These numbers don’t compare well with the figures from the spreadsheet I referenced for the 41060 distributor you are using. When I subtract the 10 degrees static advance from the spreadsheet figures I get:
1000rpm 2.5 degrees (compare your 0)
1500rpm 10.5 degrees (compare your 4)
2000rpm 13.5 degrees (compare your 6)
2500rpm 15 degrees (compare your 6.5)
3000rpm 16.8 degrees (compare your 14)
3500rpm 18.7 degrees (compare your 16)
4000rpm 19 degrees (compare your 18)
4500rpm 19 degrees (compare your 20)
5000rpm 19 degrees (compare your 20)
Your curve looks very odd it seems very flat up to 1500rpm with a huge jump between there and 2000rpm and then almost flat again. It’s hard to believe, as I can’t see how you would achieve it with 2 springs. Is there a typo in your table? My understanding (and it matches the graphs that Geo provided for the standard 41060 is that the curve is very steep between 800rpm and 1600rpm, and then flattens off - your measurements show hardly any advance up to 1600rpm.
Easy to find out. Simply set your static timing to 15 or 20degs, keep a light foot until you get to 2500 then floor it. You should immediately know if you have more oomph. Ears open for pinging…
Hi David, Do you happen to know where I might find dizzy info on the SIII"E" s…my dizzy number is 54419427. It was formally a “retard” but now an advance ( old one rebuilt and fitted by me ). This dizzy was used in lots of XJS cars.
Good idea - other stuff can cause an engine to “go flat” other than timing (including other issues with ignition). Even items like weak valve springs, which can have other symptoms, can cause your issue. Changing to a known good unit is a very acceptable means of troubleshooting.
Sorry John. I misspoke. The article I referred to doesn’t appear to cover the Series 3 distributor, and I haven’t found anything appropriate elsewhere…
Are any of you guys checking the total advance with a timing light on the engine? If so I’d be interested in learning what you used to extend the timing marks out past the 12 degrees BEFORE on the damper.
All you need is a timing light with an advance setting - a dial on the back (or an electronic feature) that you set for the advance range you want. Set the dial to, say, 30° – now when the timing pointer is at 0° that is 30° BTDC, when it is pointing to 10° then you’re at 40° BTDC.
I also added TDC marks on the other two places on the crank (for 2&5 and 3&4) but that is for a different project. Make those marks each in different colors and you can learn some interesting things.
The HF one is not wonderful, but the one I got there recently does work as advertised. The previous one did not. The dial on the back which sets the advance offset is very loose, and easy to move unintentionally. But for around $30 it did the job. The alternative is just to extend the scale on the damper by measuring the existing markings and using that as a guide to continue the scale. On my XK140 I just did this with dots of paint which show up nicely with the strobe light.
Hello all. This is my first post here. I recently purchased my first Jaguar, a '68 XKE FHC in Willow Green and am really enjoying it. The car had been with its previous owner in California for 29 years and is very complete and original. Unfortunately that originality also included what I assume was the complete original ignition system and the car was running on only 5 or 6 cylinders. Rather that try to work with the old worn out dizzy, I just replaced everything with new units from 123 Ignition (the Bluetooth programmable version), plumbed in a vacuum line from the manifold to the distributor, and used the ignition and vacuum curves provided by Phillip above in this thread (thank you!). The car runs beautifully now. Fires right up, idles dead steady and smooth, and pulls hard and cleanly through the RPM range. This thread and others here were really helpful to me as I educate myself on the XKE. Thanks all!