Gray Plugs

[Programmer]

I know the next step is silver balls--but could this preclude that by
plating microscopic
layers of aluminum onto the plugs ?

Lyndon
----- Original Message -----
From: rr <RRauscher at nni.com>
To: <gmecm at diy-efi.org>
Sent: Tuesday, May 08, 2001 7:37 PM
Subject: Re: Gray Plugs


>
> With Bruce being off-list for a couple of days, I'll add what I can. Mild
> detonation can show up in a number of ways. I've seen it as nothing more
> than a light dusting of black specks (carbon blown off chamber walls) on
> a pure white insulator, to light audible knock. Sometimes a loud exhaust
> can mask audible knock. A roughness in the engine can also be a sign
> of light detonation.
>
> What I think is happening here, is that audible knock is being covered
> (smothered) by excess fuel. I've seen this before where the fuel pressure
> was a bit high (carb & too rich), and timing was added until it felt good.
>
> It was a number of years ago that I last saw this, and at the time did not
> know what to think of it (the gray plugs). I remember checking the timing
> this guy was running & backed it off. Then checking the fuel pressure &
adjusted
> it to a proper value. He constantly over-revved the engine & shortly
thereafter
> cut the block in half (Pontiac 389). I think what Bruce is saying below
(change
> in chemistry) really explains this case.
>
> I do know that after the adjustments the engine ran much better. In
closing
> I would tend towards the gray plugs as not detonating. However, it is
showing
> that a problem does exist.
>
> BobR.
>
> p.s. speaking of plugs, what is the reason for 'spider webbed' plug
insulators?
>
> Mitch Louole wrote:
>
> > Is this another way of saying,.. Detonation was occuring,  albet in a
mild
> > state?
> >
> > >From: "Bruce Plecan" <nacelp at bright.net>
> > >Reply-To: gmecm at diy-efi.org
> > >To: <gmecm at diy-efi.org>
> > >Subject: Gray Plugs
> > >Date: Thu, 3 May 2001 14:48:23 -0400
> > >
> > >
> > >The info is from another list, but thought was worth mentioning here.
> > >
> > >Gray plugs
> > >
> > >I think most of the experienced plug readers know it's a timing (and
often
> > >a
> > >slight fueling issue), BUT it represents the change in chemistry in the
> > >combustion chamber from detonation.
> > >
> > >HTH
> > >Bruce
> > >
> > >
> >
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