technical M3 e92 rod bearings

[rsgordini]

Hi guys.

My cousins v8 may need the rod bearings to be done. We have it at bmw and they’ll confirm on Monday.

Metal shavings were found in the oil filter.

Anyways it makes a rattling noise but revs freely no noise when stationary.

My question is what’s the reason our fellow members don’t get it done by bmw and rather go through to Tunetech or sav or Budler ?

Thanks in advance.

2008
140k km.
Owned since new

 

[TurboLlew]

Generally you have to do this preventatively. By the time the glitter is in the oil and there are noises, it is quite late. While you can get away with it if it is early enough, you would ideally want to strip a few components and assess for wear on the cams or other bits exposed to oil. Either way, the state of the bearings and crank will tell more of the story.

@KPM3_30 and @Neven can comment further.

The main reason (as with any car) is that the TuneTech's/Budlers of the world simply do more of this sort of thing and have more experience doing it over dozens/hundreds of cars as opposed to the tech the dealer allocates to your car. They tend to have a different approach to looking at the issue more as a system than individual item (there are 'starter packs' of things to be done on V10s and V8s so you don't end up fixing or missing things).

That isn't to say a dealership can't perform this kind of work if they have appropriately qualified techs and the workshop foreman has them under close supervision.

Not that any dealership is perfect, but you'd sooner go to a specialist surgeon than a GP even though both are technically capable of performing a surgery.

 

[FiRi@Rennzport]

@Peter@AEW can also assist either bearings and has been doing it for years.

Maybe give him a shout

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[EATYOURVITAMIN5]

Agree with Llew above - shavings in your oil filter is already post-mortem.

As for why we generally rather take our vehicles to specialists, I don't think there is a single correct answer as everyone will have their own preference. Again, as Llew mentioned above, I am sure that the BMW techs are more than capable of doing the job but ultimately, nothing beats the peace of mind of a specialist.

Secondly - a universal reason for avoiding the agents is cost. Back when I was looking into doing bearings on the M3, it was around the ~R35 000 mark at the agents. I took the car to Sav and it was done and dusted for around ~R22 000. This, however was back in 2018 if I'm not mistaken? I can only imagine the job being nearer to R50 000 at the agents today if I had to hazard a guess.

Thirdly - (and this is a topic for debate) BMW will logically replace the bearings with OEM as per their MO. Word around the S65/S85 grapevine is that BE bearings are the only ones with a gracious enough tolerance. Others say that ACL Race bearings are the one and only etcetera etcetera.. Sav said that he only runs the ACL Race bearings of which he's never had an issue with in any of his V8s, being customers cars or his personal race cars, including the twin turbo build. So, ACL was the route I went.

Finally and somewhat controversially - Sav not only documented the entire process of the bearing replacement and sent me updates (which I might be mistaken but BMW does not do this) but also left me with the bearings that came out of the vehicle in the first place. Again, another matter of peace of mind. I don't necessarily think that a company like BMW would say they've performed the job without it being done but it's not unheard of (though, you could possibly request the old bearings back, not sure)

 

[Peter@AEW]

If you have shavings in the oil filter I would closely examine the shells and conrods that come out for signs of a bent crank.

Once the S54/S62/S65/S85 start rattling 9/10 times the crank is bent.

Crank runout from memory 0.0002mm
Bearing clearance typically 0.030 to 0.070

In addition do not be tempted to go to aftermarket bearings as that will compromise the engine.
BMW specify specific thickness bearings which allow for the correct clearance.
These engines suffer from detonation and NOT a clearance issue.
Usually the big end bearings show wear on the thrust side of the rod which is a clear sign of detonation and not a sign of insufficient clearance.
(Yes I am aware of what the American market postulates and promotes however it is their opinion)

 

[rsgordini]

Thanks for all the replies gents. Really appreciate it. Will give more information on Monday once we know.

 

[Mytfine]

Back in the 2000's all my beemers went to Tunetec because it was fixed right the 1 st time and his knowledge of the 90's and 2000's beemers were second to none. His pricing for the one time customer might seem high at the time but become a regular and it was in line with most after market shops. I also appreciated the fact that Shaun took the time to speak to me personally about my little old piece of shit beemer and treated me the same way he would a customer with a car valued 20 times mines. I will.never forget the day he chipped my 535i (good old EPROM days) and made a massive 140kw at the wheels and he spent an hour just shooting the shit with 22 year old me.

Sadly I started working more and more on my vehicles and saw less and less of him over the years but I never have and never will trust another workshop as much as I trusted him

 

[Clint@MMS AUTO]

@Peter@AEW can also assist either bearings and has been doing it for years.

Maybe give him a shout

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+1 for Peter

He can probably do it with his eyes closed by now and must have already memorized the torque specs of every nut and bolt