"Side Gapping" Plugs...brilliant or needless?
 

I've been thinking about the pros and cons of this since I first heard about it. Apparently an old racer's trick was to cut the arm on a spark plug to about the midpoint of the center electrode, clean the cut well, clean for contamination and gap .10 tighter than the proper spec. This allowed the spark to travel a short distance at an angle and the arm no longer shrouds the spark and this is the major advantage...so they say.

I was wondering if anyone has feedback on cutting the electrode on a spark plug to allow a more complete combustion, a few more HP and better MPG...so they say :)

Thanks

Me and my buddies did it back in the day. Of course, my best friends dad was an old school dirt track racer, and he let us in on all the tricks.

Did you find any difference? Basically, enough to spend the time pulling my plugs, modding, and reinstalling?

Bosch +4 spark plugs are built this way but with four electrodes. You may just want to try that and see what it does for you. Honestly though, I see all those little tricks as being only good in theory and maybe having a practical benefit in the slimmest of cases. Bosch makes good spark plugs so it might be worth a try just for the hell of it.

Autolite R series plugs are made like this. My engine builder always spec'd them exclusively. Not sure about an advantage, so to speak, because I never ran with another brand, in our race cars. He claimed they don't foul out as bad as other plugs.

I did it on one of my drag race engs. I never noticed a difference. BUT every little bit helps

I did it a couple times back in the 70's, never noticed any difference.

I dont know for sure.

But I think some of the reason to "side-gap" it is to shorten the side-electrode because then it is cooler, so less chance of pre ignition and detonation cause of an overheated side electrode tip. Especially in very high compression and engines that runs hard long. Like race engines usually do.

And at the sametime file it "round" on the edge since an spark like to spark of edges and not someting flat.

How much People cut the electrode is probably induvidually. but I think 1/3 over the center electrode is often used in normal engines.

People probably have differnet opinions though, but I think it is more of an safety issue than Power. And the plugs dont last as long either.

Back in the 70's the ignition systems were not nearly as powerful as they are today so any crutch was tried. I used to trim my plugs but it is not necessary with modern high voltage systems of today.

Thanks for the feedback. My motor has a set of block hugger headers that have really limited my plug choices. I basically have had to go with the Accel shorties until I can afford to replace the headers. I think I might give this a try even if only for the fun of modifying something!