Finally: Rod bearing replacement

[WaylonM3]

For those of you who have similar mileage and blackston data...this is what my bearings looked like. Car saw about 15+ trackdays in 2016.

[tony093]

What's your mileage?

[shimmy23]

Originally Posted by tony093

What's your mileage?

the report shows 72k

[Solo_M_Tech]

Now lets not all run out and schedule a bearing service at the same time! Seeing how there are reported bearing failures at 13k miles or less, this cannot be used as a basis for the recommended replacement mileage/oil report data. Its all a gamble. Safe bet is to change them preventatively, or shortly after a used purchase.

[Rajmun340]

another waste of money. Placebo for you, not the car.

[mi_ke]

Definitely planning on changing these out as soon as I buy the M3 I want.

[pbonsalb]

Originally Posted by JoeM3SSII

another waste of money. Placebo for you, not the car.

Its definitely not a placebo for the guys with copper showing through their bearings. Maybe the next set of bearings will wear prematurely as well, but changing the bearings is a lot cheaper than replacing the motor.

[Ab28]

Originally Posted by JoeM3SSII

another waste of money. Placebo for you, not the car.

Tell that to the guys trying to unload their cars for half the value after a bearing failure.

[WaylonM3]

Knowing how they look now and knowing that I have 4 track weekends coming up in the first quarter of year...I'm glad these are being replaced. I just figured it's easy to cough up $1200 instead of thousands and thousands more when they fail.

[msan]

Originally Posted by WaylonM3

Knowing how they look now and knowing that I have 4 track weekends coming up in the first quarter of year...I'm glad these are being replaced. I just figured it's easy to cough up $1200 instead of thousands and thousands more when they fail.

$1200?!?! That's a steal!!

[Z K]

Originally Posted by lat77

Tell that to the guys trying to unload their cars for half the value after a bearing failure.

Exactly, you're playing roulette with the M3. If the rod bearings go, you're left with nothing. Better to be preventative than sorry.

[New2Roundel]

Originally Posted by Z K

If the rod bearings go, you're left with nothing.

How many have rod bearings that have actually let go? Most forums where there is evidence of engines with catastrophic failures have some type of thread (such as the 2.0t engine failures in the Caddy ATS forums) where those people with bad luck can post up their experiences. I haven't seen one of those around here. In fact, in the 1.5 yrs I've been here, I might have read a single new thread about engine failure due to bearing wear. I'm all for getting on the "the S65 is a poorly engineered masterpiece due to crappy bearings" bandwagon, but I haven't seen the evidence nor have I seen any real science/engineering describing the cause of the bearing wear.

I'm happy to stand corrected and learn if I'm missing something.

[pbonsalb]

There is a blown engine thread.

[Ab28]

Originally Posted by New2Roundel

How many have rod bearings that have actually let go? Most forums where there is evidence of engines with catastrophic failures have some type of thread (such as the 2.0t engine failures in the Caddy ATS forums) where those people with bad luck can post up their experiences. I haven't seen one of those around here. In fact, in the 1.5 yrs I've been here, I might have read a single new thread about engine failure due to bearing wear. I'm all for getting on the "the S65 is a poorly engineered masterpiece due to crappy bearings" bandwagon, but I haven't seen the evidence nor have I seen any real science/engineering describing the cause of the bearing wear.

I'm happy to stand corrected and learn if I'm missing something.

There are 2-3 cars in the For Sale section at this very moment being sold for 11-15k...all from bearing failures.

http://www.m3post.com/forums/showthread.php?t=1344612
http://www.m3post.com/forums/showthread.php?t=1337022


I would suggest checking out the Auto Couture Rod Bearing Thread. It'll show you every set of bearings taken out of an S65 had significant wear, independent of mileage. Higher mileage cars seem to have more wear. Low mileage cars are also affected.

If this wasn't an issue then independent shops wouldn't be offering these services, companies wouldn't be manufacturing alternative bearings, and cars wouldn't be blowing engines.

It's not something that is blown out of proportion either. Otherwise perfect M3s are being taken out from this.

I had been looking at M3s for a long time. Finally pulled the trigger on a low mileage car (33k)

Bearings were pulled...you guessed it, worn.

A not so scientific explanation... the reason this happens is due to the clearance of the RBs around the crank. It makes contact, wears the lead, copper, and other metals off the RB, and that gets into the engine. Boom.

Choosing a replacement bearing, whether coated or with a bigger clearance, will avoid this. (which option is best is for another thread)

[UPSROD]

Many of the engine failures were broken valve springs!

[Solo_M_Tech]

Originally Posted by lat77

There are 2-3 cars in the For Sale section at this very moment being sold for 11-15k...all from bearing failures.

http://www.m3post.com/forums/showthread.php?t=1344612
http://www.m3post.com/forums/showthread.php?t=1337022


I would suggest checking out the Auto Couture Rod Bearing Thread. It'll show you every set of bearings taken out of an S65 had significant wear, independent of mileage. Higher mileage cars seem to have more wear. Low mileage cars are also affected.

If this wasn't an issue then independent shops wouldn't be offering these services, companies wouldn't be manufacturing alternative bearings, and cars wouldn't be blowing engines.

It's not something that is blown out of proportion either. Otherwise perfect M3s are being taken out from this.

I had been looking at M3s for a long time. Finally pulled the trigger on a low mileage car (33k)

Bearings were pulled...you guessed it, worn.

A not so scientific explanation... the reason this happens is due to the clearance of the RBs around the crank. It makes contact, wears the lead, copper, and other metals off the RB, and that gets into the engine. Boom.

Choosing a replacement bearing, whether coated or with a bigger clearance, will avoid this. (which option is best is for another thread)

The bearings are not the problem. The clearance is. Clearance is not controlled by the bearings, rather the machining of the components. Incorrectly torqued rod caps can also warp the rod bore and decrease bearing clearance. These are the reasons the bearing wear prematurely. Replacing the bearings without addressing the root cause will only create the same condition again. I believe the reason aftermarket coated bearings have faired better, is due to correctly stretched and torque rod bolts, keeping the rod bore perfectly round. Which helps keep uniform oil pressure and volume around the entire bearing surface. All speculation since there is no scientific way of proving my theory, alas its still my theory.

[BigRussia]

What year is your M3? Looking at the copper content I'm guessing an early S65? What replacement bearings did you go with? I'm considering BE bearings but Ive yet to see any longtime reviews.

[BigRussia]

What year is your M3? Looking at the copper content I'm guessing an early S65? What replacement bearings did you go with? I'm considering BE bearings but Ive yet to see any longterm reviews.

[Solo_M_Tech]

Originally Posted by BigRussia

What year is your M3? Looking at the copper content I'm guessing an early S65? What replacement bearings did you go with? I'm considering BE bearings but Ive yet to see any longterm reviews.

I would recommend the VAC Motorsports bearings coated by Calico. Calico coated bearings are used in all forms of motorsport. They have a track record for keeping the engine from seizing if the oil system fails, potentially preventing component damage. It what I personally used in my M3 and have used in bearing services ive done for customers. S54, S85 and S65.