E92 M3 bearing choice

[KidB]

So I've decided that I need to diffuse my ticking time bomb, ie replace bearings.

I'm approaching 60k kms.

I have 4 choices of bearings to choose from

BE bearings
VAC Clevite
WPC
Calico coated

I used the following wiki to determine the differences in clearances of the above bearings

http://wiki.rcollins.org/core/index...d_Bearings#Bearing_Clearance_Specifications_4

and have read most of the literature on m3post by kawasaki00, regular_guy and BMWLVR.
(http://www.m3post.com/forums/showthread.php?t=892838)


I compared the "bearing clearance per journal inch" parameter from the wiki above and listed them below in inches/inch

OEM 702/703 - 0.00083 (I have the '08)
BE bearings - 0.00116
VAC clevite - 0.00099
WPC - 0.00090
Calico - 0.00063

Engine builders in the states and Clevite (OEM bearing manufacturers) both agree that the clearance should be the industry norm of 0.001inches/inch.

Hence my choice is limited to VAC Clevite and the BE bearings.

I am in favour of the bigger clearance (BE bearings) and would like to know from the community what your take on the extra clearance of the BE bearings versus the VAC is?

I am also undecided as to what oil to use, either stick with TWS or change to M1 0w40. My preference is 0w40 as the clearance between adjacent con rods is also marginal and hence would like to know if the 0w40 can run with the extra BE bearing clearance without damage?

I only want to do this once and hopefully never worry about it again for the rest of the cars life. I do plan on keeping the car long term.




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[Xack]

How nice, you doing it yourself...Ratslaaf on the forum just did his, iam pretty sure he's got lotsa good information regarding the topic

 

[Ratslaaf]

Let me leave you with this:

The bearings aren't supposed to touch the crank. Read this sentence again.

By going for coated bearings, you're not making yourself immune to bearing failure, you're just sticking a bandaid over the issue. FWIW, I recommend going for stock bearings, but run octane plus for every tank of fuel. This has proven to bring down knock events dramatically.

I'm running LM 0W40 on my car, there's no way you would get me to put that TWS poison in my car

 

[444YYY]

Bear in mind, excuse the pun, that there will be slight wear and tear on the crankshaft side as well. Since we talking 0.0001 mm range, I would expect to see wear. Not sure if the average person will have the tools to measure this, only a lab can.

Take this into account as well...

 

[KidB]

How nice, you doing it yourself...Ratslaaf on the forum just did his, iam pretty sure he's got lotsa good information regarding the topic

I wish I could, although I have no tools nor experience in this regard so I will be taking it to a mechie.

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Let me leave you with this:

The bearings aren't supposed to touch the crank. Read this sentence again.

By going for coated bearings, you're not making yourself immune to bearing failure, you're just sticking a bandaid over the issue. FWIW, I recommend going for stock bearings, but run octane plus for every tank of fuel. This has proven to bring down knock events dramatically.

I'm running LM 0W40 on my car, there's no way you would get me to put that TWS poison in my car

I've heard that detonation can be one cause of the bearings wearing pre-maturely, but I also feel like going for stock bearings is not a good idea since the oem bearing clearance is too small.

I will switch to Mobil 1 going forward.
Where do you get octane boosters from and can you tell me what the cost is per tank of fuel?

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Bear in mind, excuse the pun, that there will be slight wear and tear on the crankshaft side as well. Since we talking 0.0001 mm range, I would expect to see wear. Not sure if the average person will have the tools to measure this, only a lab can.

Take this into account as well...

I agree. Does that mean that i will be fine with standard oem bearing clearances? Since the wear on the crankshaft journal will increase the clearance.

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[Ratslaaf]

Hey bud, detonation is the major cause of bearing failure. Going for a thinner oil helps address the clearance concerns that some may have. Going for more clearance is again just a band aid. Your oil is supposed to prevent the bearings touching the crank.

I use LM Octane Plus on my car. I think it's around R90'ish a bottle, one per tank, although pricing is going up in the new year.

 

[KidB]

Hey bud, detonation is the major cause of bearing failure. Going for a thinner oil helps address the clearance concerns that some may have. Going for more clearance is again just a band aid. Your oil is supposed to prevent the bearings touching the crank.

I use LM Octane Plus on my car. I think it's around R90'ish a bottle, one per tank, although pricing is going up in the new year.

Thanks Gert. I guess I will go with the BE bearings + 0w40 + octane boosters.

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[Peter@AEW]

Buy OE from the agents.

 

[444YYY]

KidB, I can't say which bearings to go for.
Trust the advice from Gert and A1exander. They have put together these engines before!

 

[KidB]

If I get OEM bearings from the agents, what will stop this issue from recurring?

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[Peter@AEW]

If I get OEM bearings from the agents, what will stop this issue from recurring?

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Nothing
Consider the big ends as a consumable item and you shall be a happy man.

There is no surefire way of preventing the bearings from being worn so make peace with it and enjoy the car knowing that once in a while you shall need to spend money to keep it healthy.

What your bearings and labour will cost you I have to spend every 5 years on a major service plus more.
Consider that your car is a high performance machine.

Not being blaze however if you wish to listen to Bach you need to pay.

 

[Crash_Nemesis]

If I get OEM bearings from the agents, what will stop this issue from recurring?

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Nothing
Consider the big ends as a consumable item and you shall be a happy man.

There is no surefire way of preventing the bearings from being worn so make peace with it and enjoy the car knowing that once in a while you shall need to spend money to keep it healthy.

What your bearings and labour will cost you I have to spend every 5 years on a major service plus more.
Consider that your car is a high performance machine.

Not being blaze however if you wish to listen to Bach you need to pay.

I disagree with this statement.

I ran Vac Motorsports coated performance bearings since 2010, and over 50 000km. In 2014 when checking the bearings, not a single mark on them. No sign of wear. Even after my catastrophic engine failure due to engineering mistake and my sleeves cracking, the bearings were still ok.

So whilst the issue of bearings clearance and damage may never fully be fixed, I can sure as hell say the VAC bearings work. There is a reason many race teams run those bearings.

Just my 2 cents. Use it don't use it, but in my book, results speak louder than some people's opinions...

 

[Peter@AEW]

If I get OEM bearings from the agents, what will stop this issue from recurring?

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Nothing
Consider the big ends as a consumable item and you shall be a happy man.

There is no surefire way of preventing the bearings from being worn so make peace with it and enjoy the car knowing that once in a while you shall need to spend money to keep it healthy.

What your bearings and labour will cost you I have to spend every 5 years on a major service plus more.
Consider that your car is a high performance machine.

Not being blaze however if you wish to listen to Bach you need to pay.

I disagree with this statement.

I ran Vac Motorsports coated performance bearings since 2010, and over 50 000km. In 2014 when checking the bearings, not a single mark on them. No sign of wear. Even after my catastrophic engine failure due to engineering mistake and my sleeves cracking, the bearings were still ok.

So whilst the issue of bearings clearance and damage may never fully be fixed, I can sure as hell say the VAC bearings work. There is a reason many race teams run those bearings.

Just my 2 cents. Use it don't use it, but in my book, results speak louder than some people's opinions...

Not impossible that your observation is entirely correct however it is not impossible that your observation is entirely incorrect.

There are engines that have covered 200 000km without bearing issues and of course others that have had conrods through the block at 50 000Km.

In addition your engine is an I6 which is entirely different to the V8.
The V8s have rod clearance issues which the I6 does not have.

 

[Lysis]

I disagree with this statement.

I ran Vac Motorsports coated performance bearings since 2010, and over 50 000km. In 2014 when checking the bearings, not a single mark on them. No sign of wear. Even after my catastrophic engine failure due to engineering mistake and my sleeves cracking, the bearings were still ok.

So whilst the issue of bearings clearance and damage may never fully be fixed, I can sure as hell say the VAC bearings work. There is a reason many race teams run those bearings.

Just my 2 cents. Use it don't use it, but in my book, results speak louder than some people's opinions...

I certainly saw for myself back in 2013 how good the VAC bearings looked coming out of your motor. I can attest to their quality and you may have seen that I put VAC coated bearings into my Z4. However, I find the bolded part above to be quite remarkable. There's a rather sizable ///M membership on the forum and I'm sure that they'd be interested in seeing the undamaged bearings. It may be quite educational to see pics of the old bearings, especially of the uppers.

I see though that you chose to go with a new set for your most recent build. Given that in the past you've opted for reuse when relatively low mileage bearings show no wear, what made you decide to opt for replacement this time around?

Another thing to remember is that your car runs an s54, which has only six cylinders compared to the eight found in the s65. There are many folks around the world with e9x M3s who I've seen replace their OEM bearings with a fresh set of OEMs, which is very much in contrast with the s54 crowd who typically opt for aftermarket.

 

[Crash_Nemesis]

Crank damaged on position 7, had to be machined. Went oversized vac bearings. That's why I am not using my old bearings.

You're welcome to come see them. But I'll be updating my build thread with all the details of the cause of failure and the rebuild when I find time to waste.

But, getting back into topic, my point was that the coated bearings don't wear anywhere near as fast as oem, so I'd rather go with those as both e92 and e46 suffer from the same bearing clearance issue.

 

[Ratslaaf]

Look, I cannot fault the VAC bearings. They are really, really good at remaining intact over an extended period of time. More so than the OE bearings - all things being equal.

And I'm sounding like a gramophone, I know. But bearings aren't supposed to wear in the first place. I'm sorry, but I do not buy the clearance issue as the ultimate cause of bearing failure, at least not in itself.

Lack of lubrication, less than ideal fuel, questionable partial throttle AFR's under load and driver behavior are the things that stand out to me.

The point is, replacing the bearings with something different is a band aid solution, it does not address the root cause. When I see an S65 or S85 with 150k km on replacement after market bearings I'll be convinced. Until such a time I'll stick to my guns

I actually went into detail around this very issue in my rebuild thread. Based on the research I've done, I got the impression that bearing issues were more prominent in areas where fuel quality was questionable. I urge others to verify this for themselves of course. In doing knock testing on my car, I saw a clear line between knock events and the lack of Octane boosters under the same conditions.

For those wishing to verify this, you can download Testo and run you own logs, looking at the timing retardation data to make your own conclusions.

 

[Andy1GP]

I have to resonate what Gert says. The s65 and s85 run at 12 to 1 compression and it demands proper fuel else you are asking for excessive wear. S54 is slightly more forgiving with its 11.5 to 1.

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