<VV> Spark Plug Gap

MarK Durham 62vair at gmail.com
Sat Jun 21 19:30:39 EDT 2014

There are lots opinions out there but the fact of the matter is that its
the type of and limitations of the system installed that determines how big
a gap is possible. Original systems were limited on gap because the points
and condensors amps carrying capacity were limited due to design and
metallurgy limitations.
That is why .035 works well for points ignition. Its the gap the points and
condensor could reliably sustain. My original Corvair in the late 60s would
only get 15 to 18k mikes out of a set of plugs, points and condensor. Hence
the yearly "tune-ups" that were commonly performed and were essential to
keep a car running good. . If I tried to go longer the points would burn or
the plugs would simply quit! I was on a trip once when that happened and I
had to limp in on 4 cylinders.
Today with electronic ignition you can get 100k out of your plugs and gap
is much wider and hotter for a much better fuel burn.

Mark Durham Hauser Idaho
62 2Door Coupe 4speed Red/Red
On Jun 21, 2014 10:29 AM, "Smitty via VirtualVairs" <
virtualvairs at corvair.org> wrote:

> Hi,
> This is a generic question about spark plug gap size.
> For a given motor, Corvair or otherwise, with everything in good working
> order and a good ignition system, what is the impact of running a smaller
> vs
> a larger gap size, say for arguments sake .030 vs. 035?
> ------------------------------------------------------ Smitty Says.  Bob
> you are going to make out better asking if anybody elses wife was prettier
> than yours when she was young.
> I know there are lots of opinionated people out there who will argue with
> me just because I am me.
> What matters most is lighting the fire.  I think automakers and plug
> manufacturers come to an agreement on what gap to use for a given product.
> That would be the point at which the fattest fire can be generated
> considering the wide range of conditions you mentioned.  I learned years
> ago that a set of new plugs at factory settings in a turbo would perform
> lousy in just a few short miles.  Often not able to even get boost in a
> couple thousand miles.  A CD ignition was a help but then I could often put
> the fire out under full boost acceleration.  I don't know if the spark
> wasn't able to penetrate the high pressure mixture, which I assumed is what
> was happening.  I tried increasing the gap and then lessening it to no
> effect. I tried to find the best hot rod coil system I could afford.  Then
> I found I could open the gap up and still keep the fires lit under high
> combustion pressure conditions.  Points were taking a beating carrying the
> amperage.  I chose to go that route and not convert to a points elimination
> system. Ignition points is not a dirty word to me.
> If I were to go back 40 years I would take a GM HEI distributor and coil
> with me.  GM reliability and availability of the working parts.  More spark
> than you are likely to ever need.  Set the gaps at .045 and run them till
> the electrodes are worn away and still lighting the fire like everything is
> normal.
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