Z4M Crank Rod Bearing Shells

So as this topic seems to be cropping up in various other threads of late I thought it may be useful to try to get everyone's experiences and views in one place. If I was a bit more skilled I would have included voting options for mileages, but I'm sure people will probably post that anyway!

Hopefully other M owners, and potential owners, might find it useful.

Before I bought my M I asked my local BMW Indy (Will at TWG Automotive in Camberley) about them and he said he had dealt with more head gasket failures on S54 engines than rod bearing failures, so his recommendation was an oil sample analysis.

Anyway when I bought my car on 76K miles it had never had an Inspection 2 and Ross did that for me recently, so he took a sample and now we're just waiting for the result of the analysis.

And as I'm the 8th owner I've no idea if they have been replaced before, or of how the car was driven before it was properly up to temperature.

Head gaskets on S54 engines was when it was fitted to the M3 and this used a different spec or map ECU

The simple answer:

Replace them if you’re going to keep the car long term.

If you reckon you will sell next year - don’t bother.

Happy M motoring.

PS: forgot to add - if you do decide to do the service, don’t forget to also replace the engine mounts and the oil pan gasket.

My S54 is becoming the engine equivalent of Triggers broom.

Original engine let go at 59k (bottom end bearings failed). Rebuilt under warranty by bmw with a brand new crank rods short block bearings oil pump etc.

Did a trackday on 20th June, car on 73k - engine on 14k therefore. After the 4th session it let go, diagnosis tbc but horrid deep knocking noise, so recovered to twg, who found evidence of bearing material in the oil filter. It's currently waiting to be shipped to redish for proper inspection/assessment, I'll update accordingly but very little else it could be at this stage.

Bottom line no matter how recent your bearings have been done you have no guarantee the work was done correctly and no guarantee the car was sympathetically driven by previous owners. In retrospect I would replace bearings for peace of mind immediately after purchase - easy to say now but a 1 grand bill to know the bearings are good beats the hell out of a 7k bill to rebuild a knackered engine.

Put paid to my ring trip, donny trackday this coming Monday, Anglesey in August. Gutted doesn't cover it.

Ed Doe said:

Bottom line no matter how recent your bearings have been done you have no guarantee the work was done correctly and no guarantee the car was sympathetically driven by previous owners. In retrospect I would replace bearings for peace of mind immediately after purchase - easy to say now but a 1 grand bill to know the bearings are good beats the hell out of a 7k bill to rebuild a knackered engine.

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Bit like life really, there are no absolute guarantees (well, other than death and taxes). Commiserations But on the upside now you are in bits or will be soon think of all the other stuff you can do while its in pieces :!:

BTZ461 said:

Ed Doe said:

Bottom line no matter how recent your bearings have been done you have no guarantee the work was done correctly and no guarantee the car was sympathetically driven by previous owners. In retrospect I would replace bearings for peace of mind immediately after purchase - easy to say now but a 1 grand bill to know the bearings are good beats the hell out of a 7k bill to rebuild a knackered engine.

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Bit like life really, there are no absolute guarantees (well, other than death and taxes). Commiserations But on the upside now you are in bits or will be soon think of all the other stuff you can do while its in bits.

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Don't lol. I would love to do a 3.5l vac motorsport stroker conversion with cams and solid lifters to suit - hello 450hp - but I don't have 14k to spunk on an engine rebuild - it's come at possibly the worst time in the scheme of life, I'm just really hoping I can keep the car when it's all done.

Yes, that's really sh*tty Ed - I was gutted for you when I read about it.

It's one of the things that prompted me to post this, as well as other posts about preventative replacement of bearings that turned out to be pretty worn at mileages lower than mine - and also the fear factor!

I'm starting to think I might just get them done for peace of mind as it's definitely a keeper.

Ed Doe said:

My S54 is becoming the engine equivalent of Triggers broom.

Original engine let go at 59k (bottom end bearings failed). Rebuilt under warranty by bmw with a brand new crank rods short block bearings oil pump etc.

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When was the engine rebuilt by BMW?

R60BBA said:

When was the engine rebuilt by BMW?

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7 years and 3 owners ago. To be honest if they couldn't get it right last time I'm distinctly disinclined to bother getting in touch. Will see what Redish discovers, they provide a video inspection report so will review my options at that point.

Ed Doe said:

R60BBA said:

When was the engine rebuilt by BMW?

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7 years and 3 owners ago. To be honest if they couldn't get it right last time I'm distinctly disinclined to bother getting in touch. Will see what Redish discovers, they provide a video inspection report so will review my options at that point.

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Ah so the warranty job was not done in your ownership...

So in other words you had no idea of how the 3 owners since 2013 have treated the car (ie whether they warmed it up correctly or not).

Redish are very thorough and so hopefully the news is as good as it possibly could be. Just note, if they quote you top money for the bottom end, I would opt for their full engine rebuild service priced at £3995 - https://www.redish-motorsport.com/BMWE85E86Z4MS54EngineRebuildRefresh.html

I would also ask them to warrant the rebuild also.

Both JC Racing and Simon Thorpe motors have stories of the oil relief valve sticking and then no oil pressure and this is followed by a large rebuild bill.

I have changed my rod bearings and fitted an external oil relief valve along with an oil pressure gauge.

As others have said, if it's a keeper and your knocking on 80k+ mileage, I would get it done. Trouble is once the seed of doubt is planted you might find you won't rev it out as much and enjoy it in fear of a potential failure.

I eventually gave in and did mine at 93k as I decided I was going to probably keep longer term. Bearings that came out weren't dead and there was some life left but they were worn (picture somewhere on the forum). Either way I feel much more comfortable having done it and in the scheme of things with some other work I've had done it's relatively inexpensive! Didn't see the point in oil analysis at that stage, it needs to be done over a longer period of time to gain a solid picture so that one snapshot is unlikely to give you a good idea of the wear although if they are almost dead I imagine you would have a high reading of copper. (By the way OP where did you get your analysis done, been waiting a while haven't you?!)

Head gasket was also on my list but you can test that by compression or leak down to get a good idea of health on that side.

You could do the oil pump as well but depends how much you want to spend as it's not cheap, over £500 I believe. Not heard of many failures so I decided not to. Also the oil pump seems to have been 'upgraded' over the years for the S54 so maybe we have a slightly more robust part than earlier S54's. No facts to back that up apart from on RealOEM you can see its been superseded a number of times...
Oil pressure gauge seems like a good idea though, interested in how much and how it's set up...

Apart from that, choose a good indy to do the work if you do. A lot of them rely on word of mouth feedback for work so most likely will take greater care doing it as they won't want failures in their work talked about over the internet. Munich Legends for example seem to have a poor rep these days despite being good in the past...

Wonder what Redish do exactly for that £4k rebuild, would be interested to know. Sounds punchy money wise on the face of it. James is excellent though and you can be confident in his work along with Hack Engineering. Personally Darragh at Everything M3's gets my money for work at the moment, love his personal smaller garage set up and can highly recommend. Not many places you can hang around in the garage and see what's going on while chowing down on a Big Mac meal :lol:

R60BBA said:

Ah so the warranty job was not done in your ownership...

So in other words you had no idea of how the 3 owners since 2013 have treated the car (ie whether they warmed it up correctly or not).

Redish are very thorough and so hopefully the news is as good as it possibly could be. Just note, if they quote you top money for the bottom end, I would opt for their full engine rebuild service priced at £3995 - https://www.redish-motorsport.com/BMWE85E86Z4MS54EngineRebuildRefresh.html

I would also ask them to warrant the rebuild also.

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I will be ensuring there is a warranty.

For clarity the engine rebuild cost presented there is a strip and rebuild excluding replacement of any parts beyond head gasket rod bearings and bolts - it assumes the engine was in good working order prior to rebuild. The kicker comes with how scored my the crank is as a result of the bearing failure(s) ; it cannot be reground much for various reasons so if the scoring is deep enough from spinning a bearing it could necessitate a new crank from bmw - £2200 for the part. Factor in that the corresponding connecting rod big end could have ovalled as a result of the bearing spinning, and replacing the pistons with a matching set adds circa £1300 on top again. Plus hours to rebuild, and no doubt new little end bearings. Plus a new oil pump if the bearing material has scored that internally too. £3995 is very much the thin end of the wedge at this point. It's going to be a jolly expensive track season for me, for all the wrong reasons!

@PDJ I'm strongly considering fitting an oil pressure gauge whilst the engine is apart, makes sense to have an eye on it - to be quite honest I'm not sure why this wasn't fitted as standard in the car!

@AndyBeech - you can see what is involved in the £3995 figure on the redish website. Full strip chemical clean and rebuild with new head gasket, bearings and bolts. Not bad money to be honest, especially next to what I'm likely in for!

Ed Doe said:

@AndyBeech - you can see what is involved in the £3995 figure on the redish website. Full strip chemical clean and rebuild with new head gasket, bearings and bolts. Not bad money to be honest, especially next to what I'm likely in for!

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Ah fair one, didn't see all that. Either way, tough break mate, feel for you, hopefully it hasn't done too much damage and you can get it sorted for as little as possible and get it back on the track

Did you change from using Hack to Redish out of interest as I thought I read you were going with them originally?

AndyBeech said:

Oil pressure gauge seems like a good idea though, interested in how much and how it's set up...

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Mechanical Stack oil pressure gauge
Pipped in where the oil pressure sender is under the plenum chamber near the braided hose the oil gauge pipe is not fitted in this photo but it is in this area
Fitted the gauge where the centre vent was

PDJ said:

AndyBeech said:

Oil pressure gauge seems like a good idea though, interested in how much and how it's set up...

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Mechanical Stack oil pressure gauge
Pipped in where the oil pressure sender is under the plenum chamber near the braided hose the oil gauge pipe is not fitted in this photo but it is in this area
Fitted the gauge where the centre vent was
E2413348-642A-42C1-B65B-04DF146FB913.jpeg6A24077E-C8EE-4AFE-9EDB-52F797EB9577.jpeg5DD65954-C0F5-4F5E-8A1E-6B1B6945852A.jpeg

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Nice, v clean setup. Appreciate the pics.

Thanks man, appreciate it I'm trying to be realistic about it - these things happen - don't play with the big boys if you can't piss up the tall trees and all that, but this bill is going to sting somewhat!

I'm holding out a tiny bit of hope because the knock only started when I was at ~12-1500 rpm in 1st gear just moving the car forward in the pit queue ahead of the next session - I shut the engine off within 10secs or so, then only switched it on for another 10 secs to take a video for reference. I've got everything crossed that, as it didn't let go at high rpm/load, it's not clobbered the crank and rods, but I will know for sure by the end of the week.

I have not committed to anyone yet for the rebuild, but Redish offer a strip and inspection/assessment with video, and from there I can make an informed decision on how to proceed as I'll know the extent of the damage. Car is being flat-bedded down to them on Tuesday - let me know if anyone spots it - longest trip she'll have made this year! :lol:

I will bung a thread up once I've had the assessment and decided the route forward, I'm sure it'll be of interest to some, and it'll give me an outlet too I guess :roll: heyho!

@PDJ that's a very smart setup - have you got any more pics, and how did you find the install - fairly easy? I assume you diy'd it?

I need to select 2 options.

1. Yes, as they failed @ 140k miles (on that engine, previous engine was replaced @ 23k miles under warranty, and I’ve had the car since 9k miles)
2. Preventatively on the replacement 40k mile engine

Never had a head gasket - although I did do a cooling pack refresh @ 100k miles, 6k between services, and oil change before & after Ring trips.

mmm-five said:

I need to select 2 options.

1. Yes, as they failed @ 140k miles (on that engine, previous engine was replaced @ 23k miles under warranty, and I’ve had the car since 9k miles)
2. Preventatively on the replacement 40k mile engine

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I need to share the Triggers M Coupe title with you - albeit mine just for the engine :lol: