Strange Spark Plugs, OK to Use? Options

[jrrobertson]

These spark plugs came with an engine I am rebuilding. What are they and is there any benefit to this type of plug?

[technicalninja]

It was a dumb aftermarket idea that never really panned out.

Not aftermarket!

I saw multi-electrode plugs FIRST in the late 70s on rotary engines. Singles will not work properly in that environment. As ignition strength increased in the late 80s Mazda changed to surface discharge and got rid of the electrodes all together.

The next place I saw them regularly was in BMWs.
"M"s often came with multi-electrodes from the get-go...

The BMW stuff works fine with single electrodes.

Both of these examples were years before the "Split -Fire" craziness.

I'd start with normal plugs on a T4

[Superhawk996]

It was a dumb aftermarket idea that never really panned out.

Not aftermarket!

I saw multi-electrode plugs FIRST in the late 70s on rotary engines. Singles will not work properly in that environment. As ignition strength increased in the late 80s Mazda changed to surface discharge and got rid of the electrodes all together.

The next place I saw them regularly was in BMWs.
"M"s often came with multi-electrodes from the get-go...

The BMW stuff works fine with single electrodes.

Both of these examples were years before the "Split -Fire" craziness.

I'd start with normal plugs on a T4

You are correct - first on rotary’s . . . But those aren’t real engines (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/lol-2.gif)

I was a little too flippant about how the aftermarket started pushing them as a miracle cure and adding HP to boot when they often hurt. I’ll admit to having tried them once. (IMG:style_emoticons/default/dry.gif)

Just kidding for all the rotary lovers (IMG:style_emoticons/default/happy11.gif)