Got the head off and found the head gasket was failing. I previously suspected it as the main culprit for the massive oil leak at the timing cover. It proved to be a correct assumption. It had also failed around the number one piston letting coolant into the cylinder and around the head studs.



Don't think it's the original gasket but can't be sure. Brand name on the gasket is Cargasyl. Anyone know if these are the original type gaskets used on these engines?.

Other problems found were a couple of worn rod bearings on number six piston.


One rod bearing cap nut was missing its split pin. Found most of it in the oil sump. One small piece of it must have been flushed out in an oil change possibly.

Cylinders look good with no lips on the top. I'll be taking the block, head, crank, pistons and camshafts to the machine shop in the next day or so to have everything checked and measured. Crankshaft will be polished and balanced.

If all checks out, hopefully it will just need bearings, piston rings and a valve job. Fingers crossed.

Oh, and definitely new head studs!

 

That bearing has had it in a big way! Peter was talking about oil sample analysis in the Moss box thread. That would have shown up in a big way plus other things. I'll bet there were combustion by products in your coolant as well.

 

When you get a head gasket leaking water a couple of things can happen. The head studs start to rust so first thing is getting the head off the block is really difficult but you have achieved this part. Secondly the studs can rust inside the block which is more common as here you have a cast iron block and steel studs. What this means is getting the studs out of the block to replace them can be a nightmare resulting in one or more of the studs snapping off.
Just a warning.
Lots of lubrication and small movements of the stud both to undo it and then retighten it each time until it starts to move more freely. If you just try and and unscrew it you can twist the stud and it will shear off. So loosen a slight turn lubricate then tighten getting further around with each loosening turn.

 

I did get the studs out. Let them soak over night with WD 40. The doweled stud between 5 and 6 was the most difficult to get out. Lots of WD 40 and some heat from a propane torch finally got it out.

 

I really like the Cometic MLS gaskets. They seal well, as reusable and available in various thickness to adjust the compression ratio to what you want. Ofthen the compression ratio on 9:1 engines gets uncomfortable high for today's fuels after the head and block have been skimmed a few times. A thicker gasket can be a way to save a matching numbers block and head.

 

I do have the 9:1 engine. Was planning on getting the Cometic seal but need to see what the machine has to say about the head and block to know what thickness I will need. Block has the original piston letters stamped into it so it hasn't been skimmed.

Also need to determine if the timing chains need to be replaced. There is no visible wear on the sprockets.

 

An induction heater is a big help with stubborn studs.

 

Felix, head gaskets don't fail on their own, something has to cause them to fail.
In your case I believe the engine has been overheated, hence the head gasket failure.

Have a competent machine shop check the crank for "trueness"; the block needs to be checked too as well as the head.
When the head is checked, it's not so much the deck, but the bores for the camshafts too.
Heads warp where the camshaft covers won't sit flat on the head.

A common problem is the head deck gets planed and the rest of the head is still warped _ the head has to be straightened first.
You can get your own straight edge now, they're not so expensive these days, the Chinese ones anyway.

 

I concur Jeff. One of the previous owners installed an Aluminum Radiator from XK's Unlimited. Probably because it was overheating. The first thing I'm going to ask the machine shop to do is check the head for warping as well as the block. Both of those are my main concern at this point.

 

One might have to line bore the camshaft journals.

 

The upper timing chain and sprockets may be OK but the real hidden culprit in the system is the primary or lower chain and hydraulic tensioner.
I have seen this lower chain and tensioner fail in at least 3 motors. My current Series 3 XJ6 had this failure when I acquired it (cheaply).and every inlet valve was bent.
I also had a 3.8 motor start to fail in that it jumped a couple of teeth and ran very roughly but no further damage as I caught it in time.
A friends 3.4 motor just stopped and it turned out the same lower chain fault had occurred resulting in a strip down of the engine and head which I gave him a hand to do.

The cost of a new lower chain and tensioner is relatively low and definitely cheaper than a new set of inlet valves, VRS kit and your labour.

Cheers

 

Very well said Sir. While the engine is apart anyone that does not replace the lower chain & tensioner with quality parts is nuts. One can easily pull a new top chain but not the lower. If there is any sign of wear on the sprockets replace them too. Worn sprockets damage new chains. I like Renold or Würth chains.

 

It must be the hard wearing surface that's up against the chain that fails ?
I guess once that goes, it allows the chain to become lose and jump teeth, or even the tensioner itself to move out so far forward, that it falls out ?

 

Jeff
It is not the tensioner face that fails. It is simply the chain stretches and the tensioner piston passes the limits of travel and is no longer retained in its housing.ie as you suggested "it falls out".
Then there is lots of fun chasing around the sump with a magnet on a stick to retrieve the errant piston.
Felix
On another point with the engine apart, this is the time to examine the timing cover in the rear of the water pump area.
This is a commonly overlooked point and is subject to corrosion. If corroded modern alloy welding can restore this area

Cheers

 

Corrosion behind the water pump to the degree of perforation is common. People not maintaining coolant concentration.

 

New Tensioner and guides are on the list of new parts for the timing gear. I will probably replace the chains since it's already out of the engine. Cams are in excellent condition. No sign of any wear on them! All Bearings will be replaced. Timing cover is in very good condition as well.

Big new problem is the Machine Shop I was going to use won't do the job since they are retiring! Started searching yesterday for a new shop but haven't had any luck yet. Anyone here know of good machine shop in Southern California, please let me know.

 

@Felixbobcat, quality automotive machine shops are becoming as rare as hen's teeth. Here is a listing of machine shops in the Los Angeles and San Fernando Valley areas:

https://www.yelp.com/search?cflt=mac...+Angeles%2C+CA

Hope this helps.

 

Here is another shop that has done work on Jaguar engines:

https://www.google.com/search?q=kell...&ie=UTF-8#ip=1

Kelly's Block Welding is used by Jaguar specialists in Orange County, and comes highly recommended.

 

Actually went and talked to them this morning. They do know the jag XK engine very well and can get the head done in a couple of weeks. However...they are so backed up on engine blocks that they said they probably could not look at mine for another six months!!!

 

Six months is not long in the scheme of things if it's going to be done properly.

Even more so from all the horror stories here on the forum about majour F***-UP'S when it comes to machine shops.

Accept that it may take longer then you hoped and move your dead line up.

Get you foot in the door now, you may find someone else in the mean time.