Re: melted spark plug electrodes- long! (help!)

From: Bob Tom (tigers@bserv.com)
Date: Mon Sep 25 2000 - 12:04:10 EDT


Hi, Darren

At 11:41 PM 9/24/00 -0800, you wrote:
> <snip> The thing I'm worried about is the spark plug I pulled
>from #4 cylinder has what appears to be a melted ground electrode.

A melted ground electrode is a symptom of preignition which can be caused
by usage of an incorrect plug heat range, over-advanced ignition timing, lean
fuel mixture, insufficient cooling or lack of lubrication. Since this
condition can lead to severe engine damage and you've just put in the 3923s,
pull plug #4 frequently and check its condition.

>The other 7 spark plugs have a dark red (purple?) deposit on them (no
melting)
>and varying gaps from .045-.080. I'll try to get pics as soon as I can (if
>anyone's interested). <snip>

If these are the original plugs, either they were not properly gapped or
are showing long wear. Reddish, rusty appearance on the insulator and side
electrode indicate the plug fouled by MMT which is an anti-knock additive
in gasoling used to replace lead. Plugs showing this condition and not worn
will not affect performance any more than lead deposits, and can be cleaned,
regapped and reinstalled.

If you are concerned about any damaged done by debris from the melted
electrode,
have a compression test performed.

Hope this helps.

Bob



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