[T3] Spark plug gap

[73 squareback Cincy]

On 7/2/2016 5:31 PM, Jim Adney wrote:
> On 2 Jul 2016 at 16:53, 73 squareback Cincy wrote:
>
>> looks like its .024 in the bently manual.
> I'm sure .024 works, but I usually go to .027, mostly because that's
> one of the settings on my gapper and that opens up the gap a bit and
> also seems to work. If the gap gets TOO big, the spark will find
> other places to jump and you'll get misses. If the electrode corners
> aren't too rounded, it's often acceptable to just re-gap the plug and
> re-use it. I know that the plug makers say you have to replace the
> gasket/washer, but I've never found that to be necessary.
>
> It took me decades to understand what constituted a worn out spark
> plug. Look at the center electrode: When new, it's corners are
> square, which means very large electric field which breaks down
> easily (sparks easily). As the plug is used, the corners wear away
> and get rounded; Eventually the corners get so round that the spark
> won't form and jump the gap. Then the engine starts to miss. That's
> the time to replace the plug.
>
> If the insulator looks to be the wrong color, that's usually not a
> reason to replace the plug; that's a reason to look at your mixture
> (carbs or FI) or consider using a different heat range plug.
>
> Of course, if the insulator is broken, you'll need to replace the
> plug, but you also need to figure out WHY the insulator broke and fix
> that root cause. For the record, the only cracked insulator I've ever
> seen was on my snow blower, when I heated the plug with a torch to
> clean it off and heated the insulator too abruptly.
>


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