Heavy Clutch Pedal

[mof]

When I depress the clutch on my 1970 1098cc the engine actually labours, rather than freeing up. I seem to recall that this is probably due to some worn bearings at the crank shaft. Can somebody give me an idiot's guide to the problem and the solution. I have fitted a new clutch without any difference, so it's not just a clutch problem. I do also have a judder in reverse, which I think may be down to a gearbox steady cable being too tight. Could there be some relation?

[rayofleamington]

Judder in reverse is normally down to a broken or missing engine top steady.
Even if it's fitted, you can get a small amount of reverse judder on a normal car.

If the engine struggles when you press the clutch then it sounds like a problem. It my well be the crankshaft thrust bearings. Not sure if they can be replaced without an engine strip down on a 1098. Certain things like the big ends can be done with the engine in the car (remove the sump), so it might be possible, but am not sure.

[Cam]

On a 1275 I think they can be removed / replaced after removing the main bearing cap (one of them - the centre I think) which can be accessed by removing the sump. I would say that the 1098 is probably the same.

[Scott]

Clutch drag:
Do 1098 cars still use the carbon thrust bearing as in early cars ?
The engine will slow slightly due to this design but not enough to stall.
Is the clutch over adjusted ? Too much travel can also cause the clutch to bind resulting in the engine slowing.
You can check the thrust washers to a certain degree by trying to move the crankshaft pulley in & out (engine not running of course). If this is difficult, try pushing it inwards fully via the crank handle hole, then while you have your hand on the pulley have someone inside the car depress the clutch. This action will push the crankshaft forwards. You should be able to feel a very slight movement. Any more than slight movement would indicate wear. Usually any more than 0.50mm might be some concern but I don't have definite specifications at hand.

Clutch judder:
Check the engine & gearbox mountings for softness/collapse as well as the engine/gearbox stays.

[rayofleamington]

Do 1098 cars still use the carbon thrust bearing as in early cars ?

Presuming you mean the clutch release bearing, then yes, they do. It might be a different bearing but it is still carbon. I would have suggested also to check the bearing for wear in case it has reached metal to metal contact, but as the clutch was done recently I think this would have been ruled out.
As you mentioned it will have some drag but not normally enough to make a large difference on engine speed.

[Benjy]

My engine slows slightly when the clutch is depressed. I just assumed it was a moggy thing, though I must admit it didn't make any sense to me! I meant to ask about it, but it doesn't cause any real problems and I forgot.

I'll go check the play on the crankshaft, thanks Scott. Having said that, I very much doubt I'm going to get round to stripping the engine to replace something that actually doesn't cause me much of a problem. Far more urgent things to do - like rustproofing before winter comes!

Ben

[57traveller]

Slight reduction in engine revs is quite normal when the clutch pedal is depressed.
If your idle speed is set too low the drop in revs may sound worse than it actually is.
Does the ignition light not illuminate, just flicker or is it bright at idle?