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Clutch Bearing

Posted: Tue Aug 03, 2010 7:41 pm
by Bevan IMP
Can anyone advise on the best type of clutch bearing which will fit onto the standard clutch fork.

I am looking for a roller type which will replace the standard fixed bearing to be used in conjunction with a competition clutch.

Any help would be appretiated.

thanks

Jonathan

Re: Clutch Bearing

Posted: Tue Aug 03, 2010 7:51 pm
by ganderson888
Hi Jonathan

You could speak to Colin or Graham Cashmore (Heathrow ACO) either by phone or at the National this weekend as they recommend roller bearing release bearings on their 930 Conversions.

Re: Clutch Bearing

Posted: Tue Aug 03, 2010 9:13 pm
by aldrin
Bevan IMP wrote:Can anyone advise on the best type of clutch bearing which will fit onto the standard clutch fork.

I am looking for a roller type which will replace the standard fixed bearing to be used in conjunction with a competition clutch.

Any help would be appretiated.

thanks

Jonathan
There was a VW bearing which would fit with a bit of reshaping, Beetle or air-cooled transporter
I found it by taking an imp clutch fork to a VW specialist, can't remmeber the name but they were
taken over by German French 'n' Sweedish , or Europarts.

Worked fine with a bit of copper grease on the face to help with 'off centred ness'
and a 1/4 drive socket up the slave cyl (behind the piston) to pre load the position of the clutch arm
I also had a MG midget centre plate (slightly larger than an imp one, with sprung centre)
and a 'borg and beck' cover Ithink,

There are a couple of implementations of modern concentric bearings, ford fiesta I think

Re: Clutch Bearing

Posted: Tue Aug 03, 2010 9:33 pm
by Bevan IMP
I found this picture on the forum

4519

I will pm moose to see what bearing this actually is.

Re: Clutch Bearing

Posted: Wed Aug 04, 2010 6:59 am
by Lotus-e-Clan
aldrin wrote:
Worked fine with a bit of copper grease on the face to help with 'off centred ness'
and a 1/4 drive socket up the slave cyl (behind the piston) to pre load the position of the clutch arm
Does the 1/4 socket stop the roller bearing from rattling against the thrust pad and shaft? :)

If so, I 'll try it 'cos mine rattles very loudly on tickover with the clutch disengaged.

I was going to fit a spring between the arm and roller bearing as others have done but I didn't take the time to lash one up and now i regret it. :roll:

Re: Clutch Bearing

Posted: Wed Aug 04, 2010 6:39 pm
by aldrin
Lotus-e-Clan wrote:
aldrin wrote:
Worked fine with a bit of copper grease on the face to help with 'off centred ness'
and a 1/4 drive socket up the slave cyl (behind the piston) to pre load the position of the clutch arm
Does the 1/4 socket stop the roller bearing from rattling against the thrust pad and shaft? :)

If so, I 'll try it 'cos mine rattles very loudly on tickover with the clutch disengaged.

I was going to fit a spring between the arm and roller bearing as others have done but I didn't take the time to lash one up and now i regret it. :roll:
It was a good while ago I cant remember if it rattled,
the main problem was the relaese fork was moving away from the clutch
meaning the pedal had a bit of slack to take up,

An adjustable push rod could have taken it up but that maybe would have allowed too much travel and risk pushing the release bearing too far into the clutch.

I think the imp slave cyl had a circip to stop the piston poping out, and the 1/4 drive socket was small enough to drop
down the bore and limit the travel in the other direction.

Most roller release bearings are designed to run in (almost) constant contact and carbon ones need to have clearance.
normally only relevant to adjusting cable clutches.

I think most hydraulic roller systems have a pre-load spring.

There was something else about measuring the disengagement distance required for the unworn clutch,
then setting that as a maximum travel.

It took more than one master cyl of fluid to disengage the clutch.
So I had an assistant slowly depress the clutch as i checked for disengagement ,
clamping the hose to allow a second pedal application.

and packing washers on the slave cyl mounts.

you could probably lash up an external spring to hold your clutch arm,

just looked again at your post,

your rattles with the clutch DISENGAGED ? as in your foot fully down on the pedal ?

if so you need a bit of copper grease (or another grease which wont fling onto the lining )
as this rattle is probably due to the arc of the clutch arm movement meaning the release bearing and clutch are not
concentric with each other.

the releae bearing I used was thicker round the outer housing with a groove round the outside, like two radial flanges.
part of one of these had to be ground away to let it fit the fork,
so there amount of movement was limited and the release bearing could not come into contact with the shaft.

OR if you have too mutch travel you may be pushing the centre of the cover into the centre plate,
how far 'past' disengagement does you clutch pedal move ?

Re: Clutch Bearing

Posted: Wed Aug 04, 2010 8:25 pm
by Lotus-e-Clan
Sorry my bad as the youf say these days!

I meant it rattles with the 'box in neutral, not clutch disengaged D'oh! :oops:

I'll look at fitting an external spring as the roller bearing rattle makes people think my engine building skills are suspect. :cry:

Re: Clutch Bearing

Posted: Thu Aug 05, 2010 10:48 pm
by aldrin
Lotus-e-Clan wrote:Sorry my bad as the youf say these days!

I meant it rattles with the 'box in neutral, not clutch disengaged D'oh! :oops:

I'll look at fitting an external spring as the roller bearing rattle makes people think my engine building skills are suspect. :cry:
When the release mechanisem is engaged, the clutch is disengaged ,

engage the release mechanism !

all gets confusing on a text medium.

I think the extra weight of the roller means the release bearing tips over on the release arm when it is
, engaged, disengaed , ....... um when your foot is not pushing the pedal down.

Be careful not to preload it too much with the spring as chances are (due to the arc of the relese arm) it will not be
aligned axially with the clutch, so it will grind against the cover plate slightly.

Re: Clutch Bearing

Posted: Fri Aug 06, 2010 9:57 am
by moose
the ones in the photo that i have made are nearly the same size as the carbon release bearing just slightly wider in the housing so the fork has to be ground out to accept it and then re-enforced on the back side to put some strength back into it (i did this to my clutch forks anyway for rallying) the face of the bearing is about 2 mm further out from the arm compared to the carbon one, i made no other alterations to any of the clutch system and mine never rattled i think this is due to the bearing not sticking out towards the clutch in comparison to other systems i have seen, also the extra 2 mm does not seem to effect the arc. From memory the bearings were £35 and the arms can be cleaned, ground, welded and painted in about an hour if you have the kit to do it. Anybody wanting more pics or info e-mail mike@symtechracing.com

regards

Re: Clutch Bearing

Posted: Fri Aug 06, 2010 11:09 am
by aldrin
moose wrote:the ones in the photo that i have made are nearly the same size as the carbon release bearing just slightly wider in the housing so the fork has to be ground out to accept it and then re-enforced on the back side to put some strength back into it (i did this to my clutch forks anyway for rallying) the face of the bearing is about 2 mm further out from the arm compared to the carbon one, i made no other alterations to any of the clutch system and mine never rattled i think this is due to the bearing not sticking out towards the clutch in comparison to other systems i have seen, also the extra 2 mm does not seem to effect the arc. From memory the bearings were £35 and the arms can be cleaned, ground, welded and painted in about an hour if you have the kit to do it. Anybody wanting more pics or info e-mail mike@symtechracing.com

regards
My car had no imp bits in the clutch,

MG midget centre plate, and unidentified cover, and a VW roller bearing

So that probaly explains why it needed 'adjustment' to make ot work :P

A bit of copper or graphite grease on the face of the bearing is probably still a good idea,

As the arc of the release arm means it is only fully aligned ,it at all, at one or possibly two points on its travel,

Can you remember what your bearing came out of ?