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concentric clutch

tom horse

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Does anyone have any experience of fitting a concentric clutch cylinder to a type 9 gearbox in a Spitfire?

 I've just fitted this set up to my Spitfire and sometimes  the clutch doesn't release when moving off. The cylinder seems to jam on the clutch pressure plate.

 It's fine when changing up or down the box but it frequently jams when moving off. It releases if you increase rev to around 4000rpm of when you switch off the engine.

 Does anyone have any idea as to why this happens?



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Had an issue with mine. turns out the gearbox plate was machined wrong and that meant it wouldn't seal. Ho hum. Now sorted,  gearbox will be fitted tomorrow. ( Been left to see if it leaks, results encouraging)

What bearing are you using? I think you need something with a curved face  where it contacts the cover? Assuming you are using the STD spitfire clutch. Most of the kits seem to use a  flat faced bearing, which may be the issue?

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this may be completely wrong but ----

on my TR4A I had the dreaded clutch judder (aka ratchet clutch)

This in my case was caused by the clutch diaphragm fingers being on a different centreline to the GB extension nose that the release bearing slides on.

When you depressed the pedal the CRB would slide forward and slightly cock over onto the new centreline. When you lift the pedal the fingers pushed the CRB backwards.

Th CRB would try to slide backwards but because it was cocked over would jam on the GB extension nose (wear marks to show this). Eventually vibration would release it with a mighty kick.

It would happen with no revs as the fingers did not spin it onto a new centreline.

I found that my splined GB input shaft and the GB extension nose were not concentric


Check everything.

The TR4 never had this issue as it has a flat CRB and did not spin into a new centreline



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 Thanks for all the answers.

  I had a feeling it was because the bearing I'm using is flat where as the original is curved.

It is central with the clutch plate as I made the mounting  on my trusted Myford and doubled checked, my double check  which was doubled checked by the lad before putting it all together.

 Well it's engine back out again for the (insert big number here) time and a trip to the local motor factors where I hope I can find an assistant willing to look through his stock for a suitable bearing, unless anyone on here knows what bearing would work.

 In the meantime I'll see if I can graft the original bearing onto the concentric cylinder and give that a try.

On a brighter note the  electronic fuel injection seems to be working, which has the added advantage of being able to limit the revs while the engine is run in. 

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