• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

XJS V-12 Cylander Head Removal

Share this page

M

Michael J.

Jedi Warrior
Offline
Help!!

I have a blown head gasket. I have all head stud nuts removed, but head will not loosten. I have been soaking the studs with WD40 since being told that it is not uncommon to have water rust and swell the studs binding inside the head.

Any suggestions? I have a hoist hooked up but can't pull at the angle for the studs. I am afraid to pry on the head.

I also had a problem with the chain tentioner. Service manual shows special tool , two piece, that hooks onto cam sprocket and has a rod that somehow hooks to tentioner. Instructions don't quite explain how to use it. The tools are not available. I was able to releace the catch, but I don't understand what the two piece tool was supposed to do, assuming I actually could have found one.

Any suggestions?

I'm Stumped on both.
 
You could try the "rope-a-dope" trick (I know Basil's mentioned it at times).

Remove spark plugs and thread some light rope (clothes line) down the plug hole. Turn the engine carefully, with a wrench (front pully) and the piston *might* push the head off. The best cars to do this with have manual tranmissions (you can push them in gear)....I wouldn't use the starter to turn the engine.
 
not an easy task I am afraid especialy if the engine has ever been run while low on coolant (it practically welds the thing on there) and unfortunatly there is no quik fix. The idea of useing the cylinders to push the head off sounds quite cunning as long as you are very careful. Here in merry old england it would be cheaper and easier to put a new engine in, as v 12 engines are a dime a dozen. The best advice I can give is be very careful, done wrong it could become very expensive very quickly.
lol.gif
 
Go HERE and search under "All or mOst cars" and the category "Head". You will there find a link to a detailed explaination of the "rope trick." It works.

Cheers,
Basil
 
I’ll second the “rope-a-dope” trick…..I’ve used this method to unstuck valves that are stuck open. The best type of rope I’ve found is 3/8” nylon, as it has enough “body” to thread into the plug hole. One word of caution….don’t use polypropylene rope…..I’ve had it sheared off by a closing valve and it was a B#*%h to fish it out of the hole. Does the V12 have hemi chambers? (pardon the ignorance) if so, you’ll need a good sized length of rope to do the job. Also, PB Blaster (sold at WallyWorld) is a better penetrant..IMHO.

Best of luck to you

John
 
Here's how it turned out; because the coolant has radiator sealant added, and because the head studs do not sandwich the head gasket between the block and heads other than on the perimeter, there is enough rust and stop leak on each stud to glue the head on. I used a small two ton jack and a crowbar with wood blocks to "walk" the head up the studs. 90 minutes for each head. The perimeter studs did not have this problem, only those in between the cylander liners. On the two engines that I have taken apart, one at 57,000 miles and one at 91,000 miles, the head gasket rots away in those areas and still looks like new in places where the gasket is sandwiched.

Tank you everyone who offered advice.
 
Back
Top