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Old 28th July 2013, 16:05   #41
Bolin
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Here is a video clip that shows the bad sound - the clip starts under the car near the oil filter, where the noise is loudest.

https://picasaweb.google.com/1090441...66603860461762
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Here's a recording of the engine being started, and then revved. Oddly the sound gets quieter when the engine is revved, not sure if that is due to the noise itself or the camera phone. I couldn't tell from in the cab as the normal engine note takes over above a certain number of revs. In total I revved it to 4,400rpm but the recording may cut out before then. The black picture is correct, phone was usual way up with the camera to the ground so that the mic was closer to the engine.

https://picasaweb.google.com/1090441...90504328699522

Oddly, when I did rev it to 4,400 rpm the 'check engine' warning came up, never seen it before. When the revs returned to idle it went away after a couple of seconds. I reved it again to about 4,600 rpm and there was no warning. Odd
Ok. Compare the old clips to the new ones below.

This first one was done from cold, engine not started for 7 hours, coolant temp 23 degrees. The clips starts off under the car, by the crank pulley, then moves around the top of the engine bay, before returning to under the crank pulley.
https://picasaweb.google.com/1090441...93544668537202

This second clip was done when the engine had reached 88 degrees (so bear in mind the lower idle rpm once warm) and again starts off under the crank pulley. The engine was then revved to roughly 4,200rpm and imediately released back to idle. The clip then moves around the top of the engine bay before returning to under the crank pulley.
https://picasaweb.google.com/1090441...95649042239634

Oddly the car did seem a bit 'boomy' from the exhaust when cold, and when I revved it just after finishing the second clip there was a 'cough' or 'hiccup' or missfire thing happening. I'll need to look at the exhaust, the box after the main cat is rusting away at the ends, perhaps it's got too bad. There was also an 'air' sound either being sucked in or blown out, not sure which, but didn't exactly sound like the exhaust was blowing as such. Maybe this explains the check engine light I had earlier (not come back though)?

Depressing the clutch has no effect on the vibration, which does seem to get a bit worse when revving up compared to at idle, and still gets much more noticeable when the revs are released and drop back to idle.
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Old 7th September 2013, 16:07   #42
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OK, done a fair bit since I last posted.

Cam covers, breather hoses & throttle body have been cleaned. Replacement inlet manifold has been fitted after being cleaned inside, a new aux idler fitted and new cam cover oil meshs.

Car seems noticeably quieter - largely due to the inlet manifold I suspect. However, the vibration is still there, at it's worst at about 1,100rpm (ish), plus the 'third noise' mentioned in post 36, which is now very noticeable - perhaps eliminating the other louder noises has made this more prominent.

The vibration felt worse when the revs were dropping back at they drop back more slowly than I was revving it up, so they spend time around the RPM where the vibration is at its worst.

I have done more recordings. First one - from cold.
https://picasaweb.google.com/1090441...04393873218322

I then stopped recording, revved the engine and the remaining bad noise went away for a little bit, only to come back. So I did another clip where I revved the car and you can hear the noise disappearing and then coming back. N.B. the volume seems to vary a bit, seems to be due to my phone.
https://picasaweb.google.com/1090441...04394944916386

Third clip - done with aux belt disconnected. Not really any different.
https://picasaweb.google.com/1090441...04396039547394

I'm still thinking that the crank pulley damper is the cause of this..........
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Old 7th September 2013, 22:38   #43
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It sounds a bit similar to the 'noise' in this video: http://www.youtube.com/watch?v=70riNMXBrZU

The problem in that video was apparently the crankshaft pulley bearings shot

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Old 7th September 2013, 22:45   #44
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Hmm I think that was the wrong video!

It really shouldn't be the cambelt tensioner pulley - I have just replaced it and the hydraulic tensioner, and adjusted the pulley correctly.

Before doing that the noise was different, and much louder - this is the video I posted on page 2 of this thread, before I sorted the tensioner: https://picasaweb.google.com/1090441...66603860461762

So I'm sure this is something else.
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Old 8th September 2013, 07:15   #45
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Colin

Have just caught up with your video.
I had a similar noise with a Montego audible from new.
The 'clatter' disappeared to all intents and purposes above 1500rpm.
I put it down to either a discrepancy in the valve train or a noisy piston but definately not a big end bearing.
I let it be for the duration of my ownership of 22 years and 130000 miles.
The cylinder head was never ever removed over its life.
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Old 8th September 2013, 15:34   #46
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Thanks Barry, I hope it's not that as the noise is quite annoying!

Did you also have a vibration with it? I assume that whatever is causing my noise is also causing the vibration.

Also, was your noise gone at idle after revving the engine? This is what's really odd with mine as can be heard in the last 2 videos above. Doesn't make any sense to me
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Old 23rd January 2014, 12:14   #47
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Still got this problem, but the noise has now delevoped a sort of 'chuffing' sound at idle (noticed at warm idle outside car, not checked cold idle yet).

I still think it's the crank pulley!

Any ideas folks?

Thanks, Bolin.
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Old 9th February 2014, 16:32   #48
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Does anybody know of an engine related noise that can disappear over about 2,000rpm (on a KV6 at least) and still be absent for a couple of seconds once dropped back to idle, only to then reappear?

Might be time to just replace the crank pulley and hope!
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Old 9th February 2014, 18:07   #49
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Quote:
Originally Posted by Bolin View Post
Does anybody know of an engine related noise that can disappear over about 2,000rpm (on a KV6 at least) and still be absent for a couple of seconds once dropped back to idle, only to then reappear?

Might be time to just replace the crank pulley and hope!
Yes, a loose liner, but that was many years ago on a Rover V8. Would clack on and off when idling, only to disappear later at higher revs. Drove me mad. Eventually found it with a borescope, where I could see the bottom of all the liners. One was nice and shiny, the one that moved!
Result of cold water in the radiator, I think, in retrospect. Later bored it out and fitted Ohio liners and chevy pistons,flowed the head and fitted hilift cam and bigger valves. I think good for about 220hp with a four barrel 390 Holley.
Went like stink! Still does, I guess, haven't driven the car for 8(?) years!
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Old 9th February 2014, 22:14   #50
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Many thanks Kaiser - as I don't have any coolant in the oil I think I can rule that one out.
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