Autolite....ar3933x

Putting a he!! of a strain on secondary KV... Will seek a better path.. What ignition?

Used to cut them back to stop spark scatter but never off..

We run brisk plugs in the midget, but not the sprint car or the dragster. I hate the strapless plugs because you can't read them without cutting them apart.

many of the old OMC outboards used surface gap plugs. I had one, 1982 model, used same plugs as some of the 70's motors did. Had a couple Mercs too, all early 1980's stuff.

It's been around a while. Putting in conventional plugs into the Merc's improved the idle quality a little but would tend to lose a little top end power.

Never tried them in the race car.

Once again surface gap plugs are not the same as taking a new NGK plug and cutting electrode off.

quote:

Originally posted by Curly1:
Once again surface gap plugs are not the same as taking a new NGK plug and cutting electrode off.

That would depend on the location of the tip. Obviously, an extended reach plug wouldn't work without a ton of voltage. All of them stretch the limits of ignitions.

quote:

All of them stretch the limits of ignitions.

One has to smile. We've come from points and condenser to coil-on-plug ignitions and we still "stretch the limits."

quote:

Originally posted by KWig:
Surface gap plugs have been around since mid 90's, that I know of. They are not cheap !

NGK Racing Surface Gap plugs are $68.99 EACH from Summit P/N 3235 / R0045Q-9

How much spark is really needed? Kind of like asking how much octane is needed or how "great" of oil is needed or best.

A friend made a test fixture with a sight glass that could be pressurized I think with CO2. You can thread a spark plug in, and watch it (and listen) as you raise the pressure in the fixture. I was amazed at the lower pressures (in terms of compression that is) that would cause changes in that spark even with a .020 gap. Trying to simulate boost type pressures before ignition...or during. The first fault he would see was the spark short circuiting from the boot to the plug base. Might be a good argument for dielectric grease in the boots.

I think the tiniest of sparks can ignite any fuel mixture with some dependency on the volatility of the fuel being used.

The second guessing comes in I think when we have contamination of that mixture with oil residue, left over carbon from the previous ignition and the chance of igniting it prior to when we wanted it ignited (pre-ignition). So I'm certainly willing to believe that an engine can run with the ground electrode removed - how well, how long and whether there's any performance advantages is another set of questions.

quote:

Originally posted by Canted Valve:

quote:

All of them stretch the limits of ignitions.

One has to smile. We've come from points and condenser to coil-on-plug ignitions and we still "stretch the limits."

I am referring to the strapless plugs that have to jump a large gap.