I'm after some advice....

Background info:

I have just got my car completed and on the road. Engine (Honda S2000) was only 11k on the clock but I believe it was a replacement at some point prior to be purchasing it (with the gearbox) so I don't know how old the clutch actually is.

When fitting into my kit, I had to separate the engine and gearbox to fit. A friend commented on my clutch saying it looked brand new (!) so I thought I would leave it in.

Having driven the car a little prior to passing IVA, two rolling road sessions and 100 miles on Saturday I thought it felt absolutely fine. Sunday morning did another 60 miles even faster than Saturday and a bit more aggressively too. Left the car all of Sunday afternoon and came to drive home (35 miles) to Derby.

The Issue:

After 1 minute I was doing around a steady 40-50 down a country road and accidentally hit 1st not 3rd when slowing down for a railway crossing, realised my mistake pretty quick and went back to a higher gear.

Not long after this I noticed difficulty pulling off even gently in a higher gear, and certainly couldn’t pull off at full whack in low gears like I could in the morning or on Saturday….

I managed to feather the throttle to get home and took plenty of time to build up speed. The mist helped as everyone else was going slow too. It was okay driving if I wasn’t trying to accelerate hard but too much on the throttle and it would rev up without the wheels spinning faster (or the car going faster)

Thoughts:

So..my current thoughts are:
1. I have ‘killed’ the clutch and it is glazed beyond much further use.
2. I have glazed the clutch but it may be ‘repairable’ in some way?
3. I have been told of a similar issue in the same car (GBS Zero) with the same engine (Honda S2000) where slipping occurred during a big road trip and it was thought to be heat generated, so the car was run with the tunnel tops off to let heat out and the issue went away!
4. The clutch could be so new that in fact it was only just fitted before I got the engine and it’s still in the bedding in stage?
5. Running out of other ideas…suggestions welcome!

Thanks all. Any suggestions, tests to try or general advice greatly appreciated!!

Check if there is any spare movement of clutch arm when stationary if not you need to adjust the cable to leave s small amount of slack
If hydraulic then check movement of slave if integral to the bell housing bleed it
All these steps can be done before pulling the box out

Thanks Paul(?)

It's hydraulic and I did bleed it the other day so I could have left some air/got some air in there.

I'll try and check over the system to ensure its bled and working as it should be.

Odd that it would slip as I Rev but not slip when gently accelerating? Or could that still happen with a poorly bled system?

Cheers

The clutch pedal feel hasn't changed?
ie if it has gone soft the "fingers" may have lost their tension, but that used to be a problem on cheap clutches a few years ago, thought it had gone away. But if a cheap clutch kit has been fitted (often done to save money if a car is likely to be sold etc, or if buying on price) it is a possibility.

I don't recall it having changed but I'm planning to try a short drive tonight to see if the problem is still there and I'll check anything that is suggested in this thread.

So I will check the feel and also try and work out more accurately how the slipping feels and when it occurs etc. May help work out what is wrong.

Thanks

Can you check the release bearing to clutch fork fitment is ok and has not dislodged?

I don't think I'd be able to see the release bearing very easily but I could remove the slave cylinder and try to look through the gap with a torch....

What master cylinder are you running, is it after market or standard Honda unit?

Is the plunger from the pedal to the piston being allowed to come all the way to rest position? Is their free play in the pedal as you may be holding a very small amount of hydraulic fluid back and it gives the same affect if your riding the clutch all the time.

I doubt if selecting the wrong gear on a down shift would do any damage to the clutch unless it grabbed so hard it has broken off part of the lining and its not allowing the friction plate to sit flat now.

Hi,

Running an aftermarket Master and stock Slave. The Master is the same bore as stock. I'll double check the plunger but I am sure the pedal can be pushed in gently before plunger engages...if not I can wind the thread in a little?

On your final point, I agree, but if it had broken, and wasn't able to sit down, surely I wouldn't be able to get any drive at all? unless the broken peice still provides some resistance/friction and allows a low torsional force before slipping.

I'll certainly check the M/S movement and ensure the plunger has some slack.

Cheers,

Slightly off topic but you'll want to keep an eye on the engine. Over revs on F20C engines can apparently kill them, particularly the valve gear and reportedly can spin main bearings. When your clutch is fixed take it easy and listen out for any strange noises from the engine.

Cheers Wylliezx9r, I'll take it nice and easy and not wear a helmet this time so I can listen out for any noises.

Fingers crossed it's okay as it was only a split second but I have been well warned not to try and extend the red-line limit. A friend went up to 12k and that killed his eventually as he was going around tracks using all top end revs.

So, I have been down to the garage and taken a look at the clutch pedal.
It seems since bleeding, the pushrod is now applying pressure on the pedal and not relaxed when the foot is off the pedal.
It was free to move a mm or so prior to the last time I bled the system so never thought to check.

Looks like there has been a little frettage of the pushrod on the end seal of the Master Cylinder and it has also been slightly bent:



I have ordered a new master cylinder as it is more economical than purchasing a pushrod on it's own. (It'll do for spares if needed in the future).

So I am now hoping that when I fix that, the issue of a slipping clutch will go away......that's the thought anyway!

I can only assume that the clutch wasn't able to 100% engage and thus as I applied the throttle, the pressure plate was able to back off enough to allow slippage.


Please correct me if you think this isn't correct..I'll still check other parts of the system too as a matter of course.

Thanks!

Looks like you have found it, that fits in with the symptoms.

It may also be you have too much travel, consider an adjustable stop on the pedal to avoid over extending and bending the rod.

Looks like that's it.
The thread title rang bells with me as I first fitted an "F1" "uprated" clutch to my s2000 box, and it lasted all of 250 miles before dying a death. Hopefully not your problem though.

quote:

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Originally posted by z2000

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Sorry poorly timed photo, I had loosed off the lock nut ready to remove when I decided to take a photo to show how bent the pushrod is.

Unfortunately the clevis I chose is a bit small so if the pedal decides (or the Master Cylinder pushes it!) to go further forwards, the clevis fouls on the pedal and thus you get the bending.

A simple fix will be to fit a larger clevis but I think I also need to shorter the pushrod even more ( I had already shortened it before).

Hopeffully it's all just a simple mistake of not checking the slack after bleeding the clutch again and adjusting this will bring the normal clutch feel back and remove the slipping!

Thanks for the help - will update after the weekend when I have had chance to fix.

It looks like the push rod bent because you've mounted the clevis too far into the pedal and it's bottoming out.

Either move the hole, remove some pedal or fit a longer throat clevis, but don't just rebuild what you have or it will do the same again.

Yeah you are spot on there indykid. I'm condiering a larger clevis but that'll mean the pushrod needs to be shorter and I don't want to run out of threads or limit the amount of pushrod which can go inside the Master Cylinder.

I'll see if I could fit a new hole in, I currently just use the existing/standard hole which came with the pedal.

Cheers

Cut a notch, with a Dremel, in the pedal at the contact points?

Yep, that also works well, I have seen a lot of people do that.

I shall take another look next time in the garage and see if cutting a notch wouldn't get too close to the pivot hole etc.

Cheers

Update from last night; I decided to try and straighten the pushrod, then wind the clevis further on.

I manged this and then refitted; tok the car for a drive and the clutch has stopped slipping.

It would appear that all I need to do is fit the new pushrod I have arriving this week and adjust it shorter than before along with the above mentioned notch to prevent any fouling of the clevis on the pedal.

Fingers crossed that's all the issue was.

Thanks for all the help guys!