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Re: Reading Spark Plugs

To: "ROBERT G. HOWARD" <mgbob@juno.com>
Subject: Re: Reading Spark Plugs
From: Arthur Pfenninger <ch155@FreeNet.Buffalo.EDU>
Date: Tue, 8 Jul 1997 19:03:01 -0400 (EDT)
        Ther was an interesting article in Moss Motoring last month
something that I wasn't aware of. You may have to do some re wireing if
you are using a sport coil otherwise you will only get 20000 volts out of
it just like an ordinary coil. Check it out...
...Art

On Tue, 8 Jul 1997, ROBERT G. HOWARD wrote:

> 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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