21 replies to this topic

[1989flame]

my crank bolt keeps coming loose ive bent the tabs over too but it still does it
WHY ? somebody help please

[semag]

Firstly, which type of clutch are you using? If its a verto, are you knocking the tab into the flywheel cutouts and not around the nut flats. If its pre verto, the tab needs to be over the flat on the flywheel.

[liam_italian]

Are you tightening the bolt to the correct torque?

[1989flame]

im tapping it over into the cut outs

[dklawson]

I guess I am thinking differently. Are you talking about the bolt on the flywheel end... or the crank pulley end?

[SA MINI]

Is the crank pulley wobbling around when the bolt is loose. Or is it still firmly sitting on the crank ?
I've seen many of times on other cars the crank pulley has either cracked or worn causing the bolt to loosen.

[morley]

I'm guessing pulley end, are you locking the engine to stop it from spinnying when tightening? and are you torquing it to the correct setting?

[1989flame]

no its the flywheel end

[bmcecosse]

Crikey - suggests extreme vibration to me.... Has the flywheel come loose ? Can only suggest a NEW bolt and tab washer - clean the threads on bolt and crank with thinners - good splash of Loctite Threadloc - and tighten up to the correct torque - and put the lock tabs over very firmly. Leave the Loctite to set overnight before running the engine........

[1989flame]

ive done that now cheers

[dklawson]

What actually happens is the flywheel pulls up it's taper further and in doing so. Releases the pressure on the bolt. The reason this happens is heat, as you tighten up the bolt a fair bit of heat is generated.

????
Where did you hear that? I don't agree about the flywheel pulling itself up on the taper or with heat generation being significant but there certainly would be no harm in re-checking the torque before bending over the lock tab.

[tiger99]

I think that the heat would be relatively insignificant, but what would help is lapping the taper to get a good fit.

[mini13]

what will happen is the taper will creep a bit with engine heat and heat from the clutch.

I preheat my flywheel and then stick it on, and use about 200ftlb.

[dklawson]

Mini13, what you are suggesting is a shrink fit... like when fitting a ring gear. That makes sense. However, it must be heck getting your flywheels back off.

[dklawson]

I didn't "rubbish" anything you suggested doing. I specifically said it would do no harm re-checking the torque before bending the lock tab.

What I do question is how/why/where you heard that torquing the bolt generates enough heat to affect the fit of the components.