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#1 Correct clutch?

Posted: Fri Feb 24, 2023 6:52 am
by No Quarter
I've worked on cars for 40 years, but only 2 had manual gearbox, my first car, a Spitfire, and a Pantera. So bear with me, almost no clutch experience.

The orig clutch was not part of the project I bought, probably thrown out 15 years ago, and the replacement, a new Borg Beck, I've read should be the right one, that's what I got from my vendor who knows these cars well (?). But when trial fitting, I've found 3 issues. Can you help me with what I need instead?

1. First picture, the tooth pattern on the discs, I would describe as square teeth, but the axle seems to want pointy Dracula teeth?
2. Second picture. The bolt holes at the white tape aligns with this clutch. But those holes are full of dirt and my guess is that they were never used. The holes at the blue tape looks used, that would indicate a smaller diameter clutch?
3. The alignment pins, there are three, they don't fit the Borg Beck I have, that requires two pins, and placed nearer the edge

I have reason to believe my flywheel is correct and clutch is wrong. Or? And can anybody point me to what clutch will fit, with smaller diameter, three alignment pins, and with "pointy teeth" so it slides onto gearbox axle?

I've read about clutches that are easier to press down on pedal, also read about race clutches, I don't want any of that, I want what's nearest to original. Thanks


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#2 Re: Correct clutch?

Posted: Fri Feb 24, 2023 8:23 am
by Simonpfhc
Hi Mikael,

The ‘valleys’ on the pinion shaft (you call axle) look a bit deeper that on the friction disc so that part of the profile shouldn’t really matter. Does it actually actually fit onto the shaft? The fit is very snug with almost zero movement.

The later flywheels were drilled for two sizes of clutch assembly. I didn’t think that applied to cars as early as 63. However, they are regularly drilled by owners wanting to fit the smaller clutch as they are easier to depress, which might be the case on yours. Either way, if you remove your existing dowels and fit new ones in the correct positions, your pressure plate should bolt up fine.

I would encourage you to get it fully balanced though.

#3 Re: Correct clutch?

Posted: Fri Feb 24, 2023 8:35 am
by mgcjag
Hi Maikel.......check the rim behind the teeth to your flywheel.......should have the engine number stamped on it...you will have to clean it up to see it.....Steve

#4 Re: Correct clutch?

Posted: Fri Feb 24, 2023 10:47 am
by christopher storey
There is a real possibility for confusion here . What your 1963 car should have is

a 3.8 litre engine

a 104 tooth flywheel

a 9 7/8 inch spring clutch if the engine number is up to RA5801 , OR

a 9 1/2 inch diaphragm clutch if RA5802 onwards

You certainly have the spring type clutch, which is most likely to be 9 7/8 inch diameter. I cannot see any incompatibility with the splines on the gearbox input shaft, but this is very easy to check by pushing the driven plate onto the splines. You should also check that you have the correct flywheel and not an earlier one with ( probably) 132 teeth

#5 Re: Correct clutch?

Posted: Fri Feb 24, 2023 11:34 am
by No Quarter
It has 104 teeth. Engine number (a 3.8 from a 64) is RA7502-9

#6 Re: Correct clutch?

Posted: Fri Feb 24, 2023 12:49 pm
by christopher storey
I think that the answer is that with this engine and flywheel , you need to use the diaphragm type clutch which will fit the dowels on the flywheel. It is in any event a much nicer ( although slightly less durable ) clutch to use , with very much lighter pedal pressure required than with the earlier spring type clutch

#7 Re: Correct clutch?

Posted: Tue Feb 28, 2023 4:52 pm
by No Quarter
Got a bit further. And yes, as some of you wrote, the disc did actually fit the shaft despite different pattern of teeth, did require a lot of cleaning and lithium grease

Flywheels on late 3.8s like my engine did have dual patterns to accept two different size cluthes, according to a book. So all in all I've chosen to use the 10" B/B, which is the original for my 63.

However, I need to remove the 3 alignment tabs/dowel pins and use new (2) pins. But how do I remove the old pins? Are they going all the way through the flywheel, there's a small "hill" on the opposite side, for all 3? I'm tempted to grind them off, but is there a better way?

#8 Re: Correct clutch?

Posted: Tue Feb 28, 2023 5:18 pm
by christopher storey
As I recall, the holes for the dowel pins are drilled all the way through, so if you take the flywheel off, you should be able to drift the pins out from the front side of the flywheel. However, I urge you to consider using the diaphragm clutch . It is infinitely superior in use to the spring type clutch, and diaphragm types became used in all cars from the mid 1960s onwards. Your car is not in any event original because it has a later engine than would be expected

#9 Re: Correct clutch?

Posted: Wed Mar 01, 2023 12:40 pm
by flatfloor 3.8
No need to remove the flywheel just turn it to where the rear of the pin is accessible where the starter motor bolts on and drive them out with a punch. Fully agree about using the diaphragm clutch.

#10 Re: Correct clutch?

Posted: Wed Mar 01, 2023 4:00 pm
by christopher storey
flatfloor 3.8 wrote:
Wed Mar 01, 2023 12:40 pm
No need to remove the flywheel just turn it to where the rear of the pin is accessible where the starter motor bolts on and drive them out with a punch

Ah, yes, silly of me not to realise that much quicker - and easier - way of doing the job! :bigrin: