Engine ignition test, twin plug heads, Porsche 911

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lolaT492
Posts: 4
Joined: Wed Aug 12, 2026 2:53 pm

Just need to check I'm going to do this correctly!

I have a Porsche flat 6 air cooled engine in my Class G Lola.
It has twin plugs to each cylinder due to 10.5 : 1 pistons fired by an old tech Clewitt ECU and GM coil packs.
I want to check if each plug is firing.
The cylinder at low revs (below 4000) will run smooth etc on one plug, but needs twin plugs to work well over that (in general terms).

I have a 3 year old Accuspark SP8000 ignition 'gun' which has the usual clamp to go around plug leads etc. but the handbook as been lost in the garage.

The leads are carbon core, not copper.
Question:
Do I put the clamp on each plug cable in turn, all 12 to be done, and the meter will show if a spark pulse has happened at tick-over of 1200 rpm?
Do I need to stop the engine first, move the clamp to the next lead, restart and check the display, etc, etc until all 12 are tested?

I don't really want to start/restart the engine 12 times but the coil pack warn clearly the system is very high voltage. when running.

May be a silly question here, but need to be sure.
Thanks, Graham.
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lolaT492
Posts: 4
Joined: Wed Aug 12, 2026 2:53 pm

Actually found the instruction papers yesterday.
You have to stop and re-start, test at tick over.
A job for season's end at Prescott where I'm surrounded by people who don't mind a bit of engine noise. :D
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