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Timing chain issue ?

Discuss problems you have had or are having with your Z4
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Cooky3
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Timing chain issue ?

Post by Cooky3 » Wed Oct 18, 2017 9:41 pm

Cheers Mike. Good idea but unfortunately car is about 45 miles away, then I would need to get it to James and then onto his mate who then has to travel to get it analysed....

Going to get the guides stripped anyway on a gamble as it appears this is about the only plastic bit directly located to the sump and given the particles had not been through a combustion process this is hopefully it... Fingers crossed. :thumbsup:
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Timing chain issue ?

Post by ph001 » Tue Oct 24, 2017 8:27 am

Any news on this one OP?
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Timing chain issue ?

Post by Cooky3 » Tue Oct 24, 2017 8:59 pm

Thanks for asking ph001. Was about to update.

So, had new timing chain, guides and tensioner fitted today. Oil replaced, run up to temp and noise is still there. :headbang: Everyone thinks it was guides but there you go. For reference the vid is an earlier post here...

Spoken (via James) with a specialist. They had seen a similar issue with the same engine as mine. Customer had replaced the items I have had done and apparently it then threw the chain within 200 miles causing major issues. Apparently the repairers had not replaced or cleaned out the oil pump pick up pipe and strainer. If this is blocked it can restrict oil pressure at lower revs meaning the tensioner does not work properly... Apparently cleaning it doesn't necessarily make a difference - it should be replaced. I have spoken to my guy and whilst he has not replaced it he did remove it to check it and suggested it looked OK...

Could this really be the issue?

Other suggestion has been worn cam hub but he said any movement here would throw a fault code. There are no codes. The sensors are very sensitive I believe so this would make sense surely. For the hub to be worn enough to cause the timing chain to whip or grind would surely throw something up...

In addition the engine runs sweetly at idle and performs as it should when being driven. There is no lumpiness or issues to see or hear.

Going to perform an oil pressure test tomorrow. Interestingly he has another Beemer with the same engine as mine in the shop so intends to run an oil pressure check on that too for comparison...

I have never had so much hassle with any car or bike I have owned (and that's a lot) in my life....

He is as frustrated about it as I am....

HELP.... PLEASE.... :cry:
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Timing chain issue ?

Post by ph001 » Tue Oct 24, 2017 9:18 pm

This is just crazy. It seems almost everything has been eliminated here (I'm not going to mention running it with no aux belt again as surely the garage must be certain its nothing to do with any of the ancillaries). I just can't see it being oil pressure related with the tensioner. My head is steering me back a hva issue.
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Timing chain issue ?

Post by Smartbear » Tue Oct 24, 2017 9:22 pm

I would run it without the serpentine belt to discount items driven by it, quick & easy to do so get them to do it.
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Timing chain issue ?

Post by ph001 » Tue Oct 24, 2017 9:30 pm

I just listened to the video again. The fact that it's over such a narrow rpm range just makes me think it's something resonating...which would fit the fact of no drop in performance or error codes. You say the vanos has been thoroughly inspected and given the all clear....there really isn't a great deal left. If this does go away with the aux belt removed, somebody needs a good kicking 😜😂
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Timing chain issue ?

Post by Cooky3 » Tue Oct 24, 2017 9:48 pm

He's checking that tomorrow too but everyone who has stood in front of it and listened with sound sticks / tubes have all said its coming from the timing chain area... Including me, James and three engineers including two BMW master techs....

Seem to recall people sticking eggs in leaky rads etc back in the day. I might just drop one into the engine for good measure... :?
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Timing chain issue ?

Post by MACK » Tue Oct 24, 2017 10:17 pm

I've seen the oil pickup get clogged up on more than one 2.0 N42 engine when the timing chain tensioner has been at fault and the guides have been breaking so its definitely possible.
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Timing chain issue ?

Post by Boris » Tue Oct 24, 2017 10:26 pm

Ok; I know my way around and engine (a generic one that is) I know nothing specifically about the Z4 mechanics.

But I had exactly this same sound on an "old" 47 year old to be precise, car of mine last year or at least the vid sounds the same.

Does the Z4 have a mechanical or electric fan?

Mine was the plastic fan blade hitting something, I had been resting on it while I tried to access a remote part and bent it; now as the current car had just been serviced prior to the sound appearing, has a spanner or other tool been left inside the bonnet dropped down inside near a belt and is rubbing???? This is what it sounds like to me.

Purely coincidental, but my wife's car was in for service a month or two ago at a main dealers, I went to top up the water the other day and found a spanner laid inside the engine bay. :thumbsdown:

Just thinking laterally as they say :fuelfire:

I really hope its not something as simple after all this trouble, but people do seem to go for the expensive stuff before ruling out the cheaper fix it would appear, by people I mean the "specialists".

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Timing chain issue ?

Post by 1000rr » Tue Oct 24, 2017 10:34 pm

Sounds like a heat shield loose or metal cable/shroud and is resonating at certain rpm frequencies .... you’ve changed everything it could be by now.
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Timing chain issue ?

Post by jnwright71 » Tue Oct 24, 2017 10:41 pm

Hi All,

This continues to be a mystery. However, the one common here is that every mechanic (professional or DIY) that has looked at the car has said timing chain related, and the plastic in the sump can only be there due to guide damage which must be related to guide failure or chain tension.

When Justin called me today to advise that the car was back together but no better, and having banged my head against a wall for 5 minutes, I called another BMW specialist with lots of Z4 experience. His diagnosis is as Justin has outlined, with two secondary options, but both are oil pressure related.

His main view is that the plastic swarf in the sump will have been picked up by the oil pump and could be partially restricting the pick up pipe and / or strainer. This is resulting in the tensioner being unable to hold correct tension at low RPM, but at higher RPM, the pump is pulling more oil and hence building sufficient pressure for the tensioner to operate correctly. This makes a great deal of sense to me and would explain why the noise only occurs when the engine is hot and oil thinner.

I was under the impression that the belt had been removed when the engine was hot, but from Justin’s post this appears not to have been done, so agree this is a major fail if it does stop the noise. I doubt it though, as the plastic in the oil points clearly to the fault, unless of course this is just bad luck and a completely separate issue.

The other issue that the guy mentioned today is VANOS hub rattle, again linked to low oil pressure resulting from a partially blocked pick up or failed oil pressure switch in the filter housing. However, both should throw fault codes.

Hopefully, the oil pressure check tomorrow will clarify the issue. Again, not sure why this wasn’t checked earlier, but hey ho ...

Hopefully light at the end of the tunnel.

Cheers, James
Last edited by jnwright71 on Tue Oct 24, 2017 10:44 pm, edited 1 time in total.
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Timing chain issue ?

Post by Cooky3 » Tue Oct 24, 2017 10:43 pm

Cheers gents. Re. The spanner or fan blade, it's not there when cold, nor when the temp gauge is up to temp, only when the engine is fully warm still showing normal temp on gauge.

Heat shields all checked too. I did read about an engine mount guard or something. But let's not lose sight of the plastic swarf in the sump, apparently only source would be the timing chain guides.... :headbang:
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Timing chain issue ?

Post by ph001 » Tue Oct 24, 2017 11:29 pm

Ok, oil pressure should give us some good information. Keep us posted.
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Cooky3
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Timing chain issue ?

Post by Cooky3 » Wed Oct 25, 2017 6:09 pm

Here we go then for those interested.

Oil pressure checked today from cold all the way through to operating temperature - I believe it was noted around 50psi / 3.3 bar (give or take). Is that about right? My guy has a 3.0 six pot BMW in his workshop currently (not with the same issue incidentally). Ran a pressure check on that and the two were almost identical, mine being very marginally weaker.... Full timing chain, guides, tensioner etc all done as posted and timing all spot on (he cant believe how sweetly the engine ticks over and runs).

Had to park car out the way to do another job. Came back to it and tried another idea. They started mine up and used an extendable bar to hold the revs at around 1200ish where the noise is apparent when coming on and off the revs. No noticeable noise from cold when held there. They let it run up to temperature, and as the engine got to a certain temperature the noise kicked in.... WTF is going on? How can it simply kick in when the timing gear is rotating at a constant rpm when it gets hot?

The guy has also bought an infra-red camera to apparently check for hot spots in the engine (for worn parts etc that would run hotter apparently - not sure how much people know about this). There was no obvious or specific areas that stood out.

He has been around the engine with a listening stick / screwdriver or whatever and thinks the noise is resonating within the engine but hard to pinpoint. He has held it on the sump and thinks it is audible down there but cant quite tell. He is apparently borrowing a tool that you place on different parts with varying settings which you can listen to remotely from the car to see if that gives any clues as you are away from the general noise of the car running....

He is doing me a favour and trying to fit this work in around other specific jobs to keep costs down for me and reckons he has spend about 15 hours on it to date (but at this stage says he is looking at c8 hours chargeable plus parts).... My car has been there for 4 weeks on Friday - the time is not an issue as it is supposed to be a weekend fun car; how ironic!

Should I just give up and stick in a second hand engine? Who has got one? How much? because this is like chasing ghosts.....

Or shall I just get rid and put it down to experience? (rhetorical really).

To be honest, I cant have many more sleepless nights over this debacle!
I ain't fallin for no banana in my tail-pipe!
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Timing chain issue ?

Post by Smartbear » Wed Oct 25, 2017 6:42 pm

So did he run it up after removing the belt?
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e89 Sdrive 30i, this ones busted, pass me another...
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