Talk Morgan Forums Thread Like Summary - Morgan 4/4 CVH clutch adjustment question

Hello,

I finished the restoration of my 1984 Morgan 4/4 four-seater earlier this year. First longer trips to BVAC 2023 and Italy went well - but not without issues.
After initially looking at the fuel and ignition system because I have vapor-lock issues - I am not quite certain that the root cause is heat related and I suspect that I incorrectly adjusted the clutch.

The resource I used as advise is the Gomog page. There certainly is no free-play in the cable on my car -. as a matter of fact: I need to tighten the cable to the point that the clutch release bearing is sitting on the clutch in order to be able to shift gears.
My car is LHD and there is a tube with two brackets running from the left to the right side of the car. This tube is slightly bend and I am not completely sure if the angles that the two brackets have in relation to another are correct.

The bracket on the left attached to the clutch pedal is 82.25mm long and the hole that attaches the pedal is 61mm from the center point of the tube.
The bracket on the right side is angled 59° forward and is hole is drilled 39mm from the center.
When I press down the clutch the pedal travels 37mm forward - resulting in roughly 23mm cable travel.

Now some questions:
1) Am I right to assume that the clutch release bearing should not site and spin on the teeth of clutch the entire time?
2) Should the arm that the clutch release bearing is attached to automatically pull back? (should there be a spring or something in the gearbox?)
3) Does anybody know how much travel the clutch requires to completely engage? I have a Borg & Beck HK8050 clutch - but failed to find data on this.)

Currently I considering building a new clutch shaft with new brackets myself. I could make the bracket on the right (where the cable attaches to) longer - hence increasing the travel.

All hints and information are highly appreciated.

Thanks and Regards
Tim

It took a while but here is the update I said I would post.

First of a correction: my first test of a new bell crank mentioned above was not a 15mm diameter - but 20mm. As mentioned, this was touching the gearbox. Rod diameters up to 16mm will work. This is what I finally ended up with.

When you are testing your bell crank - get a digital angle meter. When you press down the clutch pedal, both levers should change their angle the same amount. This helped me to track down the main issue - material fatigue and torsion force on the bell crank. If the lever that the clutch cable attaches to does not do this - you know that the material of the crank cannot cope with the torsion force anymore. This is turn leads to limited travel of the clutch cable.

Maybe I am wrong, but I came to the conclusion that the CVH clutch setup is with a constant-contact release bearing. This explains the description of the Gomog article as well as the fact that lever the release bearing is attached to, does not have a return spring or similar.

I changed my setup slightly by adding a spring and extending the cable travel to an intermittent setup. Both setups will work, but make sure your bell crank is strong enough. Otherwise you might make the same adjustment mistake that I did: pulling the release bearing onto the pressure plate to tightly, just to be able to get the gears in.

When you replace the clutch cable and the new one is slightly shorter: don't panic. Just get a new guide sleeve on the gearbox housing. In order to rule out material fatigue of the cable itself, I got a new cable from Brands Hatch Morgan. The inner cable was about 2cm shorter. The length of the thicker part of the guide sleeve (which is going into the bell housing) determines how much the inner cable will stick out from the cable mount close to the lever of the bell crank.

A longer article about the topic including drawings for a new LHD Bell crank can be found on my blog

I hope that helps others when they look into adjusting the Morgan CVH cable clutch.

Regards
Tim

I