Installing a 4.2L Motor in a '59 MK1
Dawn of Dyslexia
How I stuffed an extra 1.8L under the hood of my Jaguar
This is meant to be a fairly complete description of what it took to
replace the 2.4L motor in my 1959 MK1, with a 4.2L motor from a 1983 XJ6.
Ever since purchasing my Jaguar in 1992, I toyed with the idea of
replacing the motor in it with something larger. The 2.4L motor that
came in my MK1 was a real oddity. Jaguar took the 3.4L motor offered
in the XK series and de-stroked it to 2.4L for the introduction of the
MK1 sedan in 1956. It was carbureted with 2 down-draught Solex carbs
(the only post-war Jag to use Solex's), and was, even back in the 50's,
considered under powered; though it revved well, being overly square.
By the end of the 50's, even Jaguar recognized the need for a bigger
power-plant (especially for the American market) and began offering
the 3.4L motor in the MK1. This introduction coincided with the
introduction of the wide-grille MK1's for those trivia buffs out there.
To the best of my knowledge, almost all the MK1's sold in the US
(after the introduction of the 3.4L motor) were of the 3.4L variety.
I believe my car was originally shipped to Spain. It was brought to this
country (USA) by a private importer, and as such was a really unusual car for
these parts: a left-hand-drive, wide-grille, 2.4L MK1. It also has the
original MOSS 4sp; most 3.4L MK1's (ie most late 50's US MK1's) are automatics.
Anyway, back to my story: I've always thought the car was a little under-
powered, and had ideas about putting something bigger under the hood.
During a visit to a jag owner/dealer in Berkeley, I saw a project that
really gave me some ideas- he was installing the motor from a 420G into
a MK2. I subsequently learned that the 4.2L and 3.4L motors have the
same stroke (major, but not only difference is bore size), and so getting
the motor into the engine bay really isn't that difficult.
Then one day, I happen across an email message from
who has decided that he wants to install a
Chevy 350 into his '83 XJ-6.
I decided to buy his old motor, to store, and "one day" rebuild it and install it into
my MK1. It was cheap enough, that I thought it was worth it just for parts.
Only a few months after purchasing this new motor, I had some rather
catastrophic failures of my 2.4L motor, and decided that the new motor would
have to go in sooner... rather than later.
The first decision I needed to make was where to splice the drive-train(s)
together. I decided to do it at the crank/flywheel interface, using my
old flywheel, old (well really, brand new) clutch, old starter, and
old bell-housing. With unlimited funds, I would have installed a new
transmission too, either a T-5 or a supra-box, but at the time that just
Below are some of the problems I found, and how I solved them. I've also
included some of the pleasant surprises that I found:
And, I'd be happy to try to answer any additional questions.