BMW rod bearings: What is the real story here?

Slippery said:

In reply to Tom1200 :

Not an engine out fix. I have done mine on jack stands in a day. 

That's makes it far less of an issue. I have "refreshed" a few FWD cars with the block in place.

I also assume you don't need to pull the head? 

Tom1200 said:

Slippery said:

In reply to Tom1200 :

Not an engine out fix. I have done mine on jack stands in a day. 

That's makes it far less of an issue. I have "refreshed" a few FWD cars with the block in place.

I also assume you don't need to pull the head? 

No need to pull the head. 

From memory:

1. Remove clutch fan and serpentine belt.
2. Support engine with brace.
3. Raise front of car
4. Remove subframe
5. Move ps pump out of the way. 
6. Remove oil pan. 
7. Remove oil pump.
8. Change bearings. 
9. Reverse all steps. 

In reply to Tom1200 :

Bearings are engine in. On a S85 you have to remove the cross member and usually do a vanos service while you're there. 

In reply to Slippery :

The way those are worn is interesting.  The cap side show less wear, I assume/theorize, because for half of the times that the piston goes to TDC, the rod is under less tension because there is pressure on the piston. 

In reply to Docwemple :

Once you replace the garbage BMW bearings with an aftermarket set, you should never have to replace them again during the life of the engine. The VANOS line is a different story sadly.

Pete. (l33t FS) said:

In reply to Slippery :

The way those are worn is interesting.  The cap side show less wear, I assume/theorize, because for half of the times that the piston goes to TDC, the rod is under less tension because there is pressure on the piston. 

Your theory sounds right to me. Of all the S54 bearings I have seen, the conrod side always had more wear than the cap side. 

What I could never figure out is why was #5 on my engine so much worse than the rest. 

I am at 60k miles on the new bearings and I might pull the pan and have a peak at the next oil change. We'll see if #5 shows the same type of wear. 

frenchyd said:

I think you guys are looking in the wrong direction.  The problem isn't the bearings,  the problem is how good your brakes are. 
  In-line 6 cylinders will always have this problem if the brakes are real good

Yeah, well you are incorrect.

S54 = 6 inline
S62 = V8
S65 = V8
S85 = V10

What do they have in common? They all rev to 8k+ RPMs ... and the bearings do not have a wide enough surface area coupled with very tight tolerances. The 2003+ S54s went to a wider bearing, but still suffer as you can see in my pictures.

So, brakes have absolutely nothing to do with anything other than excessive brake dust on the wheels.

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

frenchyd said:

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

I am more surprised Jaguar made that "serious engineering" mistake where the bearings only lasted one race weekend on an engine that revs to what? 5K rpms?! At least the BMW ones last no less than 100k miles.

Has anyone done extensive pressure monitoring on these, to see if there is any pressure drop during braking, cornering or accel? In general on the short time cars we see wear more on the top shell due to hp and decently even wear on both when it's rpm related. 

On the pic above it's a bit odd that #5 is the worst. How does the oil go through the crank on that motor?

Slippery said:

frenchyd said:

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

I am more surprised Jaguar made that "serious engineering" mistake where the bearings only lasted one race weekend on an engine that revs to what? 5K rpms?! At least the BMW ones last no less than 100k miles.

Jaguar went to dry sump in 1954  for racing.  I failed to realize that requirement thinking 18 quarts would be enough.   Less than a season of racing taught me the required lesson.   And as I said 3 decades the bearings lasted. Going all the way to 6500rpm  that long stroke(4.17)  6 cylinder engine designed during WW2. As  Far as I know they are still in it in the Packard Museum  where it's on display. 

frenchyd said:

Slippery said:

frenchyd said:

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

I am more surprised Jaguar made that "serious engineering" mistake where the bearings only lasted one race weekend on an engine that revs to what? 5K rpms?! At least the BMW ones last no less than 100k miles.

Jaguar went to dry sump in 1954  for racing.  I failed to realize that requirement thinking 18 quarts would be enough.   Less than a season of racing taught me the required lesson.   And as I said 3 decades the bearings lasted. Going all the way to 6500rpm  that long stroke(4.17)  6 cylinder engine designed during WW2. As  Far as I know they are still in it in the Packard Museum  where it's on display. 

We are talking street engines here. 

You are hilarious.

Paul_VR6 (Forum Supporter) said:

Has anyone done extensive pressure monitoring on these, to see if there is any pressure drop during braking, cornering or accel? In general on the short time cars we see wear more on the top shell due to hp and decently even wear on both when it's rpm related. 

On the pic above it's a bit odd that #5 is the worst. How does the oil go through the crank on that motor?

Calvin also experienced the same oil surge in his Atlas 4200 drag car.  I think it was 4 passes  where he experienced  0 oil pressure for a total of 1 minute.  Good oil pressure during the pass, 0 oil pressure under braking. 
  That was discovered  due to his system of measuring everything on his lap top.  

Paul_VR6 (Forum Supporter) said:

Has anyone done extensive pressure monitoring on these, to see if there is any pressure drop during braking, cornering or accel? In general on the short time cars we see wear more on the top shell due to hp and decently even wear on both when it's rpm related. 

On the pic above it's a bit odd that #5 is the worst. How does the oil go through the crank on that motor?

I log oil pressure data on my AIM, there is no loss under braking or cornering at least not within the grip limits of my car (with 275 Hoosier R7s and some decent aero).

I may have mentioned it, but I'll admit I'm too lazy to go through the whole thread. 

Part of the reason the S-series engines have the problems they do is the bore spacing. That's why you can use an S54 crank to make a 3.1L stroker M20. 

In reply to codrus (Forum Supporter) :

I'm always impressed at the lengths folks here go to.  I have an oil pressure and a temp gauge.............that I look at twice a lap.

codrus (Forum Supporter) said:

Paul_VR6 (Forum Supporter) said:

Has anyone done extensive pressure monitoring on these, to see if there is any pressure drop during braking, cornering or accel? In general on the short time cars we see wear more on the top shell due to hp and decently even wear on both when it's rpm related. 

On the pic above it's a bit odd that #5 is the worst. How does the oil go through the crank on that motor?

I log oil pressure data on my AIM, there is no loss under braking or cornering at least not within the grip limits of my car (with 275 Hoosier R7s and some decent aero).

Thanks for sharing some (actual) facts. 

Slippery said:

frenchyd said:

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

I am more surprised Jaguar made that "serious engineering" mistake where the bearings only lasted one race weekend on an engine that revs to what? 5K rpms?! At least the BMW ones last no less than 100k miles.

I find comparing various makes on something like this pointless: 

I've pulled bearings out of a  Datsun 1200 engine that overheated so severely the head had holes melted in it, and the bearings looked better than the ones pictures above.

That fact that said engine made all of 115hp and Datsun  uses a 24mm wide rod bearing (overkill) in an already under stressed motor is irrelevant. LOL

I should probably throw in the fact that the stock Datsun bottom end is good for 9000 RPM..............pretty sure that fact is also irrelevant to this discussion as well.  

Slippery said:

frenchyd said:

Slippery said:

frenchyd said:

In reply to Slippery :

I'm surprised ( sorta) BMW would make such a serious engineering mistake. 
  Maybe they decided to throw a bone to the dealers?  Let them make money on  under engineered bearings?     80,000 miles just seems too soon to wear out bearings. 

I am more surprised Jaguar made that "serious engineering" mistake where the bearings only lasted one race weekend on an engine that revs to what? 5K rpms?! At least the BMW ones last no less than 100k miles.

Jaguar went to dry sump in 1954  for racing.  I failed to realize that requirement thinking 18 quarts would be enough.   Less than a season of racing taught me the required lesson.   And as I said 3 decades the bearings lasted. Going all the way to 6500rpm  that long stroke(4.17)  6 cylinder engine designed during WW2. As  Far as I know they are still in it in the Packard Museum  where it's on display. 

We are talking street engines here. 

You are hilarious.

What do you think Jaguar and I raced with?  Same thing for Calvin's 4200 Atlas engine. It's the same engine found in Chevy Trailblazers.  

The rod bearings fail in street use, not racing use.

In reply to Slippery :

Going to do my 2003.5 also on the floor at home with oem parts my production date is 2002-10-14 hopefully it has the reusable conrod bolts the M11 that was up to the 12/13/2002 s54 versions but you never know until I open the guts up. I would love to see your update with #5 

In reply to Tigm3 :

You definitely have the narrower bearings + reusable bolts on yours. 

I am still driving mine. I got all the parts but waiting on oil change time to open it. 

Does you car have the LED tail lights?

In reply to Slippery :

Alright cool. Non led it was stock and still is, has the original strut brace, i know the earlier ones didn't. What really is the differences between the earlier version s54 vs the later ones? other than what you mentioned, newer version has different conrods I herd. 

In reply to Tigm3 :

If your car has non LED tail lights, then it's a 2003, not a 2003.5. It will have the reusable connecting rod bolts. 

I believe the engines are mostly the same, just a different conrod design with a different bolt and possibly larger clearances later on. The VANOS oil line is different as well. 

I would try and get BE bearings from Bimmerworld. That is what I will use this time.