THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

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. This led to pinking at 2,000rpm and above, so I switched to curve 6. 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?

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.