[v12-engine] exchanging pre HE with an HE

I have a 1975 XJ12C with the original engine. The wire harness and
other accs. are pretty decrepit and should really be replaced. I
have access to a 1987 HE out of an XJS. What other components do I
need to make the swap to my car? Originality is not an issue here.
are configurations so different that I would be replacing
everything from the tail pipe to the radiator or is this easier
than that. I am assuming the ECU, ignition (wanted to go with a
Crane unit anyway) and wire harness for HE are very different.–
Stu Sanderson Series III XJ12C
Tubac, AZ, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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I have a 1975 XJ12C with the original engine. The wire harness and
other accs. are pretty decrepit and should really be replaced.
You really should redo or, replace the wiring regardless.
I have access to a 1987 HE out of an XJS. What other components do I
need to make the swap to my car?
I’m not familiar with your car so I can’t comment much more but, you
will need to use the Lucas Distributor in the HE.
Originality is not an issue here.
are configurations so different that I would be replacing
everything from the tail pipe to the radiator or is this easier
than that. I am assuming the ECU, ignition (wanted to go with a
Crane unit anyway) and wire harness for HE are very different.

A.J. Simpson
Jaguar 1986 XJ-S HE
Mercedes 1985 380 SL
718-930-8974

Visit the Jag Lovers homepage at http://www.jag-lovers.org for exciting services and resources including Photo Albums, Event Diary / Calendar, On Line Books and more !On Dec 29, 2006, at 8:12 AM, XJCStu wrote:

Stu,

Since the ignition and FI are completely different you will have to
take all the HE parts having anything to do with both. I have not done
this, but once considered it. Many have, I suspect. One big advantage
would be better fuel economy, as you know. The down side will be a
bunch
of little things that are different, e.g., wires with no place to
connect.

Since the ECU is in the boot plan on some time removing interior trim
in order to change out the harness. Also, the HE MAP sensor is
integral with
the ECU, so you will have to route a vacuum line back there as well.

IOW, it isn’t easy. If the only thing wrong with the engine is the
harness
and accessories, it would be easier to repair it. See my Web site
for some of the maintenance that might be required.

Ed Sowell
1976 XJ-S
http://www.efsowell.us/ed/myJag.html

I have a 1975 XJ12C with the original engine. The wire harness and
other accs. are pretty decrepit and should really be replaced. I
have access to a 1987 HE out of an XJS. What other components do I
need to make the swap to my car? Originality is not an issue here.
are configurations so different that I would be replacing
everything from the tail pipe to the radiator or is this easier
than that. I am assuming the ECU, ignition (wanted to go with a
Crane unit anyway) and wire harness for HE are very different.

Stu Sanderson Series III XJ12C

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