Spark Plug Voltage Firing Requirement

[Ted Borck <tborck@domain.elided>]

> Date: Fri, 26 Mar 1999 04:32:30 GMT
> From: jlandry@domain.elided (John A. Landry)
> Subject: Re: MSD
> 
> In Linda Tripp's secret telephone recording, Monica and Howard R Pletcher
> <n9ads@domain.elided> were heard saying...
> 
> >what about all the folks that swore Splitfire plugs did wonders? (I saw
> >them on TV so it must be true)
> 
> Exactly Howard!
> 
> What an utter waste of money Splitfires turned out to be... yet they still
> sell them *and* their newer platinum versions.


The operative term actually under discussion is
spark*plug*voltage*firing*requirement.*

Unless the ignition system is putting out enough voltage to fire the
plug effectively, you're losing power, fuel, time and money.

When a *new* regular spark plug is installed it has a relatively low
voltage firing requirement.

After some miles due to tip erosion, and unwanted buildup, the regular
plug needs more voltage from the ignition system to enable the spark
to jump from the center electrode to the side electrode.  If such a
plug is being fired by a marginal ignition system, the plug becomes
less effective.

With the split-fire plugs - due to the multiple tips for the spark to
jump to - its voltage firing requirement stays lower longer than a
regular plug due to the multiple tip(s).  However after more miles,
the split-fire plugs voltage firing requirement becomes such that a
marginal ignition system doesn't put out the required voltage and the
split-fire plug becomes less effective.

Gold palladium and the platinum plugs (Champion and subsequently
Bosch) plugs were first touted for 2-stroke engines.  Anyone who has
pushed a 400 Maico, Husky or Yamaha (substitute your bike of choice)
with a fouled plug through a long Florida Mud bog in the middle of a
60 mile enduro, joyously purchased gold palladium/platinum plugs when
they were released on the early 70's.

Yea - I know - before gold palladium plugs, I had a 2 plug head on my
Husky, the original plug would foul - I'd switch to the 2nd plug - and
usually it would be fouled too.

When used in 2-stroke engines of that time - regular plugs's
*voltage*firing*requirement* quickly became too much for the marginal
ignition systems and the plug would foul out. . . . .
WWAAAaaaaaaaaaannnnnnghhhhh.  And, it always happened at the worst
possible time.

With platinum plugs, the voltage firing requirement stays lower longer
and thus runs longer without fouling.

Of course I'm sure there are some Turnip, Beezer, XLCH riders, and
Porsche owners in this crowd who would have wanted platinum plugs - if
they had only been available.

So platinum plugs don't fix a marginal ignition system - they just
alow the marginal ignition system to operate the engine more
efficiently for a longer period of time.

So the bottom line is - anything you can do to improve how much fire
power your (regular, split-fire, platinum) plugs are getting - it is
money well spent.

IMHO the best thing you can do to upgrade your (point, solid-state)
igntion system it to purchase a 
*good*quality*set*of*solid*core*spark*plug*wires.*

After all, your scout came from the factory with a solid core set.

Ted Borck	tborck@domain.elided