Engine seems to be blocked

thanks Paul but to difficult for me.
i’ll modify my tools to put bigger diameter bolts
I’m trying phosphoric acid around studs, then I’ll try to heat stud with electric welder as described in Kirby’s.
By hitting gently the studs with a metallic hammer you can hear a music sound or a tac. if music sound the stud is free, if tac the stud is seized.
2 big studs at each end are free, all the small along exhaust side are free to. the rest is not and that makes a lot!!!
I’m afraid it will be very long to succeed if i don’t want to break anything

Yes, it will be: patience is a virtue!

Nothing moves, so I ordered a big metal plate and will built the magic tool.

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All the holes drilled, holes taped. metal plate fitted on the head, I’m doing all the threaded rods.


Put the magic tool in place, then screw the threaded rods slowly and carefully but nothing happened. I will modify the tool. Replace the 10mm rods with 12 mm long bolts with the nut under the metal plate ( not convenient to screw but…) and put something to prevent the rod going out of the stud.( small tubes)

Yes that seams to be the way to go.
Clearly the 10mm rods are too weak.
And if you put nuts underneath, maybe put the bolts with the head down so you have more contact area?
Just a thought.

After one week skiing I’m back with my problem.

Plate modified for 12mm bolts, small tubes to prevent the bolt to go out of the stud.But unfotunately as you can see on the second picture no move. The head is still sticked.
I have no more idea, I’m afraid of the strength applied to the tappet block bolts.
What shall I do??? Any idea?

Having never done that I can’t offer too much help…
Did you soak the studs with penetrating oil?
Maybe some kind of percussion action could help to break the bond, like with a hammer drill and a blunt chisel on top of the bolts?
Hope others will have more ideas.

The studs are have been soaked in WD40 and other different mixture for several days, I tried the hammer on the bolts to. The last idea was to rebolt the exhaust and intake manifold and push on them from the bottom with a jack and wooden blocks.
Another is heating, but what to heat ( head, studs?) and what method?

PB Blaster works much better than WD40, IMO.

Have you watched YouTube videos of The Camp Chaos Chronicles? Jaguar Preserve. He has some great videos showing difficulties removing the heads from a V12, and how he proceeds.

As Greg states, WD-40 is not the thing to use: it is not s particularly good penetrant. PB Blaster, or Kroil are.

I see that you have only seven bolts to the tappet block.
Aren’t there more threads available to secure the plate better and share the load?

My two cents…if you’re having this much difficulty its time to take it to a professional. If you get one of those heads cockeyed you are really in trouble.

Agree with the recommendation to watch the Camp Chaos Chronicles on YouTube…he has a whole video dedicated to this topic.

I think I watched all the video about that subject on youtube, and respect their recommendations but I think I am in a bad situation. I’m afraid the guy who sold me the car didn’t respect jaguar recommendation for coolant replacement every 25000miles or worse put some water!!!
I’m going forward putting more liquide everyday around the studs and wait.

It’s coolant change every two years.

And even so, I’ve heard these head gaskets are prone to rust. I know someone who’s dismantled three V12s, and every single one had some rust around head bolts, and head gasket was in a sorry state.

And im curious, why are you pulling heads? I thought your initial issue was timing chain. Or do the heads have to come off to access timing chain?

my first idea was timing tensioner but after dismantling I saw a valve stuck open, so I have to remove that B head

Any progress to the up direction?

I’m testing the magic mixture ( aceton ATFoil). I will wait and try to remove a stud because the short ones doesn’t semms to much blocked.Wait and see.


today, by turning the bolts , first tapet block bolt broken. I don’t know what to do now . Throw that car away!!!

Salut Yves,
That’s bad news indeed…

Did the bolt actually broke or it striped the threads?
If the later, a helicoil could fix that?

Is there no way to add more bolts at the tappet block?