1929 Clutch

[ChrisE]

The clutch on my 7Hp 1929 full four is slipping. If I spray it with clutch/brake cleaner it is fine for about 7-8 miles then starts slipping again. Is it worn linings? is it oil on the linings? Where can i get replaceent lining and is there an efective oil seal from the crank side and from the gearbox side? If not should i go and find an oil seal?

Thanks
Chris

[k. rogers]

Had the same problem with the Sports and came to realise I had overfilled the gearbox. There apparently isn't much to keep the oil in! Unfortunately, the handbook doesn't give a quantity but tells you to fill up to half way up the layshaft. I found this very difficult to assess peering into the gearbox with a torch and I'm sure I ended up putting too much in! This has resulted in occasional clutch slip ever since, so will be emptying the oil and starting again with quarter of a pint (suggested by more experienced club member) to see where that levels out.
I have found the best thing for the slip is Fullers Earth but its quite difficult to feed it into the clutch - the best way is on a knife - but it does work for longer.

[Chris Spencer]

Other than what Ken has stated - if you have to replace the clutch then the clubs spares team 'Jowett Car Spares' can help with its replacement and they are a couple of very helpful pre war owners within the spares team if you require further info

[k. rogers]

Not sure if your car has the same cone clutch as mine, as I believe yours is on the cusp of all the developments Jowetts made during 1929, but if it has the clutch material is made of four rows of asbestos-type rope, so not sure where or if its available nowadays. I do know someone who converted theirs using Kevlar! I would suggest making the checks I outlined first as you may not need to go down the replacement road.

[David Morris]

Hi,

Just a thought about your comment re. asbestos rope. My wood burning fire has 'rope' around the door to form the seal. It probably isn't actual asbestos now, but seems very similar?

I know our local wood burning fire shop has stocks.

Might be useful? I have used a couple of feet of real asbestos rope that I bought some time ago to wind around my Javelin exhaust pipe, where it runs through the chassis, to 'cushion' any rattles here.

All the best,

David

[ChrisE]

I'm trawling round trying to get some replacement 'rope'.

see video https://imgur.com/pcOHK04

Also, there seems to be a lot of old thick oil in the base of the clutch housing. That can't help? is it supposed to be non-oily and very clean/dry in there?

Lastly, the inner cone sits 4.5mm inside the flywheel line. is that a sign that it's worn?

Chris

[k. rogers]

It does sound like the rope has worn flat if the clutch is sitting so far into the housing - mine is about level with it. It would certainly pay to remove any oily deposits in the housing as you need it as dry as possible in there. I'm sure, as in my case, that the loss of oil through any gaps won't have helped in this respect, so now you have cured it at least it shouldn't reoccur. Did you try Fullers Earth in the clutch - it may just help in the meantime?

[ChrisE]

I believe that the old asbestos 'rope' on the clutch can be renewed but now using Kevlar rope (not asbestos). Does anyone know what the rope diameter is that I need?

[Tony Fearn]

Hi Chris.
Jowett car Spares will be open tomorrow night (Monday) I think, 7 until 9 pm.
Get in early and talk to Mike Kavanagh.
Tony.

[Dhbangham]

I only just made it back home after the Rally at the weekend with exactly the same fault on my 1929 7hp with cone clutch. I took the gearbox and cone out last night and was rather perplexed. There was a lot of oil with friction rope mixed in it splattered around the inside of the bell housing. Here are the symptoms and my observations:
a) I often have difficulty getting the clutch to slow down and stop turning, when I have stopped for a junction and then want to re-engage first gear. I can force it to stop, by pushing the clutch hard down and forcing the release bearing assembly to rub against the gearbox housing.
b) Clutch slips, especially after a long drive.

On investigation the only reason I can see that the cone will continue to spin after depressing the clutch (when in neutral at a standstill), apart from inertia, is due to "drag" caused by a "rough" thrust bearing on the engine side of the flywheel. It is the only place the Cone-clutch and engine are still in contact with each other, hen the clutch is depressed. (I am as well, and that is also caused by the clutch). Has anyone any other suggestion? I will be contacting the spare tomorrow, to see if they have a replacement thrust bearing.

As far as the rope on the cone, mine looks black and shiny in places and has oil on it, the rope has spread out and bunched up in places is not evenly and smoothly over the whole surface. I am reluctant to disturb the current material, as it might be original style asbestos with wire woven into it. I have heard that you can replace rope with kevlar, but don't know what specification i.e. what diameter rope or you can replace the rope with pads of modern friction material. Again it is not clear what grade is required. It would however need to work with oil. There are a number of suppliers online for this option.
When dismantling the clutch last night, I did wonder if my problem was that the springs were not adjusted tight enough, it was slipping simply because it was not pressing hard enough into the cone. Then I realised that if i tightened the springs, it would increase the tendency of the clutch to keep spinning when idling. So everything has to be sorted together. I have never taken the flywheel off, any hints and tips. Can it be done in the car.

The rope used on wood burners, might not be a good idea, it is glass fibre and might breakdown to an abrasive dust.

If I find anything useful during tomorrows investigation I will report back.

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[Dhbangham]

Sunday afternoon update:
a) I decided to remove the old rope and I am glad I did. It was the original asbestos with brass wire and is now disposed of properly. I was able to measure the diameter where is was undamaged under the clamp plates. It is almost certainly 1/8 inch. I have now ordered some 6.5 mm kevlar rope.
b) It turns out that I had a complete cone assemble on my spare engine. Rob Abineri and I took that out this afternoon and found that this cone has been modified to use flat friction material riveted in place. It would have been great to just swap it over, but I noticed that the rivets holding the cone hub onto the cone are loose. I will therefore replace them. We also noticed that I have been driving for 1000's of miles without the deep ball ball bearing race that supports the cone on the end of the crank case. I have now put a bearing on the current engine.
c) I tested the two thrust bearing on the flywheel side of the clutch and they seem similar and will not change them until I have tested with the new clutch ropes. It is possible that the drag was not from the thrust bearings but from the "loose" asbestos rope flailing in the clutch.
d) Several knowledgeable people inspected my gear box sprockets and told me not to change anything at the moment as I had at least 60% of my gear teeth are still engaging.
There folloows some pictures of the clutch

You can just see the mess of old asbestos rope through the hole in the bell casing

Flywheel showing front thrust washer and spider

[Dhbangham]

Monday update.
It was suggested that rather than replace the rivets holding the clutch cone hub to the aluminum cone, I should use a ball pein hammer to tighten them up. I looked at the possiblity and someone had already done that by drilling a shallow hole in the end of the rivet and hammered around edge. It might have worked at the time, but is now loose. Rather than repeating the experiment, I made a cup in the end of some silversteel to hold the dome side of the rivet and then use an a semicircular dolly over the shallow hole and a 10 ton press to spread the rivet. The pictures might show what I did better. The process was successful.

Tightening rivet showing cup support for the come side of the existing rivet

Bottom side of cone with cup support in position.

Using 2 tones of pressure the rivets tighted up and we are ready for putting back in the car.

[BarryCambs]

Hi Daniel

I've not seen one of these clutches apart before. The modification looks very neat, but do you know if this was a standard / common modification? If it's off the engine that was in the car when you bought it, then I guess you know how it performs compared with the rope ones?

Barry

[Dhbangham]

I believe it was a common "upgrade" made when rope becames less availble and when asbestos fell out of favour. Many cars used cone clutches, but mostly used leather or sometimes cork. I know my grandad used his leather belt to repair the cone clutch on his Jowett in the 30s. My memory of the clutch using the flat friction material was that it snached a bit, but was very drivable. It got me to Darlington and most of the way back without me even thinking about it.
The 6.5mm Kevlar rope has arrived an is much more ridgid than the asbestos and is not laying flat very easily. I think a 5mm diameter will be needed.

[ChrisE]

The 6.5mm Kevlar I have looks good and the right size, I just hope that it has the same friction/wear properties that were on the original asbestos ones. I ordered 5m only to find that it takes 5.6m so have had to re-order!

I have taken loads of phots, see https://drive.google.com/open?id=1-0vUc ... rxVUMUbYMu if people want to see what it looks like and maybe help others having to do the same thing.

Chris