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Faint knocking? (Clip)

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Argenta
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Faint knocking? (Clip)

Post by Argenta » Sun Sep 10, 2017 1:08 pm

Hello!

I need help on this! 😐

My MC has done ca 4000km's since new rod bearings in June.
Over the past weeks I've gradually come to hear this faint knocking sound, only on tick-over, and only really inside car with fan etc turned off.
Now it's loud enough to be audioble in this little clip from yesterday:

https://youtu.be/kGOxUHfXA0k

Any thoughts?
It can't be my new bearings can it? Revving just makes it quiet.
It's also a bit fluctuating, it's not completely constant. Like somethings loose etc.

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Faint knocking? (Clip)

Post by MrPT » Sun Sep 10, 2017 4:31 pm

When was the last major service?

Check it is actually coming from the engine and not the transmission or any of the ancillaries. If it is, personally I'd get it towed to a specialist and have the top end checked for valve clearance and/or cam follower or cam lobe wear issues. I know some people wouldn't be this cautious with only a slight tap, but you could rack up a much bigger repair bill by driving it.
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Faint knocking? (Clip)

Post by Beedub » Sun Sep 10, 2017 8:26 pm

yeah i hear it.... good pickup for sure, us s54 owners seem pretty tuned into the various noises they make and also when something changes....

it sounds louder as you move to the rear of the motor, wouldn't drive it personally.
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Faint knocking? (Clip)

Post by Argenta » Sun Sep 10, 2017 9:15 pm

Thanx.
Last major service was two weeks ago and valve adjustments was done 6000km's ago.

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Faint knocking? (Clip)

Post by mmm-five » Mon Sep 11, 2017 10:53 am

Argenta wrote: Sun Sep 10, 2017 9:15 pm Thanx.
Last major service was two weeks ago and valve adjustments was done 6000km's ago.
What's a 'major service'...as the only service besides the I1 & I2 (both involving clearances) is an oil service, which is not what I'd call a major service.

These engine can be a bit 'rattly' but that sounds 'knocky'. I can't tell whether that's from the top or bottom of the engine. Probably need someone with a stethoscope (or long screwdriver) to identify exactly where.
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Faint knocking? (Clip)

Post by ph001 » Mon Sep 11, 2017 1:05 pm

Sounds just like my S54 tbh. Not sure I would be concerned about that - normal to my ears.
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Faint knocking? (Clip)

Post by Beedub » Mon Sep 11, 2017 1:11 pm

their definitely a knocking that needs to be investigated, the ticks and metal tings are cool, this engine does sound complicated and kinda dead on idle but i think i can hear the knock OP is talking about, he's also noting its gotten louder to the point he's hearing it over the radio.
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Faint knocking? (Clip)

Post by MrPT » Mon Sep 11, 2017 1:30 pm

Could be nothing, but why take any chances? Two of the most experienced Z4M owners in the country have just chimed in saying they'd get it looked at. Especially if you had the rod bearings done not long ago - that's warrantable work.

Mine made a knocking noise like that once (under the previous owner, albeit louder) and it ended up needing a top and bottom end rebuild. It was failure of nearly all of the cam followers - forum advice probably saved the camshafts themselves, avoiding an even more eye-watering repair bill. :cry:
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Faint knocking? (Clip)

Post by ph001 » Mon Sep 11, 2017 3:20 pm

Fair enough - may just be my crappy PC speakers here preventing me hearing anything unusual.
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Faint knocking? (Clip)

Post by Argenta » Mon Sep 11, 2017 4:00 pm

Thanx again, yeah you prob need a set of earphones for this. :)
Will be back at the INDY tomorrow morning for a good check.

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Faint knocking? (Clip)

Post by Beedub » Mon Sep 11, 2017 5:35 pm

MrPT wrote: Mon Sep 11, 2017 1:30 pm Could be nothing, but why take any chances? Two of the most experienced Z4M owners in the country have just chimed in saying they'd get it looked at. Especially if you had the rod bearings done not long ago - that's warrantable work.

Mine made a knocking noise like that once (under the previous owner, albeit louder) and it ended up needing a top and bottom end rebuild. It was failure of nearly all of the cam followers - forum advice probably saved the camshafts themselves, avoiding an even more eye-watering repair bill. :cry:
dont suppose you got to keep any of the worn followers did you??? id love to see how they wear when they go bad... i can keep an eye out when the cam cover is off mine.
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Faint knocking? (Clip)

Post by AndyBeech » Mon Sep 11, 2017 6:41 pm

Beedub wrote: Mon Sep 11, 2017 5:35 pm
MrPT wrote: Mon Sep 11, 2017 1:30 pm Could be nothing, but why take any chances? Two of the most experienced Z4M owners in the country have just chimed in saying they'd get it looked at. Especially if you had the rod bearings done not long ago - that's warrantable work.

Mine made a knocking noise like that once (under the previous owner, albeit louder) and it ended up needing a top and bottom end rebuild. It was failure of nearly all of the cam followers - forum advice probably saved the camshafts themselves, avoiding an even more eye-watering repair bill. :cry:
dont suppose you got to keep any of the worn followers did you??? id love to see how they wear when they go bad... i can keep an eye out when the cam cover is off mine.

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!
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Faint knocking? (Clip)

Post by firebobby » Mon Sep 11, 2017 7:42 pm

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.
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Faint knocking? (Clip)

Post by BMWZ4MC » Mon Sep 11, 2017 7:52 pm

AndyBeech wrote: Mon Sep 11, 2017 6:41 pm
Beedub wrote: Mon Sep 11, 2017 5:35 pm
MrPT wrote: Mon Sep 11, 2017 1:30 pm Could be nothing, but why take any chances? Two of the most experienced Z4M owners in the country have just chimed in saying they'd get it looked at. Especially if you had the rod bearings done not long ago - that's warrantable work.

Mine made a knocking noise like that once (under the previous owner, albeit louder) and it ended up needing a top and bottom end rebuild. It was failure of nearly all of the cam followers - forum advice probably saved the camshafts themselves, avoiding an even more eye-watering repair bill. :cry:
dont suppose you got to keep any of the worn followers did you??? id love to see how they wear when they go bad... i can keep an eye out when the cam cover is off mine.

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.
Last edited by BMWZ4MC on Mon Sep 11, 2017 10:12 pm, edited 1 time in total.
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Faint knocking? (Clip)

Post by mmm-five » Mon Sep 11, 2017 8:20 pm

firebobby wrote: Mon Sep 11, 2017 7:42 pm 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.
Is it really such a fickle engine? I don't know if the S54 failure rate is any higher than any other high output per litre engine?

Possibly don't hear much about 'cooking' engines as they're not rare/special enough to complain about.

BTW, mine has 130,000 on it - with nothing but regular servicing and the odd 'Italian tune-up'.
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