Attached below is an Excel workbook with the mechanical advance data for a wide range of stock and after-market distributors. This has been discussed on Jag-lovers, but there is no provision for posting the file there, so I am doing so here. I had to remove some source material to get it to fit, so I have also posted the info as pdfs.

 

Nice work!!
I have 3 of these distributors: Mallory unilite from a 65 3.8S, 41207A from my 68 XKE and a Pertronix, that I am setting up for my 84 XJ6. I have been trying to find max mechanical advance (Crank Degrees) for the 84 EFI XJ6 with out success. If you know of a source for 84 XJ6 ( California) mechanical advance curves I would be very appreciative. Distributor #s: 45DM6, 41912A, DAC2992, with a 4/8/8 vacuum unit. Regards David

 

David:
Sorry, but I don't have any data on that distributor. The factory workshop manual for the E-type had the distributor advance data, you could check the factory manual for your car.

You might also try asking here on the Jag-lovers forum for the XJ: Jag-lovers - the Jaguar Enthusiasts' premier resource on the Internet

 

Andy

Thanks for the summary; I added the XJ6 S3 (LU -41912A) unit to the plot, to see where Jaguar went after switching to EFI. It looks reasonable for 87 Octane fuel and a lean EFI controlled mixture. Based on this, I will just send my LU-41912A out for overhaul, as it seems to fine for a street machine.
Best Regards,

David