The following is a (somewhat lenghty…) summary of my learnings about the cable clutch system in my Morgan. The information, drawings, and measurements below were collected/done by me. I cannot guarantee that they are 100% to the factory specs – but this is what I used for C6622 – my Morgan. If you own, repair, or restore a Morgan 4/4 with Ford CVH, this is hopefully helpful to you. Suggestions and corrections from others are welcome – just leave a comment.
For quite some time now I knew that the clutch adjustment in my car was not right. Back when I restored C6622, I just cleaned and repainted the bell crank. This is the rod (metal tube) with a lever that connects the clutch pedal on the left side to a cable attached to a shorter lever on the right side of the car. During reassembly of the Morgan I looked for information on how to properly adjust the clutch. The GoMog page is the only web reference I found on this topic. Maybe because I am not a native English speaker and just a DIY mechanic – I had a hard time interpreting it. Especially the part about “removing freeplay” left me with some questions. Information I got from other Morgan owners – either in person or in the TalkMorgan forum – left me often with even more questions.
With the old bell crank I ran into the following problem: In order to be able to shift gears, I had to tighten the cable up to a point that the clutch release bearing was riding the clutch. This pregagement of the clutch is causing the clutch friction-disc to slip under load – which means the car never fully got the power to the rear axle. This is what I experienced during the trips to the UK and Italy last year. The best way to notice this is on steep inclines. Even if you fully accelerate, you will notice that the car is not moving uphill in 2nd and 3rd gear although the revs are quite high. Last October, just after doing 8800km, the clutch disk would slip permanently. Engine revved high but the wheels hardly moved and the smell of a burned clutch was horrible. I took the engine out and replaced the clutch. The surface was of the disc was glazed. It took me a while to figure out how this is linked to the bell crank and that I caused this with the cable adjustment.
But this leads to the main question: What is correct adjustment for a Morgan 4/4 CVH? To find the answer – let us look at the pedal side first. The pedal is connected to the left lever via a small, screwed-on metal block. You can slightly change the travel of the pedal by turning this block further out or in. Initially I had this screwed in much further. Mainly because I though that the clutch and brake pedal should have the same level. But if you have issues with your Morgan cable clutch or start measuring, make sure to increase it so that you have maximum travel on the pedal side – you can always remove this later if your bell crank and cable work correctly.
When the pedal is fully pressed, the (longer) lever on the left is pushed forward. Initially, I used a caliper to measure this, but a digital angle meter is much better to check the bell crank. I had slight variations in my measurements. An angle change of 31.5 degrees between released and pressed state is what I settled for. The distance between the center of the bell crank rod and the pivot point is 61mm. Logicially, the shorter lever on the other side should also move 31.5°. The hole for the clutch cable screw is 40mm from the center of the bell crank rod. Using the formula for isosceles triangles we now know that the cable pivot point can theoretically travel a maximum of 21,7152mm when the clutch pedal is fully pressed. (there is another triangle we need to look at – more on this further below)
And of course, the right lever will do this when the clutch cable is disconnected. But with the cable attached and pulling the release bearing against the clutch pressure plate, the torsion force applied onto the bell crank caused the old 1/2 pipe-rod to twist. On C6622, the right lever of the old rod only moved by 17 degree. In other words: the cable pivot point on my car with the old bell crank was just 11.8248mm.
I could not find a specifications on how many millimeters the release bearing needs to press down onto the HK8050 Borg and Beck pressure plate to fully disengage the friction disc. Looking at the inisght of the pressure plate, I estimated that 12 to 15mm is required. 15mm is also a value I found in a posting on the a Lotus forum about the Ford T9 gearbox – not sure if this is accurate, but at least close to my guess. Even if the release bearing has constant contact (and I look into this topic further below) with the pressure plate , the result was that the there was not enough travel on the cable off my Morgan with the old bell crank. A correct adjustment was impossible.
It was clear that I need to either strengthen the old bell crank or build a new one. Getting measurements from my old bell crank was easy – but there was one important aspect I could not be sure about: The relative angle that the two levers have to each other. As the material of the old rod showed clear signs for detortion. The 59 degrees the old one had could not be taken as a correct value. Forum advise said this should be 90 degrees. This is also not necessarily correct as I found out. Maybe there is no general answer for this. In my opinion the answer also depends on the length of the inner cable. If the angle is too large – it might not be possible to attach the cable without already applying pressure to the clutch again. And importantly: the lenght of the inner cable can be influenced with the guiding sleeve that connects it to the gearbox bell housing.
To the left you see my first drawing of the side view of the Morgan 4/4 bell crank. The relative angle between the two levers here is 60 degrees. Instead of a single hole for the cable – I decided to drill in three. The have a 5degree offset. This means I could test 55, 60 and 65 degrees. As the outer holes are about 7mm further away from the pivot point, the force needed to push the clutch pedal will also change (law of leverage). The center of the cable mount and the pivot point on the lever determine the second triangle I mentioned earlier.
The first test was to cut the old rod and weld the pieces into a stronger tube. A piece of 3mm thick/20mm diameter cut to 57cm (inner distance between the levers) looked solid enough. A series of holes drill into the material allowed to weld the old rod pieces to the new outer tube. But unfortunately this was not working. First problem was that a 20mm tube will touch the underside of the gearbox. And more importantly – even though the torsion force issue was improved – I still only achieved to get about 24 degrees on the right side with the pedal fully pressed.
The second attempt was a new bell crank made out of an 1/2inch 316grade stainless steel rod. I bought the metal in the UK last year already as 1/2inch material is difficult to get in Germany. It was a really solid piece. In no way I imagined that it might not withstand the torsion force when flooring the clutch pedal. But I was wrong about this. Right after installing it, I used the digital angle meter again and found out that the angle change on the right is only ~26 degrees – not 31.5 as expected. As mentioned above – I expect ~15mm of travel are requried to release the friction disc. Great, so this should work – everything should be good now, right?
Well, I mentioned the constant contact release bearing topic above. This setup works as long as I remove all freeplay from both the outer and inner cable. To do this I tip the gearbox lever with a finger towards the pressure plate, making sure the release bearing touches it – but not pressing it done. Then I use the adjusting nut on the cable to remove the free-play. I believe this is exactly what is meant with the description on the GoMog page.
My way of testing it the adjustment is good is the following: While the engine is off and brakes are off, I put the car into reverse on a flat ground. With the clutch pedal fully pressed I turn on the ignition. If the clutch is properly disengaged, the starter will have no issue starting the engine. If the clutch is not disengaged properly, you will feel that the starter is trying to push back the car and I immediately stop the test.
On the Morgan 4/4 CVH, the lever in the gearbox, that the release bearing is connected, does not have a return spring. The conclusion I draw from this, is that it was designed as constant-contact setup. The release bearing always touches the metail fingers of the pressure plate. This is different to many other setups which are intermittent. Usually there is a 3 to 6mm clearance gap between the release bearing and pressure plate. Usually this is achieved by a return spring. There is a nice drawing in this website that pictures it. And this video on Youtube is also great on explaining how a clutch works.
There are two benefits I see from an intermittent setup. Firstly, the release bearing does not spin the entire time. This should reduce wear. Secondly and noticeable – depending how the clutch is adjusted it is less noisy. With the release bearing just touching the pressure plate lightly, there was a squealing sound. Removing tension from the cable creates a rattling sound from the lever in the bell housing. Increasing tension will change the squealing noise and eventually elimate it – but I know that this also means that the release bearing is now pressed harder against the pressure plate fingers again – something I tried to avoid.
So the next question is now: Can the Morgan cable clutch be modified/improved to be an intermittent setup? For this two things are required. a) Some form of return spring is needed and b) the travel of the clutch cable needs to be even longer to allow the added clearance gap for the release bearing. There wasn’t a simple way to mount an extension spring to the bell housing to pull back the release bearing lever.
Therefore, I opted for a torsion spring around the inner cable. I guess a picture is better than words here. My local DIY market had 15mm diameter torsion springs what are 24mm long. Good enough to test the solution by adding washers between them. As you can see they press against the cable sleeve, but they are not strong enough to press the sleeve out.
Next, I had to somehow get a few more millimeters cable travel. This can be achieved by finding the best angle for the two bell crank levers, moving the holes for the cable pivot point a bit further outwards. As mentioned before, the inner cable needs to be attached to this and needs to be long enough. The guiding sleeve can be modified for this. I had to do this anyway, as the replacement cable I ordered from Brands Hatch Morgan was slightly shorter anyway. While I was at it, I wanted to rule out material fatigue issues. My final design for an uprated bell crank is a 16mm hardend steel rod, with the ends milled down to 12.7mm (1/2inch) to use the originial mounting points. The levers are welded onto the rod with a 75 degree angle in relation to each other. I kept the orginial pivot hole – but added two additional ones – as mentioned above with a 5 degree offset.
The new bell crank has not problems with the torsion force. The material is much stronger and I was able to read 31 degrees on my digital angle meter. The 16mm diameter rod is also clearing the gearbox – there is just over 1mm clearance. The maximum cable travel is now over 22mm – allowing me to turn in the metal pivot point on the pedal side slightly – which moved the clutch pedal forward (and in turn reduces the cable travel)
After doing the first 1500km I am happy with the setup. Shifting gears feels exactly like on Maggie – my MGB GT with a Ford T9 gearbox. While a bit more strength is required to engage the clutch – it is not too heavy. There is no noise from the release bearing anymore. Acceleration and driving uphill is improved. Below you find drawings for the changed bell crank, pivots and cable sleeve in case you need to build a new one for your Morgan.
Final bell crank
Fixing C6622 
Leave a comment