Are the bolts special, only I have some spare new fly wheel fixngs bolts which are the correct thread, are they OK to use ?

They will be fine as long as you can cope with the rather thin head of the flywheel bolts when doing up/undoing them.

They are a high tensile grade and certainly holding the flywheel on is a more taxing task for them!

the bolts supplied with my westfield prop were 10.9 grade which are stronger than the common 8.8 grade bolts

on my diff they where metric 1mm thread

normal thread is 1,5 also they use 1,25...


Regards

Walter

Normal 8.8 will do fine ---propshafts on cars in the pre metric days used 5/16" UNF Grade 8 without problem.

As with all flange joints it is friction that transmits the torque so as the bolts are sufficiently tight all will be well. Recheck for tighteness after initial run and again at 500 miles.

[Edited on 4/3/05 by britishtrident]

<quote>
As with all flange joints it is friction that transmits the torque so as the bolts are sufficiently tight all will be well. Recheck for tighteness after initial run and again at 500 miles.
</quote>

Thats not true...

Its a combination of friction and bolt type etc. when you put torque on a bolt

and let it rest the torq is less. (a bit)

if you choose a higher grade number then the torque that you lose is less...(and you are able to put more torque on the bolt also..)

Soow in fact it isn't the friction that trasfers the force its the property of the bolt that wants to his starting position and that generates the torque...

TKS

What BritishTrident meant though was that whatever the type of bolt, all the bolt is supposed to do is pull the flanges together such that they can transmit the torque via friction.

Thus the camshafts on a Zetec engine, no keyway or anything else, just one centre bolt. The pulley transmits the torque to the camshaft using friction alone.!!