E90 M3 For Bearings

[325iSmk2]

What is the intended lifespan of these bearings ?

 

[Mohamaxx]

What does it cost to do bearings?

 

[F21GP]

What does it cost to do bearings?

Read carefully!!!

Peter if you don't mind - what is the ballpark figure for these bearing jobs on the E9x and E46 M's?

I am sure there are others amongst us that need this kind of info to budget and plan accordingl.

Plan between 20K I6 /25V8/30kV10 all things being equal.

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[Peter@AEW]

What is the intended lifespan of these bearings ?

Anywhere from 70000Kms to 200000Kms.

BMW is not telling and neither is CLEVITE who make the bearings for BMW.

The common wisdom is that the bearings are very narrow and that is why there are failures.
However for an engine to rev freely it requires minimum friction so therein one finds the compromise.
High revs narrow bearings more load more wear more failures.

I think that bearings need to be considered as a service item by I6/v8/v10 owners.
It works roughly to R0.30cents per Km which is a negligible cost.

 

[Peter@AEW]

Something very interesting (excuse the quality of the pic I will take a better one later)


All are the top half shells.
From right to left
1,5,2,6

Number 6 rod bearing is only now starting to wear. That spec of break up on the surface the bearing is the only blemish and the rest is absolutely perfect.

I really would be interested to hear any thoughts as to why they have worn as per the pic

 

[444YYY]

Something very interesting (excuse the quality of the pic I will take a better one later)


All are the top half shells.
From right to left
1,5,2,6

Number 6 rod bearing is only now starting to wear. Other for that spec of break up on the surface the bearing is absolutely perfect.

I really would be interested to hear any thoughts as to why they have worn as per the pic

Peter,
This should be correlated with the data stored on the ECU.
The S65 counts the number of times the engine revved above 8400rpm, also there are certain bands below this e.g. 8000 to 8400rpm etc.

Gert knows the details of this.

Get a database from all the cars, comparing bearing condition (pics) to the ecu data...

Then we may be able to understand more and draw conclusions. Minimum 10 different cars data would be needed.

 

[Ratslaaf]

Variations in clearance I'd guess. Remember that lead layer is but faaaaaarking thin. And when tolerance stacking comes into play between crank / bearing / rod roundness, then such difference in wear would make sense.

 

[Peter@AEW]

Variations in clearance I'd guess. Remember that lead layer is but faaaaaarking thin. And when tolerance stacking comes into play between crank / bearing / rod roundness, then such difference in wear would make sense.

This engine compares in clearances to Anthony's V8.
They have almost identical clearances rod for rod up till now.

If I compare Anthony's bearings to these they were worn down to copper on the top shells and were breaking up on the bottom shell.

The clearances between your v8 Anthony's v8 and this v8 are all similar and you will recall that yours were in a range of 0.076 and 0.050.

Of these 3 engines the Anthony engine had the worst wear with yours and this one being roughly equal in wear.

I have measurements on 10 engines and I am of the opinion having read a fair number of articles that clearance is not a player in the deterioration of the bearings.

I cannot even propose that the lack of lead in the construction of the bearings may be a contributing factor as lead coated bearings I have changed show equal wear to non lead bearings.

I still maintain that we have too small a sample to even begin analysing with any degree of confidence the reason for the abnormal wear.

I will post pics on the bearing of a 300K S38 engine a little later for the fun of it.

 

[444YYY]

ECU data!!!

---

Will help in providing the answer ....

 

[Peter@AEW]

 

[Peter@AEW]

 

[S65B44]

http://www.m3post.com/forums/showthread.php?t=1337998

 

[Ratslaaf]

Thanks for that link Angelo.

 

[Peter@AEW]

Car was on 100520Kms when the bearings were changed.

 

[Dewald Basson]

Something very interesting (excuse the quality of the pic I will take a better one later)


All are the top half shells.
From right to left
1,5,2,6

Number 6 rod bearing is only now starting to wear. Other for that spec of break up on the surface the bearing is absolutely perfect.

I really would be interested to hear any thoughts as to why they have worn as per the pic

Peter,
This should be correlated with the data stored on the ECU.
The S65 counts the number of times the engine revved above 8400rpm, also there are certain bands below this e.g. 8000 to 8400rpm etc.

Gert knows the details of this.

Get a database from all the cars, comparing bearing condition (pics) to the ecu data...

Then we may be able to understand more and draw conclusions. Minimum 10 different cars data would be needed.

IIRC - you need 32/34 samples for a study to be deemed acceptable/viable at varsity level. Once you have that, then all you will need to do is type it up all fancy, draw your conclusions and publish.

"A technical analysis on the lifespan and wear-rate of BMW Motorsport engine bearings"


:tease:


Nice write up Peter.

 

[444YYY]

Lol, the more measurements the better!!

Agreed!!!

 

[///Herbie]

Awesome thread. Really scary seeing all the V8 Ms for sale with mileage way beyond that of this car[FACE SCREAMING IN FEAR][FACE SCREAMING IN FEAR][FACE SCREAMING IN FEAR]



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