On Sunday, June 18, 2017 at 2:42:42 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Sun, 18 Jun 2017 10:10:25 -0400, Bob Engelhardt
wrote:

On 6/17/2017 8:26 PM, wrote:

Why? Blast cleaning is no longer recommended - too easy to get a
grain
of blast medium where it doesn't belong - doing expensive damage -
and
plugs are CHEAP!!!


I do already have a new plug. The blasting was to see if the soot
was
the problem.
It's your dime, and your time - but you already KNOW the plug was
the
problem - if you want to know if it was carbon, just wash it with
laquer thinners and bake it untill it's white. I do it with my
torch -
just heat it up with the propane torch until the porcelain tip glows
then keep it in the envelope of the flame for a few seconds - comes
perfectly clean - and USUALLY restores the function of the plug.
Years
ago with leaded gas sometimes it would have a yellow or green
"glaze:
on the insulator that would not burn off, or blast off. Some product
of sulpher and lead catalyzed by the silica in the insulator - I
believe it was lead sulphide (Germanium) - basically a cheap
semiconductor

Not to pick on you, but lead sulfide is Galena, the semiconductor used
for early "cat's whisker" radio detector diodes.
https://en.wikipedia.org/wiki/Cat%27s-whisker_detector

Used to see this all the time with Amoco premium in high performance honda engines (mid 1979s).

I seriously wish I had known about the Galena connection back then. I would have used the fouled plugs to make radios.

Now I'm imagining an episode of Gilligan's Island where the Professor makes a crystal radio out of a lead-glazed spark plug and a coconut...

"rangerssuck" wrote in message
...
On Sunday, June 18, 2017 at 2:42:42 PM UTC-4, Jim Wilkins wrote:
wrote in message
...
On Sun, 18 Jun 2017 10:10:25 -0400, Bob Engelhardt
wrote:

On 6/17/2017 8:26 PM, wrote:

Why? Blast cleaning is no longer recommended - too easy to get
a
grain
of blast medium where it doesn't belong - doing expensive
damage -
and
plugs are CHEAP!!!


I do already have a new plug. The blasting was to see if the
soot
was
the problem.
It's your dime, and your time - but you already KNOW the plug was
the
problem - if you want to know if it was carbon, just wash it with
laquer thinners and bake it untill it's white. I do it with my
torch -
just heat it up with the propane torch until the porcelain tip
glows
then keep it in the envelope of the flame for a few seconds -
comes
perfectly clean - and USUALLY restores the function of the plug.
Years
ago with leaded gas sometimes it would have a yellow or green
"glaze:
on the insulator that would not burn off, or blast off. Some
product
of sulpher and lead catalyzed by the silica in the insulator - I
believe it was lead sulphide (Germanium) - basically a cheap
semiconductor

Not to pick on you, but lead sulfide is Galena, the semiconductor
used
for early "cat's whisker" radio detector diodes.
https://en.wikipedia.org/wiki/Cat%27s-whisker_detector

Used to see this all the time with Amoco premium in high performance
honda engines (mid 1979s).

I seriously wish I had known about the Galena connection back then.
I would have used the fouled plugs to make radios.

Now I'm imagining an episode of Gilligan's Island where the
Professor makes a crystal radio out of a lead-glazed spark plug and
a coconut...

I worked with Detroit engineers and knew the underlying cause but had
no way to measure the quality of the spark in a cylinder under a
driving load, so I just replaced the plugs if the engine didn't feel
right.

The little 12V spark plug blaster I bought made them prettier but
didn't help the problem for very long. I kept some in the vehicle as
temporary spares I could give away to the needy, along with the second
headlight or brake bulb when one burned out.
-jsw