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Good evening, 

So after changing my Esprit cambelt I've noticed a bit of an odd noise which may or may not have been there before. Since my senses are on overdrive I'm identifying a whole host of new sounds emanating from the car, one of which is driving me bonkers. 

On idle, I can hear a mild "chirp" every now and again. When the engine is under load, like when pulling away from a standstill the chirping turns into a bit of a shriek. I've checked and rechecked the aux-belts and they're within spec, with 9 mm deflection for the AC and Water Pump belts and (after tonight) roughly the same, perhaps a tiny bit more for the alternator (spec says 12 mm). I thought these were slipping under load, although from my experience, I know aux belts usually just make a horrible constant shrieking noise at any speed - we've all seen that 1992 Nissan Micra roll by announcing its shame with a loose alternator belt.... 

Anyhow I've tried to identify the source of the noise and I'm flummoxed. I'm not even sure it is the belts any more - but what else could it be? An air leak (my idle is fine, nada else weird going on) - have I dislodged something while doing the belts? 

I have an odd feeling Travis will know exactly what it could be...

Anyway here's a couple of videos of the noise on YouTube. Sorry about the quality. (I'll post 'em as they're uploaded to the Tube!). You can hear the noise as I hit the gas. I've also got some from above the car and as its driving in the garage...

Sound is most clear at 47 seconds as I stab the gas:

Cheers in advance for any and all advice!

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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They're allegedly tougher, but I grant them the same respect as double platinum spark plugs.  In my book they're simply not worth the money.  The standard belt is a tried and trusted component that do

Hi Vanya, I also detected a "chirping" noise after changing the timing belt. It's there when the engine is cold but goes away when hot. At first I thought it might be a loose aux belt but they al

My cambelt chirps a bit when cold, but there's no noise when it's warm. And that's a new Gates belt, with a proper tensioner bearing, not a dodgy one. I couldn't really hear anything untoward, Vanya.

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Ah - a stuck Swedish fairy .......

i can't hear anything that sounds strange there - puzzled

 

Only here once

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Here's another vid, where it's more clear, especially the last second - it's like belt slip, but is it belt slip?:

Edit: how frustrating that it's so hard to hear in the clips, but in person it's really annoying, especially when pulling away. I'm not too concerned anything is going to break, but it'd be good to know what it is... 

And about 25 seconds into this sound clip:

If it's impossible to identify I'll run it through an EQ to isolate it... 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Nope, can't hear anything strange...

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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It's most clear 47 seconds into the first video with the camera under the car. It's really hard to capture the worst of it without the car under load (was on axle stands). Is it possible to have aux belts slip only under load and be silent at constant rpm/idle? 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Always difficult with videos, but I can't hear any belt slippage.  I can hear valves and, I believe, a bit of vacuum pump.  Other than that it sounds OK!

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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I'm with you on the vacuum pump and the valves! Good to hear it sounds ok. I'll just go out and drive it. Once I'm outdoors in open air I can spend some more time capturing it and filtering the sound to do away with misleading surrounding noise. Just before leaving the garage I thought it might have been coming from around the throttle linkage, although that makes little sense... I'll try and sleep on the matter. 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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I can't hear anything either and played each one a couple of times.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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I dont know if i hear the same thing, mine sounds exatly like yours, ive noticed noises when cold that relate to the gearbox or clutch natural noises? your throttle blips better than mine, mine tends to drop 100revs for a mili second when you blip the pedal

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Thanks for input everyone. I'll try and capture the sound a bit better this weekend. I was a bit hasty with this thread. Sorry! 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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Hi Vanya,

I also detected a "chirping" noise after changing the timing belt. It's there when the engine is cold but goes away when hot. At first I thought it might be a loose aux belt but they all seem fine.
Secondly I was thinking, what if the water pump has developed a slight leak and the bleed holes drop coolant on a belt, then it would be wet on start up but dry out when the engine gets warm.
But I have no loss of coolant and nothing on the floor under the car. Now I am thinking a small exhaust leak in the turbo area and when the metal expands due to heating up, it seals itself, but
I'm just guessing. If you can isolate the noise, it would be interesting to see if it sounds like mine. Listening to the vids I can't hear anything out of the ordinary.

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Torque times RPM equals horsepower!

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My cambelt chirps a bit when cold, but there's no noise when it's warm. And that's a new Gates belt, with a proper tensioner bearing, not a dodgy one. I couldn't really hear anything untoward, Vanya.

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Margate Exotics.

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Thanks for the input guys. Yeah this noise also disappears for me when the car is warm. Localizing it has been difficult - at one point I was also thinking it might be an exhaust leak/small crack in the manifold but I couldn't find it. Might have to do a spray bottle test. If there was coolant on the belt/pulley, wouldn't that make it go silent?

Ian, while we're on the subject of cambelts, have you re-checked tension some time after fitting? My belt lost quite a bit of tension after a couple of drives. I had the car back up on stands to check everything again and things were done up real tight - I couldn't get any movement, neither on the tensioner nor the lock nut on the tensioner. At the same time, these belts aren't supposed to have any stretch whatsoever...

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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No, I haven't rechecked the tension, because I can feel it's tight enough, and I do think there's way too much hype about it. In any case the Sparkmeister (not whilst under the influence of gin) said it was fine last time he was here, and seeing as he was the one that fitted it, I'm inclined to believe him.

The Gates toothed belts will wear, but they don't really stretch; they're purpose made as timing belts, and are used on other machines for indexing. I've never needed to re-tension one before, were you using a decent belt?

Margate Exotics.

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But - and I do not know if it's utter pish or not - I have read the gates belts can be noisey. I read a lot about them before opting for these blue belts - never read a bad review I have to say, but have read stuff about slightly noisier than the standard belt what ever that means 

Only here once

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New Gates for me as well, same as Ian. Althoug they are made to not stretch they will change tension with temperature for example. I can also see the posibility of the
outer surface wearing against the tensioner and making the belt a tiny fraction thinner, thus reducing tension. This would be most noticable when new I guess.
I measured mine this evening and it was down to 59-79Hz, it was hard to get a good reading but it still only twists 90 degrees total if you do the twist test.
Tensioner still in position and unmovable without loosening locknut. Had a reading of 114Hz when I checked in December but is was much colder then.
Going to retighten tomorrow.

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Torque times RPM equals horsepower!

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Never noticed a noisy Gates belt.  Remember, Gates is OEM for Lotus.  Yes, there will be tension variance due to many factors, one of which is rotational position of the engine.

I agree with Ian about the hype; there's plenty of belt tension tolerance.  A while back, one particular Esprit drove here with a collapsed/seized tensioner, and I dismounted the belt with thumb and forefinger.  Of course I'm not advocating that, but a few hertz on the loose side won't be terminal.

It's possible, with the right tools, to adjust tension without removing anything.  If you can do it, it's much nicer than removing aux belts.

Ian - you sure I was sober?  Do you feel lucky, punk?

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British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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Not the blue belts though ??? Aren't they slightly different - and yes this may well be a dumb ass numpty question

Only here once

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They're allegedly tougher, but I grant them the same respect as double platinum spark plugs.  In my book they're simply not worth the money.  The standard belt is a tried and trusted component that does the job admirably.  If you look after your car properly, you should never have a problem with it.

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British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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