I am not happy with the position of the clutch arm in relation to the slot in the bellhousing, looks too far forward! I have a 33mm face to pivot centre release bearing on a new aftermarket 9 1/2" diaphragm clutch, all synchro gearbox original to my 1968 240, original flywheel from 240 redrilled for larger clutch, new clutch had three dowels,
how does it compare to yours!
Looks wrong. The lever will move forwards as the friction wears but you won’t get any margin after full release like that. If it does release fully you might just about get away with it but I’d shoot for more central/thicker release bearing?
I had the same concern when rebuilding my 3.4L engine.
First I checked that the clutch would release using a simple lever - it did. It only needed a very small rearward movement for the dis-engage.
I fitted the long self adjusting slave cylinder and all seems well after a couple of thousand miles.
Here’s the picture from the rebuild
I did try with a lever and it did not seem to disengage, I will try again, I have not been able to find a deeper bearing, I could straighten the bend in the release arm but there is always the law of unintended consequences to take into account!
A Jaguar clutch is not something you want to get wrong!
I spent today stripping the rear callipers… all day!
That looks OK, the angles are different. In practice you don’t need a lot of movement at all because your releasing a clamping pressure rather than dislodging anything by a great distance. The new disk and some moving parts will also bed in a tiny fraction. I wouldn’t bend the lever. A tyre lever or heavy screwdriver will move it and if you put the gearbox in top gear and can turn the output flange by hand when the clutch is released by hand it may be fine. It’s not something you want to do twice though…
My bearing is around 33mm face to pivot centre, I may have bought a 40mm one from Ebay, may be from an E type, genuine Jaguar, or I may have bought a carbon paper weight! will let you know!
paper weight, 33mm not 40 as quoted Grrrrrrrrrrrrrrr
My 420 conversion clutch fork position looks about the same. I think it’s fine. The clutch will wear and move arm forward. The release bearing wear will move arm back. Should balance out if proper driving techniques are used.
I removed the gearbox today as I could not get the clutch to clear when using a pry bar to operate the lever, I found that the diaphragm was over compressed, it did look a little strange when I installed it, pictures show it without washers, lever position is with washers, anyhow I re-installed it with 1.5mm washers between the cover and flywheel and it all looked a lot better, and when I tried the pry bar the lever moved and the clutch cleared, and the lever looks a lot happier, the question is what to do now, I think I will use some oval washers (for a larger surface area) and leave it at that,
Something’s wrong. Possibly the friction plate back to front? Non- matching parts? There is no way you need to space the cover from the flywheel - the clutch will start slipping in no time, IMO. Did you buy a 3-part clutch kit?
A three part clutch, plate is the correct way round, It has a normal feel to it now, without the washers it is over compressing the diaphragm, looks wrong, feels wrong when you bolt it down and does not clear,
something is wrong, it is as if the flywheel should have a stepped surface but the opposite way to any I have seen, usually a raised friction surface (not on a Jag) never seen a flywheel with a recessed surface except from wear, mine is flat,
Pat
Your call Pat - you’ve got the bits in front of, and the joy reworking it if something doesn’t work out. I’ve only ever seen single plate clutches fitted to flat faces as you say. The action will certainly feel lighter because diaphragm springs have an ‘over-centre’ effect, but this presumably means less grip too?
Just runs against the grain to fit washers under the cover rather than under the bolt head, so I coukd never settle for that. Have you called the maker or vendor?
This is just wrong. Can you show photos of the three pieces ?
I will strip it again tomorrow and take more pictures, I believe the grip is correct with the washers, on a “good” clutch adding washers would indeed reduce grip but basically I had way too much without, I will contact the vendor but I bought it a while ago and it has been drilled to balance it, that may cause return issues,
Sideways view of the release carbon bearing would be good and clutch cover depth caliper reading face down from a flat surface to the face of the diaphragm release collar,
Here we go…
distance the friction plate sits above the mounting face of the cover. so the amount of bite. but this over compresses the diaphragm so deduct the washers and what works is 3mm bite.!
distance from friction face to the face of the release collar,
thickness of the centre plate
the release collar is level with the cover when assembled with the washers,
My selection of bearings, all around 33mm face to centre of the pivot, left to right, the one I had fitted, the chipped one that came with the clutch, a new Jaguar one I just got, the worn one from the original 240 clutch.
I had one 240 model,
she work with diaphragm mechanism, and with one high release bearing
only with the high!.
Never touch the steel fork.
My still new KT9702 clutch kit has following dimensions:
Those 2 would indicate that (no forces applied-just gravity) clutch plate would be protruding 3.9mm beyond pressure plate mating surface, i.e. before tightening the bolts.
Separately bought release bearing C235752 is 33mm version (surface to centre=axis).
Edit: I retried protrusion masurement with clutch plate in the pressure plate. Measurements vary every bolt hole, from 3.5mm to 4.2mm, so average may be a bit lower than inital 3.9mm, more like 3.8mm.
Hard to determine with no pressure applied to assembly.
I believe this is the important measurement to compare, how much bite / crush / pinch is applied to the centre plate when assembled, if anyone else with a spare 9 1/2" diaphragm clutch can check the distance the centre plate sits above the cover mounting surface it would be a great help, I have several similar new BMW clutches and will measure a few of them for comparison,
I have several other threads running! I think the restomod thread has been updated with me finding the left side lower chain guide laying in the oil pan! I managed to remove the front cover and have ordered a new guide, whilst I had this lot apart I thought I would tackle another thing that had been bothering me, my engine is from an XJ6 and so had the larger water pump impeller, I tried to remove the one from the XJ6 water pump and fit it to the new Mk2 pump but the impeller broke onto several pieces, I just fitted the Mk2 pump as it would probably be ok, I found that you can buy an XJ6 size impeller for little money so have ordered one, hopefully I can make it fit the Mk2 pump,
