Has anyone side gapped their spark plugs?, Does it make any difference? Options

[oakdalecurtis]

I just saw this video claiming that “side gapping” the spark plugs makes the spark much better and thus the engine run better. I’ve been around cars a long time and not heard of this. Is this real or nonsense?

[technicalninja]

Side gap and surface discharge have been around forever...

First surface discharge I hit was way back in the 70s.

Mazda rotary required exotic plugs and about 3 times the energy to fire.

The plugs with 3 or 4 electrodes just give multiple paths for the spark.

Each time it fires it only fires to a single electrode, not multiple sparks to each electrode as the packaging often depicts.

Having 4 electrodes mean as the gap increases on one it becomes easier to make the jump to another electrode and the "gap" increases very slowly over the course of the plugs life.

Those 964 plugs will slowly "square off" the center electrode as it moves to each side ground strap over the course of its life.

Iridium plugs changed all of this...

The multiple electrodes are for extended life and nothing else. Iridium life span for a single electrode made the multi-electrode plug a thing of the past.

BMW was big on multiple electrodes and current thinking has everyone using NGK iridiums.

Do to the clearance inside a rotary the surface discharge is still the way to go (and multiple electrodes if original). I haven't been active in the rotary world so long that I do not know if iridium is available in a rotary plug.

I would not modify an iridium plug but I have cut down the ground electrode to allow better flame propagation from the spark kernel on copper stuff.
By the time I'm modifying the ground strap I'm already "indexed" with the opening facing the largest section of the combustion chamber and "cheated" towards the exhaust valve.

Side gapping a plug is never, never about longevity.
At this level of preparation, the plugs will be consumables automatically replaced at much lower intervals than something I'm using in a road car (which needs to live 50K IMO).

Side gapping and modifying plugs will not do jack diddly shit to a stock or mildly modified ICE engine.

My recommendation is a Iridium single strap resistor plug.
NGK often has "iridium" and "laser Iridium"...
No lasers are used during the making but the ground strap of the "laser" is significantly cut back and pointed to unmask the spark kernel as much is possible.

This "mod" adds 50% to the cost of the plug and is un-needed IMO.
I'm a "non-laser" guy...