7 replies to this topic

[Aridgerunner]

I know the overthrow nuts have been discussed over and over for years. I think I've read every post on the subject. And I think I've read that they are not needed when using a lightweight flywheel. What I never learned is why they're not needed.

In my case I am using Mini Spares lightweight flywheel, pressure plate, diaphragm, clutch disc and their hardened plunger and a new release bearing and new overthrow nuts. It's all new from the crank to the arm. And the arm was replaced shortly before we decided rebuild everything.

I will be most thankful to anyone that explain why they're not needed with a lightweight flywheel.

Thanks in advance.

Bill

[nicklouse]

They are needed with all flywheels.

 

mine are Ti.

[Ethel]

You'd never release the clutch if there wasn't something behind the pressure plate to push against. That something  is ultimately the crank thrust bearings and the throw out stop nuts are there to prevent you pushing on the thrusts any harder than is necessary to release the clutch.

[Aridgerunner]

Thanks. I had no plans to remove them. Was just curious.

[imack]

I run them on my KAD alloy flywheel, but I've never set them by the book as I hate the feel of hitting the throw out stops before the pedal hits the floor. I set them so the pedal hits the floor at the same time that the throw out stops bottom out. It's never caused me any issues.

[timmy850]

The earliest Mk1 minis didn’t have the overthrow nuts. They also had:
Spring type clutch (not diaphragm)
No circlip in the slave cylinder

This meant that you could pump the pedal a few times and it’d lock up the crank on the thrusts or crack the main bearing caps

On later engines there was less risk of this happening, but the overthrow nuts are a good last resort to stop too much pressure on the thrusts. If they are adjusted correctly you’ll not have any problems

If you adjust them in too tight there is a chance you’ll bend or break the end off the clutch arm. If they come loose and wind in they’ll prevent the clutch disengaging and you won’t be able to select gears

[nicklouse]

Had may a Mini in the 80s that did not have the C clip on the clutch slave. It only became a thing when the verto slaves had it. 
break the ball off? Only if very worn and that would be after bending the arm or lengthening the push rod to take up the play.

 

still very possible to lock up the crank without the stops.

 

light flywheel normally also means stronger spring.  
 

the only time I have seen the lock nuts not used was on a Grass track car with a dog box.

 

But they rebuilt the engine between events.

[Spider]

The earliest Mk1 minis didn’t have the overthrow nuts. They also had:
Spring type clutch (not diaphragm)
No circlip in the slave cylinder

This meant that you could pump the pedal a few times and it’d lock up the crank on the thrusts or crack the main bearing caps

On later engines there was less risk of this happening, but the overthrow nuts are a good last resort to stop too much pressure on the thrusts. If they are adjusted correctly you’ll not have any problems

If you adjust them in too tight there is a chance you’ll bend or break the end off the clutch arm. If they come loose and wind in they’ll prevent the clutch disengaging and you won’t be able to select gears

 

Just to clarify here, it was early in 1961 that they did fit the Over-throw Nuts and they still had the Spring Clutch. They got sick to death of fishing worn thrusts out of the gearbox under warranty,,,,