S65 Rod Bearings (again)

[asimmalik]

Hi guys

I'm sure this topic has been covered before but I'm struggling to find a definitive answer. I'm looking at buying an E92 M3 which has had it's rod bearings replaced, I believe with ACL bearings. Most of these cars have now had them replaced at some point but I've yet to find people who have changed them more than once.

My question is are these intended to be "lifetime" replacement once the job is done. The car has now done 50k since they were changed and I'm wondering if they will be due to be changed again soon? Or can I can sleep easy in the knowledge they have been replaced, albeit a while ago.

[Hants PHer]

asimmalik said:

My question is are these intended to be "lifetime" replacement once the job is done. The car has now done 50k since they were changed and I'm wondering if they will be due to be changed again soon? Or can I can sleep easy in the knowledge they have been replaced, albeit a while ago.

You'll get mixed opinions on this issue but here's mine: I would replace the rod bearings on any S65 M3 I bought, unless they'd been done a few hundred miles prior to purchase. That's because you have no idea how the previous owner(s) has/have treated the car. Proper warm up is vital on these engines if you want the RB's to last.

Last change 50k miles ago? I would definitely want to replace and would factor that into my purchase price. Cost at a specialist is around £1500 but remember that you get a full oil/filter change and new engine mounts as part of that.

[Mr Tidy]

I've no experience of the S65, but have an S54 and I think the bearing shells issue is common to both versions (and probably the S85 too).

I bought my car with 76K miles and 7 previous keepers and decided to bite the bullet and get the shells replaced at 78K. They weren't too bad but half of them were showing copper so it was worth doing for peace of mind. Despite having spent many years at Sytner my Indy also fitted ACL shells which seem a popular choice.

As you don't know how the car has been treated for the last 50K miles it's a gamble, but maybe it would be £1,500 or so well spent to avoid a much bigger bill if you get a spun bearing!

[asimmalik]

Hants PHer said:

You'll get mixed opinions on this issue but here's mine: I would replace the rod bearings on any S65 M3 I bought, unless they'd been done a few hundred miles prior to purchase. That's because you have no idea how the previous owner(s) has/have treated the car. Proper warm up is vital on these engines if you want the RB's to last.

Last change 50k miles ago? I would definitely want to replace and would factor that into my purchase price. Cost at a specialist is around £1500 but remember that you get a full oil/filter change and new engine mounts as part of that.

Yeh this is the line of thinking I was going with too. Good bargaining point too if nothing else, even though the seller was keen to point out they've already been done.

[survivalist]

Hants PHer said:

asimmalik said:

My question is are these intended to be "lifetime" replacement once the job is done. The car has now done 50k since they were changed and I'm wondering if they will be due to be changed again soon? Or can I can sleep easy in the knowledge they have been replaced, albeit a while ago.

You'll get mixed opinions on this issue but here's mine: I would replace the rod bearings on any S65 M3 I bought, unless they'd been done a few hundred miles prior to purchase. That's because you have no idea how the previous owner(s) has/have treated the car. Proper warm up is vital on these engines if you want the RB's to last.

Last change 50k miles ago? I would definitely want to replace and would factor that into my purchase price. Cost at a specialist is around £1500 but remember that you get a full oil/filter change and new engine mounts as part of that.

If it’s a private sale I’d sound out the owner. If it’s from a dealer then I’d definitely replace it. Although not as catastrophic, I’d also it be interested in what other maintenance had been done especially things like rear subframe, bushes, springs and dampers etc. Can add up to a decent amount of parts and, especially, labour as these cars get older.

[abucd4]

I’m not an S65 guy but I have just spent the last few days getting lost in M539’s e92 rebuild playlist and you may find it useful.

I’m not here to add any knowledge, (I personally have none) but just to point out the videos. TLDR from
watching the lot: replace rod bearings AND main bearings on the s65. He does also mention some variants of bearings but I can’t remember which.

It allegedly affects the s65 more than other engines e.g. the V10 due to the dual row timing chain (vs single) placing a slight upward pressure on the crank.

Ep3-7 covers most the engine stuff and covers the why. It gets wonderfully nerdy. Well worth a watch if you’re going to invest in an example.

https://youtu.be/UjDVOsdfXjc?si=yyFZkNQ4tSUlWUw0