My next event is the AR Autolite series copper for the 4.7 this weekend if I
can find some. Try these...
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Steven St.Laurent
Test Engineer
Test Branch, GSD, MCTSSA
MARCORSYSCOM, USMC
760-725-2506 (DSN 365-2506)
Work:mailto:stlaurents@mctssa.usmc.mil
Home:mailto:saint1958@home.com
-----Original Message-----
From: Chris Lambert [mailto:mopar88@efortress.com]
Sent: Monday, November 06, 2000 7:07 PM
To: dakota-truck@buffnet.net
Subject: DML: projected-nose plugs good?
I am currently testing this very concept in my 4.7... i am running a bosc
copper plug, the 7561 i believe. It is reccomended for the 4.7 cherokee
and so far i am impressed for the most part, it runs good and has really
good power and economy, but the computer is having a hard time learning how
to idle with them in... you know like it always has with the 4.7 5-sp...
but overall i like them... they lead to lots of traction issues on a tight
corner (grin)...
Chris
"Drive it like you Stole It..."
>A little something I found, from a long article on sparkplugs.
>
>One of the biggest improvements in spark plug design in recent times was
the
>projecteded-nose configuration introduced (if memory serves) back in the
>'60s. These plugs have what their name says: Both the ground wire and the
>center electrode extend farther into the combustion chamber, and move the
>spark gap with them to a point about .200-inch beyond the plug shell.
>
>A projected-nose plug looks like its electrodes and insulator are terribly
>exposed to the fire inside the combustion chamber. But these extended bits
>also are out there where the incoming air/fuel charge can do a fine job of
>cooling them. In an engine, the projected-nose spark plug runs hotter has
>better resistance to fouling at light throttle openings, yet is cooled by
the
>blast of air and fuel it gets when you crank up a bunch of throttle.
>
>The down side (isn't there always one?) of projected nose plugs is that in
>some engines there just isn't enough clearance for them among the other
>hardware, valves and piston crown, also occupying the combustion chamber.
>It's a point to watch, but where there is room, and assuming the
appropriate
>heat range is available, projected-nose type plugs are the best choice.
>
>An engine's ignition advance must be tweaked a little to adjust for the
burn
>rate changes produced by the different nose configurations. The old
retracted
>gap racing plugs needed more ignition advance because they started the fire
>back in a hole. Projected nose plugs start the blaze out where it can
spread
>easily, so an engine fitted with such plugs need less advance.
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'00 CC, Packin a 287 Magnum, 5-sp, Gibson Duals, Traction Bars, Spring
Clamps, Magnum Front Plate, Quick D Intake, "Smoke Em" Decal, Paint
In bed-liner, More to come
http://www.intense99dak.com/chris.htm
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