Faint knocking? (Clip)

[BMWZ4MC]

Once the case hardening has worn through, they're soft as butter....

 

[BMWZ4MC]

What was the mileage?
Can only imagine that could happen with a lack of oil, oil pump fail or something of the like? Certainly doesn't sound normal!

The followers wear due to inadequate case hardening as opposed to being a direct consequence of a lack of lubrication. If ignored, this leads to a consequential wear of the cam lobes. Schrick sell BMW followers with additional case hardening which (they claim) prevents the problem.
There has been much speculation that the problem affects only cars that have been thrashed from cold or tracked, or that it is a result of incompetently adjusted followers, but there's no evidence that any of this is true and the problem is surprisingly common amongst Z4Ms and E46 M3s.

But a failure of nearly all of them and the bottom end as well? If it was purely the case hardening then nearly everyone with an S54 would have to replace them at some point and that doesn't appear to be the case so...logically something else must be going on?
You say common but...I've spoken to a few independent specialists in the S54 world and from what I've been told I wouldn't say it's common, depending on you're definition of the term.
As the old saying goes, you only hear about the one's that have problems, not the many that don't.

Ive spoken with a few reputable Indys too and the good ones have seen quite a few. That Schrick sell modified followers demonstrates there's a market for them.
Anecdotal evidence of course, but no more so than the postulations that about cars thrashed from cold and track day specials being those that fail :wink:

 

[MrPT]

jeeezzzzzzzz the flat spot on that follower is insane.... These are seriously tough material as well, the cam lobe must have been worn off! Also agree with your comments totally.

The lobes were fine. Surprising, but they were checked by CPC and reinstalled without reprofiling. The valves were lapped and reseated too, which makes me think that the followers and the valve seats were damaged by some of the clearances becoming too tight. It was about £2k of work, excluding the replacement DLC-coated Schrick followers and updated springs.

As mentioned above, the case hardening on the followers has apparently been known to fail and then the follower will go very quickly (and not at the cost of the camshafts, if caught early enough). The case hardening can be damaged by "scuff" wear, which is something finger followers are particularly susceptible to, and this is accelerated by poor oil quality. Makes sense, but doesn't sound as damaging as a genuine valve clearance issue.

 

[NavZ]

Might be cams/followers.
Does the sound follow the revs ie. increase in line with the revs? (not necessarily volume but tempo)

 

[MrPT]

But a failure of nearly all of them and the bottom end as well?

Bottom end didn't fail. Owner took the car to a BMW dealership initially and they replaced the bearing shells, which didn't fix the issue. Probably just a lazy diagnosis based on historical issues with E46 M3s.

After some investigative work, I'm pretty sure mine was caused by skipped valve clearance adjustments during Insp II (not while under forum ownership but I know the indie quite well).

Just to clarify this for anybody that's interested. Clearances were in spec but not adjusted back to the middle of the acceptable range (or slightly north of it). This is in line with BMW guidelines, but probably not something that should be skipped, given what we now know about these engines. To me it doesn't make sense to skip it, once you already have the lid off.

 

[BMWZ4MC]

I doubt that alone would be enough to cause such marked failure.
I think there was a design issue with the followers (hence the Schrick modification). Perhaps there were good and bad batches or perhaps there is an inherent predisposition to accelerated wear in all and in some engines another factor precipitates failure.

 

[dannytheduck1985]

Why did BMW build such a fickle engine, reminds me of the Triumph Stag in the early years. These engine issues and the sky high road tax just don't appeal to me on the M cars.

please don't come in here talking shite. These are very robust motors, and have no less issues than the next performance engines.... We are talking decade old engines and most have seen the rev limit a good few times, as thats what ///M made it to do....

On the case of the solid top end, ferrari...used the same tech in the f12 TDF now a million quid car, and Porsche has just used it in the latest GT3........ its race derived stuff and things go wrong....

Sorry but first line like a wrecking ball, love it

 

[MrPT]

Hah. Having met Fred I'm sure he can take it.

I doubt that alone would be enough to cause such marked failure.
I think there was a design issue with the followers (hence the Schrick modification). Perhaps there were good and bad batches or perhaps there is an inherent predisposition to accelerated wear in all and in some engines another factor precipitates failure.

Quite possibly, yeah. I always thought that Schrick coated the followers specifically for use with its high performance cams, but it's telling that they don't advise against using them with stock cams, i.e. they see the cam surface as being tough enough and not vulnerable to being damaged by the uprated coating.

So annoying that there still isn't much conclusive evidence re. all of this. It's going to cost some poor owners a lot of cash over the next few years. I wish I had the clearance specs from the Insp II and also the camshaft positions of each of the damaged followers. That would at least be another "fact" to chuck into the mix.

 

[firebobby]

Why did BMW build such a fickle engine, reminds me of the Triumph Stag in the early years. These engine issues and the sky high road tax just don't appeal to me on the M cars.

please don't come in here talking shite. These are very robust motors, and have no less issues than the next performance engines.... We are talking decade old engines and most have seen the rev limit a good few times, as thats what ///M made it to do....

On the case of the solid top end, ferrari...used the same tech in the f12 TDF now a million quid car, and Porsche has just used it in the latest GT3........ its race derived stuff and things go wrong....

Sorry but first line like a wrecking ball, love it

NOT FUNNY, I cried myself to sleep last night after such an unneeded attack :roll:
Obviously hit a nerve though :lol:

 

[ph001]

Just to clarify this for anybody that's interested. Clearances were in spec but not adjusted back to the middle of the acceptable range (or slightly north of it). This is in line with BMW guidelines, but probably not something that should be skipped, given what we now know about these engines. To me it doesn't make sense to skip it, once you already have the lid off.

Having done the valve clearances myself a couple of times I can say that the adjustment to get them from one end of the tolerance range to the centre is extremely small. In fact I found that checking them first thing in the morning (7'C) and then again in the middle of the afternoon (approx 18'C) is enough to move them from the centre to the end of the specified range. The window really is that small which is why BMW state that it must be done at a specific workshop temperature (20'C IIRC). Given they then run at 90'C during normal operation you can extrapolate that the design margin must be pretty large.

I've never seen any direct evidence that valve clearance at one end of the range (but not centred) would ever cause any damage. I'd be pretty amazed if it did.

 

[MrPT]

In fact I found that checking them first thing in the morning (7'C) and then again in the middle of the afternoon (approx 18'C) is enough to move them from the centre to the end of the specified range. The window really is that small which is why BMW state that it must be done at a specific workshop temperature (20'C IIRC). Given they then run at 90'C during normal operation you can extrapolate that the design margin must be pretty large.

That's interesting and makes sense.

Well done for doing them yourself! Think I'll go down that route at some point.

 

[ph001]

Yeh it's not hard at all but you do need to be quite diligent. The only faff is the stupid jubilee clips on the inlet manifold. What a pain they are. Everything else is very straight forward, just make sure you have some good quality vernier calipers and a decent selection of shims. They are not expensive.

 

[Viren]

Doesn't sound like anything. If it were rod bearings you would know it very quickly. Even if its top end, which it does not sound like it is as the noise should increase with rpm, your very unlikely to cause significant damage. Although if your worried just go see a Indy. I worry about all sorts of noises however have come to accept this car is very noisy and you would know if something goes wrong.

 

[Fishy Dave]

Why did BMW build such a fickle engine, reminds me of the Triumph Stag in the early years. These engine issues and the sky high road tax just don't appeal to me on the M cars.

I'll bite too :evil:
I agree about the road tax :thumbsdown:
The engine however is superb, I see them raced every month in E46 M3 with no engine failures that I can remember in the last 5 years (30 min qually and 40 minute races). Most of them have standard internals save for rod bolts (ARP) and bearing shells every year or two years as a precaution. These are race winning cars. I compare this with most other makes and models that race at the front of the grids and most have to uprate crank, rods, pistons, cams and more and even then they break.
It's impossible to know what percentage of Z4M have worn their engines sufficient that replacement parts were needed but I have a strong opinion that it is considerably less than the equivalent Porsche engine. When the followers or bearing shells have needed replacement at least they haven't damaged the block or head in the process.
For a road car engine producing more than 100bhp per litre, revving to 8000rpm with a wide range of care and treatment I think they are pretty tough.
Just IMO, will take you for a spin in mine next time we meet

 

[firebobby]

Why did BMW build such a fickle engine, reminds me of the Triumph Stag in the early years. These engine issues and the sky high road tax just don't appeal to me on the M cars.

I'll bite too :evil:
I agree about the road tax :thumbsdown:
The engine however is superb, I see them raced every month in E46 M3 with no engine failures that I can remember in the last 5 years (30 min qually and 40 minute races). Most of them have standard internals save for rod bolts (ARP) and bearing shells every year or two years as a precaution. These are race winning cars. I compare this with most other makes and models that race at the front of the grids and most have to uprate crank, rods, pistons, cams and more and even then they break.
It's impossible to know what percentage of Z4M have worn their engines sufficient that replacement parts were needed but I have a strong opinion that it is considerably less than the equivalent Porsche engine. When the followers or bearing shells have needed replacement at least they haven't damaged the block or head in the process.
For a road car engine producing more than 100bhp per litre, revving to 8000rpm with a wide range of care and treatment I think they are pretty tough.
Just IMO, will take you for a spin in mine next time we meet

Don't come on here biting people, I've enough teeth marks in my R send
May take you up on a spin though at the AV8 next weekend :wink:

 

[Argenta]

Ok the update isn't much, I've had it to 2 different indy's and one of them could not hear anything. The other one did hear what I hear but had no clue as to what it is.. They did say the new rod bearings were prob not to blame, as per the fact the "rattle" is only at idle and goes away with revs. They could also hear some VANOS & waterpump noise so they advised me to do the VANOS overhaul I'm planning this winter, then listen again next year.

Thanx for all input!

 

[dannytheduck1985]

Sounds like bottom end to me.

 

[john-e89]

Ear plugs in you can definately hear a knock, keep us posted please OP.

 

[Spaniarduk]

Hello [ref]ph001[/ref], or anyone who's done the Valve clearance check and shim replacement themselves.

1. Is it really as complex to do as many (including BMW) make out to be?

2. What special tools to you need, apart from the plastic tool with the magnet to remove the old and deposot the new shims in place?

3. Where do you source the replacement shims from? Any specific brand? Retailer? OEM BMW?

4. Is it possible to purchase individual shims in the required thicknesses?

Thanks in advanced.

 

[ph001]

Hello [ref]ph001[/ref], or anyone who's done the Valve clearance check and shim replacement themselves.

1. Is it really as complex to do as many (including BMW) make out to be?
Not complex at all as mentioned above


2. What special tools to you need, apart from the plastic tool with the magnet to remove the old and deposot the new shims in place?
You’ll ideally need the correct tool for the throttle body circlips. I made one by grinding an old crimp tool. You don’t need a special plastic tool with magnet, the shims come out very easily with just a magnetic screwdriver etc

3. Where do you source the replacement shims from? Any specific brand? Retailer? OEM BMW?
Yes, bmw oem.

4. Is it possible to purchase individual shims in the required thicknesses?
Yes, all available separately.

Thanks in advanced.