It is also advisable to pull the plugs when the engine is cold with aluminum
heads and always use antiseize!
I would take the car on a road trip on the highway of several miles and see
how the plugs are then.
If you're afraid you are burning lean then richen it up a bit - I would
rather burn a bit rich than too lean.
Mike
----- Original Message -----
From: "Marc Sayer" <marcsayer@home.com>
To: "Roadster list" <datsun-roadsters@autox.team.net>
Sent: Thursday, March 15, 2001 12:37 PM
Subject: Re: Plug Color Mystery
> Teddy Seidenfeld wrote:
> >
> > > Date: Tue, 13 Mar 2001 19:58:31 -0800
> > > From: Marc Sayer <marcsayer@home.com>
> > > Subject: Re: Plug Color Mystery
> > > Nathan Ruffcorn wrote:
> > > >
> > > > Hey all-
> > > >
> > > > The weather was great today! I've been able to get the roadster out
for
> > > > the past three days straight. The bugs are slowly getting worked
out,
> > > > making each run more enjoyable. As always, it attracts lots of
attention.
> > > > I'm especially enjoying the 3.9 rearend/2L combination. <grin> It's
easy
> > > to
> > > > accidentally bark the tires when pulling away from a stop light. For
> > > > leasure driving, out of traffic, I routinely start in 2nd and skip
to 4th.
> > >
> > > >
> > > > In an effort to get everything just right, after each run I have
been
> > > > pulling the # 1 and # 3 spark plugs to judge the mixture of each
carb. The
> > >
> > > > plugs have been whitish/grey so I've been gradually richening it up.
> > > > Yesterday, out of curiosity, I decided to pull all the plugs. I was
REALLY
> > >
> > > > surprised to find #1 and #3 the same color (whitish/grey) and #2 and
#4
> > > the
> > > > same (brown). What am I missing?! I admit, I'm no master tuner but I
know
> > > > that cylinder #1 & #2 and #3 & #4 should at least correspond
together.
> > > >
> > > > Other factors (symptoms):
> > > > -Rebuilt carbs from Z-therapys
> > > > -Seems to surge a bit at highway speeds (65-70mph)
> > > > -Hesitates under gradual acceleration, but seems to immediately
"come
> > > alive"
> > > > with a heavier foot.
> > > >
> > > > Please let me know if I'm missing anything really obvious.
> > > > Man these cars are fun!!
>
> This just goes to show, I should never answer posts when I am tired. While
my
> original reply was all true, it has nothing to do with what is described
here. I
> got the cylinders confused and thought he was describing the pattern I
> explained. But I see now his pattern is something else. I apologize for
creating
> any confusion. I agree that valve adjustment is the place to start. I
would also
> check the ignition system. Try swapping the plugs around (put the plugs
from 1 +
> 3 into 2 + 4 and vice versa) and see if the pattern reappears. A word of
warning
> about plug color, though. The only way plug color can tell you anything is
if
> you start with clean plugs or run at a steady speed for at least a minute
or so
> to "clean" the plugs, and cut the engine as soon as your test run is done.
If
> you leave the engine running while you come to a stop, get off and on the
gas,
> or let it idle at all, the reading will be affected. Also many fuel
additives
> nowadays mess up the coloring of the plugs and make plug reading
impossible.
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