///M Rod Bearings, Vanos Bolts & Motor Mounts

[Beedub]

and this is where i believe some of the shifting issues/ gearbox grinds come from.... ( not my image although mine were compressed but not by so much....) you can clearly see the accelerated wear caused by heat

another image show how close this rubber unit is to the exhaust manifold , and the attempt at shielding it from the heat.... again note the heat cracks around the base..... note how the cracking eases on the opposite side of the heat source.

is this a massive issue ?? not really.... most people would never notice i guess under normal DD circumstances, but when you start to use your///M car as intended... the issues flag up in certain characteristics.... That said the z4m is a very reliable and solid car.... i wont be without mine....

 

[Stuart Truman]

Beedub, surely your car is an exception though? With 500bhp and corresponding torque you'd expect increased wear and tear on the mounts etc...

Not knowing the rotation of the engine, it would be interesting to know if the highly compressed mount was in the rotational direction of the engine when under load.

 

[Beedub]

Beedub, surely your car is an exception though? With 500bhp and corresponding torque you'd expect increased wear and tear on the mounts etc...

Not knowing the rotation of the engine, it would be interesting to know if the highly compressed mount was in the rotational direction of the engine when under load.

100% i honestly cant dispute that fact....my 500+ hp shows up things alot wont experience.... as things fail ill post it up for all to see.... im looking forward to pulling my rod bearings to see how much , if any wear has been added by "boost"...... i'll do it shortly and post up pics for you all to see....

i will however concur, on the grand scheme of things the z4m has very few issues and the ones it has got can be rectified pretty easily.... its a great car....

 

[Beedub]

Beedub, surely your car is an exception though? With 500bhp and corresponding torque you'd expect increased wear and tear on the mounts etc...

Not knowing the rotation of the engine, it would be interesting to know if the highly compressed mount was in the rotational direction of the engine when under load.

not to sure on the rotation.... i think it tilts back under load... the hotter side getting compressed under heat causes the deformation maybe?????

 

[exdos]

I'm just a little concerned that these rather generalist comments combined with "OEM suspension is rubbish" etc makes rather poor reading to newbies and those outside the forum. The thing is, neither does it express or reflect precisely or in a balanced manner about a specific subject. :thumbsdown:

Ouch! I'll bite. It's my honest opinion that the OEM suspension is terrible for everyday road use and I've given my reasons for this at length in other threads elsewhere. In view of the fact that few other Z4M owners on this forum seem to have ditched their OEM suspension for aftermarket suspension would put me in a minority, so does being in a minority make my views unbalanced?

These cars are great value for money, entertaining and approacheable by the vast majority of drivers.

I totally agree, but like all other cars, they are not 100% perfect, and I can't see any problem with discussing what we, as individual owners, consider to be their shortcomings, even if these shortcomings aren't seen by other owners. I've previously suffered catastrophic bearing shell failure with a S54 engine in another car, but it didn't put me off buying a Z4MC or stop me from singing the praises of all the good things.

Here's my bearing shell failure at 33k miles

 

[Beedub]

ok, onto the bearings now........ 35k mile, street car... no track work... if you know what your looking at, you'll know this is very bad!!

http://www.bimmerboost.com/showthread.php?27920-Z4M-Bearing-wear-35k-mile-car

lets look at other ///M platforms....

http://www.m3post.com/forums/showthread.php?t=786615

anyway enough harping on about it.... the point im trying to make is, low displacement, high out will always come with its flaws..... and again.... ill pull mine and post up the pics... im going to "guess" ill see accelerated wear on these already flawed parts... but rest assured these issues aren't exlcusive to track cars.... thats the point im trying to make.. enjoyed this thread btw... its got some nice differing views.. thats what a forums all about right??

 

[Beedub]

I'm just a little concerned that these rather generalist comments combined with "OEM suspension is rubbish" etc makes rather poor reading to newbies and those outside the forum. The thing is, neither does it express or reflect precisely or in a balanced manner about a specific subject. :thumbsdown:

Ouch! I'll bite. It's my honest opinion that the OEM suspension is terrible for everyday road use and I've given my reasons for this at length in other threads elsewhere. In view of the fact that few other Z4M owners on this forum seem to have ditched their OEM suspension for aftermarket suspension would put me in a minority, so does being in a minority make my views unbalanced?

These cars are great value for money, entertaining and approacheable by the vast majority of drivers.

I totally agree, but like all other cars, they are not 100% perfect, and I can't see any problem with discussing what we, as individual owners, consider to be their shortcomings, even if these shortcomings aren't seen by other owners. I've previously suffered catastrophic bearing shell failure with a S54 engine in another car, but it didn't put me off buying a Z4MC or stop me from singing the praises of all the good things.

Here's my bearing shell failure at 33k miles

i wonder why bmw limited to revs on early s54s...... could it be insufficent bearing lubrication???

im happy to call the bearings maintenance item.... i'll be moving to the vac coated units.... (see from my post above)...

 

[exdos]

i wonder why bmw limited to revs on early s54s...... could it be insufficent bearing lubrication???

im happy to call the bearings maintenance item.... i'll be moving to the vac coated units.... (see from my post above)...

BMW were caught out with the bearing shell failure in the early S54 engines made in 2001 and they came up with several reasons/excuses. Eventually, they discovered that the bearing shell tolerances were too tight, and they did a recall for all cars except the S54 Z3MC/MRs, in which they claimed that the reduced redline at 7600rpm, bearing shell failure couldn't occur. I know of at least nine occurrences in UK Z3MC/MRs. The tight bearing shells generated heat and didn't allow lubrication at high rpms. Also, the conrod bolts would stretch from the very high piston speeds so that the bearings became elliptical rather than remain round, which then allowed the crankshaft to smash the bearing shells. Both bearing shells and conrod bolts have been revised since then.

This is NOT a problem with the S54 engine in the Z4M, because BMW sorted the problem long before the Z4M went into production.

I agree that bearing shells should be considered a maintenance item if you use your car as more than a DD. It's cheap insurance.

 

[tomscott]

So as im a guy who is no where near as knowledgable as you guys. Obviously the only way your going to know the rod bearing shells warn is if you pull them? Or are there other things that will tell you bar an oil analysis.

The engine mounts are these in any way visible? Will they give a visible leak?

Mine has 56.5k on it and I know it has been tracked as I found images on flikr of it about a year after I bought it. Which made me feel fairly sick.

Bmw Z4M Coupe. by Denniske, on Flickr


BMW Z4M Coupe. by Denniske, on Flickr

These pics were taken in October 2008

This makes me extremely worried after reading above comments. I have no idea whether these things have been looked at on the car. There is nothing in my service history or paper work that would suggest so anyway. Also my warranty runs out in November so would like to get anything that could be a possible problem before that time. Dont want to end up buying the car at the end of the term and having these big payments to sort things that could be big issues.

 

[Beedub]

So as im a guy who is no where near as knowledgable as you guys. Obviously the only way your going to know the rod bearing shells warn is if you pull them? Or are there other things that will tell you bar an oil analysis.

The engine mounts are these in any way visible? Will they give a visible leak?

Mine has 56.5k on it and I know it has been tracked as I found images on flikr of it about a year after I bought it. Which made me feel fairly sick.

Bmw Z4M Coupe. by Denniske, on Flickr


BMW Z4M Coupe. by Denniske, on Flickr

This makes me extremely worried after reading above comments. I have no idea whether these things have been looked at on the car. There is nothing in my service history or paper work that would suggest so anyway.

no other way of telling unless you get high lead reports in oil analysis.... or pull them... worn / heat damaged bearings/ poor lubrication will be evident immediately.... BUT..... your using your car as the ///M division designed..... dont baby it or worry about it... its one of those things...

the mount is an item you'd need to get under the car and remove the reinforcement plates to inspect... again, you'd proably not even notice a worn unit under normal use.... dont think your bearings are bad or your mounts are bad ect ect, im just trying to show certain items need to be looked at whatever your use on this car...your car is doing great and using the revs, getting the oils up to higher temps, hard use is imo nothing but good for an engine like the s54 ( thats what it was designed for).... but in doing so.... things need to be maintained theirs no right and wrong here..... so tom.. in other words.. dont worry.... maintain it, enjoy it, drive it properly

 

[exdos]

Tom,

If I were you, I wouldn't worry about bearing shell failure. If you've had your car for a couple of years without problem, then BS failure isn't imminent. I sleep very sound even though I've had the BS failure in the past.

OIl sampling is a way of testing, but the oil needs to have been in the engine for a good while so that there's enough contaminants to give a proper picture of what is in the oil. Visual inspection is the only real way of examining the bearing shells and you need to drop the sump and undo the conrod bolts to view, so if you do this, you may as well arrange to replace the bearing shells and conrod bolts at the same time, irrespective of what you find.

I like the second photo you posted! You should have a day on track yourself at some point to see how good the Z4MC is.

By and large, the S54 engine performs better the harder it's driven with the proviso that you should always allow the oil to get up to proper working temperature before you give it some.

 

[Beedub]

Tom,

If I were you, I wouldn't worry about bearing shell failure. If you've had your car for a couple of years without problem, then BS failure isn't imminent. I sleep very sound even though I've had the BS failure in the past.

OIl sampling is a way of testing, but the oil needs to have been in the engine for a good while so that there's enough contaminants to give a proper picture of what is in the oil. Visual inspection is the only real way of examining the bearing shells and you need to drop the sump and undo the conrod bolts to view, so if you do this, you may as well arrange to replace the bearing shells and conrod bolts at the same time, irrespective of what you find.

I like the second photo you posted! You should have a day on track yourself at some point to see how good the Z4MC is.

By and large, the S54 engine performs better the harder it's driven with the proviso that you should always allow the oil to get up to proper working temperature before you give it some.

john ended this nicely.... pretty much nail on head.....

 

[tomscott]

Cheers guys makes me feel better.

Your right the car is used as intended 90% of the time it goes out it gets a good run round the lakes always up to temp before doing so and the engine feels very strong to me and on the Cumbria national meet it didn't skip a beat with 300 miles of hooning. But I think I may get one of my mates who was a BMW mechanic for 20 years to give it a look. Its due an oil service in 2500 miles so may well get an oil analysis done

I do fancy doing a track day! Would be cool to do one with some other forum members would be good craic! Might learn something too! You guys always know so much and as much as I love cars I would love to learn to get my hands dirty and not have to rely on BMW.

I agree with both last statements and if it needs doing it needs doing the car is def worth it and I want to keep it.

 

[exdos]

Cheers guys makes me feel better.

I would love to learn to get my hands dirty and not have to rely on BMW.

I'm pleased about that.

Believe it or not, the Z4MC is a good car to learn how to do some mechanicing. In comparison to a lot of other cars there's quite a bit of space to work in and it's "modular" where you can see what all the different bits are for so it's generally self-explanatory when you are working on it. There are some great illustrated "how to's" on t'internet so you can assess all the jobs before you start. You should try an oil and filter change or a brake pad/disc swap as a starting point and take it from there. All my mods cost me parts only, which is the incentive for me to play with spanners. If you get stuck, there's always someone on a forum willing to give you the info you need. 8)

 

[tomscott]

I may just give it a go! Thanks Exdos

Your always very helpful, same with you Beedub

 

[ChawenHalo]

I'm just a little concerned that these rather generalist comments combined with "OEM suspension is rubbish" etc makes rather poor reading to newbies and those outside the forum. The thing is, neither does it express or reflect precisely or in a balanced manner about a specific subject. :thumbsdown:

Ouch! I'll bite. It's my honest opinion that the OEM suspension is terrible for everyday road use and I've given my reasons for this at length in other threads elsewhere. In view of the fact that few other Z4M owners on this forum seem to have ditched their OEM suspension for aftermarket suspension would put me in a minority, so does being in a minority make my views unbalanced?

End of quote

Honestly John, you're saying race/ trackday orientated suspension gives a better ride in town than OEM? That's a trick that neither Ferrari, Porsche, AMG etc have managed to pull off with traditional suspension, hence all the electronic type dampers etc. Only very light cars such as Lotus manage that. Lastly no aftermarket suspension manufacturer claims a better more comfortable ride than OEM because it simply is not the case. This does not distract from the fact these modifications can improve the performance of you're car's handling characteristics in specific areas. Yes I do think you saying OEM suspension is rubbish to be far exaggerated and generally counter productive to anyone outside this forum. We of course all know what you mean, yes the rear does hop about on camber ridden and bumpy roads, however the car never tramlines of deflect off its course, you just have to manage the throttle imputs, and that's part of the car's character, you have to drive it thinking, much like you would approach a turn carefully or trailbraking in a 911 to reduce understeer. Rubbish, it is not. Flawed, these cars are not either. Yes they have their weaker point, but I'm sorry the convertible was never designed to handle 500 bhp and an added 30 kg or however many the compressor has added. If you modify / enhance your car's performance whether in the handling or engine department, its only logical that there are other trade offs and compromises and further modifications to make, which in turn will generate further compromises such as less comfort in town driving, tramlining, NVH, brake squeel etc.

 

[Beedub]

I'm just a little concerned that these rather generalist comments combined with "OEM suspension is rubbish" etc makes rather poor reading to newbies and those outside the forum. The thing is, neither does it express or reflect precisely or in a balanced manner about a specific subject. :thumbsdown:

Ouch! I'll bite. It's my honest opinion that the OEM suspension is terrible for everyday road use and I've given my reasons for this at length in other threads elsewhere. In view of the fact that few other Z4M owners on this forum seem to have ditched their OEM suspension for aftermarket suspension would put me in a minority, so does being in a minority make my views unbalanced?

End of quote

Honestly John, you're saying race/ trackday orientated suspension gives a better ride in town than OEM? That's a trick that neither Ferrari, Porsche, AMG etc have managed to pull off with traditional suspension, hence all the electronic type dampers etc. Only very light cars such as Lotus manage that. Lastly no aftermarket suspension manufacturer claims a better more comfortable ride than OEM because it simply is not the case. This does not distract from the fact these modifications can improve the performance of you're car's handling characteristics in specific areas. Yes I do think you saying OEM suspension is rubbish to be far exaggerated and generally counter productive to anyone outside this forum. We of course all know what you mean, yes the rear does hop about on camber ridden and bumpy roads, however the car never tramlines of deflect off its course, you just have to manage the throttle imputs, and that's part of the car's character, you have to drive it thinking, much like you would approach a turn carefully or trailbraking in a 911 to reduce understeer. Rubbish, it is not. Flawed, these cars are not either. Yes they have their weaker point, but I'm sorry the convertible was never designed to handle 500 bhp and an added 30 kg or however many the compressor has added. If you modify / enhance your car's performance whether in the handling or engine department, its only logical that there are other trade offs and compromises and further modifications to make, which in turn will generate further compromises such as less comfort in town driving, tramlining, NVH, brake squeel etc.

loooool dont spit your dummy!!! its all fun and discussion...

btw johns suspension setup isnt track orientated, he's never once said it was....ever......

 

[exdos]

Honestly John, you're saying race/ trackday orientated suspension gives a better ride in town than OEM? That's a trick that neither Ferrari, Porsche, AMG etc have managed to pull off with traditional suspension, hence all the electronic type dampers etc. Only very light cars such as Lotus manage that. Lastly no aftermarket suspension manufacturer claims a better more comfortable ride than OEM because it simply is not the case. This does not distract from the fact these modifications can improve the performance of you're car's handling characteristics in specific areas. Yes I do think you saying OEM suspension is rubbish to be far exaggerated and generally counter productive to anyone outside this forum. We of course all know what you mean, yes the rear does hop about on camber ridden and bumpy roads, however the car never tramlines of deflect off its course, you just have to manage the throttle imputs, and that's part of the car's character, you have to drive it thinking, much like you would approach a turn carefully or trailbraking in a 911 to reduce understeer. Rubbish, it is not. Flawed, these cars are not either. Yes they have their weaker point, but I'm sorry the convertible was never designed to handle 500 bhp and an added 30 kg or however many the compressor has added. If you modify / enhance your car's performance whether in the handling or engine department, its only logical that there are other trade offs and compromises and further modifications to make, which in turn will generate further compromises such as less comfort in town driving, tramlining, NVH, brake squeel etc.

What I am saying is this: The Z4MC's OEM suspension is a complete mismatch F<->R when the car is supposed to have essentially a 50:50 static weight distribution, so why is there such a considerable mismatch in front/rear spring rates? The OEM suspension has 11mm springs at the front which make the steering light and imprecise on acceleration and makes the front end dive on braking and the 19mm rear springs are way too stiff for a decent ride on our bad public roads in the UK. How can an 2 x 11mm springs effectively control 50% of the car's weight in the same way as 2 x 19mm springs? Hooke's Law tells us it can't be done!

As you know, I fitted AC Schnitzer Racing suspension shortly after buying my Z4MC, and whether ACS genuinely think that this suspension system is a true "racing" suspension set up, or not, I have no idea. However, this suspension kit comes with 14mm front springs and 16mm rear springs, which to me represents a much better F<->R spring balance, which will inherently stiffen the font and soften the rear spring rates relative to OEM, which will tend to reduce the problems that I've identified with the Z4MC's OEM suspension.

If the dampers are then set up according to the road conditions, i.e. softish for bad public roads and stiffish for smooth tracks, then it is possible to produce a much more comfortable ride than OEM and on public roads the handling is also better because the rear doesn't bump and bounce like it does OEM. I am very surprised that your recent Bilstein PSS10 suspension installation hasn't been set up to demonstrate the benefits of adjustable suspension to you.

As it is, I have have my car set up for fast-road driving which also has a MUCH better ride than OEM (you're more than welcome to come and try), and when I was at The Ring last month, I also adjusted the suspension to be appropriately stiffer on that circuit, in order to improve the handling at the car's limits at the expense of ride comfort. It is possible to have the best of both worlds, but you have to experiment and test drive to find the best settings and be prepared to adjust the suspension settings for the circumstances at the time you need the appropriate settings.

 

[ChawenHalo]

I have no doubt you've improved on OEM handling for your needs and what you believe is a better set up.

As regards to the B16 kit, its off topic to what I saying but I am satisfied that it's improved various aspects of the car's handling on public road (I have yet to try on track) but I certainly was not in the illusion hoping it that would improve the ride comfort in town and low speed on bumpy roads :lol: , and it does not. Anyone expecting improved comfort levels with aftermaket suspension (unless specified like some damptronic set ups), is mistaken. I know of no racing/ serious car preparation outfit that would tell you otherwise.

Whether you go to Thorney/ Sympsons/ ACS/ Hartge or Delage over here, (or Lohen for my Mini ) they will tell you the same thing. If you want more performance, it is available but there is a trade off.

Lastly, as to fiddling with camber, caster other geometry and suspension set up, well put it this way, if Bilstein have created a kit specific (as in springs, valves etc) to the Z4MC and I've got it installed by a 25 yrs experienced racing professional, somehow, I doubt I'll do better, not being proffessional car tester or suspension engineer and all. And frankly, I want the assurance that the set up is performing, safe and valid on the limit and all circumstance. For example: the car's understeer on track is mainly because you've got a cast iron block at front, and whist you'll dial a lot of it out with geo etc you'll expose yourself to snap oversteer. What gives one way is taken on an other. Its all about compromises.

I love the fact that on this forum we have such a diversity but what I'm miffed about is that a couple of you insist on the fact that OEM is rubbish and you guys can do way better. What you are doing is orientating the performance envelope of your car in a particular direction and that is your choice. I hugely respect what you both do but neither of your cars have gone through 1000's of miles of testing nor are you professional suspension engineers. Whilst you have an otherwise healthy and empirical approach to all you mods some of your claims read like you're endoctrinating other readers towards your way being the only way and better than OEM. Frankly, it just is not the case.

I had a long conversation with a good friend who worked as chief suspension engineer for Mitsubishi rally cars and SuperAguri F1 and he made it perfectly clear that OEM set ups are there for 3 reasons: style/ comfort of the car; performance and safety (Under various circumstances). There is no tweeking aftermarket that will improve all 3 of these aspects, its all about balancing more towards one and taking from the other aspects.

Stiffening the cars as we are doing for track purposes of course improves feel, mechanical grip and overall performance but it will also make the car more edgy, lively (does the Z4M need more of that? ) tramline and a lot less proggressive.

 

[exdos]

what I'm miffed about is that a couple of you insist on the fact that OEM is rubbish and you guys can do way better. What you are doing is orientating the performance envelope of your car in a particular direction and that is your choice. I hugely respect what you both do but neither of your cars have gone through 1000's of miles of testing nor are you professional suspension engineers. Whilst you have an otherwise healthy and empirical approach to all you mods some of your claims read like you're endoctrinating other readers towards your way being the only way and better than OEM. Frankly, it just is not the case.

Why are you getting so "miffed" by my opinion? If you don't agree with me, that's perfectly fine by me; I won't take umbrage

On the AC Schnitzer website here: http://www.ac-schnitzer.de/en/bmw-cars/about-us/development/suspension/ there are a few quotes which I happen to agree with, based on my own experience of the ACS Racing suspension on my Z4MC and other adjustable suspensions:

"The philosophy is simple: "Better fast than hard". This quote would really be nothing special if it did not come from a famous person - a racing driver who has been responsible for suspension development at AC Schnitzer for decades. A man who has every curve on the "North Loop" stored in his popometer, and whom the trade press like to call the "Suspension guru from Aachen": Manfred Wollgarten. With this simple sentence, he expresses our entire suspension philosophy in a nutshell. "The car must in principle handle as well as standard"; and he is convinced that "Forgiving load change responses and gentle understeer on the limit are important - in the end AC Schnitzer customers are not professional racing drivers. Our suspension can handle both country roads and tracks equally well. For sporting drivers who often go to race tracks we offer special racing suspensions. As the damper compression as well as the sway bars are adjustable the handling of the car can be modified."
"Only when a set-up has achieved optimum results under all conceivable driving and race conditions, and combines sports handling with maximum suspension comfort, can it be offered for sale as an AC Schnitzer sports or racing suspension."

So it would appear that AC Schnitzer reckon that it's possible to have both suspension comfort and handling, be it on public roads or on track and that's exactly as I've found is the case with both the ACS Racing suspension on my Z4MC and KWV3 (with front coilovers) on my Z3MC. The beauty of adjustable suspension lies in the "adjustability", but to benefit from this feature you must experiment with different settings to find the best settings for the circumstances and then adjust appropriately when circumstances require the changes. Until you have a series of different settings for different circumstances logged for reference then you won't be getting the best from adjustable suspension. My "Ring" settings are terrible on public roads because they're too stiff.