Does using dual spark plugs per cylinder make any difference?

[gmax137]

Sometimes, the second "plug hole" is for a compression release. Seen on old Brit bikes, if they don't have a "valve lifter."

 

[Flyboy]

During WW2, the test before takeoff was to run the engine up to temperature and speed, then cut one magneto at the time to check the fall in RPM. A "magdrop" of more than say 150 RPM, cancelled the flight.

I have a double toggle switch panel somewhere here, labelled "Magnetos".

Exactly right. Still done today on light piston planes, although it's more of a maintenance check every so often.

 

[Averagesupernova]

Sometimes, the second "plug hole" is for a compression release. Seen on old Brit bikes, if they don't have a "valve lifter."

That could be but I do recall a plug in each hole and a wire on each. The Odyssey I used to ride only had one and I don't recall a comp release.

 

[gmax137]

That could be but

Sorry @Averagesupernova , my comment was not directed at your photo. More of a general comment.

 

[Averagesupernova]

Sorry @Averagesupernova , my comment was not directed at your photo. More of a general comment.

Hey that's ok.