7 replies to this topic

[AndrewM]

Hello there,

As the title says I have a 1968 MK2 Cooper which is currently being fully rebuilt and restored.

 

Current task is rebuilding the Engine and gearbox which is going well so far!

 

I am in the process of assembling the flywheel and clutch parts and am trying to find the torque figures for tightening the 9/16" bolts (six of them) which hold the flywheel hub to the flywheel (2 part flywheel). I plan to use star washers as originally specified along with Loctite on the nuts just to be on the safe side, but I have searched Haynes and BMC manuals along with TMF search all to no avail for the torque figure. So does anyone out there with experience of these early flywheels know the answer?

 

 

[DeadSquare]

May I quote my BMC manual, of about that date,

 

"Set screw,driving strap to flywheel....16 ft lb"

"Set screw, clutch spring housing to pressure plate....16 ft lb"

 

 

So I should think that the 6 bolts that you mention, would be the same.

 

As a matter of interest, why did you remove the hub from the flywheel, and did you mark both pieces so that you can replace them correctly ?

Edited by DeadSquare, 19 January 2026 - 09:40 AM.

[Spider]

If this is the Hub to the Flywheel, there were no star or other washers there. Torque for them is 35 lb/ft and the small amount of protruding thread is staked in 3 places.

If you mean the back plate and the drive straps, as Deadsquare has said.

[AndrewM]

Hello DeadSquare and Spider,

 

Many thanks for the swift replies!

 

DeadSquare - Thanks for the torque figures for the fixings on the flywheel itself. I removed the hub from the flywheel in order to get some machining done on the flywheel and rest assured I marked it and the hub for orientation to aid reassembly. 

 

Spider- Thanks for the torque figure for the 6 hub to flywheel bolts, the reason i mentioned the star washers was that I took some off and they are also listed on the Somerford parts page relating to the 2 part flywheel  https://www.somerfor...heel-and-clutch

I was planning to 'stake' the threads as you suggest as I noticed this had been done when I removed the nuts.

 

Thanks again. I can get back in the workshop and crack on now!

[DeadSquare]

To centre things; 

 

Wedge the crank verticaly, tail up

Oil and fit the primary gear.

Slip over the pressure / back plate.

Fit the clutch plate and ensure that it slides easily on the splines.

Slide the flywheel gently onto the taper.

Align things, insert bolts and almost nip them.

With a little tap here and there, test, holding the primary gear and lifting the flywheel, it should slide easily on the splines.

When you are satisfied, tighten a bit at a time.

Edited by DeadSquare, 19 January 2026 - 02:12 PM.

[Spider]

Hello DeadSquare and Spider,

 

Many thanks for the swift replies!

 

DeadSquare - Thanks for the torque figures for the fixings on the flywheel itself. I removed the hub from the flywheel in order to get some machining done on the flywheel and rest assured I marked it and the hub for orientation to aid reassembly. 

 

Spider- Thanks for the torque figure for the 6 hub to flywheel bolts, the reason i mentioned the star washers was that I took some off and they are also listed on the Somerford parts page relating to the 2 part flywheel  https://www.somerfor...heel-and-clutch

I was planning to 'stake' the threads as you suggest as I noticed this had been done when I removed the nuts.

 

Thanks again. I can get back in the workshop and crack on now!

 

It is possible some may have had Star Washers in here, I've not seen them, however, I've never fitted them up with Star Washers and would never do so as they are 'frail' and have a habit of splitting, especially under these higher torque settings. I find it odd too that they would use Star Washers when they Stake the threads.

 

I can't say for sure, but I * think * there's an error with the Somerford listing (they are usually very reliable). I agree they show a 3/8" Star Washer (item #4), however those for the Diaphragm (item #45), what are also a 3/8" Star Washer thy list as being NLA.

[DeadSquare]

I was once bawled out by a Civil Aviation Inspector for using a centre punch to make 3 indents to spread the 'bottom' of some bolts that needed to stay in place and would be replaced at the next overhaul, because it was "archaic and had no place in the modern world".

 

As I pointedly rubbed my finger over the wedge in the hammer handle, his voice dropped and faltered.

[Spider]

I was once bawled out by a Civil Aviation Inspector for using a centre punch to make 3 indents to spread the 'bottom' of some bolts that needed to stay in place and would be replaced at the next overhaul, because it was "archaic and had no place in the modern world".

 

As I pointedly rubbed my finger over the wedge in the hammer handle, his voice dropped and faltered.

 

I do use Loctite and have great faith in it, however, I'm still 'archaic' with certain fasteners and stake them. Low tech but works and can be seen that it will work, it gives a very high assurance !