[AT] Spark plugs

[Gene Dotson]

    Maybe I am a guy who likes to fiddle more than most. I
probably change spark plug types, carburetor settings and
timing more than the average person, depending on the time of
year, temperature and operating conditions.
    Cold temperatures and and heavy working condition means
more dense air going to the engine, so I use the colder plug
and a little richer mixture. Believe it or not, cold air gives
a hotter cylinder gas pressure than warm moist air.
    If I am just doing odd jobs or parading in warm weather, I
go to a hotter plug and lean the mixture to prevent soot
fouling.
    Like Farmer, I have a shelf full of plugs I have saved and
rescued from the trash bin. I match them up in sets and bead
blast them in my blast cabinet. I have AC 47 and 48, Champion
D16 to D21 and autolite 386 and 387. These cover the range in
my Case tractors.
    Two years ago, I took my Case VC to our club plow days and
under load when the engine was warmed up it would start missing
under load. Checked the plugs and it had Champion D21's so I
put in a set of Champion D16's and the tractor ran fine.
    I had trouble with the plugs fouling in my "V" Case, which
is used mainly for pulling my small dump trailer, so pulled out
the D16's and put in the D21's I took from the VC, which is the
same engine, and both tractors are very happy now.
    Mixing plugs in the same engine is not taboo either. If you
have one cylinder that is burning oil and fouling the plug,
then go a range or two higher in that cylinder. The oil being
burned keeps that cylinder cooler anyway so the hotter plug
just evens things out.
    The application guide is just that, a guide. If the
recommended plug isn't doing the job, then adjust it to your
own needs. Application guides are for engines that are worked
as they were designed to work, under a load for 10 or 12 hours
a day at full operating temperature. I would imagine less than
15 percent of the tractors owned by the members of this list
are run this way.
    As for brand loyalty, I prefer AC plugs, but as to
reliability, if you put them all in a bag and shake them up,
you never which comes out first.

                        Gene

        (Who probably has the cleaneat spark plug threads
around.)



----- Original Message -----
From: Robinson <robinson at svs.net>
To: Antique tractor email discussion group
<at at lists.antique-tractor.com>
Sent: Tuesday, March 23, 2004 10:09 PM
Subject: [AT] Spark plugs


: You know I have read all of the spark plug threads here for
years now
: and I am always a little amazed at how frequent the problems
are. With
: all of the old tractors here and trucks and cars and mowers I
have just
: never generally had any on going spark plug problems. Any
that failed
: were usually waaaay past due to be changed. I have a big box
full of
: saved old plugs (it is an inherited disease) that my father
started
: saving up back in the 30's and if one wouldn't clean up and
fire right I
: have been known to take one out of the box and stick it in to
get back
: in the field in a hurry. BTW the ones that won't work at all
don't get
: tossed in the box.   :-)
:
: Maybe it is just the way I hold my mouth when I drive
stuff...   :-)
: --
:
:
:
: "farmer"
:
: Just when I was getting used to yesterday, along came today.
:
:
: Francis Robinson
: Central Indiana USA
: robinson at svs.net
:
:
:
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