Static Timing...

[Mad Mart]

...with leccy ignition.

I have a Powerspark electronic ignition fitted to XJX and was wondering if it is possible to do static timing?

[Jon Tilson]

Yep....
Arrange the crank as desired at about 11BTDC and have a meter on coil minus. Rotate dizzy and watch meter kick
as leccy ignition triggers ( ignition on obviously). Works for me...

Jonners

[Mad Mart]

You put the -ve lead of the meter on the coil -ve. What about the +ve lead of the meter?

[Jon Tilson]

Meter set to voltage scale....25 will do. Battery volts will be half full scale. ( Assuming analogue meter ).

Meter +ve lead on coil minus, meter negative to earth. You are looking for the voltage change at the trigger point.

Coil plus will always be at battery or ballasted coil volts. Coil minus goes from zero to battery/ballast/open circuit volts at the sparking point on a points system as the points open. The trigger unit is doing the same thing - turning the low tension side of the coil off at the trigger point, so the spark comes out of the HT lead....etc.

Sorry if I'm not explaining clearly.

Jonners

[Mad Mart]

Ah! yes, of course. Thanks Jonners.

[soe8m]

And when you check afterwards with a strobe it's 5 degrees off.

Jeroen

[Jon Tilson]

Typically not far off......
Depends on the slop in the dissie....

Mine was pretty close...minimal further adjustment with the strobe.

Jonners

[MIG Wielder]

One explanation might be that with a voltmeter over the electronic switch it is actually doing real static timing. As soon as the engine is started and running the distributor advance may be starting to move especially if the idle revs are a bit high. I think the manual quotes static timing by strobe < 600rpm.
Tony.

[GTS290N]

But as long as you're not 180 degrees out it gives you a rough starting point before using the strobe.

[Mad Mart]

Connected my DMM up and I was getting about 2.4V on the -ve coil terminal. No amount of turning the dizzy made any difference. I then checked the Voltage on the +ve lead and found I only had the same there. I shall investigate further tomorrow.