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-   -   Series 3 xj6 stuck cylinder head (https://www.jaguarforums.com/forum/xj6-xj12-series-i-ii-iii-16/series-3-xj6-stuck-cylinder-head-163600/)

DC73 05-30-2016 11:25 AM

Series 3 xj6 stuck cylinder head
 
So ive read everything I can find and tried it all and I still can not get the head to separate from the block. Every nut has been removed and the cam sprockets are detached, I tried using a 3 ton engine crane to pull it up, but it picked up the car and maxed out the crane. I have soaked, tapped, pryed and wiggled everything, every direction possible. Any ideas on another method to remove it without damaging the mounting surfaces?

Darrenmb 05-30-2016 11:34 AM

Have you tried removing the studs???
Bottle jacks will work too.
When i did mine i just attached cherry picker to head and lifted until wheels.were.just off.ground, took two days but went out one morning, car was back on ground and head was hanging on its straps.

motorcarman 05-30-2016 11:49 AM

Loosen and/or remove ALL the studs and go on with your life!!!!!!!!!!!!!!!!!!
Some of the studs will likely stay in the head but can be driven out while suspending the head between 2 work surfaces.

When I worked on these cars everyday, I had 2 identical wood work benches with wood blocks nailed in place (to keep the head from sliding back and forth) and separated EXACTLY enough to have the bottom of the head OPEN to the floor.

The studs were driven out and the holes cleaned with round wire brushes and flex hones.

I use a 7/16" stud remover (the socket type) and clean the threads with a chaser later.
https://cimg0.ibsrv.net/gimg/www.jag...09cb15bda7.jpg


You can inspect and replace corroded studs (especially near the starter) before they break upon re-torque. PAY ATTENTION to the lengths and the PLACEMENT.

bob

Fraser Mitchell 05-30-2016 05:25 PM

Is the engine out of the car on an engine stand ?


Reason I ask is that if you remove the long studs, one or two might snap half-way down, and leave the remnant stub in the block. OK, head can then come off, but you have to deal with these stud remnants. Adjacent to each stud is a core plug that must be removed to get at the bit of stud left in. Using a variety of "mechanics tricks" you need to get these stubs to unscrew, so you can replace with new studs. In fact, a full set of long studs is really essential if the engine hasn't been touched since the 80s.


If the engine is out of the car, getting to these core plugs is really easy, but much harder with the engine still in the car. Taking out all the core plugs also allows you to clear the crud out of the coolant jacket. It can get really clogged up in there, especially at the rear of the block. On the rear face of the block is a cover plate that can also be accessed to assist in clearing out the block.


When I had all the long studs out, I vacuumed out the stud holes, and then had a special tool made up of a plug tap that allowed me to clean up the threads, with some grease to collect the crud. This was a tap bronze-welded to a long piece of bar with a tommybar at the top that went in each stud hole on the deck of the block.


I never had a problem getting the head off the block. I must have been very lucky !

yarpos 05-30-2016 05:30 PM

Just out of interest , why is this such a thing with these motors? I have never seen these elsewhere (maybe just means I need to do more heads). Some resist a bit but nothing like picking the car up and still not letting go. What does this design? material? or just age?

Fraser Mitchell 05-30-2016 05:44 PM


Originally Posted by yarpos (Post 1471990)
Just out of interest , why is this such a thing with these motors? I have never seen these elsewhere (maybe just means I need to do more heads). Some resist a bit but nothing like picking the car up and still not letting go. What does this design? material? or just age?


Steel studs in an aluminium head, with the studs bathed in coolant, as they pass through the coolant jacket. The you have people putting in plain water, so corrosion gets really serious, then age to let it all lock together over time.


The original XK engines up to the mid-sixties had short studs so the corrosion was much less, and getting heads off was not a problem.

o1xjr 05-30-2016 06:13 PM

2 Attachment(s)
Not easy, but we got there eventually using bottle jacks.

Attachment 130856Attachment 130857

yarpos 05-30-2016 07:19 PM


Originally Posted by Fraser Mitchell (Post 1472003)
Steel studs in an aluminium head, with the studs bathed in coolant, as they pass through the coolant jacket. The you have people putting in plain water, so corrosion gets really serious, then age to let it all lock together over time.


The original XK engines up to the mid-sixties had short studs so the corrosion was much less, and getting heads off was not a problem.

Ahh, dissimilar metals, heat, water, age, nice combination. I've only ever done one alloy head motor and it didnt have much age on it. Too bad the later improvements ended up making things worse for the maintainers and restorers.

DC73 05-30-2016 09:20 PM

The engine is still in the car and the intake manifold is still attached, im trying to put a head gasket in it as it has started to leak.

I left it hanging overnight but it didnt do anything and im trying to do everything I can to avoid pulling the studs, breaking them in the block is the last thing I need.

Im worried about hanging it because the car sits so low I have to use a jack so it will clear the cherry picker, and when it breaks loose it will drop the crossmember on the jack, instead of tires on the ground. Not sure how to avoid that

Doug 05-30-2016 09:54 PM

Removing the studs really is the easiest way but, yeah, if one breaks....gah!

I've done the bottle jack method. It works !

If you think you'll want to remove the intake manifold at some point, do it now, while the head is on the block. The manifold gets stuck just as badly as the head does. It's much easier to remove the manifold with the head in place so you have something solid to work against

cheers
DD

NBCat 05-30-2016 10:12 PM

This is quite common with the XK engine if the headgasket has never been replaced.

Spray the head studs with rust remover to free the head from the studs. 'Bottle jacks' can be used to remove stubborn heads if you first spray the studs with penetrating oil to free the studs. Once the studs have been removed, the threads can be cleaned and fourteen new studs installed according to length.


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