I’ve been looking widely to confirm I have the correct vacuum advance/retard unit for my pre HE fuel injected 1978 XJ12 S2 here in Australia and have not been able to get a concise part number. The vacuum unit in my car is not working and I’m afraid it is not the correct one.
I found the following vacuum unit suppler and they have some great information on the following webpage - Distributor # to Unit #
I’m thinking the vacuum unit for my car is the 6 10 8 unit, but would like further reassurance before comiting.
1976-79 XJ12/XJS ENG # XJ12-7P37048-on 36DE12 41742 54429459 6 10 8 cap / link
1978-79 Cal XJ12 36DE12 41770 54429628 6 10 4/5 8 7R Adv/Retard
In my web search I came across the 731 page “Experience in a Book” by Kirby Palm. It has a section on ignition vacuum advance which references the “Advancing by Vacuum” articles by Roger Bywater of AJ6 Engineering, these were published in the “XJS Bulletin” magazines published by Kelsey Publishing between August 1998 and June 1999. I’m specifically interested in obtaining Issue 2: 1976-80 V12 vacuum advance systems, including California and Australia.
I’m hoping this article will tell me which vacuum unit is required for my distributor.
Any help locating this article or advice on the correct vacuum unit would be appreciated.
Welcome David,
Maybe this will help:
https://parts.jaguarlandroverclassic.com/catalogue/xj-s-5-3-1975-81/electrical/mobile/index.html