Con rod bearings - Munich Legends

I didn't know the bottom end was prone to failure - but 74k is low.
If the motor currently holds good oil pressure, then my choice would be to keep a good service regime and enjoy the holiday!

If you do end up changing the big end shells, will you also be replacing the mains?
 
Con rod bearings only. Have a look at 'con rod issues s54 / m3' on the net. Or rather don't if you don't fancy changing yours :wink:
 
Fortunately I don't have that engine!
I hadn't realised they had a potential Achilles heal.
So from what you say it's only big end bearing that wear? I always thought they were bomb proof.
 
No. Its the con rod shells that can, happened more on earlier incarnations. Small risk, but worthy preventative maintenance for me.
 
So the preventative fix is only the big end shells? Do the bolts also have to be replaced ?

I would have thought that worn bearings would have had a warning like low than specified oil pressure when hot and at tickover speeds ?
 
Thanks for that info !
I was on the right track when I suggested the big end bolt replacement ?
It seems that bolt stretching and the resultant shell rotation is the route cause as opposed to a simple bearing failure.

I think I would be changing the bolts as well especially if you are keeping the car - it's also nice to keep as part of its history.
 
Well, collect the car in the morning after con rod shell replacement at Munich Legends. Spoke to them this evening and it appears it may have been a very good decision. Apparently the bearings are scored and worn, I will take a picture tomorrow and try and post.
 
autobahner said:
Well, collect the car in the morning after con rod shell replacement at Munich Legends. Spoke to them this evening and it appears it may have been a very good decision. Apparently the bearings are scored and worn, I will take a picture tomorrow and try and post.
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Do you mind me asking how much they charged for this.?

Thanks
 
Yorkie Z said:
autobahner said:
Well, collect the car in the morning after con rod shell replacement at Munich Legends. Spoke to them this evening and it appears it may have been a very good decision. Apparently the bearings are scored and worn, I will take a picture tomorrow and try and post.
Click to expand...


Do you mind me asking how much they charged for this.?

Thanks
Click to expand...

Very interested to hear the cost.

If mine is a keeper then I'll look to get this done before it hits 70k
 
I'll find out tomorrow. Will let you know. Keeper or not, great peace of mind. It was around £600 :cry: However, had they been immaculate I would have considered it a waste, as it was it was money well spent!
 
autobahner said:
I'll find out tomorrow. Will let you know. Keeper or not, great peace of mind. It was around £600 :cry: However, had they been immaculate I would have considered it a waste, as it was it was money well spent!
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£660 that's a pretty good price. Let's face it, everything on the M is expensive.
 
That sounds pretty acceptable to me as once-in-a-lifetime preventative maintenance job. Mine were replaced at ~50k by the previous owner. They showed no signs of movement but were down to the copper in a couple of places.
 
Its peace of mind for me and if I sell the car I can do so with confidence. What made my decision was seeing another, same reg, same miles, colour and supplying dealer having had the exact same problem, only that car had an engine rebuild due to worn shells.
 
I thought these engines were durable?
Replacing the big end shells at 50k seems low - assuming the service regime has been followed.
 
ronk said:
I thought these engines were durable?
Replacing the big end shells at 50k seems low - assuming the service regime has been followed.
Click to expand...

They were replaced by a dealer as an initial response to what ultimately turned out to be top end failure (excessive follower wear), along with the oil pump.

Quite interested in autobahner's pics.
 
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