Listers:
The below procedure was sent to me off list in response to a request for
information
on the disassembly of the head and block. I said I wanted to understand the
XK engine
and how it works
I am very much impressed with it and begun using it on the head disassembly.
I asked the
author, who wishes to remain anonymous if I could post it to the list.
I believe anyone who takes something apart, and wants to understand its
operation, and
how to get it back together will benefit from it.
Here it is.
Regards
Lou
71 XJ6
As anyone who has ever had, or been, a child between the ages of
eight and ninety-five knows, any one can take something apart… but not be
able to put it back together…
I applaud your willingness to learn a craft that often requires
years of proper study, training and experience.
Since your engines will require professional rebuilds, most
professional mechanics do not like to work on basket cases… pieces are
lost, broken and it just takes longer to sort thru all the bits to
reassemble the engine, believe it or not. However, I agree with your want
and need to understand the mechanical workings of the venerable Jaguar
engine.
I assume you have a Service Manual, appropriate tools, etc., and
most of all some form of a parts washer (an oil drain pan, stiff bristle
brush and a five gallon can of kerosene, will do) use in a well ventilated,
spark/flame free area… keep a fire extinguisher very close at hand at all
times, plus, go to your local pharmacy and buy a box of unpowdered exam
gloves-- not the latex type as they dissolve in petrochemicals, they will
protect your hands from absorbing anything toxic… use them during the
disassembly and they will keep your hands clean, as well.
If you are ready, let the carnage begin.
While the engine is still in the car or on the engine stand, drain
the oil… allow to drain overnight… it helps a little.
Remove those parts, like carbs, intake & exhaust manifolds, that you
will not be delving into, as a unit. The big chunks are easier to reinstall
later.
Follow the procedure lined out in the service manual on the
disassembly of the engine, with the following extra step: After every
single part you remove, including nuts, bolts, washers, etc., note exactly
which bolt came from which hole (sometimes different size or length bolts
are used to hold various parts)… Do the notation on a 3x5 card. Then
clean the piece, and all it’s associated bolts, to a very high standard.
Dry and place in a freezer baggie (avoid sandwich and zipper type baggies,
they are too thin and the zipper fails after a couple of uses… get a
couple of boxes of pints, quarts and one box of gallons) along with the 3x5
card. It wouldn’t hurt to jot down the order in which you removed the
parts in a notebook As an example: water pump first, oil pan next, etc.,
follow the basic process outlined in the service manual…
I know this is a lot of writing, but these acts will ingrain the
process in your memory.
The cleaning of the parts is how every apprentice mechanic started out
many years ago.
You can’t know how to identify a part unless you know what the part
looks like without thirty years of grease, road grime and grunge on it, now
can you?? 
Don’t get in any hurry to disassemble the engine… this is a steep
learning curve and attention to details is a huge factor. The tear down
will probably take you weeks, at a minimum.
Inspect each part after you have cleaned it, look for faults… cracks,
dinged areas. anything that you think could cause a problem to it’s
operation, Also, pay extremely close attention to any markings, regardless
of how small or insignificant they may seem to be and note them in your
notebook., these markings/numbers can sometimes help tell you who made the
part, it’s size, sometimes the actual part number. Generally all sorts of
apparently useless information… until you need to replace that part… then
it becomes very important…
As an example, Connecting Rods can go in two ways, only one is
correct.
In your notebook, write down every mark, number, etc., make a rough
sketch if necessary to determine where these markings are, in relation to
their original position.
This is how you learn about the parts and their dependability, or lack
of as the case may be.
I trust you have a work bench of at least 4’x8’ as eventually you
will be laying out the internals of the engine on said bench… Nothing is
to be on the bench except those Jag internal engine parts, cleaned, laid out
and identified as to what went where, and how. Place a 3x5 card next to
each identified sets of items. One card for all the rods, another for all
the pistons, however, use a felt-tip pen to write the cylinder number on
each piston, especially if you separate the pistons from the rods.
It is important, for you to keep each rod cap, rod bearing, nuts,
etc., with the rod they were originally fitted to. Same with the mains.
Don’t bother removing the rings from the pistons, you will probably break
them in the process.
On the cam chains… locate the alignment marks, rotate the engine
until they all line up (take extreme care in rotating the headless engine,
as the Jag’s upper cam chain will bind and break the aluminum “tower” where
the cam sprockets live), as per specs… count the links of the chain between
the lower and upper timing marks (the SM show tell you about this process).
Each link is the side plate on the chain, note it on the 3x5 and in the
notebook.
Once you have the entire engine disassembled and cleaned, reassemble
the engine like you were actually rebuilding it. I like and use a product
called Lubri-Plate on all bearing shells, oil the pistons and bores before
refitting. If you want, you can use the old gaskets, just don’t glue them
down, no sense undoing all that cleaning. I wouldn’t torque the bolts, etc,
because the gaskets won’t have the original compressibility and might cause
damage to the threads, just tighten everything firmly.
This time consuming adventure will give you a feel, as well as the
hands-on experience to understand what all is involved in the rebuild
process, and should reduce any intimidation factor you may have. Plus, the
pro who rebuilds the engine at some future date won’t be cussing you for
handing him a botched job to repair.
This exercise will not make a mechanic out of you, but a budding parts
changer… being a true mechanic involves, at a minimum, the ability to
listen to an engine and determine with 99.9% accuracy, any problem within
the engine.
Final thought… You cannot take too many or too detailed notes… what
seems simple on disassembly becomes a nearly unsolvable jigsaw puzzle on
reassembly. Use your digital to take a series of pictures as you remove a
part, show the disassembly process as a before, during, and after sequence…
If you have a video camera, so much the better, tape the actual disassembly
process… this requires a second person to film while the work is being
done… be sure the cameraman doesn’t film hours of the bald spot on the back
of your head.
Take your time, study everything and I think you will do fine…===================================================
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