With that not being much of a stretch - I finally managed to get the head off my S2 4.2. I was unable to load pictures tonight but I will post them shortly.
It appears that the head may have been done once shortly prior to my ownership. All of the stud bolts are in great shape with those at the front and back still cadmium plated.
Here's the thing - aside from buggering up the head gasket removing it, there seemed to be little wrong with it. The block mating surface looked really good too (pics coming). I understand that aside from gasket failure a cracked block will result in coolant in your oil and cylinders etc. The studs at cyl 2 and 3 had coolant all over them when I removed the acorn nuts before I even had the head off.
There is a lot of blackened flaky crud in cyl's 3,4,5 with a little in 2. Can I assume that it's from burning coolant? With a quick visual inspection I didn't see any obvious cracks but I'm not sure where or how to look. Can there be issues with the head - not the block causing all of this nightmare?
The symptoms were:
-Overheating
-fluid in exhaust
-white clouds of exhaust smoke

Thanks for any and all direction.

Solo out

 

Not unusual. This is a "wet stud" engine. I never understood why. The washers under the cylinder head nuts are 'supposed' to keep all the water inside

A dab of sealant where the studs come thru the gasket will keep coolant out of that area.





The burning coolant steams away all that carbon so it sounds like #2 might be where the problem is





Foggy memory here but I recall the cracking usually occured between cylinders right at the top---at the head-to-block mating surface. Others will chime in.




Sure. For one thing, it might have a slight warp that prevents the head gasket from sealing. Fairly common


Cheers
DD

 

I'd suggest you have the head checked with a machinist's straight edge to make sure the head is not warped. You should also have the head pressure tested. Sometimes a crack can form and open up when the heads get warm. Pressurizing the head with about 20 to 30 PSI should do the trick. If you found no head gasket deformation and find no cracks or warpage in the head you can deduce its the block. To verify install the head with a new gasket and pressure test the cooling system again with up 20 psi of shop air. Use a valve up stream of the pressure gauge so you can see if the pressure holds over time. It would be best to use block off plates to seal up the motor so you'd be testing just the heads and block and not the radiator and hoses. I don't think block off plates or caps exist for an XK so you have to make them or source them from other applications. If you do have a leak under pressure, get out the bottle of soapy water and check all the external points. If no external leaks can be identified use a mechanics stethoscope to listen inside the cylinders through the spark plug holes.

This thread may be worth a read in your case.

https://www.jaguarforums.com/forum/j...-1987-a-32768/

 

Look for cracks between cylinders 1-2, 2-3, 4-5, and 5-6. The cracks will be in the cast iron, not the liners. With bad blocks, (like I had !!), there will be visible sinkage due to the loss of bridge strength in the casting. You might have to polish the block surface with some fine emery paper to see them. If you have them, the block is scrap unless you put lipped liners in. This involve a complete engine strip and rebuild. Or you can find a later engine from a post-82 car.

If you just reassemble and don't do any repairs, you will suffer continual head gasket failures. Don't ask how I know !

 

Thanks guys for the great info. I figured I'd bring the head to my machine shop and let then do an inspection while I give the block a good once over. So, not cracks evident yet but have a look at the pictures and see if there is anything that you don't like, guys.
Head bolts look newer and the block surface visually looks good with no corrosion around the coolant holes. Trying to get the bloody thing off I did manage to break something else. The upper timing chain roller guide. I have to pull all of that out now. grrrrr!

 

Off topic, but.....

Obviously NOW is the time to address any repairs to old, brittle wiring, vacuum hoses, coolant hoses etc. You have lots of working room.

Cheers
DD

 

The pics show what I would expect, but to check for the cracks I mentioned, you need to polish the metal between the bores and look for hair-line cracks. These cracks start at the water passage about 1" below the deck of the block and creep up until the deck is reached. The head gasket is not sufficient over the 1/16" thick liners to stop combustion gases from going into the water jacket via the crack, pressurising it, and forcing out the coolant via the expansion tank and pressure cap.

The good news for you is that your block, a "7L" type, is less prone to cracking than the later "stronger" 8L blocks. Eventually in the early 80s, the water passages were redesigned as vertical slots on the top of the block, and the liners were eliminated.

 

I did read elsewhere here that my 7L block is beefier so I hope it holds true. I am resisting any big 'might as well' adventures but there is a lot of cleaning and detailing to do.
In the mean time I'll send my exhaust manifolds out for ceramic coating, bead blast my own parts at my shop.
Ok, Is there anything I can't clean the block with that may affect the cylinder walls? ?
Big one - how the #@!&% do you get the front cover off the engine? I have a spare block at my shop I am tinkering with and I have no idea how to get it off. All bolts are undone and I am ready to use a prybar on it. I need to get this thing off.

My wiring harnesses are all new.

Thank you for the continuing support...

 

Quote:

Big one - how the #@!&% do you get the front cover off the
engine?

Put that pry-bar back into the cupboard right now !! Front timing cover is secured to the sump at the bottom and to the head at the top. It is not designed to be removed unless you're overhauling the engine.

Anyway, here's a tip. When you do have the timing cover off, check the casting walls by the water passage from pump to block. They can be so corroded, the wall will eventually fail and let coolant flood into the engine. If you find one off another engine the block has to be faced with the replacement cover bolted on or you'll get a lip where cover and block deck meet threatening the integrity of the head gasket seal.

 

Yup, looks like many another critter in similar circumstance. Agree, the gasket surface must be meticulously clean. Then examine carefully for hair line cracks. Some might be harmless. But, no major issue as if necessary,m the can be repaired by the stich system.

I use a big framing square to check for true surfaces. That and a feeler guage usually suffices. My machinist son flips, but it works!!

Beware of overskiming a head. The cam saddles will be closer to the deck of the lock and chain issues can result.

Clean, clean, clean are the watch words.

My old flat head Fords had some dry studs and some wet. I was perplexed as to sealer vs antiseize. I used both. It worked well.

Old machinists had a n elixir for leaky studs. Some type of saline solution to add to the coolant. It would crystalize in the leaks areas and form a seal.

A Canadian company has a similar product for sealing leaks in cracked concrete. it really works.

 

So I broke the end off of one of the cam pulley 'slider guides' for lack of a better term. Do I need to get the timing cover off to replace it? I feel like I'm pecipitously close to needing pulling out the engine...

Separate questions -
will a 7L block hold up to say 400hp with a power adder?
Is there a better transmission option over the model 65 from the factory? something with overdrive for lower rpm on the freeway? The detents on the shifter probably won't line up but I can live with that.
Thanks again for all of the help.

 

I ran down to the garage and snapped a couple of pictures of the broken part..

 

This feature of the casting was put in to assist when assembling or dissembling the engine. It enables you to set the engine at a specific point, (normally TDC on cylinder 1 or 6), and to then undo the two (sometimes 4) screws securing the cam sprockets to the cams and attach them loosely to these slotted protrusions using appropriate nuts and washers on the thread you will see on the end of the cam sprockets. Were you wondering why there was these threaded studs on the end of the cam sprockets ? Now you know !

The slot in the casting then allows you to remove the head, but still keep the chain on the two sprockets so valve timing on the sprockets isn't disturbed. The sprockets can be moved up the slot so the head can lift off.

Of course you have to put the cams back on the head correctly too ! (if you take them off).

So the damage you have doesn't stop the engine running, but makes it slightly more awkward to take the head off if you're not going to disturb anything else. YOu would have to make sure the sprocket on the open slot is secured sufficiently to stop it falling out. Or use a bit of wire and gash tape to close the gap in the slot. You are American, so no doubt have that little bit of "Yankee ingenuity" I admire so much when reading the posts on this forum

 

I dunno. 'Tis the reciprocating assembly that counts in longevity, I think. Not so much the block. But I'm no authority on hot rodding XK engine.

400 hp from a 4.2 sounds like a tall order. What are your plans here?





The most popular choice is GM's TH700, or 4L60 as it was later known. Lots of Jags are running around with 'em

Cheers
DD

 

Dude! I'm Canadian!! I live just outside Vancouver. Port Coquitlam British Columbia. We have been known to solve a problem or two... :-)
So you are saying that I can put everything back together and not worry about that broken end? I will do something to 'fix' it though. Does it matter if these sprockets may have rotated or moved? Without tension the chain is rather floppy. Can I assume that not rotating the crank on the block and cams in the head is the real issue? If so - I'm fine.

 

Set your crank shaft pulley to top dead center with the pointer and then make sure both your camshafts are set to the notchs, you may then have to rotate the toothed inside wheels of the camshaft sprockets so the 4 bolt holes line up. Sounds complicated but is very very easy. Just be careful if you are turning the camshafts in the head as the valves will hit and you will bend the inlet valves, probably easier to remove one camshaft-set the remaining cam to the notchs and then reinstall the previously removed cam with the notchs lined up.

 

I'm thinking head work, cams and a supercharger.

 

Ouch!!! I'd be tempted to try to fix the cam gear mount. I invented the nomenclature!!
1. Get a service with portable TIG to weld the piece back on.
2. Drill four holes for pins to align and support the broken end in place. Loctite the pins and broken edges to secure.

We yanks have progressed from baling wire to duck tape and even up to pop rivets!!
Duct tape was originaly for HVAC use in sealing duct joints. Improved versions are now Duck tape, a brand name!!

Recently, the mad geniuses on "Myth Busters", skinned an ultralite aircraft in Duck tape. Lots of it. it flew just fine!!! Gutsy pilot, eh?

In WWII, the Seabees in the South Pacific needed machinery to grade airfields and quick. No time for ships and the cargo aircraft of the time were not what they are today. so, they cut the graders in two or more pieces. On arrival, they were welded back together and the grading began.

 

Ouch ! OK, well, Canadians are included in my comment !! It's easy for a Brit to miss the Canadian state initials (BC in your case)

 

With an engine that old, I would like more certainty as to what work has already been done. Do you have any info on previous work ? Reason I ask is because the length of the stud above the block deck can look really nice, yet be like a giant's toothpick where it sits inside the water jacket.

For my own XJ6, (a 1980), in 1991 had to take the engine & gearbox out as the block was cracked between all cylinder pairs I mentioned. I had already had two HGFs. So once the engine was out, I stripped it down totally ready to rebuild around an uncracked block (a 7L like yours). I took out the studs on the replacement block and they didn't look too good. It has been known for the stud to break as it is being unscrewed, and a little stub left in the block. Fortunately this didn't happen to me. The only cure then is to take out the core plugs by the studs and try to turn the stub with something. If you have the core plugs out, most people flush out the water jacket, and you would be amazed what comes out !

Really it all depends how much work you want to do, and whether you enjoy doing it. I did want a reliable car, and was a real nutcase for motors then. I still wonder how I am still married 32 years down the line !