The Morgan wiring loom is finally finished and back in C6622. It was a good thing I tested everything on the workbench – besides an unexpected failure of the horn (it has a short circuit and blows the fuse right away) – everything is working well now. I took an insane amount of time to do it has tidy as I possibly could. Overall I am happy with the update fuse&relay box design. Quite a bit of the learnings will be incorporated into Mildred’s new loom.
With our summer vacation trip in just a few weeks, I hoped to be able to do a test drive. But the clutch issue that I could first not figure out or solve prevented this. The cable clutch on the 4/4 CVH model is operated by a rod with two levers, which transfer the movement of the clutch pedal from the left side to the right, where a cable in turn connects to the lever in the bell-housing of the Ford T9 gearbox.
No matter what I tried – I cannot adjust this cable without pre-engaging the clutch. As I learned the hard way – this results early clutch failure. But why is this happening? The lever on the pedal side has a total length of 82.25mm( 3.25 inch) and the center of the two moving points is 61mm apart. With my calipers I measured that the pedal moves approx 36mm when I fully press is down.
The cable lever is shorter and the centers are for the cable and the rod are 39mm apart. Using the formulas for isosceles triangles – the pedal lever roughly changes 34degrees. Using this angle and the 39mm length – I calculated that the cable should pull the clutch lever about 22mm. This makes sense. Although I could not find precise specs for the Borg&Beck Hk8050 clutch – multiple sources say that a typical clutch for the T9 gearbox need 15 – 17mm to engage fully. Adding 3 to 5mm that the release bearing should be away from the clutch fingers – this is probably the correct travel required.
But no matter what – the clutch lever does not move that much. I measured multiple times and I get 11 to 13mm travel. Well, extending the lever on the cable side would result in more travel. 52mm on the lever should I crease the travel by 8mm easily. Sure, it will also require more pedal pressure (which is already quite stiff) – but worth a try. Wjth a piece of metal screwed to the lever as extension – I saw virtually no increase in the travel on the gearbox side. Could this be an issue with the cable? A replacement is about 30GBP and without hesitation I ordered one – ruling this out cannot hurt.
But while having dinner an idea popped into my head: why not measure the angles on both levers? Back in the garage with my digital angle meter from my table saw I tested the pedal lever first. A little less that the 34 degrees I calculated but close. I should have exactly the same reading on the right side at the cable lever. But: this is not the case. This proves that the rod itself is the issue. The torsion force is so high that the material twists. A quick calculation shows that with 19 degrees and 52mm the cable will only travel 17mm – but I only measure 13mm on the gearbox lever.
Building a new rod was on my list anyway. I sincerely hope this will be the solution to my clutch issue.
In addition to the Morgan I had a small fix on the MGB pedal box. And a late birthday present from my wife for Miffi arrived – I love the look of the Monte Carlo roof rack. Maybe unnecessary – but I still think it looks great😉
Fixing C6622 
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