Back to ignition timing 1985 Series 3 XJ6
#1
07-03-2020, 09:48 AM
Back to ignition timing 1985 Series 3 XJ6
Finally removed the faulty Pertronix distributor. Opened it again and sure enough, the advance rod is binding (does not retract). Compared the distributor housings on the Pert and the Lucas and the slot positions are identical. Installed the Lucas capsule on the Pert and it still binds up. Finally gave up and just reinstalled another original Lucas unit, as mine was very stiff to rotate.
From surfing the net, I came across the following statement regarding XJ6 ignition timing "A stock XJ6 series III is set up with somewhere between 8° and 17° static timing advance depending on the year. The distributor advance curves are different to accommodate. This makes it tricky to give useful tuning information in a general sense; it must be applied differently for the different distributors. This XJ6 was one with 17° static advance and that means that the distributor is designed to add less mechanical advance than the 8° ones are." I got the other Lucas one from Robert Laughton here in St. Catharines (Canada) and I'm not sure what year it is from, so I do not know if the mechanical advance springs/weights are the same as my original Lucas one.
Asuming they are the same, I set the timing as per my handbook (1985 - 17deg. static). At 800 RPM with vac. disconnected and plugged, set timing to 17 degrees BTDC. Smooth idle. Gear engaged drops to 700 RPM. AC on idle drops to 600-650 RPM. Engine does not die or stutter/stumble.
Reconnected vac. line. Timing advances to 22 degrees BTDC. Idle rises to 900 RPM. Readjusted to 800 RPM. Engaging gear and AC on, reading are as above.
Test drove the car and feels good. No pinking under hard acceleration. Rechecked timing all OK.
Question 1- What are others using for dynamic (vac. connected) idle timing setting?
Question 2 - Should I be setting it to a certain advance condition at a higher RPM? - I have heard that something like 32 degrees at 3000 RPM is what it some use
I plan to become an ignition expert at the end of all this.
By the way, Robert has 60 plus Jags on his property, mostly all XJ6's, XJ12's and a few XJ-S's, and containers full of used parts, including lots of fiddly interior bits. Robert posts here.
Regards, Ian.
From surfing the net, I came across the following statement regarding XJ6 ignition timing "A stock XJ6 series III is set up with somewhere between 8° and 17° static timing advance depending on the year. The distributor advance curves are different to accommodate. This makes it tricky to give useful tuning information in a general sense; it must be applied differently for the different distributors. This XJ6 was one with 17° static advance and that means that the distributor is designed to add less mechanical advance than the 8° ones are." I got the other Lucas one from Robert Laughton here in St. Catharines (Canada) and I'm not sure what year it is from, so I do not know if the mechanical advance springs/weights are the same as my original Lucas one.
Asuming they are the same, I set the timing as per my handbook (1985 - 17deg. static). At 800 RPM with vac. disconnected and plugged, set timing to 17 degrees BTDC. Smooth idle. Gear engaged drops to 700 RPM. AC on idle drops to 600-650 RPM. Engine does not die or stutter/stumble.
Reconnected vac. line. Timing advances to 22 degrees BTDC. Idle rises to 900 RPM. Readjusted to 800 RPM. Engaging gear and AC on, reading are as above.
Test drove the car and feels good. No pinking under hard acceleration. Rechecked timing all OK.
Question 1- What are others using for dynamic (vac. connected) idle timing setting?
Question 2 - Should I be setting it to a certain advance condition at a higher RPM? - I have heard that something like 32 degrees at 3000 RPM is what it some use
I plan to become an ignition expert at the end of all this.
By the way, Robert has 60 plus Jags on his property, mostly all XJ6's, XJ12's and a few XJ-S's, and containers full of used parts, including lots of fiddly interior bits. Robert posts here.
Regards, Ian.
#3
07-08-2022, 08:38 AM
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