TR6 clutch in TR3A

[dwaters]

I have a TR6 clutch assembly, bearing etc  mounted on a drilled/modified for TR6 clutch flywheel on my 3A. I haven’t yet fitted the external spring to the 3A slave cylinder and it all seems to work with the standard TR3A hydraulics . The clutch “bites” when the pedal is approaching the top of its travel. As there isn’t a spring in the TR3A slave cylinder do I need to fit the external TR3A slave cylinder spring to pull the piston “out” or do I need to fit a TR6 slave cylinder? (The car has a modified for TR3A saloon gearbox with A type O/D).

Thanks

David

[RogerH]

Hi David,

have you fitted the TR6 diaphragm pressure plate AND the correct TR6 release bearing.? Please say yes.

When the release bearing is pulled away by the pressure plate springs it will just move ack to a position that is just off/ just touching the pressure plate.

Not ideal but will work. 

If you fit the external return spring then you may find that pedal travel will increase slightly as the friction plate wears.

[dwaters]

Hi Roger

Thanks for the speedy response! Thankfully I can answer “yes” to both.

David

[Andy Moltu]

Off the top of my head there is no need to fit aTR6 slave cylinder. 

The 4a ran essentially the same clutch cover and plate and release bearing as the 5 and 6s with a different slave.

In theory the 6 slave has a spring in it to hold it in place but there are lots of repro saves with no springs and these don’t seem to be problematical so the absence from yours should not be an issue.

 

[dwaters]

That’s good news, many thanks Andy.

David

[Andy Moltu]

Going back a few years some recommended using an adjustable push rod and a return spring for 4A,5 &6s using the Koyo (Toyota) release bearing. Ultimately this seems to have been OTT but was I recall the set up on the early cars.

[BlueTR3A-5EKT]

My TR3A runs that TR6 Laycock clutch set up with original hydraulics using return spring and adjustable pushrod on the slave.  My only criticism is the heavy clutch pedal.  I will have to venture into 0 .7” or 0.625” clutch master cylinder territory to remedy the pedal pressure ( existing is 0.75” standard Girling)

[Andy Moltu]

Should not be heavy.

One of the myths about TR clutches.

The B&B in the 4a is similar to my Audi A3 and heavier then the Laycock in the 6. 

Unless the mistake of fitting an uprated cover has been made. Did that once and regretted it. Given that it was 30 years ago and playing high level sport at the time is an indication of the force required.

 

[dwaters]

Thanks for all the replies, I’ve used the B&B clutch too Andy and with the standard TR3A hydraulics it seems to be ok. I’ll try with and without the external slave cylinder spring and see if there is any noticeable improvement.

Thanks again

David

[Ralph Whitaker]

On 7/2/2022 at 9:25 PM, BlueTR3A-5EKT said:

My TR3A runs that TR6 Laycock clutch set up with original hydraulics using return spring and adjustable pushrod on the slave.  My only criticism is the heavy clutch pedal.  I will have to venture into 0 .7” or 0.625” clutch master cylinder territory to remedy the pedal pressure ( existing is 0.75” standard Girling)

I had a spare plate and cover for a Vitesse 2 litre, and used that on my 3a with the saloon box and correct bearing,  standard girling hydraulics, and the pedal is heavier than I expected it would be, and heavier than my Vitesse with the same set up, but not unduly so, and not as heavy as my Vivaro van. You do notice it though after driving my Honda CRV which is commendably light by comparison.

I have the pushrod on the centre hole on the operating arm and thought about trying it on the lowest hole which should ease pressure in return for a longer pedal travel.

Ralph, 

[BlueTR3A-5EKT]

11 hours ago, dwaters said:

Thanks for all the replies, I’ve used the B&B clutch too Andy and with the standard TR3A hydraulics it seems to be ok. I’ll try with and without the external slave cylinder spring and see if there is any noticeable improvement.

Thanks again

David

That setup is exactly what TR4A uses.  Same diameter master and slave and are pedals.  Be sure not to over extend the adjustable push rod when installing or the required bearing to clutch cover clearance will be lost.

Peter W

[dwaters]

7 hours ago, BlueTR3A-5EKT said:

That setup is exactly what TR4A uses.  Same diameter master and slave and are pedals.  Be sure not to over extend the adjustable push rod when installing or the required bearing to clutch cover clearance will be lost.

Peter W

Thanks Peter, I’ll check the push rod.

David

[Trumpy3]

David.

I have used an Exedy Sports clutch kit (pressure plate, clutch plate, thrust bearing) on my TR3A for about 12 years with no problems. I am using a 2500 saloon box, no external return spring but an internal one. I use the original 2500 thrust bearing spigot and bearing. To do this you need to retrain the 2500 fork. Also utilise the center hole in the actuating leaver. I use all original hydraulics.

The clutch feels good with take up about 2/3ds off the floor. I am using a TR2 flywheel that gives me a total of about 13 lbs reduction in rotating mass. The only negative I have with this setup is when driving around town, you need to give it a few revs on take off to compensate for the lower rotating mass of the flywheel/clutch combination. This should not be an issue with the standard TR3A flywheel. It is interesting to note that the TR4/A with the diaphragm clutch has a heavier flywheel. Maybe to give the same total mass as the TR3A.

Brian