7 replies to this topic

[johnnysti]

Hi all

Since fitting my new engine ive done nearly 600 miles in it bedding it in and staying below 4-4500rpm.

Last night i set the gap on my clutch arm thing to 20thou with a feeler gauge and have just gone to check it (after a 50 mile drive) and the gap has gone and the arm is resting on the adjustable bolt.

Is it ok to re-set it to 20thou again? Is it just finding the right spot or is there a problem with it? Its finding the gears fine.

Will it eventually set itself as i keep adjusting it?

Thanks


Johnny

[mini13]

Hmmm,

thats rather quick for the clearance to vanish...

sure you did the lock nut up?

you are checking it with the return spring removed?

have you done any hard starts for the first ime on this clutch?

I'd reset it and keep and check it again and see if its moved again.

[johnnysti]

Thanks for the reply mini13.

The spring was still on when i set the gap last night. Im still taking it easy on the engine at the mo so havent gone to mental with it as yet.

Do you think i will need to keep doing the gap untill its decided that its set? I did do the nuts up tight last night but like i said the spring was still on. Is 20thou the right size gap?

One other thing is that when i un screwed the nut the arm didnt move towards the engine very much at all from what i could see.

Johnny

[mini13]

Ok,

to clarify,

Do you mean the big nut on the end of the engine or the small 7/16 bolt that pushes against the inside of the arm?

[mini13]

when i adjust a clutch I...

1) remove the spring on the master cylinder to clutch arm.
2) push the clutch arm away from the engine to remove any slack.
3) with the slack still taken up measure and adjust the 7/16 bolt as necasary.

It is possible that a new clutch plate can take up the adjustment, as the new plate beds in the pressure plate will be allowed to move away from the engine toward the flywheel, this in turn pushes the release bearing away from the engine, which inturn pusses the arm toward the engine taking up the 20 thou on the 7/16 bolt.

20 thou isn't a great deal anyway but if you look at the leaverage ratio on the clutch arm you'll see that the clutch only needs to wear about 8 thou to take up that 20 though at the 7/16 bolt

[johnnysti]

Ok,

to clarify,

Do you mean the big nut on the end of the engine or the small 7/16 bolt that pushes against the inside of the arm?

Sorry. I mean the small 7/16 bolt.

What i cant get my head round is if you push the arm away from the engine, how do you know what to set the gap to? If you take up the slack and then set a gap with it pushed away, when it returns under load from the sprin, it will be resting on the small bolt and not haf a gap.

Edited by johnnysti, 09 March 2007 - 06:50 AM.

[mk=john]

The gap is essential, because, if you think about it, when the clutch pedal is released and the engine is running (in any gear), the release bearing must not be rotating. This 0.5mm gap allows a clearance between the bearing and the clutch assembly because the clutch return spring pulls the arm toward the engine, and hence the release bearing away from the clutch.

Only when the clutch pedel is depressed and the clutch arm moves out, the release bearing then touches the clutch assembly and therefore rotates.

The only things I can think of why your gap is diminishing quickly, could be the spring (the one within the clutch friction plate) is damaged and it has been permanently squashed. But I doubt this very much. or, there is excessive wear in the clutch cover clevis pin or the clevis pin hole allowing the arm to slightly shift position.

I do doubt these, but stranger things have happenned!

John

[mk=john]

I notice you said in an earlier that you checked and set the gap with the cutch return spring in place? This is wrong, you must always unhook the return spring when setting the gap.

Tha haynes manual is reatfor step by step procedures, but where the manual falls over is that it doesn't explain WHY you set the gap with this method!

Just to explain again, with the spring in place and your foot off the clutch pedal, the clutch arm is pulled toward the engine so the arm rests against the small stop on the clutch cover. (therfore there is a slight gap between the rotating bit of the release bearing and the clutch assembly).

Now, with the clutch return spring removed, if you pull the clutch arm away from the engine as far as you can, the release bearing actually hits the clutch assembly. So, when driving the car and changine gear, the clutch arm is thrown out, hence the release bearing rotates while pushing against the clutch assembly.

The gap is essential, because whenever the clutch pedal is release (Ie, your foot off the pedal) there should always be a small gap between the release bearing and the clutch assembly. (e.g. you dont want the clutch bearing rotating when driving on the motorway, as it wont last that long!!!!!)

The 0.5mm gap is this value and is the optimum. It gives just enough clearance between the clutch release bearing, and at the same time is not too much so that the clutch has too much slack.

John