The fellow who was giving the Tech Session at which I heard this was
Hal Kramer, retired electrical engineer.
The context was T-series engines and MBTE blended fuel. Hal was talking
about the benefit of opening the plug gap to 025 (vs the book's 020) and
of opening the gap to 040 for the Lucas Sport Coil, and suggested the
rule of thumb of one thou per thousand volts.
Bob
On Sun, 28 May 2000 10:16:54 -0600 David Councill <dcouncil@imt.net>
writes:
> 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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