Anything and everything GT6.

(Posted by assoc. member Malc - spannerman - on behalf of Chris).
1973 GT6 Mk3
It's been doing it for ages now and the clutch doesn't drag, slip or bite viciously but works perfectly. So why does it twitter in the manner of a trapped sparrow (best way to describe it!) with the foot off the pedal - the sound stops on applying just a bit of pressure. It happens whether the engine is out of gear or when driving.
?????
Malc

Hi Christine / Malc

Sounds like it could be the clutch release bearing,

Unless you really need to take the gearbox out, worth leaving alone until you have to, or unless it becomes to annoying.

It may be a release bearing fault, and if so, it can only be sorted by taking the gearbox out. However, it might just be this:
On the 6 cylinder cars, the clutch release arm has a spring clip that retains the arm on the ball-ended pivot. I had this spring clip break and gave exactly the sort of noise you describe, especially as revs rise. Putting your foot on the clutch pedal places the clutch release arm under pressure (it's held securely between the pushrod from the slave cylinder at one end and the pressure of the clutch cover diaphragm spring at the other) and so cannot then "wiggle around". (With the clutch pedal released, the arm is free to move slightly).
As there is no way the release arm can fall out, I left things as they were and matters got no worse over many thousands of miles. (I might have replaced it when I changed the clutch, but I can no longer remember.)
As the release arm is visible (and almost accessible!) through the bellhousing, you might be able to see it fluttering slightly when the noise happens. If you can hold it still, or press a screwdriver, hammer handle etc against it when the noise happens, and the noise then stops with the arm held still, you can probably work out if this is the cause of your sparrow twittering!

Interesting. After my new box went in I had no clutch twittering, but a few hundred miles later I get some tapping when you rest your foot on the clutch pedal that goes away after pressing further for a perfect gear change. We knew the release arm was spring-less when it was reassembled but hoped it would just sit there (couldn't find a replacement in time). Does anyone know of a supplier? With my intermittent overdrive and canaries in the clutch, I'm wondering whether I should have left well alone!!
Jonathan.

My GT6 has been making the same noise for the last 7 years or so. During this time, due to normal wear and tear, I have replaced the release bearing, changed the gearbox and fitted a couple of clutches. The only thing I haven't replaced is the release arm. The spring is intact on mine, but there is noticeable wear on the pins which locate on the bearing carrier. My own thoughts are that the wear in the pins is introducing some play into the mechanism which is causing the twittering. I have not found a supplier of new release arms, and all the s/h ones I have looked at are in a worse state than my own.
The only cure at the moment is to wind down the window, and listen to the exhaust instead

Andy Todd ( Wirral AO )

An alternative to winding the window down (only preferable to a 6 cylinder exhaust when the weather outside is really bad of course) is the universal automotive solution of turning the radio up! (You could always fit a louder sports exhaust system!)
Seriously, have you tried sourcing the release arm or bearing carrier as a Dolomite part? (new or second hand) as I think they are the same part or at least interchangeable.

I shall look into that, I have also thought about the co-axial release bearing assemblies that are available from Cambridge Motorsport & Demon Tweeks but wether they will fit the GT6 gearbox is another matter.
The twittering is not so bad that I want to take the gearbox out again in a hurry, but I have a sports exhaust and a big sound system so I am covered for all weathers

Andy

My GT6 does exactly this - chattering (in neutral or any gear) until you put the slightest pressure on the clutch peddal. Mine started following replacing my gearbox and changing the release bearing "whilst I was there". That was well over a year ago now.

I had assumed it was a faulty release bearing but maybe it is the release arm. In my case it is unlikely to be wear as it was fine before the gearbox change. Maybe I didn't fit the release arm into the clip properly?

I've also changed the bellhousing so maybe its wear on the pivot ball joint that the clip attaches to?

Anyway, I intend to get the gearbox out and fix this in the next couple of months as it is really beginning to annoy me.

The clutch release bearing should be continually & sufficiently in contact with the spring diaphragm fingers to ensure that it rotates with the clutch assembly at all times i.e., irrespective as to whether or not the clutch pedal is depressed. To achieve this there is a spring within the slave cylinder that is supposed to provide a slight amount of hydraulic pressure sufficient for this purpose.
The noise is caused by the bearing chattering against the fingers of the diaphragm. This is aggravated by worn pins on the release arm and wear in the bearing carrier collar. Relocating the anti spin pin in the collar will provide a different operating point for the pins to bear on. Fixing the wear in the pins is not so easy. The simple solution is to add a spring to the operating arm to provide a bearing preload of a few pounds force. There is an excellent article on the Buckeye Triumphs website describing owners experiences and solutions.

Peter

Section : Clutch

Clutch twittering?

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