Mini Spares

[GraemeC]

You don't happen to have one of the new fangled cranks without a c-clip do you?

[minimad]

IMG_1192.JPG

Not sure it would stretch the flywheel, more likely the threads in the crank and bolt but the flywheel torque setting is 110-115 ft/lbs not 160+

only torquing the flywheel bolt to 110ft lbs , plus steel flywheel , plus steel crank , plus grey diaphram putting out 130 hp plus equals :

[minimad]

You don't happen to have one of the new fangled cranks without a c-clip do you?

Yes , it is a new fangled crank without the C clip , l got another new flywheel and fitted it exactly as l always fit them INCLUDING torquing it up to 160ft lbs and it works fine now . They have a bronze bush that goes between the primary gear and the leading edge of the flywheel which you have to machine to get clearance and yes l did check that the primary gear could still spin after l had fitted both flywheels . Boss on the failed flywheel is approx 5mm less dia than 2nd one .

[GraemeC]

I have the same type of crank and hate it with a passion.
The fitting of the flywheel and it’s resultant position is not guaranteed to be repeatable - there’s too many factors that can influence where it sits on the taper and it can(will) be different every time.
To use that to set the clearance is just barking, especially as you can’t check it once assembled.

The fact you initially said 160lbft+ ie anything over 160 rather than exactly the same figure every time is just one of those factors.

And yes, I have heard the flywheels move as I swing on the bolt - they will if the torque being applied is enough to get them over anything that has stopped them going further on. They will all stretch a little bit as you tighten them - that’s how you get the interference fit needed (they don’t actually stretch but the metal goes into elastic deformation, similar to a properly torqued bolt).

Given the chance I would go back to a standard design crank at the drop of a hat. And despite the marketing, I’ve not heard or seen of one crank breaking at those grooves.

[minimad]

I have the same type of crank and hate it with a passion.
The fitting of the flywheel and it’s resultant position is not guaranteed to be repeatable - there’s too many factors that can influence where it sits on the taper and it can(will) be different every time.
To use that to set the clearance is just barking, especially as you can’t check it once assembled.

The fact you initially said 160lbft+ ie anything over 160 rather than exactly the same figure every time is just one of those factors.

And yes, I have heard the flywheels move as I swing on the bolt - they will if the torque being applied is enough to get them over anything that has stopped them going further on. They will all stretch a little bit as you tighten them - that’s how you get the interference fit needed (they don’t actually stretch but the metal goes into elastic deformation, similar to a properly torqued bolt).

Given the chance I would go back to a standard design crank at the drop of a hat. And despite the marketing, I’ve not heard or seen of one crank breaking at those grooves.

l bought one of MEDs kits and it came with this kind of new fangled cranks as part of it . l had never had experience or even heard of the old syle cranks with C clip breaking @ the C clip ever before and myself ( being the suspicious type of person that l is ) thought that it was really just a marketing ploy to save a machining operation therby making it cheaper to manufacture . l'm like you Graeme , if l needed a new crank l would not go for one of these non C types again .

[GraemeC]

And annoyingly, they will supply with the grooves if you ask. But they don’t tell you they have that option when you order.