[Shotimes] Re: new plug design

[Paul Nimz]

This is from a SHOforum post and I am not the author.  The link is
http://www.shoforum.com/showpost.php?p=257864&postcount=3


    These are the current plugs for the V8 AGSF32FMF4.

    Some snippets about the new plug design......

    ...I meant to tell you, when my wife and I were at SEMA week before last,
I visited the Motorcraft booth, and had a lengthy discussion with a Motorcraft
rep. with my experience with the Motorcraft double platinum plugs for my 3.0L
FFV (I'm sure you have seen my posts on using AGSF12PPs, instead of the
AGSF22PPs, a hotter plug that Ford is now recommending). The Motorcraft rep.
recommended a new platinum plug, a "fine wire" plug (AGSF12FMF6). Sometime
ago, I got the e-mail address of an engineer at Motorcraft (James Power), so I
sent him a note asking him about the new Motorcraft "fine wire" platinums. He
talked very positive about the new plugs (I'll forward his e-mail to you...).



    Here is the email from the Motorcraft engineer that he is referring to:

    ...Fine wire means a .030" to .040" dia platinum nickel alloy rivet welded
to the end of the center electrode. There is about three times the precious
metal than what is found on a 'P' level enhancement. The P's are made by
crushing and welding a small special lump of Platinum nickel so that it is a
disc about .003" thick.

    The effect of the point on the center electrode is reduction of required
firing voltage and that aspect slows down the erosion of the sidewire.
Consequently, we can use a single 'finewire' enhancement to replace the double
'p' designs for service and get the same durability.

    Some auxiliary advantages of the reduced firing voltage is less stress and
therefore better life of coils and wires, etc. and cold foul misfire is
improved. Don't go crazy getting some because our systems are robust without
it and the improvement is modest and mostly unrecognizable except for special
cases. We use it in production as a durability measure for those engines that
wear out plugs fastest.


    Your SHO forum friend brings out a point ....that has been the argument
all the time for using DP plugs with EDIS!

    I raised the same question with the Motorcraft engineer, and I'll try and
explain his response. One thing to understand first, when a coil "discharges"
(due to the induced field from the coil primary into the coil secondary), the
voltage will only build up until the spark occurs, and will not increase any
more. There are several parameters that effect the voltage required for the
plug to spark. In addition to the gap, and pressure/composition of the
cylinder charge, the physical structure of the plug electrodes also determine
the spark voltage. A "blunt" electrode requires a higher voltage to spark,
than a "sharp" electrode. With the "fine wire" center electrode being sharper
than the platinum bead on the older DP plugs, the spark voltage is lower with
the new "fine wire" platinum's. With this lower spark voltage, there is less
energy, so electrode erosion is reduced. Because of this, platinum is not
needed on the outer (GND) electrode. I'll keep an eye on mine to see how they
do!!

    I hope this answers the question on why only the center electrode is
platinum on the new "fine wire" plugs. As explained by the Motorcraft
engineer, there are several side benefits to the lower voltage:

    1) lower misfires
    2) longer coil pack life
    3) longer plug wire life

    These points alone are reasons NOT to increase the plug gap wider than the
recommended gap. I have seen many posts about gapping plugs wider than the
recommended gap!


    Paul Nimz
    '97 TR
    '93 EG mtx




      ----- Original Message -----
      From: Stan_Phillips@divintech.com
      To: Kirk J Doucette
      Cc: v8sho@v8sho.com
      Sent: Wednesday, September 29, 2004 8:47 AM
      Subject: RE: Camweld re-assembly questions



      Kirk (or anyone else that can provide info),
      The car is finally getting put back together...no car for 3 weeks (can't
wait).
      It's almost like having your b***s cut off !!

      Question about the plugs.
      I've read in previous emails about you specifying agsf32fm plugs.
      The plugs that I pulled from the car are awsf32fm....do you know what
the difference is (which is better) ??
      I've gone to the Motorcraft site, and they list both, but they don't
give me any more info.
      Enlighten me if you would.

      Thanks,
      Stan Phillips
      Diversified Information Technologies
      (570) 343-2300
      ext. 3010


            "Kirk J Doucette" <kirk.doucette@verizon.net>
            09/16/2004 03:12 PM
           To "Rich Larsen" <rlecads@xmission.com>, <v8sho@v8sho.com>
                  cc
                  Subject RE: Camweld re-assembly questions







      It was close to the proper tq, they still need to be properly tqed
after.
      I use a race car header wrap from areoquip

      -----Original Message-----
      From: Rich Larsen [mailto:rlecads@xmission.com]
      Sent: Wednesday, September 15, 2004 1:56 PM
      To: 'Kirk J Doucette'; v8sho@v8sho.com
      Subject: Camweld re-assembly questions

      Hey Kirk,  As you were zipping up my engine back in Tulsa, you
mentioned
      that the purchase of a 1/4 air ratchet was one of your best decisions
and
      you had a list of reasons, one being that it had just the right torque
for
      most of the nuts on the intakes etc.  What were the other reasons?
      Also, what do you use to insulate the wiring harness?  Is it readily
      available?

      Thanks,

      Rich Larsen
      96 TR - Kirked in Tulsa




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