The U.S. Army had distressing results on heavy
armored vehicles with mechanical fuel pumps and
carburetter systems, from the M3 Grant through
the M26 and M41 lines. So, when they went over
to the improved M46/47, they adopted a mechaical
fuel-injection system for the tanks but went with
an S.U. electric fuel pump on the carburetted
recovery vehicle version of the M48/M6, the M88
gasser. This was later replaced by a diesel
version when the Army got petrol off the
battlefield -- after all, it properly belongs in
the tanks of Alpines and Tigers!
The Army's experience with these S.U. fuel pumps
was a glowing satisfaction at a piece of
excellence properly designed and properly built,
with clean instructions on maintenance and clear
explanations for how to fix problems. S.U. pumps
were the delight of the Army's motor pools for
several decades and we were sorry to see them go,
so reliable and sturdy they were.
Now, on to carbs. There are two basic systems
for carburetion. One relies on "constant volume"
of air pushed through it. These are the carbs
most of us know. I would cheerfully argue that
this design reached its peak with the 28 PCI from
the Deutxcher Vergasser Gesellschaft, sold under
the Solex brand. But others took a stab at
making them, from Carter and Holley to Zenith
and lesser-known works such as Ford. These
carbs have the virtue that they can be built for
a single application, with preset everything, or
can be made to allow everything to be replaced,
from venturi tubes to all of the six or eight jets in the various circuits.
The alternate is the "constant downdraft" carb,
where the volume varies but changes to allow a
maintenance of a steady pressure of air moving
into the engine. S.U. made these first but the
design peaks with the Stromberg CD (get
it? "constant downdraft") line of carbs. These
were the acme of their design. CD carbs provide
better power and better fuel efficiency but need
a lot of careful attention to detail in selecting
the right needle. (I once made a VERY good
friend by providing him the specs and order
number for the needles needed for his Alpine V
after he moved from sea level to Denver. He is
dead now, but his widow and I are very much still
in touch -- I have the only surviving copy of his
memoirs though, in light of my latest move, I cannot find it ...)
Consider a premier carb such as a Weber. These
are grand carbs but you have to have a shop near
you with all of the various tubes and jets on
hand. You really have to fiddle with
these: there just is no general solution. But,
then, once you get them set up right, they are
deathless and will go on going on for 75,000
miles (3,227,984 kg for our metric friends <he
grins>) or so, when wear on the engine will start
to lead to some bleeding and loss of compression,
and then you've either got to rebuild the mill or
tweak the carb. The same goes for the humble but
kind Solex 28 PCI: I have lost my kit of jets
and my supply of bodies and parts in my last
divorce, but nil nisi bonum mortuis. But there
was a time when I contemplated putting a 28 PCI
on each of the cylinders of my Alpine V. It
would have been a terror -- no venturi tubes,
just some filing, 140 mains, and let's gut it out.
Or think of four S.U. HS2's, one on each
cylinder. Damn! It would have sucked air like a
1940's moonshine runner. You Left Coast guys
don't understand the basic mechanical and
fuel-system knowledge that can be found in an
Appalachian high-school drop-out. I am of
Hllbilly stock (I was once accepted as a
"Hillbilly" translator in the Franklin County,
Virginia, that home of NASCAR. Yes, I have a
degree from Yale and my immediate family include
alums of the Naval Academy and Antioch and the
like but, in the end, we still all have one leg
shorter than the other, a product of running
around the hills in search of the goats, cattle, pigs, and chickens ... )
See THUNDER ROAD: you can rent it through your
NetFlix subscription. This deals only
tangentially with Virginia, where I live, though
the Federal task force was headquartered in
Bristol, VA. But it is the lore of these
guys. They'll rig you anything you want, so long
as it doesn't involve fuel injection. Shucks. I
ought not speak so fast: maybe they're cranking
the car's computers. What do I know? My '84
Audi 4000S, with its McCain/Palin sticker, keeps
on keeping on. When it gets old, I'll have to
fiind a new car. I am looking for a 1957 or '58
VW Bus. No hu-hu. My car yet runs, though
Clytemnestra does not like summer starts. She
has a problem with the cold-start circuit in her
computer and tends to treat the fuel system as if
it was always 50 degrees F (237,919 joules, for
you metric guys! Again, <he grins>)
Keep on Keepin' On!
Marc
Marc
msmall@aya.yale.edu
Cha robh b`s fir gun ghr`s fir!
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