Yup, I've got a deep 12mm that fits one of my torque wrenches. I wasn't sure if it was working properly (the wrench), so tried switching back to my old school gauge one which has a 3/8 drive rather than the 1/2in on my deep socket. That slipped on the bolt and caused the rounding on the shoulders seen there. Once I've tightened the bolts I'll retry with my deep socket and torque wrench.

Cheers, Ben

Crap. I tightened the stud, and started torquing the head bolts. SNAP! Hmm - either I'm stronger that I realise, 18ftlb is a lot less than I think it is, or the stud was weakened.

Of the previous description of Rick's torquing of head bolts, I struggle to believe that these took the correct torque. Luck was slightly on my side - I managed to get the rest of the stud out of the block. But - it seems Ecas don't list them...... I guess I should replace the rest of the studs to be on the safe side ?

therin lies the problem of "guestimation"

get it wrong once and the dammage is done

Are studs normally changed during a head change? AFAIK some cars specify this when replacing head gaskets.

Got a new set in the post from Mr Pembro, hopefully fixed before the end of next week!

No
unless pitted with rust

some tuning websites specify a very high torque, but as its the original studs and original alloy casing i tend to keep to the higher end of the factory range 1kgfm( 10Nm or 7ftlb) first then 2.5kgfm(24.5Nm or 18ftlb) "front back bottom"

studs should be tigtened to 1kgfm(7ftlb) in the cases before the heads are fitted

Sean

Ben,
wonder if it's worth checking the calibration of your torque wrench?
Or sacrifice an M8 bolt, by putting it in a vice with a couple of washers and a nut on it, then winding the nut up to the same torque as you used on that head stud which sheared?
Most stock bolts are likely to be 8.8 grade or lower, which will be less stern stuff than that of which the head studs were made.

There must be a certain irony involved in obtaining s/h head studs from Rick, btw...

ken.

Ha - yes, I see the irony

I'll see what I can do with regards to checking the calibration of my torque wrench. I'm still quite shocked that I managed to shear the stud!

not really that shocking

the studs can be quite badly pitted also if its already been strained and your not used to applying the correct torque there is a tendancy to give it the beans with a ratchet thats twice as long as you normally use and hence applying twice the force

also remember to stop as soon as the wrench clicks dont be tempted to give it "a wee bit more to be on the safe side"

take care also that if you use the metric scale that you dont give it 25Kgfm rather than 25Nm. Kgfm is 9.81 times that of Nm

Sean

new to me studs and washers fitted. Tappets set, and it's running and sounding like a 2cv should!

Thanks for all the help!