Thanks a lot!
Nicholas McKinney wrote:
> At 10:34 PM 4/1/98 -0600, you wrote:
> >Hopefully this won't lead to the debate the last spark plug question led
> >to. What does it mean when a spark plug is hotter or colder? Given
> >that I have MSD 6A and Blaster 3 and headers, should I shoot for hotter
> >or colder or stock plugs when it comes time to change them?
>
> Well Robert, a hotter plug retains more heat than a colder plug. You want
> the plug to run about 750 degrees if I remember right. With the variables
> of localized cooling and chamber temperature/pressure you will sometimes
> have to vary the plug somewhat. Unless you have really super modified the
> motor stock types will probably be just fine.
>
> Here is my way of reading the plugs if it helps:
>
> 1) put a stock new set in
>
> 2) after 50~100 miles pull a couple of the plugs, and with a loom (handheld
> 10x microscope with a light) look at the center electrode where it meets
> the porcelain. You should see a light blueing of the center electrode
> metal if the plug is hot enough. Autolites may not show this well since
> they are darkly colored.
>
> 4) after a 1000 miles (street truck here) take a small flexible light (in
> the automotive section) and position the bulb so that you can see the area
> where the porcelain meets the metal casing on the chamber side of the plug,
> the porcelain should be lightly tanned only at the base. If this line is
> black then the motor is slightly rich (keeping the pedal down will do
> this), and the line should be only at the base, not halfway up or something
> is either too cold, too rich, or the timing is a little weak.
>
> 5) any coloring should be dry appearing or you got problems.
>
> 3) with gasoline the plugs should otherwise look like they just came out of
> the box. The porcelain will appear a little "drier" than a new one, but
> that should be it.
>
> 6) most important, take the loom and look at the porcelain carefully, if
> there are small spots that look like "fly shit" you have detonation whether
> you heard it or not. You never want to see these spots.
>
> Smokey Yunick about 5 years ago wrote an excellent article in Circle Track
> about plugs if anyone can find it. I have no clue where my copy is at the
> moment.
>
> Hope this helps
>
> Nicholas
>
> Nicholas McKinney
> Applied Industrial Technology, Inc.
> www.usaait.com
-- Mailto:rotrottmann@davidson.edu http://thelma.davidson.edu/rotrottmann/web/default.htm Davidson, NC- Now St. Louis, MO- May 19th 95 Sport 318 Auto 2WD
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