9 replies to this topic

[samsfern]

hi all, today i decided to change the fanbelt on the mini, i had to use some leverage between the crank and radiator mount bracket thing, then i noticed that the crank pulley was moving back and forth, so i presumed the bolt must be loose, so removed rad so i could check, the bolt was tight! That says to me that its endfloat in the crank, its a lot more than normal!

[Stevie W]

Yes!

Certainly seems to be excessive crank end float which means your crank thrust washers are FUBAR!

Are you running an excessively heavy clutch diaphragm? Maybe the clutch throw-out stop is not adjusted correctly and placing too much force on the thrust washers when you press down the clutch pedal.

I believe excessively worn thrust washers can drop out with disasterous results!

I think it's time for an engine out, split from gearbox and replace the washers, sooner rather than later.

Steve.

Edited by Stevie W, 20 March 2010 - 08:11 PM.

[samsfern]

hi, thanks for the reply, im running a standard clutch pressure plate with an uprated friction part, its a verrto clutch setup and the two big nuts are adjusted correctly as the book says. There is some chattering going on when its not moving, but i think that down to the fact that it has straight cut drop gears, so not sure there, it doesnt knock when i pull away or anything.
I wanted to wait until the summer before i going tugging engines out, but to be honest im not worried if it does go, as ive got another modified engine out of a mini i rolled, to go in. But if its still good by the time i get round to doing the swap, then ill rebuild it.
Thanks, sam

[Pauly]

I wouldn't wait for it to let go, if theres noticable endfloat on the pulley end then its sounds like serious wear, better to inspect now rather than later when you have a scrap engine which you wont be able to sell on.

[samsfern]

saying that i may pull it out the sunday after brooklands then.... I would have liked to wait for things outside to warm up a bit though.

[Sprocket]

Which bit are you levering? If its the outside of the crank pulley, it could just be the pulley. The pulley is a two piece unit with a rubber isolator in the middle. The outer edge will move relative to the center with enough force.

Easiest way to ceck the end float is to fit a DTI gauge onto the center of the crank bolt, then lever the crank towards the driver side. with the aid of a second person, get then to depress the clutch. the deflection measured on the gauge is the end float. much over 0.005" needs investigation

[samsfern]

i was levering on the outside of the pulley, but it didnt feel as though it was rubber moving. I think ill have to investigate further tommorow then thanks

[Paul Wiginton]

If you have no more than 7 thou float and the revs dont drop when on the clutch then its fine.
If its a good spec engine it could have built with upto 8 thou float, I build mine to this figure - as do many racers

[Ethel]

Also the bolt could be tight in the crank without actually pressing on the pulley. Pull the pulley then try pushing on the bolt.

If you have no more than 7 thou float and the revs dont drop when on the clutch then its fine.
If its a good spec engine it could have built with upto 8 thou float, I build mine to this figure - as do many racers

[bmcecosse]

I agree - check the ACTUAL movement of the crank before getting into a panic! It would have to be massive to let the thrust washers drop out - i've never heard of such a thing happening. Up to 10 thou is fine, anything from 10 to 20 is obviously not ideal, but not anything to panic about either.