Cylinder Head Torque Settings, Vitesse 2Ltr

[Peterrc]

I have had my cylinder head converted to unleaded and am about to refit it.  The recommended torque setting, Triumph and Haynes, is 42 to 46 Ft Lbs.   I discussed this with the machine shop as I thought that was a bit low.  He produced a booklet that said that is the setting for 3/8 inch studs.  I have 7/16 inch studs and he says the torque setting should be 60 - 80 Ft Lbs.  What do the 'Experts' think?

[Richard B]

7/16" (MkII studs) is 65 lb/ft


the 42 -46 lb/ft setting is for MkI studs

[Peterrc]

Richard_B wrote:

7/16" (MkII studs) is 65 lb/ft


the 42 -46 lb/ft setting is for MkI studs

Thanks Richard that makes sense.
Peter

[Pete Lewis]

please also  check the washers are flat and not suffering distortion from the nuts,  all  3/8 studs are the 42-46  and Mk2 with 7/16" studs are 65+  to achieve these torques you need lets  call them heavy duty washers and nuts or they will easily strip or loose torque in early life
canley sell the correct ones .

for example a std 3/8unf nut is 29-31 lbsft   and 7/16"unf  s 42 -46    so as heads pant about a lot the torque is increased and high quality nuts and washers are imperative to make a lasting job .

Pete

[Velocita Rosso]

.....and no one has mentioned, if refitting the head it`s wise to fit new studs and nuts.
If you have no knowledge of how many times the head has been off before, you may not know how much the studs have stretched