Morris Minor Owners Club

Hey all, I'm in the midst of changing my Mog to a 1275 engine and ribcase gearbox out of an MG Midget. I installed a new clutch kit, Borg and Beck branded, from a trusted supplier, and changed to Declan Burns' excellent rose-jointed clutch linkage with a bearing fork from a Minor 1098 (the bearing is from the 1275 clutch kit - though I know that's no guarantee it's correct). I believe I have installed it all correctly, got it centralized and such, though I admit I'm by no means a clutch expert.

Now that it's installed and the linkage adjusted, the clutch is extremely difficult to engage - the linkage is smooth as silk (props to Declan) before the bearing reaches the pressure plate, then it takes a whole lot of muscle to push it down to the floor. There is a marked metallic "pop" midway through the travel, both up and down. I have not run it on starter power yet, and the engine is not connected up sufficiently to fire, so this information is all strictly at rest.

Here's a video: https://www.facebook.com/MogAndFriends/ ... 125698328/

I know the Spridget clutch takes more effort to engage than the 948 clutch (what I had before) but surely not THIS much! (Besides, Declan's kit is specifically modified to fix that issue with a longer pivot arm.) And surely not with the popping sounds. Has anyone got any suggestions? Have I got a bad clutch kit and need to go back to the supplier? Have I installed it wrong somehow? What haven't I thought of?

You must use the correct 1275cc Midget release arm and thrust to get the most out of the conversion.

See link for details.

http://www.gerardsgarage.com/Garage/Tec ... arings.htm

The 'pop' could be the release fingers trying to go over centre.

So both issues (the bad sounds and difficulty engaging) could be caused by the incorrect release arm? I'll see if I can find the old 1275 type in my spares - I hope I was smart enough to hang on to it.

UPDATE: I have located the old fork. 22G169 instead of 22G168 in the link you provided, but it looks identical - Phil, can you tell me if there's an appreciable difference I'm not seeing between the two part numbers?

Something else occurs - I fitted ESM's LHD gearbox front cover (http://www.morrisminorspares.com/gearbo ... ew-p830915) because I needed it to be LHD to use Declan's excellent clutch linkage. I wonder if this cover has a different pivot point for the fork, exacerbating the issue?

So long as the distance between the release arm pivot point and the pivot point of the release bearing is the same then it will work.

Is the profile of both release arms except for the release rod end of course the same?

The front cover for both 1098cc and 1275cc ribbed (R/H drive) gearboxes is Pt No: 22G118. As regards the ESM front cover Pt No: 10G132 (L/H drive) I cannot advise as to whether the pivot point is the same as for the R/H drive gearbox but just rotated for L/H drive

Have you used the 1275cc release bearing which is deeper.

I know that when I fitted the 1275cc Midget engine and gearbox to my Minor and using the Minor mechanical linkage it was not straight forward even with the correct Midget release arm and release bearing. It had to be fettled/adjusted to get it all working well.

Phil

I used the bearing that came in the clutch kit, which was sold as being for a Midget 1275...but of course that doesn't mean it's correct. As far as adjustment I've done up the linkage so I get the correct pedal free play, but I gather there's more to it than that.

When the rain clears out, I'll pull engine and gearbox back out and try to change the arm, and at that time I'll take measurements and report back.

I finally had the engine and gearbox back out yesterday and got the fork changed. No damage was obvious on the clutch pressure plate or throwout (release) bearing. I took off the front cover of the gearbox and measured the fork fulcrum point against the old Midget front cover, and they are the same within 1/100th. The bearing is correct for a 1275.

All reassembled now - just waiting on some bits for the clutch linkage, and then we can have a test.

Got the linkage done. It's somewhat better with the correct fork - a much reduced, "normal," amount of effort to depress the pedal, and the sound of metal popping is lower - but there remains a marked feeling of popping (a catch and then sudden give) in the middle of the pedal travel, both up and down. With the linkage disconnected from the clutch fork, it's all smooth as silk with no catch.

Here's a new video: https://www.facebook.com/MogAndFriends/ ... 861201740/

I have two ideas:

• A bad clutch pressure plate
• Overextension by the mechanical linkage (as opposed to the Spridget's original hydraulic slave cylinder)

The second option isn't a problem I've seen mentioned in other threads - clearly many Minor owners have used a mechanical linkage on the 1275 with no problems. I see around the internet (https://www.mgexp.com/forum/mg-midget-f ... 455/page-2) that the Midget slave cylinder gives 1/2" - 3/4" of travel. My linkage seems to be giving a travel in that range (looks like about 5/8" at full pedal depression).

I have watched your video and the action is normal for a diaphragm clutch.
The construction/design of the diaphragm clutch will give you the popping/over centering feeling.
If the clutch is working I would take no further action.
My own diaphragm clutch action is similar.
Converting to a hydraulic system would help but not cure the problem.

You're kidding!
Maybe it will seem better once I get it on the road...I'll proceed with hooking everything up and check that the clutch works under load.