clutch2

LotusCarlton.co.uk

VXR8

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Clutch Release Mechanism and Bell Housing
I want to find a way of preventing the pin and fork seat from being exposed to all the dust
within the bell housing. I bought a new fork and a modified pin. I decided to mount a plate
over the face of the fork pin end which faces the clutch and flywheel. First thing to do was
clean up the mount face, ie grind away the cast lettering and generally deburr any casting flash.


New fork and modified pin as supplied.



Cleaned up.



Next cut and shape a plate to fit using M6 counter sunk screws, drill and tap the fork.

I had to re-shape the pin head because at full tilt the head would touch the cover plate, the
material removed served no function anyway.





This is the pivot pin seat in the fork, with just a small amount of lapping the actual seat contact
area seems very small, perhaps only about 1mm, I lapped this using a drill, and then polished
with brasso to give a bigger contact area.........not sure whether that was right or wrong thing to do
but it's done now ;-)

This picture shows the seat face of the original pin and fork, much bigger contact area
than the new pin and fork, glad I did this now as without grinding/lapping the contact
area was tiny.

The modified pin has a larger neck diameter, I will need to check that at full clutch pedal, the pin
neck does not foul the fork hole rim. This checks out ok.



Next was the other side of the fork, although it faces away from most of the dust, I wanted to give as
much protection as possible. This rubber boot was the only thing I could find, too big but something like
it will work. I have some rubber track rod end boots being sent to me as samples.

I still wanted some way of lubricating the mechanism every now and then as eventually the grease
would seep out, not too worried about that in itself, it should only fall to the bottom of the bell housing
(if I'm lucky ;-)
With a clamped type boot there would be no need to have to re-pack grease, but I have no easy way
of doing this, another plan forms...........

I'm thinking about installing a grease nipple into the side of the fork, but for this I will need a hole in
the bell housing to insert the grease gun filler tube.
I got hold of a second hand bell housing (thanks Paul) which looks original, it has a crack in the pin
mount hole which is very common.

I hope to have it modified to the same spec as pictured in previous page.

Another thing I noticed was that I think there should have been flat which mates with the pivot pin
flat, this had been crushed, probably because the pin was not in correct orientation, an easy mistake
as you can't see how it goes into the hole during assembly.

Viewed from inside with the fork laid in approx position, access looks ok.
I want to use an M5 45deg grease nipple, then just a very small hole from the fork thread breaking into
the pivot seat.




The clutch hydraulic pipe is secured within a cast/machined hole in the side of the bell housing, while
it was off, I removed half of it because then I do not need to split the pipe joint to remove and re-install
the bell housing, this of course means no need to re-bleed the clutch slave cylinder. I'll find some other
way of securing the pipe work.

Having second thoughts about the grease nipple, Graham C (cheers mate) has good idea, screw in a
straight bleed nipple and attach a tube which exits from the bell housing inspection hole that I previously made.
Seems a better idea, did have doubts about this myself, ie being able to tighten the 45deg grease
nipple to correct orientation might be a problem, there after if it broke off or became lose could be a pain.



Well, that is my plan, I've had projects go tits up before now but got to start somewhere;-) I have
an idea that something very similar has already been done but I've no idea who did it.

"The answer is out there"........seems a very familiar phrase ;-)

Well well, looks like I've been duplicating experiments again, I just found out it was Stefan Engström
http://www.lotusomega.se/public_html/mods/350clutchmod.htm
who has already perfected a method for greasing the pivot area, I might adopt this method and even
make another hole in the bell housing for access, a straight run tube looks much better.
Further, I just contacted Stefan, he tells me Gunther with Lotus No267 was the first to implement
the grease system, so I feel better that this is a tried and tested method.