Plugs and gap with pertronix electronic ignition

[MS73HD302]

Curious what y’all are running. I use autolite 45’s with .42 gap

 

[DirtDonk]

I settled on a .042" gap too if I remember. Tried everything from .032 to .050 (that one sucked!) and was happiest over time when staying within the .040 to .042 range if I remember.
Been so long since I had to gap a plug on one of my rigs I'm not as sure as i once was! But those numbers are pretty basic and I'm pretty sure those are the ones I used in the end.

This was the same with Pertronix, Dura Spark and MSD, with or without the Jacobs ignition.
And by the way, that Jacobs could jump a 4" gap and still preferred .042 when in the engine and running!

Paul

 

[omureebe]

I thought MSD recommended something like 0.045-0.050, so different system but kinda the same. I went with 0.045 and nicely brown once used!


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[DirtDonk]

Yep, and GM used to use .050 and some even larger gaps. But in my case the engines just ran better and for longer with the smaller gaps. Things like combustion chamber shape and compression may have as much to do with the happy-gap as the amount of current available at the tip of the plug.
But that energy from the ignition really helps!

Bottom line is you can use these as starting points, try going larger and smaller and just settle down on the one that works best.

Paul

 

[sprdv1]

Curious what y’all are running. I use autolite 45’s with .42 gap

not many responses.. the experts like DD will let you know as seen

 

[sprdv1]

Yep, and GM used to use .050 and some even larger gaps. But in my case the engines just ran better and for longer with the smaller gaps. Things like combustion chamber shape and compression may have as much to do with the happy-gap as the amount of current available at the tip of the plug.
But that energy from the ignition really helps!

Bottom line is you can use these as starting points, try going larger and smaller and just settle down on the one that works best.

yes sir...

 

[MS73HD302]

Sounds good to me. Be replacing plugs soon Sounds like I’m on the right track.