Clutching at straws

Post by **minor_hickup** » Thu Jul 27, 2006 11:07 pm

Apologies for the pun!

When the clutch is at the end of its life will there be no adjustment on the clutch adjusting rod?

The reason I ask is because my clutch has been slipping lately. If I was to put the car in gear with the handbreak on it would stall, but whe pulling up hills you hear the revs rise, if you back off the power you feel it grip again. However if you were to floor it the revs would rise significantly with little or no increase in speed.

However the engine is a bit leaky, could it be the crank rear main oil seal (im sure I added a word there)? If so would I need to disasemble to engine to change it or could I get at it by lifting the motor out and removing the flywheel?

Post by **bmcecosse** » Fri Jul 28, 2006 7:42 am

My view is it's easier to lift the engine than struggle under the car with the gearbox- others of course have different opinion. Either way - replace the clutch plate - and check why the rear seal is leaking - could be excessive pressure in the engine (clean the breathers and connect one to engine vacuum) - or high oil level - or worn main bearings (crank regrind). The crank of course is more easily dealt with if the engine is removed !

Post by **Alec** » Fri Jul 28, 2006 8:06 am

Hello MH,

"When the clutch is at the end of its life will there be no adjustment on the clutch adjusting rod?"

Do you mean there is no free play between the actuating mechanism and the clutch release lever, if so the clutch will probably slip? It is unusual that you have no adjustment left?
(The various pins and link bars do wear but this normally results in drag as there is not enough travel at the release lever due to excessive slack in the linkages.)

Alec

Post by **simmitc** » Fri Jul 28, 2006 8:34 am

How many miles on the clutch? I reckon that you should get at least 130,000 (at least from original clutches, I'm not so sure about modern ones.....

). If the adjustment is right to the end of the thread then it could be either causing the problem or the result of an extremely worn clutch. Also check that there is a retrun spring between the clutch operating fork and the engine back plate, then check the free play of the pedal. Measured between the top of the pedal and the floor, you should be able to press the pedal lightly by finger pressure until it becomes much harder as the operating bits all engage. This measurement should be 3/4 inch for 948cc and 1.25 inches for 1098. If the linkage is worn then replace it (again, how come my 1963 linkage lasted 200,000 miles, modern stuff only a few years?). Most suppliers now offer a kit of all linkage parts including bushes. If all else fails then engine out (I agree with bmecosse) and check for oil and the causes of oil. Clutch can be replaced without any further engine strip down, but if the problem is an oil leak then it's open-ended as to how much work is required.

Do you have the history of the car - has it done this for a long while, has oil consumption gone up etc. Good luck.

Post by **minor_hickup** » Fri Jul 28, 2006 11:05 am

Yeah it using a bit more oil, well leaving t on the garage floor. Its not a huge amount but definately a noticeable amount. The car has done 68,000 miles on the original clutch. It used to slip a bit when changing up into 4th, but there was far too little free play. After adjusting it was better. But it will occasionallyslip on hills, some days it worse than others. I've only had the car for about 18 months before that it was layed up for about 7 years.

When the clutch is at the end of its life will there be no adjustment on the clutch adjusting rod

No I meant that if there is nop adjustment left then the clutch has gone. I was hoping that because I have plenty of adjutment it may mean the clutch has plenty of meat on it.

Post by **bmcecosse** » Fri Jul 28, 2006 2:28 pm

Sounds like oil on plate then.

Post by **minor_hickup** » Fri Jul 28, 2006 3:11 pm

Does that mean the oil seal needs changing or plate as well? Also how easy is it to change the oil seal?

I take it its an engine out job, is an engine crane necassary or could a couple of strong lads pull it out?

Ratbag · Post by **Ratbag** » Fri Jul 28, 2006 3:19 pm

minor_hickup wrote:Does that mean the oil seal needs changing or plate as well? Also how easy is it to change the oil seal?

I take it its an engine out job, is an engine crane necassary or could a couple of strong lads pull it out?

If the plate has had oil on it, it'll need changing too. For the cost/aggro ratio you may as well put a complete clutch in while the engine is out.

It is possible to heave an engine with just two of you plus a rope sling BUT it's far safer, more controllable with a crane (hire one). The crane comes into its own when putting the lump back, however - lining up the box is far, far easier with the fine control you have.

Cheers,

Phil.

Post by **Kevin** » Fri Jul 28, 2006 4:20 pm

If you do change the clutch dont forget the input bearing as this will help the gearbox last longer.

Post by **bmcecosse** » Fri Jul 28, 2006 5:37 pm

There is no 'oil seal' as such - it's a scroll. But when the main bearings wear it can't cope. Often the reason for leakage is pressure in the block - so I urge you to check for that. Hot engine - idling - take oil filler cap off - is there a plume of fume/smoke ? Ideally - there should be nothing.

Post by **chrisd87** » Fri Jul 28, 2006 7:01 pm

But when the main bearings wear it can't cope.

Hmm, that's quite funny as the bottom end in my engine is completely toast (oil light now comes on when engine is hot and idling, plus dreadful growly rattle) and I'd always assumed it was mains as it's not displaying typical 'big end symptoms' (regular knock), but the engine doesn't use or drop any oil

. Never mind, I have a spare crank that I'll put in soon.

Post by **minor_hickup** » Fri Jul 28, 2006 7:31 pm

Ok thanks all, its all a bit daunting, I've never done anything like this.

Post by **minor_hickup** » Sat Jul 29, 2006 3:43 pm

BMC I took the car for a good run today and when I got back left it idling, then took off the oil filler cap and didnt even get a wisp of smoke. I take it thats good?

Post by **bmcecosse** » Sat Jul 29, 2006 3:57 pm

Yep - sounds good! Badly worn engine puffs away like a steam engine.

Post by **rayofleamington** » Sun Jul 30, 2006 12:48 am

How many miles on the clutch? I reckon that you should get at least 130,000 (at least from original clutches, I'm not so sure about modern ones.....

Modern clutches will last a billion miles and more - it's not mileage that kills a clutch it is pulling away (especially if boy racing) and the modern favourite - using the clutch instead of the handbrake when stationary on a hill.

and also a miniscule amount of wear from gear changes (unless they are done at full throttle!)

The 'overcapacity' on a modern clutch is now much lower than it was in the 1940s. Why pay extra for extra un-needed materials and carry round extra weight (causing worse fuel eonomy) for something not actually needed?

The problem of short clutch life comes when they are abused - a clutch is designed and tested for the 'normal' life of a car. The lower torque safety factor comes first because of of cost pressure but also with the huge torque output of saloon engines there just isn't room to fit a clutch that will transmit double the engine torque.

Anyway - bac to the original question - yes a worn clutch will reduce the amount of adjustment travel left. If you have run out of adjustment then there may be some additional problems - most likely is worn out linkages.

also regarding your point about changing the 'rear crank oil seal'. There isn't one to change! It relies on a scroll machined into the crank which stops working if the crank/bearings are sloppy.

Post by **minor_hickup** » Tue Aug 01, 2006 5:56 pm

Well the car seems ok at the moment. Apart from the other day it hasn't slipped at all. So I'm not going to do anything drastic unless it reapears with avengeance.

I really need to change the sump gasket as it dribling from the back and the side. How do I check the condition of the mains and big ends?

Post by **Kevin** » Tue Aug 01, 2006 6:10 pm

How do I check the condition of the mains and big ends?

Usually any wear is obvious by the condition of the surfaces and if there is any form of scoring you need to check the crank as well.

Post by **minor_hickup** » Sun Sep 03, 2006 10:22 pm

I definately need to sort the clutch now. However I'm worried that if i go to change the clutch and find out it is oil leaking form the rear of the engine, how would I stop that? I'd hate to contaminate a brand new clutch plate with oil.

Post by **Kevin** » Mon Sep 04, 2006 1:17 pm

I'm worried that if i go to change the clutch and find out it is oil leaking form the rear of the engine, how would I stop that?

Well there is a kit to eliminate that problem but I have not used one so cant comment on its effectiveness, but wait until you are sure what is the problem.

Post by **bmcecosse** » Mon Sep 04, 2006 1:21 pm

Take the rubber bungs out the side of the gearbox bellhousing (if they haven't fallen out already) and look inside with a good torch - if it's all swimming in oil then there's the problem. If it's dry - likely the plate is just worn out.