Hi Rick,
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
On Mon, 07 Jul 1997 20:50:47 EDT gofastmg@juno.com (Rick Morrison)
writes:
>
>On Mon, 7 Jul 1997 18:40:03 -0400 Adrian Jones
><AdrianJones@compuserve.com> writes:
>>Hi Folks,
>>Here's an interesting little topic. ( Well I think so anyway)
>>Is it possible to "fine tune" your carb mixtures by looking at the
>>condition of your plugs? If so, here's some questions:
>>A recent post said that the outer plugs (#1 and 4) tend to run rich,
>>at
>>least on an MGB. Does this apply to a Midget and if so , why?
>
> Yes. Both have the two exhaust valves adjacent to each other,
>effectivly doubling the heat that must be transfered, added to
>slighlty reduced water flow around the two centre cylinders adds up to
>a pair that run slighlty hotter, consequently slightly leaner
>
>>If the engine was burning oil or if there was a slight ignition miss
>>on o=
>>ne
>>or more cylinders, wouldn't this confuse the issue. =
>
>Yes. these problems, when noticed should be addressed before plug
>condition can be used as a tuning tool
>
>>Is it OK to use a brass wire brush to clean the plugs.
>
>NO. any wire brush will leave minute tracks across the insulator
>which can lead to lessend plug effeciency and longevity.
>
>
>JC Whitney has something that uses grit and is powered by the car
>>battery=
>>=2E =
>>
>>Cost $8. Anybody used it?
>
>Got one ( not from J.C. Whitless) and it does a reasonable job on
>normal plugs. Not so good on heavily fouled or sooted ones. Just
>remember to get all the grit out before reinstalling the plugs
>
>>Are we looking for a light brown color? The cleanest plug so far,#4,
>
>>has=
>> a
>>definite reddish deposit.
>
>This can sometime be caused by additive and/or dyes in the gasoline
>you are using. You might switch brands for a while with a new set of
>plugs, and see if the condition changes.
>
>>Don't we want a slightly rich mixture for more power? Wouldn't this
>>eventually foul the plugs with carbon? =
>
>If the plugs are getting carbon fouled, it's too rich. The carbon is
>the result of less than optimum combustion.
>
>>Should the spark plug gap be kept at 25 thou. I have a Sports Coil
>>but
>>regular CB points.
>>In the mornings, I need to do the "in and out and in and out" thing
>on
>>the
>>choke as I go through the gears to keep it running smooth until it is
>>warmed up nicely. Is this normal
>
>Yep, perfectly normal.
>
>>Like the man says, "Old farts want to know!"
>>
>>Adrian. (Being an old fart sure beats the alternative!)
>
>>From one old fart to another.
>Rick Morrison
>72 MGBGT
>74 Midget
>
>>
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