4A Clutch cover issue?

[adriantr4]

Hi

I have completed engine and gearbox work with both out of the car, TR4. I have a new pressure  cover, clutch plate, release bearing & carrier, fork, pin (and cross-drilled the operating shaft for a roll pin),  There was a bit of damage, so plenty of new parts.

All the new parts fit well, and I confess to having work done to convert to a 4A clutch system. Principally I shortened the gearbox extension and had the flywheel redrilled and lightened.

No issues, and the gearbox attached to the engine without too much bother, before which we re-checked bearing free to move and clutch plate the right way round.

We then attempted to activate the clutch by putting a stilson on the clutch arm - but once the bearing made contact we could not move it further. The amount of force to do so seemed like something would break?

My friend who was doing the work with me "helping" was a professional mechanic and has been around TR's for years. He said when he put a 4a clutch in he was able to activate/test it with a bit of bar quite easily.

I don't know the make of the clutch plate or cover: the clutch plate has "Flywheel Side" in both English and German, and maybe "ap" as a logo, nothing obvious on the cover.

Any ideas? My friend thinks the cover is faulty, jammed? How much pressure is normal?

Thanks, Adrian 

 

[stuart]

When you fitted the box did you wire the lower end of the clutch arm in the forward position? i.e. the thrust bearing being held at the rear of the extension.

Stuart.

[adriantr4]

No we didn't, but I 'm fairly sure the clutch arm was ok, hanging vertical & not jammed. Thanks.

[Chilliman]

You'd be surprised just how much force you would need to do what you're describing on a new diaphragm pressure plate.

[adriantr4]

Very true, and thanks. Any idea the pressure required - and any idea how to ID the parts? 

[Z320]

Hi Adrian,

your "ap" clutch cover was also sold as Borg&Beck, which is the UK badge of "ap" (Automotive Products / USA).

There is a old and a new design, the new one has the noticable stronger diaphragm spring, much stronger than your old TR4 "9 coil springs" - cover.

Anyway, if you feel it is absolutly  stiff, there could be something wrong. In my opinion the cover can't "jam"

Ciao, Marco

Edited May 14 by Z320

[adriantr4]

Hi. Problem solved. We swapped the cover plate for a 4a Borg and Beck item and could move the clutch arm with a Stilson. Hence, we proved that the clutch is working ok.

I think the first cover plate (obtained from a specialist who is a friend with a stash of parts) was a TR6 item. This needs more force to activate, but even so the resistance was colossal. It was brand new and looked fine: but with two us standing on it via a plank of wood barely moved the fingers. I think it was probably ok, but I didn't want to risk putting a faulty unit in the car and then have to remove it.

The Moss TR6 parts book mentions that the TR6 clutch hydraulics need to be in tip-top condition, that's certainly true.

Thanks, Adrian 

[Chilliman]

Glad to hear you're sorted..👍

Edited May 15 by Chilliman

[Trumpy3]

I understand that the pressure plate for the TR4A, 5, 6, 2000, 2500 are all the same and only the spline in the clutch is different on the saloons. 

From your info it certainly looks like you have a problem. Was there slack in the activation leaver when fitted to the engine. I have found pressure plates with higher sitting fingers that removes the clearance between thrust bearing and pressure plate fingers.

Brian

[Ralph Whitaker]

48 minutes ago, Trumpy3 said:

I understand that the pressure plate for the TR4A, 5, 6, 2000, 2500 are all the same and only the spline in the clutch is different on the saloons. 

From your info it certainly looks like you have a problem. Was there slack in the activation leaver when fitted to the engine. I have found pressure plates with higher sitting fingers that removes the clearance between thrust bearing and pressure plate fingers.

Brian

Indeed, my 3a is fitted with a 4a flywheel and the spare clutch I bought some years ago for my 2 litre vitesse.

Ralph

[Trumpy3]

Ralph

Utilizing a TR4A flywheel negates the need to get the original flywheel re drilled. I prefer to re drill the original flywheel as it is lighter than the TR4A unit and I did not have a 4A unit which aren't plentiful down under. I think the TR4A flywheel is heavier to compensate for the lighter clutch.

When I first decided to take my car on the track I used a TR2 flywheel and diaphragm clutch as it reduced the rotating mass by about 12lbs. Made the pickup much better but not as good in traffic due to the loss of inertia. I have now gone back to a TR3A flywheel, a great compromise.

Brian

[BlueTR3A-5EKT]

38 minutes ago, Trumpy3 said:

Ralph

Utilizing a TR4A flywheel negates the need to get the original flywheel re drilled. I prefer to re drill the original flywheel as it is lighter than the TR4A unit and I did not have a 4A unit which aren't plentiful down under. I think the TR4A flywheel is heavier to compensate for the lighter clutch.

When I first decided to take my car on the track I used a TR2 flywheel and diaphragm clutch as it reduced the rotating mass by about 12lbs. Made the pickup much better but not as good in traffic due to the loss of inertia. I have now gone back to a TR3A flywheel, a great compromise.

Brian

You need to change the starter motor too to match the flywheel and ring gear assemblybeing used.

[Trumpy3]

Peter

Yep, if you have a hytorque starter you only need to change the pinion. This of course is only required if changing from a shrink fit ring gear (early TR) to a bolt on ring gear (later TR) or visa versa.

Brian