HPC Clutch drag

[mark not max]

Found it very difficult to select 1st this morning. Went for a blat and generally so long as the car was not stationery everything seemed fine. However, this evening reverse is making a crunching sound and again 1st is very difficult to select.

 

I am told this amounts to clutch drag. I would be grateful of a list of items to check before arranging for the engine to come out to inspect/replace the clutch.

 

If the clutch is to be replaced should I replace the standard clutch or fit an alternative?

 

I would appreciate your thoughts

 

Mark

[Nick Chan]

Has it only recently started with this problem? Assuming you have a cable clutch, is it possible the adjustment nuts have come loose and need attention? If they are loose, wind them closer to the pedal box. Try 5mm or so and see if this makes a difference

[Foxy Smith]

Hydraulic or cable clutch?

[mark not max]

Nick - thanks I shall check.

 

Foxy - cable.

 

Regards, Mark

[Dickie Normuss]

Mine's done this for as long as I can remember irrespective of set up and through two clutches.

 

VX HPC - Loud and proud here

Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere

[Mavic82]

Mine drags a little to especially when hot but cable adjustment has no effect. Same as Ric's I guess.

 

Gentle teasing of the clutch peddle solves the issue. However if yours has just started I would suggest adjusting cable to check.

 

Guy

[Paul Deslandes]

Unless you have a clutch pedal stop or you're pushing the pedal all the way to the pedal box wall, adjusting the cable will only alter the position of the pedal. It won't move anything in the clutch itself or adjust the position of the CRB. For some reason it sounds as though the centre plate is not fully releasing from the pressure plate or the flywheel. Assuming your HPC has a Vauxhall engine, I wonder if you have the so-called pot flywheel and the washers between the clutch cover assembly and the flywheel have been left out. If they have, and unfortunately I don't think you can tell without separating the engine and gearbox although you might be able to see through the clutch lever hole, you may have incorrect clutch movement which might cause this problem. The washers in question are placed between the flywheel and the cover assembly, not under the head of the fixing bolts. Not sure this is your problem but might be worth a look.

Otherwise a warped centre plate but I would have thought you would notice clutch judder when engaging. As a temporary strategy, if it'll go in, try putting it into 2nd to stop the box rotating before quickly going for 1st or reverse. We used to do this in the old Fords/Morrises with 3 speeds and no syncro on 1st or reverse.

 

Paul

 

 

[Dickie Normuss]

Paul, when we changed my friction plate and cover the original did indeed have the spacer washers which I believe was a standard mod from the factory. We decided to leave them out when fitting the new one and it's fine apart from slight drag sometimes but it did that before

 

VX HPC - Loud and proud here

Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere

[Bob Simon]

All this business about the washers under the clutch cover has me puzzled. Why did not Caterham simply bend the clutch arm or put a spacer under the pivot point? How about a thicker CRB?

 

The washer application seems awfully agricultural. The spacers are reducing clamping pressure. There's got to be a more elegant solution than this.

 

-Bob

94 HPC VX Evo III

 

[Paul Deslandes]

Pretty crude I agree Bob, but it does seem to work and I must say I never had any problems with mine with either slipping or dragging, in spite of 250 hp. The only time it went wrong was when the splined centre boss rotated within the centre plate. I'd certainly recommend that Mark checks that the washers are there, just in case this is problem and its come on with wear.

BTW Bob, you're throttle cable mod with the roller/pulley works a real treat and is a huge improvement in throttle action.

Paul

 

 

[Bob Simon]

Thanks Paul,

 

Glad the throttle mod worked for you.

 

It's fortunate I read this thread as I was just about to refit my engine into the chassis without the aforementioned washers in the clutch cover. My first impression was someone had assembled the clutch wrong. The Haynes Calibra manual showed no washers so I binned them. Now I see there was a purpose for them. The power of BC saves the day. 😬

 

I had a good hard look at the clutch arm. It's a Ford part, probably a holdover from Kent block applications. Bending it would be out of the question. It's heat-treated, hard as nails. It would have to be annealed, bent, and re-processed to have any trust in it. Too much fiddling about I'm afraid.

 

The pivot point can't be spaced practically as it would need roughly twice the distance as the spacer washer/clutch cover solution. It would move the arm frightfully close to the clutch cover lumps when the clutch was disengaged.

 

Looks as though I'll be putting the washers back in just as God and Caterham had originally intended. 😶‍🌫️

 

-Bob

94 HPC VX Evo III

 

[mark not max]

Thanks for all of your posts on this. I am pushing to pedal to the pedal box wall, so I will make an adjustment and see if things improve. I will not get on to this until later in the week, but shall report back.

[ECR]

As a matter of interest you can modify the Ford clutch arm.

Grind 2 vees partway through at the bend then flatten it out as required and then weld up the vees. If left like this it will fail so weld an inverted piece of 15mm (?) angle iron to the rear of the arm spanning the bend. I have done this twice to give more actuating movement on non standard clutches. Works a treat.

 

As you say, the Ford arm is a tough piece of work ....

[Bio]

Thinking back....a long time ago.....When I fitted the engine and box together and before fitting the engine in the car I tried selecting gears and found the clutch arm hitting the rear of the cut out in the bellhousing before fully dissengageing the clutch center plate.

I elongated the slot in the bellhousing to allow full movement of the release arm and also fitted a clutch pedal stop so not to over stretch the clutch cable.

 

John

[mark not max]

Well guys after a weekend of clutch drag (which in no way stopped me using the car) its over for now.

 

Last night I fiddled around with the cable a bit, nothing precise. Tried to start the car and it turned over but would not start. Pushed the start button again and there was a fairly loud clonk. When I pushed the button again, nothing. Oh dear.

 

Had a look around, stratched my head and tried the button again and it started straight away.

 

Put it in reverse and no crunch. No other selection problems when I took it for a spin.

 

Not sure about the clonk, but the only other difference was the weather. Quite a few degress cooler. So only one thing for it, better arrange a sunshine tour with 5* breakdown cover.

 

Thanks for your contributions.

Mark