Hello great jaguar minds,
Does anyone know the correct torque figures for the two longest head studs to the block on my 1989 XJS V12. I am replacing all 20 of the longest studs, these are the ones either side of the liners, and I'm struggling to find any kind of information

Thanks,

Neil.

 

l would think you need the same length stud inserted to the same depth as the original. You will not have a torque value as such with no load on the stud.

 

check out ARP for info on stud replacement!

 

If you are asking about torqueing the STUD only into the block, not the nut on the stud when the head is being replaced, just wind them finger tight to the bottom of their holes having cleaned the threads in the block carefully. They do not have to be tight on the block threads. The nut on the stud squeezing the head down does the torqueing, as Baxtor said.

 

The torque setting for the nuts are 51ftlb for 7/16 and 28ftlb for the 3/8, there is no torque spec for the stud in the block, screw them in as far as they go.

 

Thanks for the replies, much appreciated, I suspected there would be no exact figure due to the thread depth in the block in relation to the thread length on the stud. Just need a second opinion.

Thanks again,

Neil.

 

I'll see this tomorrow. I have this data.

 

 

very good xjsv12,, good info.
ARP sells hundreds of thousands of studs, bolts, nuts of all types with much R&D .

and that is what they say about studs into aluminum castings, besure threads are clean and tighten stud down to around 8/10ft lbs, you want the stud to be tight enough so NO movement will occur later when in use!

NOW someone in has installed the steel thread inserts down in the block( maybe the turbo boats in AUS), but that maybe overkill,donno!

 

"DONNO" This is slang. It means "I don't know the answer" or something else???
I have difficulties with translation. Sorry.

 

Studs in Aluminium tend to catch then snap. My 6.0L block had a couple of studs snap so the block has had Time Serts installed.