These are the plugs Ford supplied
on the Model T for most of its run. Early records are
scarce, but Ford was using the Champion X by 1911, along
with a few other brands, and continued using them
through the end of Model T production in 1927. Today you
can still buy new Champion X plugs, but many people run
the originals in their cars. Millions of them were made,
so there are still a lot of good ones that work like
Like the Model T itself, the
Champion X plug changed over the years. They're not all
the same. Some folks are very meticulous in making
everything on their cars "correct" for the year. If it's
in good condition, any Champion X plug made in the past
hundred years or so should work in any Model T. But if
you're going for all the correct parts on your T you'll
want to find plugs appropriate to the year of the
It took Ford about six years to produce the first
million Model T's. The second million took about a year
and a half. By 1921 they were making a million Fords a
year, and in 1923 produced two million. The greatest
volume of Model T production being in the twenties, it
follows that today plugs from the twenties are most
common and the earlier versions are harder to come by.
But the production of over three million Fords during
the teens means there were twelve million plugs on the
cars, not counting the millions more sold as
replacements. So even the earlier Champion X plugs can
be found with patience and vigilance.
So what are the differences among
the various versions of the Champion X plug? There is
precious little information on exactly when changes were
made, but advertising of the period can give a hint to
some of them.
All X plugs fall into two
basic groups – the early plugs made in the teens
and early twenties (left), which can be
completely taken apart, and the later "brass
hat" ones that can't.
At the top here is a plug
from the early twenties completely disassembled.
It has ten parts that include copper washers
that go above and below the flange on the
porcelain insulator. These washers originally
had asbestos padding in them to provide a seal
and cushion the porcelain. The bottom plug is
one of the current ones being made today. The
center post is attached to the crimped-on brass
cap and can't be removed from the porcelain
insulator. There is one narrow copper ring that
goes under the porcelain.
Taking a closer look at
the tops of the two types of plugs, we can
clearly see that the center post of the earlier
version, held in with a flat washer, lock
washer, and nut, is a smaller thread size than
that on the later plug with its crimped-on cap.
The thread size on the earlier plug is 5-40, and
that on the later one is 8-32.
There are several stages of Champion X evolution. The
first shown here is from the early teens. The only
printing on the porcelain is CHAMPION X. #2 is from
later in the teens. CHAMPION is printed higher and REG.
U. S. PAT. OFF. has been added below the X. #3 is from
the early twenties. The porcelain has a bit of a taper
and two ribs have been added at the top. This is just a
guess based on the advertising, but I believe it's
around 1923 when the big change comes (#4). The base of
the plug is longer to accomodate the Ford's "new" higher
head introduced in 1917. Why is there a six year gap
between the coming of the high head and the change to a
longer plug base? I have no clue. The other big change
at this point is that the plug can no longer be taken
completely apart. The center post now has the 8-32
thread and is crimped in. This version is pretty
uncommon, and I suspect it wasn't around long. #5 is the
"brass hat" version of the plug that came along in the
mid-twenties and has been around ever since. It is by
far the most common Champion X plug. Finally, #6 is the
modern version sold today, easily recognized by the
Here's a set of
plugs from the teens, ready to use. The steel
bases and collars have been treated with gun
A set of brass hat
plugs from the mid-twenties and later, also
treated with gun bluing.
Using a small wire brush
to clean inside threads.
A box of bases and collars
shows that long bases are much more plentiful
than short ones.
Here's an unusual early plug. The base is steel,
but the collar is brass.
Apparently I got the collar too tight on this
plug, and it cracked the porcelain. That sent me
on a search for better gaskets.
search led me to these copper crush gaskets.
They have a squashable asbestos substitute
inside. With an OD of 3/4" and an ID of 1/2",
one of them will fit under the porcelain on a
brass hat plug, but it won't fit over the cap to
be used on top. On the earlier take-apart plugs
with ridges on the porcelain, you can use one
washer on top of the insulator and one beneath
to provide plenty of cushion. The straight-sided
insulators are like the brass cap ones, too wide
for these to fit over the top. On those plugs
you can only use these underneath the insulator.
A little about shopping for Champion X
You can buy the new ones from the Model T parts dealers
for $25 to $30 each. You can get them from Rock auto
parts for about $25. Good originals often turn up on
eBay for considerably less. The same goes for swap
meets. If you're patient and keep your eyes open, you
can build a full set without spending a fortune. I usd
to pay as much as $10 each for any good Champion X, but
in recent years I've set a limit of $7 for very nice
common ones. I might go as high as $10 for especially
nice ones from the mid teens. Often they can be had for
Article by S. Jelf