Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 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

The angle between the arms of the bell crank should be at 90 degrees, so pedal throw and clutch throw are equal. It's quite common for these to close up ver the years as the shaft twists, giving reduced clutch travel. There should be a tiny amount of play in the cable, you don't want to be dragging the release bearing all the time. A common mod is to weld in webs onto the arms to resist further twisting.

Thank you - this is what I needed to know.

Looking at the tube in my car, I believe it might be better to get a piece of 0.5inch stainless steel rod and build a new one.
The travel will not be completely the same as the length of the brackets is different - but 90 degrees make more sense

Sounds like a good plan. The RHD cars only have a short shaft so they tend to be stiffer, but the long shaft necessary for a LHD setup is bound to be more prone to twisting.

Some notes & my learnings for other owners of LHD Morgan's with cable clutch:

1) Finding the right angles is the tricky part
With a 90° angle between the bracket (recommended above) on the connecting shaft pictures above, there might not be enough adjustment possibility on the cable. (see picture below)
After bending it back to make it fit, I estimate the angle is between 80° and 85° - I will measure it shortly and post and update here.




2) A bit of free-play is needed
Even after reading the Gomog instructions on the bottom of the page a few times - I find them difficult to interpret.
It says "Any free-play previously in the cable is thus taken". Maybe I misunderstood this. The way I read it was that the release bearing touches the clutch pressure plate - thus riding and spinning with it the entire time.

At my local garage I was told that in most cases the recommend travel (gap between release bearing and pressure plate) is 1/4inch or~6mm.
On the Morgan however - there is no return spring or other mechanism that pushes the bearing away from the plate.

Right now - I slackened the adjuster nut one full turn to have a minimal gap. If I give it more play - the clutch travel is not sufficient to get the gears of the Ford T9 gearbox in smoothly.
I am still not 100% certain if this is correct. If somebody here has a better explanation on how to do this - please share !!!

3) ALWAYS remove this bar when removing the engine to e.g. replace the clutch!!!
Even if you support your gearbox bell-housing - chances are that you bend or damage the bar otherwise.


4) Replace the original bar if possible
The factory installed 1/2 inch diameter steel tube will twist at some point. Sure, you can bend it back, but this will not hold for a long time and the weaken the material even more.

On your next trip to the UK or anywhere in "imperial world" - buy a 1/2inch diameter and 25-1/4 inch long (~64,1cm) stainless steel round bar.
It is somewhat expensive and difficult to source in mainland Europe.

Metric 12mm round bar is too thin for mounting points (unless you are going to create your own and replace the factory ones)
I just tested a 15mm diameter rod (which I had) with ends trimmed down to 12.7mm on the lathe - this is too thick and touches the bellhousing. I now found a place that sells 13mm diameter round bar - will try this next.

For the brackets you need 1/4inch (~0.6mm) thick and 3/4inch (~2cm) wide steel flat bar.
One bracket is ~3 1/4 inch - the shorter side about ~2 1/2 inch long.

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

I don't know how many miles your 4/4 has done. After 75,000 or so, I found my car's clutch increasingly difficult, and like you, I ran out of adjustment.

At 90,000 I even shortened the cable, and not long after that the cable snapped; luckily while I was parked.

I bit the bullet, and had the clutch replaced, along with the throwout bearing. The bearing was completely shot!

This made such a difference, and I could again select first gear while stationary!

I'd recommend have your throwout bearing checked, with a view to replacement. This may fix your car's ills.

Oh that it was really overdue to exchange the bell crank on my car
My parents did 280000km (roughly 180000 miles) before I started the restoration back in 2020.
It was stripped C6622 done to the chassis, frame was repaired and every component overhauled.

The new clutch failed after 8800km (actually just the friction disc had glazing)

In my opinion shorting the clutch cable is not the right solution if the bell crank suffers from fatigue.
The cable of course might also be an issue - I have replaced mine but my tests with newly built bell crank show that the old cable does not stretch under load.

Regards
Tim