Engine Tapping

They haven't 'failed' they've just moved out of tolerance - as they will do as they & the lobes wear.

The problem with measuring the clearances is that if they're within the tolerance allowed then there's no need to change them.

They might only be 1% inside of that tolerance, but they won't be replaced/switched, and so 1000 miles extra could take it out of tolerance. If that happens on a few then it'll get rattly quickly, but as long as you're not doing mega mileage or track days in the meantime then there shouldn't be an issue.

IIRC, mine had 0 at one inspection, 6 at another, and 3 at another.
 
Ok - good to know, thank you.

As my next inspection is due in two services time, i'll definitely get them fixed now. Just one of those things i guess - i don't mind paying it if resolves the issue and prolongs the cars life, car ownership is no fun with clouds of uncertainty hanging over them!
 
Better that the tolerances are too great (and the valve train a little rattley) than too tight. The hardened outer surface of the cam lobes is very thin - see the images on page four of the link I posted.
Steve, I don't know how much it would cost if this were the problem, but new camshafts and cam followers would be on the cards plus all the consumables required when dismantling the top of the engine... :cry:
 
Dropped it off end of the day today with George @ Technosport - good bloke, definitely knows his S54's (having a race version pumping out 400bhp+ NA), the garage is full of M owners P&J's he's been tasked with fixing. Impressive garage - the amount of OEM CSL's lying around ready to be fitted, and the selection of V8 M3's, e46 CSL's, e46 M3's, Z3MC's, Z4MC's and other random M cars sat on ramps made me very interested!

From listening to it post ~1 hour traffic driving he actually seems to think it might not be valve shims, as the noise appears to be not loud enough for what he'd expect there, and is potentially further to the right of the engine block rather than in the engine block itself. But he definitely confirmed there is an abnormal rattle/tapping.

It's not looking like a positive outcome (due to the uncertainty), but at least he knows his stuff to trawl through the possibilities and find the cause. I'll update as soon as i hear something back from him (he's waiting to work on it from cold start tomorrow AM).

Fingers crossed!
 
Yep just called - sounds like the exhaust side shims were significantly out (which would explain why the sound wasn't obviously coming from the cam side) so he's fixed and rebuilding it to take it for a test.

I think he was slightly surprised to find this - probably due to it not creating the sound he'd of expected - i think that much shimming required would of generated more noise - and not the noise i had. anyway - we'll see. Definitely knows his M engines (great vid of his e46 racer pushing 450bhp NA on a dyno on their website!).

Will follow up again later for his verdict.
 
Hah hope so. Will be nice to have it running smoothly. Just trying to think of things i can ask them to look at whilst its in the garage for their expert opinions.
 
Quite a few on my exhaust side too, 13 out of 24 adjusted in total iirc at 44k miles :)
 
Any noticeable change in feel post fix, Adam?

A bit concerned the noise isn't resolved - i know nothing about VANOS stuff and the sound could definitely be the front end of the engine. Any ideas what it could be / costs?
 
Is the noise still abnormal Jimmy? Just had a detailed listen to my engine and it sounds pretty similar. I'll upload a video as soon as I can (28,500 miles)

Either way I'll watch with interest, but I always thought the S54 was a notoriously tappety engine.

Could others post up videos of their engines also, for comparison?
 
jimmybell, where in SW London are you, as I'm working in Brentford Mon-Thur, so we could always meet up for a mutual listen.

Although mine's got 104k on it, so probably sounds like a bag of spanners anyway :oops:
 
its hard to hear on my video to be honest (you NEED noise cancelled headphones i think) - only on the engine bay one can you hear it when it's directly over the engine front (theres a reason i pan back to the same spot). its also more obvious at 3-4krpm.
 
I'm in Earlsfield, mmm-five, however i suspect it'l stay in the garage until fixed .. as long as i'm confident he's not taking me for a ride!
 
Odd that the exhaust valves were all out soon soon. How many miles since the previous adjustment?

I was speaking with my service advisor the other day, inquiring into the costs of servicing a Z4M. He said that unless the owner tends to really thrash his car (or excessive tapping is noticed) they don't bother doing the valve adjustment until Inspection II.
 
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