cylinder head

[g4pyd]

Hi,
I have looked but can not find any torque setting for cylinder head nuts, is there such a thing?If not how do I do tighten them up?? mine is 32 sv..
Regards Colin

( may not be able to read replies for around a week it all depend on wifi at campsite)

[Trevor Wilkinson]

Having stripped the odd thread at 25lb/ft I now settle for about 22lb/ft. you will need to re torque quite frequently during the first 500 miles or so.

[Ian Grace]

I've had the same problem with several head nuts over the years, so I always replace my head nuts with new high tensile nuts which are far less prone to stripping than the original mild steel nuts. Of course it also helps if the stud threads are in good condition.

[Toby]

This has been the bane of my life over the last 6 years! "tight" is the official morris figure, I agree with Trevor, I have snapped/pulled studs and cracked a block at around 24lb. Catch 22 is that ideally on an engine this old that has been regularly decoked for the first 20 years of it's life new studs would be best, the drawback is that trying to renew the studs invites more trouble! I do them to 19lb/ft then go round again with a spanner by feel. The beauty of a spanner is you get more of a feel for the job. Run it up hot then retighten a bit by hand. My Bentley ownerfriend can't believe 19-22lb would work and describes it as "not even tight"

[Ian Grace]

Right Toby, I have never liked using a torque wrench - prefer to feel what is going on. And we've all had that sinking feeling when tightening with a spanner that LITTLE bit more and you feel the thread giving way.

I took my fabric saloon on the 1994 VSCC Jubilee rally - trailering it over to Malvern from Germany, where we were living at the time. A valve spring broke on the Light Car rally and the head had to come off back at our rented cottage the next morning. I managed to find a spring in a local bike shop and had the head back on in an hour or so. I ran it up and all was fine, except there was a slight weep from the oil feed to the head. I nipped the bolt up a quarter of a turn and the *&^%$# thing sheered off - flush in the head!

Put car on trailer, take it into Malvern, visit a Morris 8 friend to find a replacement 1/4 BSF bolt of about the right length, over to a workshop to have the broken bolt drilled out and head thread cleaned up. Back on the rally later in the afternoon. So another lesson learned - with 100 psi to contain, this bolt has to be done up TIGHT, so I always use new ones in this position now.

[Trevor Wilkinson]

Surely the idea of a decent torque wrench is that it takes the guesswork out of "feel". " Feel" can alter depending on the position of the spanner and the position/accessibility of the nut being tackled, a torque wrench will always give the the same tightness.

[Ian Grace]

A torque wrench is obviously a good idea, but on the OHC engine at least, it is all a matter of accessibility - as the OHC rocker shafts run across the top of the head nuts. And if you fit the bronze rear rocker shaft support, the two rearmost nuts are underneath it and very difficult to get any sort of spanner on them when the engine is in the car and the rear end of the head is close up against the firewall.

Peter Hills has commented further from India:

"For DS 9936 (M10228) I worked on the problem and since I had the cam support extension phosphor bronze bracket from Mike Dowley of Sports and Vintage. Longer head studs helped for a start. However to tighten the head requires investing in a set of claw sockets, then throw away those not needed! You need to modify the 5/8 BSF by carefully grinding the outer material to permit full movement when mounted on certain nuts. The real benefit was doing it when ‘hot’ and the car had noticeably more power."

[Simon]

I acquired a 13mm x 3/8" drive crowsfoot socket at Beaulieu and ground it out to fit 5/16" nuts. Colin Lee has used it without complaint!! I do not know what torque he used, must ask him.

[g4pyd]

Hi everyone, Thanks for all the Info all Taken in,when I had my rebore the engineer took all the studs out and what ever he ecountered is anyones guess, What is a Crowsfoot socketis it for a OHC engine cos mine is a Sv,
I have stripped a stud in the Block and have a question regarding this but will start a new thread( no pun intended.)
Thanks again for helping what a fantastic site this is Colin (still drying out after Hols)

[TomDrewett]

Crows Foot is something like this http://www.teng.co.uk/m386513-c-teng-to ... 136_pd.asp

Marvellous things, it took me an age to figure out how to torque down the cylinder head on my M Type due to lack of space for a spanner or socket until somebody suggested one of these. I hope its of help. Tom

[g4pyd]

Thanks Tom, I was wondering how to get at number three nut under dynamo when retorquing when warm
Colin