I think this is the best you will find in the archives, as I recall. I
think most people just experiment until they find the gap they think works
best. I set mine at .030" (I think).
I an not aware of the "spark plug gap is .001" per M volts" rule but I sure
wish it could be confirmed. All I know of is the vague "increase the gap".
David
67 BGT
71 BGT (w/sports coil)
At 08:19 PM 5/28/00 +0000, you wrote:
>Reading back through the archives (as I do before changing ANYTHING on
>my car), I was looking for some comment on the increased gap recommended
>when you install a Lucas Sports Coil. Everyone says 'increase the gap'
>but I was seeking something more definitive and found the following from
>wayyyyyy back. Any comments anyone?
>
>Way back in history, MGBob said:
> >
> > Date: 08-Jul-1997 08:24:06
> > Subject: Re: Reading Spark Plugs
> >
> > Addressing the Sports Coil idea, at the GOF Newton sports coils
> > were mentioned. In the discussion, it was stated that a rule-of-
> > thumb for spark plug gap is .001" per M volts. Since the standard
> > Lucas coil delivers about 22-25M volts, depending on incoming
> > voltage, the spark plugs should be gapped at .025. The Lucas
> > sports coil delivers about 40M volts, so the plugs should be gapped
> > at .040 to utilise the extra power. This was new to me, but it was
> > then explained that Champion and NGK make plugs called "large gap"
> > or something similar, that are especially configured for the extra
> > gap and extra voltage. One might wish to check clearance between
> > plug and piston if compression has been increased.
> > Bob
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