Thread: Spark plug gap

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In trying get info on the same problem I have read the following:

1. Increased gap tolerates leaner mixtures with less misfire.
2. Increased gap requires more energy
3. Increased compression dictates a smaller gap or more energy due to the density of the air.

Opinions are welcome. Seems like a crap shoot in a way but if it were that critical, I think a lot of DIY's would have stumbling engines. Best way IMO would be to gap it how you think best (based on feed back or whatever) and then pull the plugs and read them after a few weeks and make adjustments accordingly.

yup denny has it... to elaborate on the higher RPM part, your coil has to charge a magnetic field to spark, and the wider gap has higher resistance and so it demands more juice to get the spark across it.... the more juice required the more powerful magnetic field is generated, the higher rpms make it to a point that the coil cant get a fast enough charge to dictate a powerful spark..... thats why all newer cars are going to coil over plug... and also why i'm working on converting my race engine on my mustang to coil overplug.... if only i could afford magnetos like top fuel cars use.... that'd be fun....cept then i'd need a fuel cutoff switch

Good info, except this part....

Of course, changing the gap changes your timing so adjust
accordingly.

How in the world does this happen? ...the timing dictates when the distributor sends the energy to the wire that fires the plug, so gap has no effect on when this happens.