I am restoring my 71 Series II. I have tried everything I found on this site to remove the head from the block: soaked the studs, tried to remove the studs with a tool, and got all but two out...they broke off. I tried to suspend it an inch off the ground to see if that might break it lose, but nada! I tried compressed air through one of the spark plugs but it didn't do anything. I am at my wit's end so anyone please give me an idea. I can tell you it was rebuilt in the 90s in Tulsa, OK, before I purchased it. I drove it to and from work in OKC, then drove it to Scott AFB Illinois when I was transferred, out to Robins AFB, GA when assigned there, then to OKC when I retired. It was not overheated when I drove it, but I parked it 9 years ago and started to restore it but lost interest which I have found again.

 

It is possible to get a little bottle jack under the head on the inlet side, resting on the wide section at the bottom of the block, I'm not sure about the exhaust side though. Bear in mind I have never had a head not unstick, so have never done this myself.

Don't take this the wrong way, but have you removed the nuts off the 5/16"studs at the front of the head ? Two each side that go downwards into the block, and two at the front that fix the head to the timing cover .

I am puzzled it won't unstick if it's a dry stud engine, not the horrible long stud version that came later.

 

I tried jacking and had removed the nuts--did that before! I am at a real loss.

 

Have you tried filling cylinders with oil (liquid) installing spark plugs and turning engine over. Can't hydro-lock if bolts are off and might throw through headgasket, but may just pop head enough to get pry bar under it. Might even remove head studs as you need new anyway.

 

I've heard of similar stories. Have you tried simply re-installing
the plugs and cranking the engine over?

 

I will try the liquid route. I have turned the engine over by hand--it's out of the car. I also tried compress air into the cylinders. I did verify all the nuts are off...can't be too careful. I'll say a prayer tonight at church.

 

If all the main head studs are removed, there is nothing stopping it from coming off ! Actually, I don't think you can get the single dowel stud off until the head is off. It is at the rear of the engine but what side it is I can't remember.

Please confirm it is a short stud engine. Sometimes the later long-stud engines get swapped into these cars.

 

Yes sir, it is the short studs engine. I have never seen anything like this! Oh, two of them broke off so there are pieces remaining through the head.

 

OK, you have two short lengths left of two head studs, but with the rest out, and the small diameter, (5/16") stud nuts removed there is nothing holding the head on !!
I assume cam chain sprockets are removed and attached to their temporary carriers. You can leave the cams on, of course.

Could you post a couple of photos from all angles, please, it might jog my memory.

 

If the studs are corroded going thru the head then that could be the problem.
A long time ago I had this problem on a non Jag engine and I used a knife blade positioned at one corner and hammered it in. I tried positioning the knife blaed in the middle of a visible gasket. Obviously there is a risk of damaging the block or cylinder head however I was lucky and got the head and block apart slightly. Still had a lot of work after that but got the head off the block.

 

I'm thinking the electrolysis is getting the upper hand in this issue. Guys at the Jaglover's
site have reported this issue many times. The combination of the length of the steel stud passing thru the equally tall aluminum head is a deadly combination. Most guys, removing these heads start with, first, removing the head nuts, then, start cranking the engine over to try and loosen it all. But, this is all aftereffect.
Perhaps, flooding the stud tubes with Kroil or a similar rust buster product.

 

There is a very interesting video on u tube about removing the heads from a Jaguar V12 engine.
Search 'Jaguar V12 engine head removal'
Paul B

 

Was this head finally removed?

 

Good question....Was the head removed???

I just went through this myself...Stuck head , on my '70 OTS....(4.2L)...
Here's how we did it...
After securing the cams (absolutely first thing), and setting the engine at TDC...
Removed all 20 nuts....Sprayed "safe cracker", and 50/50 acetone-ATF , down
the studs. We made no attempt to remove the studs from the top of the head.(fearing the possibility of broken studs)...
Attached engine hoist to four manifold studs (one at each corner)...I had made lifting straps from 3/4" flat bar...Attached "C" links to each one, then nylon rope across head, back and front, to each "C" link...
Attached lifting hook to both ropes, and put some upward pressure on the hoist.
Using nylon wedges, we drove the wedges with a dead-blow hammer....More pressure, more wedge (back and front...both sides)
Took two guys , 3 1/2 hours to get it off...
What was holding it????...Goop, built up over years, between the studs, and the head....
Getting the studs out of the block was also a challenge....Using a vise-grip near where the stud meets the block, and a pair of nuts , with a lock washer in between , at the top.....VERY carefully, both turning at the same time. A real stud remover, the type that slips over the stud shank, would have helped
tremendously.
Edward

P.S....Should thread sealer be used at the bottom threads of the long studs???

 

I have tried several of the suggestions, including ones from Jag Lovers site, but no luck. I tried wood wedges but the intake manifold is stuck too; it's almost as if someone used a sealant on the head and manifold. I have never encountered this problem before. Anyway, where can I purchase nylon wedges? I am located near Oklahoma City. Time is getting short...the body is almost finished as I am using some GI Bill to attend Vo Tech and get to use my own car as my project. Thanks very much for everyone's inputs. I will get there.

 

Jag does not call for sealer on studs. Light oil after cleaning threads, new bolts, I use an anti-seize on studs smooth area, not on threads, and torque to specs.

 

I know one doesn't use sealants on the head...it just appears someone did on this or it could be the buildup around the studs or even an additive for a "fix leak" that caused this to seal as solid as it has. Again, thanks for all the help, I have a friend making me some nylon wedges.

 

Have you applied heat to the block? Careful of aluminum. Have you tried an electrical heat charge to stud. Like reverse osmosis and let a trickle electric heat on stud to try and melt or burn whatever is holding it. Low voltage at first and build up without hurting aluminum. Or can you put the whole thing in a oven and heat to 200 and see if that loosens things up. Just using imagination here. Hammer what is exposed of studs and create vibration to loosen, done that.

 

If I'm reading this right, there are only two broken studs left in the block....So, they are not the real problem.....Don't forget that you will have to wedge near the front , where the short studs go through....
Don't be afraid to whack the nylon wedges....It will take some patience...believe me....You can also use a long pry bar, VERY carefully,
but don't put more than light force on it...If you get even 1/16" upward movement, drive that wedge in.
If sealant was used, heat , as mentioned , is a good idea....If you use a heat gun, and keep playing it on the corners, followed immediately with a wedge, it might be enough to break it loose....Keep upward pressure with the hoist, as that will be the "key" to getting it off, IMHO.
I had one other "crazy" thought....If you put a hoist on the head, and put enough upward pressure, the whole block may lift....(I lifted the front of the car, slightly)....With a piece of thick carpet, or rubber mat, underneath the pan, if you could lift the thing about 1/2", then use the heat gun, maybe the weight of the block would break it loose....

Regarding sealant on the long/medium studs, I now see that the entire base of the stud is in coolant, so sealant has no reason for being....I am using sealant on the corner (short) studs, however, since they are in the top of the block, and I believe the source of a coolant leak, that caused head removal in the first place.
Thanks for info.

Edward

 

There had been talk at some point of feeding rope into the spark plug holes to fill the combustion chamber, then hand cranking the engine and hopefully lifting the head. Just a thought.