Clutch driven plate

[David Morris]

Hi All,

Can someone please advise us on the correct driven plate to use? In collecting together clutch plates to use on rebuilt Javelin engines, we find we have two versions of new driven plates. The big difference seems to be the length of the central splined boss. On one version the length of the boss relative to the outer edge of the linings is symetrical, projecting about 12mm on both sides of the plate. On the second set of examples, the length of the boss, again relative to the outer surface of the linings, is approximately 7mm on the flywheel side and approximately 18mm on the pressure plate side.

I have a recollection that someone has discovered this difference before? I believe it leads to difficulty in clutch operation and we would like to fit the right version, to avoid problems after the engine has been installed. Also, some driven plates have six springs fitted and others have four. I also have a memory that one version was termed by Borg and Beck as their 'de luxe' model? Again, does this make a difference?

Many thanks,

David

[Srenner]

The number and color of the springs affect the "harshness" of engagement when the clutch is released. Generally, more springs yield a softer grab, fewer springs a stiffer engagement. A racing friction disc has no springs. Collar length can be measured by mocking up the parts prior to installation.

Good luck!

[Robin Fairservice]

For my 1950 Javelin, the splines on each side are different lengths. The workshop manual has a section through the engine which shows which way round the clutch goes. The clutch is a standard Borg & Beck clutch and it showed up in the manufacturer's catalogue. Mine was rebuilt by a local brake & clutch company which usually works on large logging and raod transoprt trucks!

[Keith Clements]

The original is asymmetric. I have tried others but these did have a problem with the lever hitting the rotating plate. Whether this was caused by the symmetric splines I do not know.
I suggest installing and rotating to check any fouling.

[David Morris]

Dear Keith,

Many thanks for this. We have both types and will now probably use the asymmetrical one. As Robin says, the sectioned engine illustration in the handbook does show the central bosses with different lengths. The symmetrical one I have states on the Borg and Beck original box that it is for a Javelin/Jupiter, but I now doubt this!

Thanks again. All the best,

David

[jowettgeoff]

The ones I've used have always been assymetrical, and have been marked 'flywheel' on one side, indicating which way round they go. Despite this, I managed to assemble one back-to-front, and spent a miserable week doing the Pirelli Classic Marathon with a severely slipping clutch. Not good in the Alps and Dolomites!
G McA