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Topic: Timing chain rattle or not? (Read 732 times) |
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amigafan2003
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Timing chain rattle or not?
« on: Sep 28th, 2007, 6:27pm » |
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When my engine is hot, I think I have a timing chain rattle (Cosworth 24v).
But that's the thing, I THINK it's the timing chain, bear with me while I explain.
It's an intermittent rattle as in it a quick rattle, then nothing for a few 2nds, then a quick rattle again. When looking from the front of the car, the rattle is coming from the left hand side. Now the odd thing is, you can hear a servo kick in every now and then on the engine, which I imagine to be the air con compressor and the rattle stops or changes tone and frequency. Would the air con kicking in change the sound of a timing chain rattle?
I know I keep 2nd guessing myself about the timing chain and that I already have the blades and gaskets on order to check it out, but I just like to know what I'm up against ebfore I start something complicated!
Thanks in advance for any help.
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Matt
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Re: Timing chain rattle or not?
« Reply #1 on: Sep 28th, 2007, 7:38pm » |
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yes the ac pump would change the tone as it puts load on the engine, turn the ac off and mover the selector switch off the windscreen setting if its on that as this will automatically turn the ac on or off independently.
as its on the left hand side it could also be the belt tensioner on its way out, power steering pump or even the alternator
you could drop the belts off and start the car, but dont run it for very long, if the rattle stops you know its not the chains but one of the above
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FDS2000 Scans - Birmingham
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tintin
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Re: Timing chain rattle or not?
« Reply #2 on: Sep 28th, 2007, 8:30pm » |
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i had an intermittent rattle on my cossie, only when engine was warmed up, thought it was timing chain, turned out to be a blocked cat feeding back up. hows the car running? might be worth considering.....
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'95 Cosworth Ultima
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amigafan2003
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Re: Timing chain rattle or not?
« Reply #3 on: Sep 28th, 2007, 11:01pm » |
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Quote:| you could drop the belts off and start the car, but dont run it for very long, if the rattle stops you know its not the chains but one of the above |
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Now that's an idea. I assume the water pump is driven by the belts and that's why you shouldn't run it for long?
Quote:
Fantastic, pulls nice and strong and no fault codes on the OBDII scanner either.
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Matt
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Re: Timing chain rattle or not?
« Reply #4 on: Sep 29th, 2007, 7:23pm » |
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hi,
yes the water pump is belt driven, also, you would be just relying on your battery to power everything,
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FDS2000 Scans - Birmingham
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amigafan2003
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Re: Timing chain rattle or not?
« Reply #5 on: Sep 29th, 2007, 7:35pm » |
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Okay, did a quick test this afternoon - AC off (pump not on) - quite a pronounced rattle, although intermittent. AC on full (low setting, pump on) rattle lowers in volume and becomes a very light rattle but consistent.
Only happens when the engine is up to operating temp.
Still no idea what the cause is.
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Baz
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S Reg. 1998 24v Cosworth S2.9 COS (Deceased)
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Re: Timing chain rattle or not?
« Reply #6 on: Sep 30th, 2007, 9:25pm » |
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I had something similar on my previous Cossie. It turned out to be a dodgy bearing on the alternator which had broken down and was whistling and rattling away merrily...
may be worth a check
Baz
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amigafan2003
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Re: Timing chain rattle or not?
« Reply #7 on: Oct 2nd, 2007, 8:32pm » |
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Did another test this afternoon:-
No rattle when cold.
If left to idle for a couple of mins, the rattle normally dissapears.
If there is a rattle, rasing the revs slightly makes it dissapear.
If the rattle has gone, moving the steering can induce it to rattle again but if the steering is returned to the center position, the rattle normally ceases again.
I have a vid clip of the rattle - when it is rattling, that is when I am turning the steering:-
[IMG]http://img.photobucket.com/albums/v25/amigafan2003/th_VIDEO_056.jpg[/IMG ]
Still haven't had a chance to remove the belts to test - still worried about cooking the engine.
Someone please remind me, why do I love cars so much? 
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Matt
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Re: Timing chain rattle or not?
« Reply #8 on: Oct 2nd, 2007, 8:44pm » |
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could possibly be the power steering pump then
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FDS2000 Scans - Birmingham
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howiedintheplace
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Based near Evesham
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Re: Timing chain rattle or not?
« Reply #9 on: Oct 3rd, 2007, 11:59am » |
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Your simply guessing mate.
You need to remove the cam covers & have a look.
Shine a torch down & you can soon tell if the timing gear is O.K or not.
A bit of gasket sealer latter & it has simply cost you a bit of time.
But at least you will know 
Don't run the engine for more than a minute without the water pump. No water pump = localised boiling = can cause headgasket faliure.
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Dave
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