Jag Mk2 electronic ignition

Hi, I have got hold of an Electronic distributor of the type 123, which I am about to install in my Jag Mk2 3.8 model 61. In order to make it “difficult” for an amateur, there is a “Wood” of possible settings/advance curves given in a small pamflett which followed.(15 in total) Has anyone in the forum experience/knowledge which curve should be used for my Jag. Look forward to advise,


We used the JAG-6 curve that probably best fits all the inline Jag XK engines. If you need a lot more technical details, see MK2 Restoration Blog - 123 DISTRIBUTOR CURVES

This is how I set up my '62 E. You need to have a look at your workshop manual and then overlay the best matching 123 curve. Paul

Thanks for advice. It appears that there are various experiences re selection of advance curves and not point blank which one to choose. However, - today I found a web site for 123 in Holland with a service shop who took on installation and settings work for subject distributors. I provided the data for the original Lucas distributor and the XK engine.

Their advise were, quote “to set curve B. If it starts to “ping” when testing at 3000 rpm, set curve 8.” I suppose I initially will try that and evaluate the outcome.

Unfortunately, “my mechanic” has gone on summer holiday so it will be a few weeks until I can try it out.

Anyhow, thanks for the engagement from you Jaglovers

Regards Øystein

I set mine on curve 8 and it’s really good. I might try curve B one day - it looked a bit aggressive - past 3000rpm as it’s a fair bit more advanced than the old distributor. Paul