off is absolute madness (IMO).

If a major failure occurs you can pick up a decent engine for less than $5k. If it's just a bearing failure with damaged journals, then you can grind the crank and use .25mm thicker coated bearings.

Anyone got any rod bearing failure figures on an S65? At worst it must be a fraction of a percent

Far too much paranoia occurring over nothing, but I'm sure that won't go down too well here.

Owners should just enjoy one of the best engines ever produced and chill

[Z K]

Originally Posted by Yellow Snow

I am not talking about the initial revolutions. I am talking about the first portion of the first rotation of the crank. The rod that lands near tdc will scrape the top bearing as it gets moving. A thicker oil will give better protection than a thin oil in this scenario. A tighter clearance will also give more surface area for the oil to cushion.

When a car is sitting and then you crank it, there is no oil in the rod bearing at all for the first revolution. The crank is not sitting inside oil, gravity will drain all the oil out of the crank when the car sits. When the oil starts pumping and lubricating everything is when it gets lubed. So in your case, it makes no difference what kind of oil is in the engine - there is no oil to lube that first spin!

[Yellow Snow]

Originally Posted by Z K

When a car is sitting and then you crank it, there is no oil in the rod bearing at all for the first revolution. The crank is not sitting inside oil, gravity will drain all the oil out of the crank when the car sits. When the oil starts pumping and lubricating everything is when it gets lubed. So in your case, it makes no difference what kind of oil is in the engine - there is no oil to lube that first spin!

There is a residual oil film between the two surfaces. I prefer to have 10w60 TWS (As specified by the M division)doing this very important job

[W///]

Originally Posted by Yellow Snow

There is a residual oil film between the two surfaces. I prefer to have 10w60 TWS (As specified by the M division)doing this very important job

You are making it sound like 0W40 vs 10W60 is like water vs molasses. I'm assuming you've seen the 2 side by side right?

[Malek@MRF]

Originally Posted by Yellow Snow

I am not talking about the initial revolutions. I am talking about the first portion of the first rotation of the crank. The rod that lands near tdc will scrape the top bearing as it gets moving. A thicker oil will give better protection than a thin oil in this scenario. A tighter clearance will also give more surface area for the oil to cushion.

Where are you suggesting the wear takes place? Once everything is revolving and the hydrodynamic oil film takes place the bearing won't wear. Why is the top bearing wearing more than the bottom?

Clear is clear. Nothing is wearing even if the clearance is only .03mm.

BMW designed this engine with some serious R&D facilities and knowledge. (Especially after the S54 problems)

Clean 10w60 TWS every 7k miles and careful start procedure are key here. Talk of removing the crank to get a thou ground off is absolute madness (IMO).

If a major failure occurs you can pick up a decent engine for less than $5k. If it's just a bearing failure with damaged journals, then you can grind the crank and use .25mm thicker coated bearings.

Anyone got any rod bearing failure figures on an S65? At worst it must be a fraction of a percent

Far too much paranoia occurring over nothing, but I'm sure that won't go down too well here.

Owners should just enjoy one of the best engines ever produced and chill

You are suggesting that 10W-60 will remain between the bearing and crank better than 0W-40 would after 1-2 days of non-operation. 10W-60 will not outperform 0W-40 in this aspect after 1-2 days of non-operation as oil will have already drained away. 0W-40 is less viscous compared to 10W-60, but it doesn't behave watery either.

As suggested before, the rod clearances are simply too tight for S65 bearing diameter. Generally 0.001" per inch of journal diameter is ideal.

As for BMW learning from prior mistakes, no they haven't been the best at doing that. The E9x Sub-frame failure is indicative of that as well. A problem that has plagued M3's since the E36 days. Just recently BMW has realized that unitizing the sub-frame on their performance cars is mandatory.

[regular guy]

Originally Posted by Yellow Snow

A tighter clearance will also give more surface area for the oil to cushion.

Here's the surface area of the journal with and without extra clearance.

Factory: 4.6607 sq. inches.
Extra Clearance: 4.6573 sq. inches.

That's 99.927% of the original surface area.

[Yellow Snow]

Originally Posted by regular guy

Here's the surface area of the journal with and without extra clearance.

Factory: 4.6607 sq. inches.
Extra Clearance: 4.6573 sq. inches.

That's 99.927% of the original surface area.

I just nabbed this main bearing pic for a simplified illustration and to show the principle. (Yes it's an exaggerated clearance)

Journal sitting at rest



First revolution where metal to metal surface contact occurs as the journal climbs into motion

[M3PO]

Originally Posted by bigjae1976

I think the whole disagreement is on the question of what to do. I plan on starting to do an oil analysis on my E90 M3 once I get up to 80k miles.

You could be in a world of hurt by then. I am at 64k and I don't think my bearings will last that long. I sure as hell would not want to just be finding out about the issue then.

Originally Posted by Yellow Snow

I just nabbed this main bearing pic for a simplified illustration and to show the principle. (Yes it's an exaggerated clearance)

Your cute little picture doesn't change anything. We all know how the crank moves at start up. You're just wasting everyone's because you won't admit you are wrong.

As everyone else has said numerous times, the first single revolution will have NO OIL regardless of what oil you run. The overwhelming majority of wear happens as the oil is warming up. This is where oil choice is important.

Can we please just move on now?