THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Just to update this thread, for the benefit of any future readers, as my engine has a CR of 9:1, I was recommended to try Curve 0 on the 123 distributor, which is the one with the least aggressive advance curve. I have done this and set the static timing to 10 degrees BTDC, per the 123 manual.

This seems to deliver a perfectly acceptable level of performance throughout the rev band that S-type owners are likely to use and, crucially, without any pinking.

Does anybody use one of these distributors and, if so, which curves have you used and how did you find them?

For the record, I fitted the 123-JAG version in August 2016 and initially used curve [b]B[/b]. This led to pinking at 2,000rpm and above, so I switched to curve [b]6[/b]. That's fine up to about 2,500rpm, but pinks somewhat thereafter under heavy load.

My engine has a CR of about 9:1 and I use 97RON Super Unleaded.

I retarded the timing to 4 degrees BTDC (the manual says 5 BTDC for 9:1) and it did help slightly.

So, I'm now considering alternative curves (it seems curve 1 would be the next one to try) and/or further retardation of the timing.

Does anyone have any experience to offer on this?