Sprite clutch adjustment

Not sure about this combination but you should make sure that the pivot is at the correct point. Its no good using adjustment at the end of the travel as this will make the clutch pedal heavy.

Yes, and the 9-spring will be heavier as well.

Difficult to tell without separating the box and the engine (which I am about to do). I see that the 948 and 1098 forks and release bearings have different part numbers. I had kept everything to 1098 standard except the clutch, but it seems I was wrong to do that. Oh well, back to the garage.

I'd say you'd need the 1098 flywheel and clutch. Unless the 1098 clutch fits the 948 flywheel. Isn't it a diaphragm clutch by then?

I have pulled it out of the car again now, and done a lot of fiddling. I tried slipping a 12" lever over the end of the fork to see if I could get the clutch to disengage. It just seems to come to a solid stop, although maybe I'm not strong enough! The fork is not at the end of its travel when the release bearing is contacting the clutch. I tried an old 6-spring clutch and got the same effect. Also tried taping some spacers to the clutch release plate, but it still won't work. These are such simple mechanisms that I can't understand what's going on - whatever is wrong should be obvious.

In answer to Dave, I would have to use the 1098 flywheel for that clutch, and in any case I sold that!

Yes it's the right way round. One odd thing. The release plate on the

I have done some further diagnostics on this problem. Here is what I did:

1. Put an old clutch in - this works OK.
2. Freed up the release fingers on the 9-spring - they were stuck after years in storage (the pressure plate is totally unworn, so I'm sure it has never been used).
3. Installed the 9-spring without the driven plate - this releases OK.
4. Installed the 9-spring with driven plate. This won't release.

I have noticed that the release plate on the complete 9-spring when installed is about 4-5 mm nearer the engine than is that of the old

So the problem is not primarily related to the release fork. I have experimented by `adjusting' (ie bending) this to get the geometry right. I have checked through the hole in the bell housing and the geometry is right. There is something wrong with this pressure plate, and I think it has not been set up correctly.

I should be able to post some pics at

No doubt it is. Clutches are designed to work with specifically shaped flywheels. Sometimes the flywheel is flat all the way across so the pressure plate locates at the same level as the friction plate. Sometimes the friction plate surface is recessed compared to the pressure plate surface, either by just a gnat's willy or in the case of many VW and other clutches by half an inch or more.

As you fit a pressure plate and tighten the bolts it pushes the plate disk away from the block and the release fingers pivot about their fulcrums and get pulled nearer the block. If you have a pressure plate designed to go on a recessed flywheel and are using it on a flat one it will run out of travel. The plate can't release because it is jammed tight against the inside of the housing and the release fingers have no more travel although they will bend in further if you operate a release bearing against them. That ties in with your other comment that the fingers are several mm closer to the block than on the old plate.

So I suspect the pressure plate you are using is the wrong one for the flywheel or vice versa. You may be able to solve it by machining something off the friction plate surface of the flywheel so the release fingers don't move so far on assembly.

-- Dave Baker - Puma Race Engines

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I have the 1098 release bearing. Also of course I am not using the 948 remote housing as there is no need. Here is a further update:

I adjusted the release fingers to try to achieve a compromise between the clamping pressure and the height of the release plate. With the recommendation of about ¼" gap between pressure plate and flywheel before doing up the screws, the release plate was hopelessly too near the flywheel for the fork to operate at a sensible angle. Even after adjustment of the fingers the release plate position still isn't ideal, but I decided to take a chance and put the unit back in the car. The clutch now operates, but my God it's heavy! It should only be 50% heavier, as it has 9 yellow springs and the standard one has 6 yellow springs.

I have decided to continue with the rebuild and come back to this later. If the clutch is no good it's very quick to heave the unit out again and fit a better one. I'm getting good at this!

One final question. I anticipate the output of the engine will be about 75 bhp at the flywheel (according to Vizard's book). Will a standard clutch handle this OK? If so I will forget the 9-spring.

It's not the BHP but maximum torque that matters, and I doubt you'll get any more out of a naturally aspirated engine than the 1275 delivered. I had a 1275 Midget which I drove pretty hard, but the clutch survived well.

I did quite a few engine swops on 'B' series cars - usually involving fitting 1800cc units to earlier models - and never found a problem like yours. Can't see the A Series being any different.

IIRC, I usually used the flywheel off the original engine, though. And gearbox mounting plate.

I would suggest as you have uprated the engine you use the heavier duty clutch as you are likely to drive it harder. Depending on what you have done tuning wise you may not increase max engine torque or may increase it a bit, but you will have raised the point of max torque to a higher RPM so increasing HP. HP being related to torque and RPM. The standard one may take the torque although I think they were marginal as standard, the coil spring clutches clamping load decreases as the clutch plate wears, whereas a diaphram clutch maintains a much more constant load. It is fairly easy to fit the 6.5" 1275 diaphram clutch, IIRC the bolt pattern is the same but it has 3 instead of 2 locating dowels. This does require machining the new dowel hole and getting the flywheel balanced would be a good idea. I went this route when building a 1420cc engine,