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Discussion Starter #1
There is a "tark tark" sound ( roughly 4 times per second) when the car idles. The sound disappears when I press on the clutch pedal. So I think it is somehow related to the clutch. Wonder if anyone knows the cause. ( my engine has just goe through a full rebuild - replaced piston, rings valve...etc, so it can't be the engine..I think )
 

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71 Berlina 74 GTV 17 Giulia Q4
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did you replace any clutch components on your GTV, that's purely an assumption and we all know about those:eek: since we're in the GTV thread.;) but seriously it would be good to have the specific information as to what car we're talking about.
 

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Does the noise change when the idle speed is increased to, say, 1200+ RPM?

Gentlemen,
The clues indicate that the car is a Series 1 RHD model 10545 1750 GTV between the chassis numbers 1450001 and 1454000. Course I've erred before...
 

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Pushing clutch pedal in of course pushes the crank forward ... so I hope it is nothing wrong in that department.

Pete
 

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Discussion Starter #6
Sorry guys, its an MK1 1750, my bad. Thx Papajam.

Can't remember if the noise remains when it revs up 1200 rpm, will try tonite. I did rebuild the clutch 2000 miles ago with new clutch assembly and syncros from Centerline. There were no noise at the beginning ( after the rebuild ) but gradually getting louder and louder. The sound is familiar as heard from older cars with a manual transmission.
 

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I have the same sound since I had an Alfetta transplant done. I had my flywheel lightened as well and googling has uncovered similar symptoms in some cars who have lighter flywheels. Of course google is not exactly the best way to get info, but I've driven my car quite hard for more than 5000km's already with absolutely no ill-effects to the transmission. I had a full engine rebuild done last year and all the clutch and gearbox components are fine.
 

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I have the same - believe it's the gearbox input shaft hence it goes away when clutch depressed :).

Mine has been that way for a couple of years with no ill effects . Waiting for next winter to get the gearbox out and rebuilt

Andy
 

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Mine had a rattle just like this for years. It was the clutch fork pivots. Took an amazing amount of work but not lots of $$ to finally find and fix.

Robert
 

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I have the same - believe it's the gearbox input shaft hence it goes away when clutch depressed :).

Mine has been that way for a couple of years with no ill effects . Waiting for next winter to get the gearbox out and rebuilt

Andy
same here...after reading every thread on the subject i could find, i suspect the most likely culprit is the input shaft bearing. i've also been driving mine this way for quite some time with no ill effects.

the noise does suck, though.
 

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I'd guess throw-out bearing. When you press the clutch in, it goes away, at higher revs, you can't hear it. My '69 1750 makes a similar sound, as does my '69 Datsun. I've tried everything on the Datsun and nothing has changed.

Will
 

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I'd guess throw-out bearing. When you press the clutch in, it goes away, at higher revs, you can't hear it. My '69 1750 makes a similar sound, as does my '69 Datsun. I've tried everything on the Datsun and nothing has changed.

Will
IIRC, from my readings, it seemed that the opposite is true...if it's the throwout bearing, the noise happens when you depress the clutch pedal, and goes away when you release it. if the sound goes away when you depress the pedal, then it's most likely the input shaft bearing.

perhaps one or more experts can clear this up for us once and for all? :)
 

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IIRC, from my readings, it seemed that the opposite is true...if it's the throwout bearing, the noise happens when you depress the clutch pedal, and goes away when you release it. if the sound goes away when you depress the pedal, then it's most likely the input shaft bearing.
My understanding too. The throw-out bearing is usually idle until you push on the clutch pedal, put pressure on it and make it spin. If it is worn you may hear a screeching noise and possibly even feel something through the pedal when that pedal is depressed.

As to your noise, I'd also put my money on the input shaft bearing. It is not an uncommon problem in older gearboxes and if there are no other symptoms, bear with it until you have to do something else - eg: synchros, oil seals etc.

Chris
 

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The throw-out bearing is idle until you push on the clutch pedal, put pressure on it and make it spin. If it is worn you may hear a screeching noise and possibly even feel something through the pedal when that pedal is depressed...... I'd also put my money on the input shaft bearing.
Well, I'm not so sure.

Throw-out bearings can make a slight chirp when unloaded - even when they aren't under load, they still rub against the pressure plate fingers and can spin a bit. If the sound were a screech when the clutch pedal was depressed, then sure, I'd be confident that it was coming from the throw-out bearing. But I don't believe the absence of that symptom excludes the throw-out bearing as a suspect.

But, hey, I havn't heard the noise personally, and admit that it could be anything: the input shaft, the exhaust system rattling, ..... And I do agree with the prescription: just leave it be until the next clutch replacement, or until your symptoms worsen.

psk said:
Pushing clutch pedal in of course pushes the crank forward ... so I hope it is nothing wrong in that department.
Doubtful. Crankshaft thrust bearings are pretty beefy and pretty reliable. And, if the crank were moving axially, I think you would have symptoms more dire than just a slight "tark tark" sound.
 

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Discussion Starter #15
My mechanic says it has something to do with a spring that has lost some spring rate due to old age. I will try to record the sound and put it on youtube over the weekend. Anyway, thx for all your input :)
 

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I would say almost certainly release/throw out bearing. Nothing too much to worry about unless, as mentioned it starts making a more serious noise.
For general information, good quality input shaft bearings are getting hard to find currently. There are two types - one a split/two piece bearing and the other a single unit. These relate to the style of gearbox and if the bearing is held in with a nut or a circlip (nut is later style). The bearings are both the same size and effectively interchangeable, but (from memory) the single piece one can go in both style boxes, wheras the two piece one should really only be used in the earlier style box. I can check this in need...
 
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