MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Which clutch brand?

I have used both Borg and Beck and AP on "B's"....Does it make any difference on MGA's?....
I see where Scarborough Faire sells the Borg and Beck at a great price.
Edward
Edward Wesson 52TD

No opinions on this?
Edward
Edward Wesson 52TD

I have some information on MGB clutches that should fit in the MGA but don't.
http://mgaguru.com/mgtech/clutch/ct_102a.htm

I haven't used an MGA clutch since the mid 90's. When I did use the MGA clutch, I never had to replace a pressure plate. Seems like those things are robust and last a long time, and they can be rebuilt.

For some years I was using generic 8-1-10 clutch discs. That means 8" diameter, i" hole, and 10-splines. It is a very common part between the mid 20's and early 60's, used mostly with 6-cylinder engines. You might find out the hard way that 8-1/4" disc works and 8-1/2" disc does not fit inside the clutch cover. You may also find the the paper laminated friction face can tear loose and jamb up the clutch, perhaps the first time you get aggressive with it. I have long since switch to using the major name brands, mostly with solid phenolic friction material.

There is another world of interest in competition clutch parts, good for racing, but not much benefit for street use.
Barney Gaylord

Barney
Are you saying that the clutches sold for "A's", are for "B's"?....
My car is a 1600, what size clutch should I get?
Edward
Edward Wesson 52TD

To fit a B clutch you need a B front gearbox cover, and the matching operating fork, and a flywheel machined to take the B cover locating pin pattern

The issue Barney quotes with the B clutch interference with the HiGear kit was me. It turned out that the casting shop used by HiGear had changed their casting method without telling HiGear. This meant that the new castings were sagging slightly and therefore the required clearance was missing. HiGear changed the design to compensate for this - I just had a long set of grinding and testing for fit before it all went together. I did get a partial refund as compensation, but it was a lot of trouble and I suspect others would have given up.
dominic clancy

No. The A and B clutches are different. The A clutch has a 3-arm lever arrangement to pull back the pressure plate. The B clutch has a diaphragm with multiple thin fingers to do the same job. The B clutch is thinner than the A clutch, and it uses three alignment pins instead of two.

To use the B clutch in the MGA you have to remove the alignment pins from the flywheel, then locate, bore and install three pins in the appropriate positions to accept the B clutch cover. Alternately you can install an early MGB flywheel (which is 8 pounds lighter like late MGA 1600-MK-II).

To mate the B 3-main engine to an A gearbox with MGA clutch you can use the MGA flywheel. That engine is a bolt-in.

To mate the B 3-main engine to an A gearbox with B clutch you need the 1962-1963 B flywheel (or convert the A flywheel with change of alignment pins). To mate a B 5-main engine to the A gearbox you need the 1964-1967 B flywheel. You can then use the B clutch, or convert the flywheel by change of alignment pins to accept the A clutch.

To use the thinner B clutch you need the gearbox front cover from any B 3-synchro gearbox 1962-1967, plus the B release arm and B release bearing. In all cases use the engine rear plate that matches the gearbox. For an A rear plate and a 5-main crankshaft you need to bore out the center hole in the rear plate to accept the B rear seal, and plug the drain slot in front side of the plate.

For your 1600 you can use either MGA or MGB clutch as you choose. With the i600 gearbox and B clutch there may be a slight interference between clutch cover and bellhousing around the 10:00 o'clock position. This depends on the gearbox case casting, and possibly on the manufacturer of the B clutch cover. It is cured by a little grinding inside the bellhousing at point of interference, not to difficult. This is not nearly as bad as the interference that Dominic ran into with the HiGear bellhousing for the 5-speed.


Barney Gaylord

I'm "assuming" (there's that word again), that a twin-cam gearbox is a 10 spline, like the ordinary 1600 gearboxes...Is that correct?
Edward
Edward Wesson 52TD

Yes, all Twin Cams had the 10 spline.
However you can never be sure what a previous owner might have done.

Mick
M F Anderson

As a side note do the B pressure plates weigh the same as an A?
gary starr

A standard B box input shaft is not 10 spline, It also has to be turned down to fit with an MGA crankshaft
dominic clancy

B pressure plate is lighter than the A unit.
B input shaft is 23-spline, same as the MGA 1600-MK-II. Use a clutch disc than matches the input shaft splines.

The early MGB with 3-main engine has same size spigot bush as the MGA. The 5-main engine has larger spigot bush, but you can buy an adapter bushing to bring it down to fit the earlier gearboxes.
Barney Gaylord

Barney - when you say that the B pressure plate is lighter than the A is this the same as saying the pedal pressure is lighter? I plan a swap to a B clutch when I next take my engine out and would not want the B clutch to be any heavier on the foot, my A (Mk2) is heavy enough that I finding quite tiring in traffic after long periods.
J H Cole

B clutch is lighter weight, but about the same pedal pressure. You should not get tired leg holding the clutch down in traffic, because you should not be holding the clutch down. Riding the clutch pedal wears out the graphite clutch release bearing.
Barney Gaylord

Exactly why I'm gonna be changing the clutch next week...
Either the pressure plate is weak, or the disc is worn, (or both)from someone riding the clutch (PO)...
Sadly, the car has less than 16k total miles, and only about 4 years since restoration.
Still driveable but barely ...Pedal 3/4 up before car starts rolling, even after bleeding slave.
Once rolling, car is a joy to drive , though.
Edward
Edward Wesson 52TD

Edward,

I would not be in a hurry to remove that clutch.
The system is self adjusting for wear in the disc and thrust bearing.
Does the clutch slip? A poor condition disc or pressure plate will give clutch slip.
It appears that you have a hydraulic problem.
You need to see how much travel you are getting at the slave pushrod.

Mick
M F Anderson

Mick
Hydraulic problem was my first thought, but we tested and bled the system, and all appears to be working right there....The clutch does seem to slip when changing gears, and I could swear I smelled burning clutch disc, but I can't be sure.
Only way to be positive is to pull the lump....I will change the clutch, throwout bearing, spigot bushing, and pressure plate , no matter what. I ordered a new hydraulic hose, just in case the old one needs changing.
(Even though I did not see any sign of swelling or collapsing...It's a good part to have on standby).
I will also look for leakage from the tranny front seal, and engine rear seal....Some leakage is to be expected, but not enough to ruin the disc...(after all that's why they have a hole and pin in the bottom of the bell housing)....
I'm probably going to have to reface the flywheel, as well...(hoping that it's not too bad).
Anyway, it's not something that I am looking forward to, but with these old-time cars, it's to be expected.
Thanks for the input
Edward
Edward Wesson 52TD

This thread was discussed between 29/05/2013 and 02/06/2013

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.