Can spark plugs that look healthy be sick?

Steve Lusardi wrote:
> Unless you are using leaded gasoline or burning lube oil there is no color
> change, as there is no more ash. The lead in gas created lead bromide ash
> which lubricated the valves and valve seats. That ash appeared as a light
> tan deposit on the plugs. Eroded electrodes and anodes indicates over heated
> plugs, so if you are using the correct heat range, no or very low erosion
> will occur. So, the answer to your question is, yes, you can have a bad plug
> due to ceramic cracking, carbon tracking or resister failure and have it not
> be visible.
> Steve

That's interesting about the tan coloring no longer being an indicator
of a healthy engine and a correct air fuel mixture. Someone needs to
tell the writers of shop manuals. Leaded fuel began being phased out in
the US in 1973 and have been totally banned for on-road vehicles for 12
years now.

>
> "Simpson" <"tinauxide butylflex"@epoxy.com> wrote in message
> news:AUgFj.35283$J41.27952@newssvr14.news.prodigy.net...
>> I pose this question in my ongoing quest to improve performance on my 87
>> Dakota without spending unnecessarily.
>>
>> Actually, it's not the spending that bothers me. I just don't feel like
>> changing my plugs. Condemn me for a lazy good-for-nothing if you will, but
>> that's just the way it is today.
>>
>> The reason I know that they look healthy is that every once in a while I
>> pull one to see how it's doing.
>>
>> Hello, plug
>> How ya doin'?
>> I come to watch your changing huin'
>>
>> (huin' - slangy contraction of 'hueing', from 'hue', a gradation or
>> variety of a color; tint)
>>
>> The plugs have nice, unworn, square electrodes and are properly gapped
>> and, over all, have a nice healthy appearance, albeit the ceramic
>> insulators are a bit on the white side. Can I assume that they are in good
>> shape? Or is there some internal condition, unseen by mortal eye, that can
>> develop, that causes plug performance to deteriorate?
>>
>> The truck idles a bit rough, nothing at all severe, but something that I
>> think could be improved. I am ruling out the fuel delivery for the moment
>> and concentrating on the ignition. The cap and rotor appear to be in good
>> condition. The ignition wires all measure a bit below the low end of the
>> resistance range as specified in the service manual, 250 to 600 ohms per
>> inch. Mine are about 200 to 220 ohms per inch and are not that old.
>
>


--

Chuck Norris can fool all of the people all of the time and Chuck Norris
supports McCain.

McCain -- it rhymes with Hussein, Bahrain, cocaine, insane, wolfbane,
chest pain and chow mein.

I know that and I agree with your observation of shop manuals. I build a lot
of motors and now have to use a 4 gas analyzer to tune, as there are no
visible indicators anymore on the plugs. You only see ash now with racing
fuel.
Steve

"Simpson" <"tinauxide butylflex"@epoxy.com> wrote in message
news:X0bGj.30157$R84.19579@newssvr25.news.prodigy.net...
> Steve Lusardi wrote:
>> Unless you are using leaded gasoline or burning lube oil there is no
>> color change, as there is no more ash. The lead in gas created lead
>> bromide ash which lubricated the valves and valve seats. That ash
>> appeared as a light tan deposit on the plugs. Eroded electrodes and
>> anodes indicates over heated plugs, so if you are using the correct heat
>> range, no or very low erosion will occur. So, the answer to your question
>> is, yes, you can have a bad plug due to ceramic cracking, carbon tracking
>> or resister failure and have it not be visible.
>> Steve
>
> That's interesting about the tan coloring no longer being an indicator of
> a healthy engine and a correct air fuel mixture. Someone needs to tell the
> writers of shop manuals. Leaded fuel began being phased out in the US in
> 1973 and have been totally banned for on-road vehicles for 12 years now.
>
>>
>> "Simpson" <"tinauxide butylflex"@epoxy.com> wrote in message
>> news:AUgFj.35283$J41.27952@newssvr14.news.prodigy.net...
>>> I pose this question in my ongoing quest to improve performance on my 87
>>> Dakota without spending unnecessarily.
>>>
>>> Actually, it's not the spending that bothers me. I just don't feel like
>>> changing my plugs. Condemn me for a lazy good-for-nothing if you will,
>>> but that's just the way it is today.
>>>
>>> The reason I know that they look healthy is that every once in a while I
>>> pull one to see how it's doing.
>>>
>>> Hello, plug
>>> How ya doin'?
>>> I come to watch your changing huin'
>>>
>>> (huin' - slangy contraction of 'hueing', from 'hue', a gradation or
>>> variety of a color; tint)
>>>
>>> The plugs have nice, unworn, square electrodes and are properly gapped
>>> and, over all, have a nice healthy appearance, albeit the ceramic
>>> insulators are a bit on the white side. Can I assume that they are in
>>> good shape? Or is there some internal condition, unseen by mortal eye,
>>> that can develop, that causes plug performance to deteriorate?
>>>
>>> The truck idles a bit rough, nothing at all severe, but something that I
>>> think could be improved. I am ruling out the fuel delivery for the
>>> moment and concentrating on the ignition. The cap and rotor appear to be
>>> in good condition. The ignition wires all measure a bit below the low
>>> end of the resistance range as specified in the service manual, 250 to
>>> 600 ohms per inch. Mine are about 200 to 220 ohms per inch and are not
>>> that old.
>>
>>
>
>
> --
>
> Chuck Norris can fool all of the people all of the time and Chuck Norris
> supports McCain.
>
> McCain -- it rhymes with Hussein, Bahrain, cocaine, insane, wolfbane,
> chest pain and chow mein.