\input lpg-defs

\graphic{180pt}{The vehicle featured in this LPG fuel conversion
project -- my 1963 Rambler Classic~550 Station Wagon, with a
late-model (well, 1970) 232~ci. 6~cylinder engine. 3,150 lbs. of
finely wrought steel. Substitute your favorite car here.}

\bigskip
\section{INTRODUCTION}

There already is a practical alternative to gasoline as a motor
vehicle fuel. It's cheap, doesn't require exotic equipment, and 
is retro-fittable to most existing vehicles. And except for
producing bulk CO$_2$, pollution-free. It's Liquefied Petroleum
Gas, or LPG for short. 

This book describes how I built my LPG-powered automobile,
provides some background information, and lists my limited (so
far) experiences in operating an alternative-fuel car day to day.
My goal is to outline the process I went through, provide the
basic technical information to build your own LPG-powered
vehicle, and give you an idea of what it's like to use it in
real-life terms.


\section{WHY LPG?}

Liquefied Petroleum Gas, or LPG, is the correct name for what's
commonly called propane, butane or bottle gas. It's actually a
mixture of propane, butane, ethane, methane, and other gases. It
is generally a petroleum product, but it can also be made by
removing water and CO$_2$ from Natural Gas.  Physically, it's a
gas at room temperature, and compresses into a liquid at
reasonable temperatures and pressures, which is why it's called
Liquefied Petroleum Gas. It's odorless, but has a stinky odorizer
added so that you can smell leaks.

It's non-toxic enough to cook with indoors and heat your house;
indoor warehouse forklifts use it without ventilation; Safeway
buffs their floors with a 
propane-powered floor buffer. It's also a claimed 
environmentally-safe aerosol propellant, quickly replacing freon
in many cases.

There are a number of reasons why I wanted an LPG car: I hate
being dependent on the oil industry; when I'm done with this
project (See the GETTING AWAY FROM PETROLEUM section) I'll only
use LPG on long trips; extremely long engine life; 250,000 miles
is routine, 400,000 miles rumored; reduced oil consumption, and
waste oil is less toxic than a gasoline-engined car; near-zero
atmospheric pollution; potential to operate on other ``waste''
gases (methane, etc); and it allows turning larger, simpler,
cheaper, less-efficient vehicles into practical alternative fuel
vehicles. It's also technically interesting, and I simply like
traveling unusual paths.

I am hard-pressed to find LPG's inherent drawbacks. Of the
limitations of my car compared to an equivalent gasoline car, all
are because mine is homemade, and the ``system'' out there wants
you to buy gasoline. 

I live in an industrial neighborhood of San Francisco. I use my
car within the city, and for long-distance trips, which I've
engineered my car specifically for. I believe my usage is within
the realm of ``normal'', as far as ``every day'' vehicle use
goes. 

\newpage
\section{OTHER FUELS}

I'll give a brief rundown of potential or possible portable power
sources and some facts and opinions on them. For a sense of
scale, the very latest in efficient gasoline automobiles, say a
Ford Festiva, will carry 4 people plus itself (total: 2200 lbs or
so) about 50 miles on one gallon of gasoline under best
conditions. One gallon of gasoline contains about 37
kilowatt\slash hours (KWH), so for comparison purposes this is
what I'll use. 

(A kilowatt is 1,000 watts; expending 1,000 watts (heating water,
running a motor, etc) continuously for one hour is a measure of
work done, and a kilowatt/hour (KWH) is a decent human-scaled
amount of work; one ``horsepower'' is 746 watts.)

ONE PERSON pedaling an efficient bicycle fairly hard can generate
about 100 watts of energy; kept up for an hour is a fair amount
of work, and in techie terms, is called, appropriately enough,
100 Watt/Hours, or 1/10th of a kilowatt/hour. Do this for 370
hours, and you're there\footnote{*}{OK so you'd be healthier, not
get stuck in traffic in the city, spend almost no money, have a
better perspective on the world you live in, waste no energy, use
no fossil fuels, get to sneer at nerve-wracked commuters, and you
could still use a car to take long trips on weekends. But the
point of this was motor vehicles, now wasn't it?}.

ELECTRICITY in San Francisco costs about 12\cents\ per
kilowatt/hour. (Electrical utility power is highly subsidized;
actual system-wide cost is much more.) That gallon of gas would
be about \$4.44.

Storing electricity is difficult and expensive. To store that 37 
KWH-worth of energy, you would need about \$4800 worth of 
hi-tech lead chloride cells, weighing 2400 lbs -- you'd still
have to generate the energy to put in them. (Also a good excuse
for the centralist 
powers-that-be to push nuke plants.)

SOLAR POWER form solar panels (PhotoVoltaic, or PV) generate
electricity ``for free'', once you own them. Today's 
state-of-the-art PV technology converts about 13\% of the sun's
energy striking them to electricity {\it when aimed properly}; a
panel capable of generating 37KWH in 8-hours worth of bright
sunlight would cost \$33,500 (96 ARCO M-75's, assuming a better
price than the Real Goods 1990 Sourcebook)\footnote{*}{There are
practical ways to make an electric vehicle, and this is not one
of them -- it's merely for comparison purposes. For information
on electric vehicles, write to HOME POWER MAGAZINE; see SUPPLIERS
\& SOURCES.}.

\graphic{250pt}{Good-size solar PV panel, looks like 180 Watts or
so. Installed in a well-designed system in the right part of the
world, adequate to power a small house. (See Home Power and Real
Goods in SUPPLIERS \& SOURCES.)}

HYDROGEN sounds like the perfect fuel until you try to make it or
store it. In theory a non-polluting source, in practice it has to
come from somewhere, and guess what -- commercially available
hydrogen is usually made from petroleum-derived methane. In the
laboratory it can be made by breaking water molecules into its
component hydrogen and oxygen, but it that takes huge amounts of
energy, far more than you recover when you burn the oxygen and
hydrogen later for power. Even with a perfect storage medium and
100\% efficient fuel cell, you might as well simply store the
energy you'd use for wrestling with hydrogen atoms and use it
directly to do the work you originally intended. One pound of
hydrogen contains 36KWH. It's volume depends on the storage
medium.

METHANOL (and ETHANOL) is pretty powerful stuff; at 23KWH a
gallon similar enough to gasoline; 16 gallons of methanol has the
same energy as 10 gallons of gasoline. It can also be produced
from fermentation of organic matter, and apparently in Brazil
lots of commercial fuel alcohol is, making it a renewable energy
source there. Here in the U.S. most methanol production is from 
petroleum- and lumber-industry byproducts. It's also the most
likely candidate for home production on a decent scale, second
maybe to electricity. It's attractive as a motor fuel because it
fits in existing fuel-dispensing systems and equipment. 

(It is my cynical belief that any large-scale use of methanol in
the U.S. will be because the petroleum industry can produce it
profitably from their existing technologies and fit it into their
product lines. It's not a very clean fuel, pollution-wise; see
below.)

PROPANE -- LPG is yet another ``byproduct'' of the petroleum
distillation process, but can also be produced by removing
unwanted junk such as water from natural gas. By a coincidence of
physics these gases liquefy at reasonable temperatures and
pressures, so that one gallon of LPG (liquified; about 270
gallons in gaseous form) contains 27KWH of energy; 13 gallons of
LPG is equivalent to 10 gallons of gasoline, even though to use
as a fuel they are handled very differently.


\vskip\parskip
\begintable
 | LPG | GASOLINE | METHANOL\cr
lbs/gal. | 4.24 | 6.4 | 6.84\cr
BTU/gal. | 91,500 | 126,000 | 79,400 \cr
Octane | 110 | 96 | 100+\cr
Boils at: | -44\degree F  | 85 -- 390\degree F | 149\degree
F\endtable

\newpage
\section{METHANOL VS. PROPANE}

From an ``alternative'' point of view, alcohol (methanol or
ethanol) seems to be the winner at first glance, because it is a
renewable fuel; if made from fermented organics such as plants,
no more carbon dioxide is produced in combustion than is bound
when the plants are grown or replenished.

Unfortunately there are a number of problems with using alcohol for
existing applications. One slight problem is the simple fact that no
organically-produced methanol is available in the US, and home
production of a decent volume is not a trivial task. Also, methanol,
like any liquid fuel, simply does not burn completely in an internal
combustion engine. The theoretical products of methanol combustion, as
for gasoline combustion, are carbon dioxide and water. In real life
there is unburnt fuel, carbon monoxide, and various hydrocarbon
fragments from incomplete combustion combined with the high pressures
and temperatures of the cylinder combustion process.

Basically the problem is that liquid fuels are liquid -- even
after vaporization in the carburetor, swirling in the cylinder
head etc, fuel droplets remain unburnt, because of the short time
given for each cylinder to fire to operate the engine. (Internal
Combustion engine design is well known and outside the scope of
this article -- but if you want my two-cents worth on how to make
it work, read the HINTS FOR MOTORHEADS section later on.)

Gaseous fuels simply don't have this problem -- the individual fuel
molecules are by nature separate, and burn very nearly completely. A
poorly tuned gaseous-fuel engine still burns far cleaner than a
well-tuned liquid-fuel engine.

Though the sheer volume of gas needed is intimidating, fermentation
methane, dried and compressed into liquid, would be at once renewable
and non-polluting. Most likely you could have the same vehicle operate
on commercial LPG (long trips), or methane from fermentation.

Also in LPG's favor is that pound for pound, it contains less carbon
than gasoline or methanol -- an LPG powered vehicle produces
signifigantly less CO and CO$_2$ per mile. 

\newpage
\section{MOTOR FUELS, SAFETY \& TOXICITY}

Having now used both gasoline and LPG, I far prefer handling LPG.  My
now-infrequent trips to gas stations (in other peoples' vehicles) are
like visits to toxic waste sites. It's amazing what we get used to!

A gasoline spill, by accident, or more ordinary dripping hoses at a
gas station, is a toxic nightmare. In addition to being exceedingly
flammable, gasoline runs into streams and soak into the soil,
poisoning everything it touches. Its vapors are explosive. It's a
known carcinogen. Even if the fire hazard is overcome, the toxicity
lingers on.

An LPG spill is just as flammable (or it wouldn't be a useful fuel!),
but instead of poisoning the environment, it boils away as fast as it
can absorb heat. LPG is non-toxic. It's vapors can collect in low
spots, where it is a fire hazard, since it is heavier than air. Once
the gas has dissipated, there is no further hazard.

Basically, we're just used to gasoline, most of us growing up assuming
the stuff is everywhere, and we have systems to deal with it. LPG is
``new'' and somewhat alien, but on the whole no worse, and once you're
used to it, safe and easy to handle.

\section{WHY LPG?}

It is tempting to think in the wrong terms; cars as transportation
devices, gasoline as a fuel, etc.  The facts are -- cars are a
product. Gasoline is a product. If they could sell us buggies made of
straw and sticks, and fuel made of ox poop, they'd do it if it made
them money. LPG is a by-product of the petroleum distillation process;
some of the lightest components off the top of the distillery stack.

Gasoline, and the other bulk products from petroleum distillation are
highly compact and profitable products; why would they want their
secondary products to replace their main profit items?! Hence oil
companies toying with methanol -- it must fit into the profit picture
-- first.

In other words, you can't rely on them for making ``correct''
decisions, based upon environmental impact and other factors. No
surprise there.

\section{LIQUID FUELS}

Liquid fuels are lousy for internal combustion (IC) (or more
accurately Infernal Combustion) engines, simply because they never
vaporize completely. Until I used LPG as a motor fuel, I never thought
about how much of the complexity and tune-up hassles in IC engines is
simply due to lousy fuel. In principle, carburetors are simple; in
fact they are horrendously complex and subtle devices -- choke,
manifold heat, accelerator pump, power jets, etc -- to make them act
as desired, because liquid fuels don't like to vaporize. In the rest
of the engine -- complex cylinder head designs to increase burning;
air injection and catalytic converters to convert the unburnt fuel to
other legally-allowable toxic junk.  Fuel inject\-ion attempts to get
around some of this by mechanically vaporizing the fuel with extreme
pressure, but at greatly added complexity and cost, and still has all
of the other problems. Not to mention the computers and feedback
systems to keep things within Federal emission standards.

\graphic{270pt}{Ugly, unwanted, smelly, messy.}

When LPG enters the engine, it is a already a gas. Essentially zero
unburned fuel leaves the engine. Complete burning means almost zero
Carbon Monoxide (CO). There are no toxic additives such as lead, and
therefore none of those related compounds are generated. What comes
out is carbon dioxide and water. 


\section{GASEOUS FUELS}

One way to think about the physical properties of LPG is to think
about how you'd have to handle water and steam on say, Venus. The
outside temperature is such that if you were to pour some on the
ground, it would immediately boil into vapor and ``disappear'' into
the atmosphere. To store it, you would need to keep it under pressure,
in cylinders strong enough to hold it, plus a safety margin. This is
exactly how LPG acts in our range of temperatures. The boiling point
of any liquid (the temperature at which it vaporizes) increases with
pressure; to keep water in it's liquid state at 300\degree F you'd
have to keep it in a container at just over 67 pounds/square inch
(PSI); at 350\degree F, 135 PSI.

LPG acts the same, but at much lower temperatures; at 80\degree F it
must be kept at 130 PSI to keep it liquid. The fact that LPG fuel is a
gas, and not a liquid, at first seems like a liability, but is it's
strong point, as you'll see later.

%\graphic{270pt}{Heating the room this especially cold winter 
%with one of the car's extra gas cans.}

\newpage

\section{ROAD TRIPS AND FUEL AVAILABILTY}

I completed the LPG conversion of my car in October, 1990. When I
first wrote this book, in April 1990, I had only limited experience
with the car, which was covered fairly well in the first edition. I
have had two technical problems since the first edition of the book;
both are mentioned in the {\bf MY PROBLEMS} section later in this
book.

Since that time, I've taken a number of long road trips. In brief --
everything went better than expected.  The car ran great at all
altitudes (sealevel to 9900 feet), in hot (104\degree) and cold
(35\degree) weather. Fuel availability was good in most areas during
daylight hours, poor at night, and in a few places hard to get. At no
time did I run out of fuel however.

This seems an appropriate place to mention a lot of information that
doesn't fit into a table or chart. I'll simply describe my subjective
experiences of driving an LPG car on my various road trips.

The first thing everyone asks (after ``doesn't it blow up?'') is
``where do you buy fuel?''. We're so used to seeing gasoline stations
everywhere, we overlook the shiny white tanks that LPG generally comes
in.

Fueling up with LPG is a completely different experience from buying
gasoline. With gas stations at nearly every Interstate exit and
highway intersection, the thought of having to search for LPG is
daunting. In fact, it's not that bad. LPG is very common in rural
areas; you start noticing the telltale white tanks all over. Many
rural gas stations have smallish LPG tanks off to one side.

If you insist on driving on a near-empty tank, and getting \$2 worth
of fuel in the middle of the night, you'll have to either change your
habits or stick to gasoline.

On the Interstates, LPG stations are found on the outskirts of town.
Nearly every large town or city has one of the regional or national
distributors, who generally have the lowest prices. 

Finding LPG during daylight hours is easy, early eves not so easy,
late at night difficult in rural areas, since most LPG there is
non-vehicular. However on a recent trip to Denver, I was able to
easily drive all night, fueling up at truck stops and small towns in
Nevada. 

LPG is sold by the gallon; prices vary widely. The lowest prices are
at the distributors themselves, and the highest at the local mom'n'pop
store with a 100 gallon tank for the RV'ers. At a time when gasoline
was about \$1.15/gallon, LPG at a distributor in New Mexico was
\$0.95/gallon, and a mom'n'pop in California \$1.35/gallon. The lowest
I've ever paid was \$0.59, the highest \$1.50; as you can see, the
prices vary widely. During this time, I was typically paying
\$1.20--\$1.30/gallon at a typical gas station's LPG service.


\section{ROAD TRIP EXPERIENCES}

I've taken a half-dozen or so long (1,000 mile or longer) road trips
since the first edition of this book. In over 14,000 miles of driving,
I had one mechanical failure, and it was due to my LPG system. (I'll
not mention the rock that cracked my windshield on an Arizona highway
in February, the headlight switch that dropped dead just as I pulled
onto a Nevada highway at night, or the taillight fuse that blew in
California when my clock decided to fail.)

The failure was actually a problem built-in from the start, that
caused me grief on a number of trips, and incorrectly diagnosed in the
first edition (how embarrassing). See the {\bf MY PROBLEMS} section
for details; but briefly, I had two check valves in a system that
wanted only one, and they fought each other. Once I installed the
correct part the problem went away forever. The parts supplier was
partly at fault, as I bought the complete system from them. I had
other problems with this supplier as well.

@@@

Running out of fuel on the road would be a major inconvenience, as
even AAA doesn't seem to know anything about LPG motor fuel.  I've
worked out a simple, safe and reliable ``gas-can'' system; see below
for details.

\section{ON THE ROAD (ANECDOTES)}

What follows is a collection of random anecdotes gathered from my
travels so far. 

There is a service station in Santa Rosa CA that has a for-real LPG
pump! The blue sign on Route 101 shows the fuel-pump graphic with
``LPG'' on it. LPG distributors have been undergoing merger-fever like
other industries; one is Chevron.

The car runs much better, even at high (7000 foot+) altitude. It
starts instantly, with no warm up period; I wait a few seconds for
engine oil pressure to come up, then drive off -- no sluggish
performance, because there are none of the usual gasoline-pampering
devices to ``warm up''.

As of January 1990, California LPG vehicles need to be ``smogged''.
The car simply has to meet the smog specifications for that model and
year, which is amazingly easy. The testing machine simply has a
setting for ``propane'' fuel.  When the auto center I went to found
out the fuel was LPG, they panicked. It took a call to the Smog Board
arbitrator to get it all straightened out. California is the most
stringent state in the U.S. for smog controls.

Most LPG station attendents I ask say they fill very few LPG vehicles;
one on Route 5 said one or two a month.

In California you can also get a sales tax exemption -- a sticker you
apply to your window, that exempts you from paying sales tax on LPG
motor fuel. It costs \$36 (Jan 1991), is good for one calendar year.
Call the Franchise Tax Board for details. I had to explain to them it
was for a passenger car; the person on the phone started rattling off
commercial GVW requirements.  Presumably most of their customers are
truck fleet owners.

On the road, I asked a veteran Canadian RV'er with an LPG pickup (150
gal. tank!), what's the situation on LPG availability around the U.S.
He said California was the worst. (If this is the worst, things aren't
so bad.) I wonder about the dense NorthEast.

There was  was -- a ``national LPG motor fuel directory''. I found
a book called ``The Propane Directory'' for California, circa 1984,
compiled by Liquefied Gas Directory of America, Inc.  (See SUPPLIERS
\& SOURCES). I have yet to contact them to see if they still publish
it. 

A quick scan of the Yellow Pages under ``GAS - PROPANE'' for San
Francisco lists 15 locations. 

U-HAUL's national ``RV World'' stores always carry LPG, and some
are open 7 days. Most campsites carry LPG too.

All KOA Kampgrounds have LPG, some 24 hrs/day.

On a trip down the Northern California's Route 101, I found LPG to be
plentiful, though somewhat spotty at night.

Join AAA and request their list of campgrounds for areas you travel
in. The campsite listings list propane services. Bug AAA about LPG
fuel-availability guides, vehicles, service; they need to be told
we're out here.

Other avenues to follow that I haven't yet -- truck stop franchise
chains, oil companies, service companies, all want to sell you their
goods and services. A call or letter asking where to buy their
products should be fruitful.

Engine oil stays yellow and odor free 2000 -- 3000 miles after an oil
change. It never gets as dark and smelly as it did gasoline.  Same
engine.

%\graphic{200pt}{A typical LPG fuel filler with the locking door 
%open. The round Acme fuel connector is in the center, and the
%gas vent in the lower left corner.}

\newpage

\section{BUT IS IT AN ALTERNATIVE?}

This construction book is only the first phase of my project, and
unfortunately not the interesting part, regarding truly
alternative fuels. I don't have bags of money, and I have to
arrange things in a manner I can actually get them done, and
still accomplish my long-term goals.

Access to decent test equipment is the obstacle to getting real
numbers on emissions. Commercial smog stations have \$30,000+
invested in their machine, and will charge you big bucks (\$45
per test) in order to recoup the expense. Home type equipment I
don't have, and haven't yet investigated, as to accuracy and
sensitivity -- it must be able to measure extremely low levels of
hydrocarbons (HCs) and carbon monoxide (CO).

From a non-global-system perspective, LPG is a winner. Your
vehicle will last far, far longer, maintenance is simpler and
less frequent, so you can at least slow down your part of the
consume/discard cycle. And you can do it {\it today}. 

From a global-system point of view it's definitely a short-term
gain, as you immediately eliminate the toxic parts of vehicle
emissions. At the moment it is not a major motor fuel, and you
get to work in the margins of the petroleum industry, and if you
can produce your own fuel gases, get out of the loop entirely.


\section{GETTING AWAY FROM PETROLEUM}

The ``alternative'' part is next -- getting away from the oil
companies! 

The next phase of my project is to make my own LNG -- Liquefied
Natural Gas -- by drying, cooling and compressing the natural gas
delivered by PG\&E to our building, into a container from which I
can fill my car.

Technically, here's the basic process. Natural gas is very
similar in makeup to LPG, except that the ratios of the gaseous
components is different and varies with geographical location,
there is less BTU/pound than LPG, and it contains some water
vapor. As far as the physics of liquification it's the same as
LPG. 

My design goal is 10 - 20 gallons of LNG per week maximum. Pretty
thorough safety systems are required, to shut off the compressor
when the tank reaches the standard 80\% full; probably a
calibrated scale to weigh the tank as it fills. The whole thing
will be outside for obvious reasons. I still need to determine
the overall energy used to for this conversion -- it may not be
worth it from an energy point of view.

The method I will probably use involves cooling the gas at low
pressure to make the water ``fall out'' and precool the gas
before compression (which raises the temperature). The cooler
will be made from a refrigerator compressor, and two lengths of
copper tubing soldered together, wound into a compact shape and
insulated; one will carry the refrigerating freon, the other
natural gas. 

For compression I'll probably use an 
automobile air-conditioner freon compressor. Though designed to
work with oil added to the freon as a lubricant, my guess is that
it will run fine as an oilless compressor, with a greatly reduced
life. Compressors can be easily obtained from a junkyard or
roadside abandoned vehicle.

Legally, it doesn't exist. Natural gas isn't taxed for motor fuel
use, and my guess is if you ask, you will get blank stares and
suspicious questioning. I also don't think the Fire Department
would like it very much either.

Obviously this system could compress any other water-laden gas
you might have laying about -- fermentation methane for instance.
Though you'd need a pretty decent volume of it to serve for
general purpose vehicular use.

And now onward to the whole point of this book, design and
construction.
\newpage

\section{SYSTEM DESIGN}

The ``typical'' older American car or light truck is a perfect
candidate for LPG, as they tend to have large displacement,
carbureted, water-cooled engines. Four, six, eight cylinder
doesn't matter. 

Air-cooled engines would require a different converter\slash
regulator design. I don't know what an LPG carburetion system for
a 
fuel-injected engine would look like. Better ask an LPG service
center.

I'll assume that you more or less understand the major systems in
an ordinary automobile -- an internal combustion engine that
converts stored chemical energy (fuel) into motion by burning it,
a transmission and such to move the wheels, suspension, brakes,
and all that to make it practical. The only thing different in an
LPG vehicle is the fuel system.

A basic LPG fuel system isn't really much different than a
gasoline system. There's a fuel tank, some hoses, a fuel filter,
and a carburetor. The biggest difference is that LPG is under
pressure, so the tank is heavy gauge steel with various safety
features, the filter doubles as a fuel shutoff, and there's a
regulator\slash converter that turns the liquid LPG to a gas
explicitly before entering the carburetor.

The hose used to carry LPG to the engine compartment is heavy
neoprene covered with a stainless steel mesh, with a fabric
covering. It's rather bulky (about 3/4 inch), but rugged and
designed for 1750 pounds per square inch (PSI). An LPG tank left
in the sun will generate a few hundred PSI, so there's more than
enough safety margin there.

\section{DUAL FUEL SYSTEMS}

You have the choice of installing an LPG only or dual LPG\slash
gasoline system. As you might guess, the dual-fuel setup is a
compromise; you'll get maximum performance, simplicity and
economy with the single fuel setup. That is what I chose. I
talked to the owner of a 1970 GMC pickup who converted to dual
fuel when the truck was new (181,000 miles, no motor overhaul
yet) and says he runs mainly LPG, and gasoline when LPG isn't
convenient. You may have trouble with the carburetor gaskets
drying out and such; talk to the LPG equipment dealer for
details. The GMC owner had no complaints, so maybe all that's
overrated. 

\newpage
\section{BEFORE YOU BUILD}

LPG experts will tell you two things you will need to make it all
work -- a good ignition system and a good cooling system. And
they're absolutely right. LPG requires a good hot spark, and an
ignition marginally OK for gasoline will run terribly on LPG. I
had a classic textbook example of this happen to me; read about
it in the PROBLEMS section.

An electronic ignition is probably a must. My car had 
old-fashioned points and spark coil, to which I added an
Autotronics Multiple Spark Discharge ignition, which cost me \$89
in 1986. It works flawlessly, simple to install, and a set of
points now lasts 50,000 miles. 

You need a good cooling system, not because the engine runs any
hotter, but because the LPG regulator\slash converter uses engine
coolant to provide the heat to convert the liquid LPG to a gas.
(Even ``cold'' water works -- it just has to keep it above
freezing.)

An LPG conversion does not require any special modifications to
the engine. Since LPG has fewer BTU's per pound than gasoline,
and the engine is designed to take in a fixed volume of
fuel\slash air mixture, you'll get about 10\% less horsepower for
a given engine. To help compensate, LPG has an octane equivalent
of about 110 -- meaning you can advance the ignition timing a
lot. The actual loss depends on the specific engine, but it will
probably not be noticeable.

If you're willing to mess with engine internals, you can
eliminate any loss, and actually improve performance over
gasoline, by one or two methods: increased compression ratio (up
to 12:1, compared to ordinary 7 or 8:1) and a ``propane''
camshaft. This is what I did, since I was rebuilding the engine
anyways I was willing to spend an extra \$200. Later for more on
this subject.

\newpage
\section{HINTS FOR MOTORHEADS}

You can skip this section if you don't care about the internals
of Internal Combustion (IC) engines. You might find it
interesting if you are about to rebuild yours. It assumes basic
knowledge of IC engine design.

Regarding liquid vs. gaseous fuels -- essentially, if you gave
enough time to the combustion process, you'd end up with 
near-zero unburnt fuel. In other words, lowering the engine speed
to say 3000 RPM absolute maximum, instead of average 5000 RPM.
However this is completely counter to all accepted theory and
practice -- efficiency is measured by the amount of power
generated vs. the size of the engine (called Volumetric
Efficiency, or VE). Modern cars have small but 
high-speed engines; the horsepower is derived by revving a tiny
engine very high; high VE. Slow it down -- terrible performance.
For older, over-engined cars -- like 60's American 6's and 
V-8's -- this is {\it not} an issue; they are huge displacement, 
slow-turning engines; low VE. My AMC 232 ci. 6 cylinder is nearly
4 liters, and only 90 horsepower! But don't let numbers fool you,
it generates tons of torque -- in general around-town driving it
runs 1000 -- 2000 RPM; 60 MPH in 3rd gear with overdrive engaged,
is only 1800 RPM. 

The heart of the engine is the camshaft -- it is a shaft with cam
lobes, two per cylinder; one intake, one exhaust. The camshaft
determines at what point in the up/down cycle of the pistons the
intake valves let in fuel, and exhaust valves let out burnt fuel.
It sounds easy, but there are incredible subtleties and terrible
compromises.


\section{THE ENGINE}

I built my engine specifically to run LPG, back in 1988. Since I
knew it would be a while before I could afford all the LPG
equipment and get around to installing it, the motor had to run
on gasoline also. The compromise was easy, and not much of a
compromise.

There are three areas affected by fuel choice -- compression
ratio, cam timing, and exhaust valves and seats. The biggest
compromise was compression. 12 to 1 isn't too high for propane,
but is too high for gasoline. My engine was about 8 to 1 stock.
The machinist (Mike at Folsom Auto Supply) found a stock piston
from another engine that raised compression to about 10 to 1, a
decent compromise for no additional cost; since I was boring the
cylinders .030" oversize I had to buy new pistons anyways.

I had a camshaft custom made by Crower Cams, though any good cam
grinder should be able to do it. I told them over the phone my
application (to their credit they didn't laugh) and told 'em dead
stock except for the compression ratio, and, importantly, to move
the torque peak much lower (I never rev the engine beyond 3500
RPM.) They came up with the following: 240\degree\ duration
intake and exhaust, .390" valve lift, with intake valves open at
-13 ATDC, close 15 ABDC, exhaust valves open at 23 BBDC, close at
-21 BTDC. 

\graphic{200pt}{My AMC 232 ci 6-cylinder propane motor, with
gasoline carburetor.}

\looseness=-1
In most gasoline engines, the camshaft is designed to compromise
two contradictory things; getting as much fuel into the cylinders
as possible, and keeping the burning fuel in the cylinders long
enough to burn completely. For a short period, both valves are
open at once (called ``overlap''), and the mass of the exiting
high-velocity exhaust gases is used to suck in new fuel/air;
unfortunately this works best at one engine speed only, and some
unburnt fuel is sucked into the exhaust.

My propane camshaft traded high-speed horsepower (VE) for
complete combustion -- zero overlap, valves open and close at the
top and bottom of the Otto engine cycle, and cylinder filling and
exhausting is accomplished by high valve lift, and simply waiting
longer for it to happen. Screw VE!

The last item to improve is to use hard exhaust valves and valve
seats, such as Stellite. Hard valves are not available for my
engine, alas, though I was able to get hard valve seats. The
ignition temperature of LPG is somewhat higher, though not enough
to worry about if you can't get them; I doubt it will make even a
5\% difference in valve life.

\section{CHOOSING COMPONENTS}

There seems to be two major manufacturers of LPG systems, Impco
and Century. Impco seems to be the simplest and easiest to
install, and is what I used.

An LPG system consists of a filter\slash shutoff, converter\slash
regulator, and carburetor chosen to fit engine size, and hoses,
connectors and other more common components. Component costs
don't vary much with size; if I remember correctly the 
next-size-up regulator\slash converter was \$10 more.

\graphic{228pt}{LPG fuel tank as installed in my Rambler. This
tank was meant for a large van, and is rated at 20 gallon
capacity; in fact, it only holds 16 gallons of fuel. (The photo
greatly exaggerates how much the tank actually hangs down.)}

\section{VEHICLE LPG FUEL TANK}

The fuel tank is the single most expensive component, and the
hardest to fit. Since my car is LPG-only, I removed the gasoline
tank and put the LPG tank there. If you are doing the
installation yourself, you'll have to carefully choose a
location. Most passenger car and van installations will use
``siamese tanks''; two smaller tanks welded side by side to make
a larger, more compact tank. Alas, they are also more expensive.
I was able to get one for cheap because the dealer had a stack of
them from a contract that fell through. Each installation will be
different. Visit the dealer with tape measure in hand. 

With one exception, the LPG fuel tank {\it must} be installed
outside or under the vehicle, and all hoses outside the passenger
compartment. Safety is the issue, and no different than
a gasoline-powered vehicle. The one exception is trunk mounting
of the LPG fuel tank, especially in sedan-type automobiles with
the gasoline tank still in place. In this case, the trunk area
{\it must} be sealed off from the passenger compartment with
foam, and vents to the outside cut in the body at the lowest
point, to allow potential LPG vapors to escape.

The filter\slash shutoff does what it's name implies. The filter
element lasts 100,000 miles, and mainly keeps out junk that may
have been in the tank when it was made; the fuel itself is quite
clean. Since the fuel is under pressure, the shutoff turns off
the fuel when the engine is not operating. The Impco system uses
engine vacuum to do this; some models, and the Century brand, use
a more complex electrical system. 


The fuel hose is high-pressure reinforced neoprene, and the
dealer should stock just about any size required. It's fairly
expensive, but make sure you get enough -- the only thing worse
than too long is too short! Under no circumstances should you run
fuel lines -- LPG or gasoline -- through the passenger
compartment.

\graphic{120pt}{A typical LPG connector and size \#6 hose, before
and after assembly.}

You will also need a handful of connectors for the hose. They are
a pain to install, but take the time to do it right -- fixing
leaky connectors after installation installed means removing them
and doing it a second time. Not fun.

The carburetor is fairly easy to install. You'll get an adapter
to fit the intake manifold and the throttle lever is made to
accommodate a custom fit. It took me a few hours to lay it all
out, and make a throttle linkage with hand tools.

Last but not least -- the fuel gauge. You can use your existing 
in-dash fuel gauge. There is a wide range of tank sender units to
fit most cars, that connect to the original wiring and work in
the usual manner. A 90-Ohm unit fits most cars.
You'll also need a fistful of sheet metal screws and plumbers
tape, for mounting the fuel hose to the car. A decently stocked
``junkbox'' helps, though most everything else you'll need will
come with the components you buy.


\graphic{234pt}{Overall view of the engine compartment. The
convertor/regulator and filter\slash shutoff are visible on the
right inner fender, and the carburetor, in the foreground, has
it's air filter in place.}

\section{LPG COMPONENT INSTALLATION}

Figure out where the LPG components will go. Placement isn't
critical, but you will want to keep these things in mind.

\graphic{285pt}{Closeup of my LPG fuel tank installation. A very
tight fit.}

1. Mounting the tank will be the hardest part; gasoline tanks are
made-to-fit the car, and LP tanks don't come in such convenient
shapes. Mine fit fairly well, but hang down a bit). 

2. Running the LPG hose requires a bit of care. You don't want it
exposed where running over a rock or curb could crush it, and you
should attach it to the underside of the car every foot or so, as
any flexing will eventually wear through the protective covering.
After a week of operation, I found mine had been chafing at a few
places. Attaching it every 12 inches with plumbers tape solved
that.

3. Mount the regulator as low as possible, (less sensitive to
coolant level) and close to the carburetor. My installation came
out pretty neatly, with a one foot section of hose between the
filter and regulator, and an 18 inch piece of vapor hose to the
carburetor. (For most installations you can simply connect the
filter\slash shutoff and regulator\slash converter together as a
unit with a short pipe nipple instead of hose.)

\graphic{250pt}{Regulator\slash converter (a) and filter\slash
shutoff (b) mounted on the inner fender. Note the water
connections coming from front of the engine (left) and heading up
to the heater on the firewall. The LPG hose is at (c) and the
vapor hose to the carburetor is (d).}

4. The water connections aren't fussy; as long as you get decent
water flow, and keep the radiator full, you're all set. 

5. Carburetor installation is simple. You may have to fabricate a
throttle linkage, but it's designed to be easy, and you can get
adapters for nearly anything. The Impco carburetor has a throttle
lever that fits on either side of the throttle shaft, and there
are many adapters available that rotate the carburetor 90\degree.
It's also far shorter and more compact than a gasoline
carburetor, so there will probably be no interference with other
components.

\graphic{240pt}{Carburetor, minus air filter, with the vapor hose
coming over the top of the engine. Note the regulator\slash
converter and filter\slash shutoff barely visible in the
background.}

6. The fuel filler system is more complex than for gasoline, but
still simple. It consists of a brass threaded ``Acme'' adapter,
and a small gas vent valve. Get the more expensive model with a
locking cover; the other style available is for fork trucks and
such, and any idiot wandering by can let all your fuel out by
opening the gas vent valve! The cover type also looks much
better.

%\graphic{240pt}{Fuel-filler system with the locked door open. 
%The Acme filler connector is in the center; the vent valve is in 
%the lower left corner.}

\newpage

\section{STARTING IT UP!}

When you first install the system, it will be empty of fuel. I
used my ``gas-can'' (see below) to put a gallon or two of fuel in
the system and check for leaks.

First, use plumbers' bubble-leak detector or soap solution to
check for leaks. I used a pump sprayer with Dr. Bronners liquid
soap and water.

1. Open the LPG liquid valve, and look, listen and smell for
leaks. A squirt of soap at all connectors helps. If you find a
leak, try tightening a bit; if a little is good a lot is {\it
not} better; you'll just wreck things. Check where the hose
enters the connector. A leak there means you take the miserable
thing apart, cut an inch of hose off, and reinstall the
connector. Check for leaks up to the filter\slash shutoff.

2. Start the car -- no fancy preliminaries. The regulator\slash
converter will purge itself of air, and it should start within 5
- 10 seconds. The throttle must be opened a small amount.

You will have to tweak the idle speed and mixture. I set the idle
too high at first, and adjusted it after it was running.

3. At this point, check for leaks after the filter\slash shutoff. 


4. Tune up the car normally. No special settings are required,
and for emissions/legal purposes, none desired. Set the ignition
timing dead stock. If the car was previously in tune, all you
should need to do is set the idle mixture and speed on the new
carburetor.

5. After a thousand miles or so, check the spark plugs. Spark
plugs will last considerably longer, as there are no fuel
additives to build up on the insulator during combustion. Check
for the right heat-range plug -- if the insulator color is too
white, or if it looks burnt, get plugs one range colder.


\section{TYPICAL PROBLEMS}

There are some problems unique to LPG fuel systems, and because
the components are mechanical devices, they can fail. Here's some
tips on troubleshooting and repair.

In general, if you find frost on LPG components (liquid service
valve, filter\slash shutoff, regulator\slash converter) you have
a problem. If it happens to the liquid service valve, it may be
that the internal excess-flow safety valve snapped. Close the
valve, wait a few minutes for the frost to dissipate, and reopen
the valve. 

If the converter/regulator is frosted, you have an engine-coolant
flow problem. Assuming it's installed properly, it probably means
low coolant level, a loose waterpump fanbelt, bad water pump, or
other mechanical failure. Normally, the converter/regulator runs
about as hot as the radiator.


\section{NO FUEL FLOW}

If your engine ``runs out of fuel'', and you've checked the
obvious (tank empty?) you can check for proper fuel flow right up
to the carburetor, component by component. The following applies
to Impco systems, but the same approach works for all
manufacturers.

1. Disconnect the vacuum hose that goes to the filter\slash
shutoff, at the manifold end. 

2. Disconnect the vapor hose from the carburetor.

3. Suck on the vacuum hose. (This operates the shutoff, allowing
LPG to enter the regulator\slash converter; you'll need to supply
a constant source of vacuum to the filter\slash shutoff to keep
it open for testing the fuel supply.) You should hear LPG vapor
escaping the vapor hose. If vapor is available, the problem is in
the carburetor or elsewhere in the engine. 

4. If there is no vapor after step 3, and the filter\slash
shutoff is connected to the regulator\slash converter with a hose
(as opposed to a short pipe nipple), loosen the connector between
the two as you suck on the vacuum hose. Liquid LPG should escape
(keep your body out of the way). If it does, the regulator\slash
converter is faulty. You can disassemble the regulator\slash
converter and clean it; it contains only rubber diaphragms and a
few springs.

5. If no liquid LPG is available, either the filter\slash shutoff
is dead or the LPG hose from the tank is crushed or plugged. Turn
off the liquid service valve on the tank, and disconnect the main
supply hose at the filter\slash shutoff. Then momentarily open
the liquid service valve; LPG should rush out of the hose into
the atmosphere, quite noisily. If not, the hose is plugged. If it
does, the filter\slash cutoff is suspect.


\section{MY PROBLEMS}

Only on long trips, when
filling up, the fuel would enter the tank extremely slowly, less than
a gallon a minute. At times, at high temperature especially, the
problem became severe. I even took it to the LPG dealer I bought the
parts from, and they were stumped as well.

Finally it failed, and hard. I had just driven 280 miles, about my
range limit, to Farmington New Mexico. I went to fill up at a KOA
Kampground, and the definitely empty tank would not take a single
gallon of fuel! Long story short -- I managed to get to an actual LPG
vehicle service station (Randall's Repair, see {\bf SUPPLIERS AND
RESOURCES}, and determined that the check valve on the fuel-filler
was sticking. However the problem persisted after replacement.
Randall then noticed that I had two check valves; one built into the
tank (required) and one at the fuel-filler, where the hose is
connected. There can be 

I had a few problems with my installation, most of which showed
up during the first week of driving. All were annoying but easy
to fix.

I had to remove and replace one connector, where the hose from
the tank fitted to the filter\slash shutoff. The brass fittings
connecting the filter\slash shutoff to the regulator\slash
converter leaked; I had to remove them and add teflon pipe dope
(which I should have used when I first assembled it).

I also had a textbook case of ignition troubles. On my first
highway run, the engine started ``cutting out'' at high speeds,
and when I slowed down to about 50, it smoothed out. Since the
only new thing on the engine was the LPG system, I theorized
various complicated fuel problems. When stumped, I called the
dealer, who asked ``does it backfire through the carburetor?'' to
which the answer was ``yes'', which always means -- ignition
problem! But it's the same ignition I've had for years! No
kidding -- and by wiggling and tugging ignition wires, I found
the wire from the distributor to the electronic ignition was oily
and poorly crimped!

I crimped on all new ring terminals, and soldered them all for
good measure. I also found a crack on the ancient (ca. 1970)
spark coil, and replaced it for good measure. No more problems!
The moral is that LPG makes higher demands on the ignition than
gasoline, but nothing that a decent system can't handle.

A problem that appeared occasionally on long trips -- when
attempting to fill up, LPG simply wouldn't go into the tank, or
it filled extremely slowly -- a gallon per minute or less! I
tried everything -- changed inlet valves, reinstalled filler hose
and fitttings, no luck. On a recent road trip it happened again,
and after trying four different LPG stations, I dropped into an
LPG dealer. An employee said he'd seen this before, on vehicles
in extreme-heat conditions -- the LPG in the vehicle tank heats
up, the pressure increasing to or beyond the filling-station's
pump pressure. The solution is to cool off the tank and let some
gas out the vent to drop the pressure. I sprayed the tank with
water from a hose and vented gas for a few minutes, and then I
was able to fill the tank normally.

In my case, it was simply an unwanted side effect of my
particular installation -- the muffler is within 4" of the fuel
tank, and on long trips, heats the fuel up enough to bring the
pressure up enough to prevent new fuel being added. (See the tank
installation photo; you can see the muffler behind the tanks.)
The solution in my case is to install a sheet-metal shield to
keep muffler heat away from the tank. The heat involved is not a
fire hazard, but just enough to raise the tank pressure.

Obviously you will want to watch out for this.

\newpage
\section{THE GAS CAN}

No one I talked to had ever heard of a ``gas can'' for LPG,
something I thought was mandatory for a practical vehicle.
Standard practice is to tow an out-of-fuel vehicle to a filling
station! I also wanted to be able to carry extra fuel for when I
couldn't find a filling station on long trips.

The solution turned out to be easy. I bought a standard LPG
container, and made up a special hose and adapter to fit it. One
end is a standard POL tank connector, and the other is the
special fuel filler connector, with about three feet of size \#6
hose. 

\graphic{270pt}{The gas can components; the 5-gallon tank on the
right and the made-up hose (POL one end, Acme the other) on the
left. In the foreground are two nice accessories; an adjustable
wrench for the POL connector and some spare O-rings for the Acme
connector.}

Portable LPG containers are meant for dispensing vapor for camp
stoves and the like; all instructions say to operate them in an
upright position. This is because the vapor boils off the top of
the liquid in the container, like a tea kettle, and tipping would
cause liquid to flow out -- which is exactly what we want. Here's
how to fill your car from your gas can:

\graphic{366pt}{Donna giving the ol' Rambler a fill up. Notice
that the gas-can is held upside down.}

{\parskip=4pt
1. Fill the portable LPG container normally.

2. Connect the hose to the portable LPG container.

3. Connect the fuel filler to the car.

4. Turn the portable container upside down.

5. {\it Open the LPG container valve while holding the tank
upside down.} Close the valve when you've dispensed enough fuel,
or the hissing (indicating fuel flowing from the can to your car)
stops.
}

(When dumping gasoline into a car tank, gravity moves the fuel,
and the air displaced by the liquid gasoline simply flows out the
filler neck. Not so with LPG -- at a filling station, LPG is
forced into the tank with a pump, with the vent open to detect a
full tank.)

When you open the valve at step 5 above, the pressure in the 
gas-can will force LPG into the car's tank, until the pressure is
the same in both tanks. Luckily -- the car tank is so much larger
than the 
gas-can that nearly all the LPG will enter the car tank. With my
20 gallon car tank empty, and a 5 gallon gas-can containing 4.5
gallons (its maximum capacity), about 4 gallons of fuel are
delivered into the car's tank.

For added safety and to prevent loss by leakage or the valve
opening, I disconnect the adapter hose from the tank, storing it
in a plastic bag to keep it clean, and install a brass plug in
the tank, and tighten it. Even if the valve is opened, LPG will
not escape. I keep a 5 gallon tank bungie-corded in the back of
the car, with room for a second on long trips.

\section{ADDED FEATURES}

Here's some things you might want to keep in the car:

A 10 inch adjustable or 7/8 inch open-end wrench, for the gas-can
hose fitting. At the least, you'll need one to remove the gas-can
hose when you fill the can.

Get a bunch of spare O-rings for the filler neck. They are cheap
to replace, and will eventually wear out, and I had mine fall out
once after a fill up. Without one, you won't be able to fill the
tank! 

Store the gas-can hose in a plastic bag to keep it clean.

\newpage

\section{COST}

Here's a breakdown of costs from my receipts for this project.
I've arranged the tables with the major, not-optional items at
the top. If you can scrounge hose and connectors and other useful
doodads obviously you could save a lot of money.

The following items are essential, but probably scroungeable to
some degree. You might also check truck junkyards, as many
commercial and fleet vehicles use LPG. Used equipment is fine, as
long as it is undamaged.

\let\hf=\hfill

\vskip\parskip
\begintable
{\bf Major Components}\hf          |\hf Quan| Cost \crthick
Filler Valve Assembly\hf             |\hf 1       |\hf 45.00 \nr
filter\slash Shutoff, Impco VFF30\hf                |\hf 1       |\hf
56.50 \nr
Converter/Reg., Impco Model L\hf    |\hf 1       |\hf 110.00 \nr
Carburetor, Impco CA125\hf                |\hf 1       |\hf 67.00 \nr
CI-28 Air Filter Cover\hf                |\hf 1       |\hf 9.44 \nr
K\&N Air Filter\hf                       |\hf 1       |\hf 13.00 \nr
{\bf Cost:}\hf                               |       |\hf{\bf\ 300.94}
\endtable
\vskip\parskip

The LPG fuel tank is obviously a non-optional item. It is the
single most expensive component, and the hardest to fit. The
price of the LPG fuel tank will vary widely, depending on your
application. Used tanks are a definite possibility.

\vskip\parskip
\begintable
{\bf Fuel Tank\ \ \ \ \ \ \ \ \ \ \ }\hf|\hf Quan| Cost \crthick
LPG Motor Fuel Tank\hf                 |\hf 1       |\hf 400.00 \nr
{\bf Cost:}\hf                               |       |\hf{\ 400.00}
\endtable
\vskip\parskip

\vfill
\newpage

These are definitely candidates as ``junk box'' items. The exact
quantities will depend on your installation; for example, you
could eliminate a foot or so of hose and the connectors and pipe
fittings between the filter\slash shutoff and regulator\slash
converter if you had the room to connect the two with a short
pipe nipple. LPG hose is specifically made for LPG fuel. I don't
think I'd want to make substitutions there. 

\vskip\parskip
\begintable
{\bf Hose; Q. is length in Feet}\hf|\hf Q.| Price | Cost \crthick
LPG Hose, \#6\hf                  |\hf 14      |\hf 2.54|\hf
35.56 \nr
LPG Hose, \#8\hf                  |\hf 4       |\hf 3.32|\hf
13.28 \nr
LPG Hose, \#4\hf                  |\hf 4       |\hf 2.64|\hf
10.56 \nr
Vapor Hose \hf                             |\hf 2       |\hf 3.68|\hf
7.36 \nr
Vacuum Hose\hf                         |\hf 3       |\hf 0.38 |\hf
1.14 \nr
{\bf Total Cost:}\hf                       |       |       |\hf{\bf\ 
67.90} \endtable
\vskip\parskip

\vskip\parskip

\begintable
{\bf Connectors, etc.}\hf                |\hf Q.      | \$ ea.| Cost
\crthick
90\degree\ Elbow, \#6 Hose\hf         |\hf 4       |\hf 6.50|\hf
26.00 \nr
45\degree\ Elbow, \#6 Hose\hf         |\hf 1       |\hf         |\hf 1.28
\nr
Straight Connector, \#8 Hose\hf         |\hf 2       |\hf 3.28|\hf
3.56 \nr
Straight Connector, \#4 Hose\hf         |\hf 2       |\hf 1.84|\hf
3.68 \nr
Male Connector \hf                     |\hf 2       |\hf 0.60 |\hf
1.20 \nr
Brass Elbow\hf                                |\hf 2       |\hf 1.86|\hf
3.72 \nr
Zinc Hose Elbow (vapor)\hf      |\hf 1       |\hf    |\hf 1.44 \nr
Male Connector (crankcase)\hf  |\hf 1       |\hf    |\hf 1.34 \nr
Water Hose ``Y''\hf                        |\hf 2       |\hf 1.98|\hf
3.96 \nr
{\bf Cost:}\hf                               |       |       |\hf{\bf
\ 46.18} \endtable
\vskip\parskip

\vfill
\newpage

Most of these components are the Gas Can described earlier.  You
can of course use any size portable LPG tank you find convenient.
The 
Acme fuel-filler connector is the single most expensive
component, as it's a bit unusual.

\vskip\parskip
\begintable
{\bf ``Gas Can'' and spares\ \ \ \ \ \ \ \ \ \ \ \ \ \
}\hf    |\hf Quan| Cost \crthick
Acme 1-$3\over4$" Connector\hf            |\hf 1       |\hf 33.78 \nr
Portable LPG Cylinder, 5 gallon\hf       |\hf 1       |\hf 27.61 \nr
Hose Set (2 connectors, 3 ft hose)\hf        |\hf 1       |\hf 10.00 \nr
O-rings\hf                              |\hf 3       |\hf 3.00 \cr
{\bf Cost:}\hf                               |       |\hf{\bf\ 74.39}
\endtable

\dots And here's the total sum for this sample system:

\vskip\parskip
\begintable
{\bf Total System Cost\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
\ \ \ \  \ }\hf|\hf \crthick
Motor Fuel Tank, 20 gal.\hf         |\hf 400.00 \nr
Major Components\hf                   |\hf 300.94 \nr
Hoses\hf                                |\hf 67.90 \nr
Connectors \& Misc.\hf                        |\hf 46.18 \nr
Gas Can System\hf                       |\hf 74.39 \nr
{\bf Cost:}\hf                               |\hf{\bf\ 889.41}
\endtable

\section{CONCLUSION}

I wish I had the resource\$ to experiment with other automobile
chassis. For example, the Datsun 510, Volkswagen Rabbit, and
other 
simply-designed ``boxy'' sub-compact cars are probably ideal. And
the ultimate would be a tiny car with a small, 
high-perf\-ormance engine with a turbocharger. Turbos produce a
lot of heat, which undesirably raises the (gasoline) fuel/air
mixture temperature; fancy (expensive) cars use intercoolers to
cool the fuel/air mixture before it enters the engine. Well --
LPG has the opposite problem -- how to get heat into the fuel to
gasify it! 
A turbo-heated fuel system would use a decent percentage of waste
heat, and the small engine/turbo system would produce power upon
demand and minimum fuel consumption otherwise. Anyone got a
grant?

\newpage

\section{SUPPLIERS \& SOURCES}

{\bf Home Power Magazine}, {\it Box 130, Hornbrook CA 96044-0130
(916)\dash 475\dash 3179} Aptly subtitled ``The Hands-On Journal
of Homemade Power''. Subscriptions available.

{\bf Real Goods Trading Co}, {\it 966 Mazoni St, Ukiah CA 95482
(800)\dash 762\dash 7325 (in CA (707)-468-9214)} Their
Alternative Energy Sourcebook really is ``A Comprehensive Catalog
of the Finest Low-Voltage Technologies'', each section containing
background technical information on batteries, power sources,
lighting systems, etc.

{\bf Suburban Propane}, {\it 2440 Whipple Rd, Hayward CA 94544
(415)\dash 471\dash 7221} LPG components, systems and fuel. Check
the Yellow Pages for one near you.

{\bf Solar Mind Magazine}, {\it 759 South State \#81, Ukiah CA
95482 (707)\dash 468\dash 0878} Issue \#3 was on hydrogen
vehicles and solar/hydro\-gen sources. Subscriptions available.

{\bf The Propane Directory}, {\it compiled by Liquefied Gas
Directory of America, Inc., 2888 Highland Drive, Salt Lake City
UT 84106} I have no further information at this time, even
whether or not they still exist.

{\bf Folsom Auto Supply}, {\it 1048 Folsom St, San Francisco CA
94103 (415)\dash 861\dash 0800} Auto parts supply and machine
shop service. They use water/alkali solvents in their hot-tanks
instead of petro-based solvents.

{\bf Crower Cams}, {\it 3333 Main St, Chula Vista CA 92011-5899
(619)\dash 422\dash 1191} Custom camshaft grinding.

{\bf Handbook of Chemistry and Physics}, {\it Chemical Rubber
Company, 41st edition.} 

{\bf Pocket Ref}, {\it by Thomas J. Glover, Builders Booksource,
1817 4th St, Berkeley CA 94710 (415)-845-6874} An indispensible
pocket version of the CRC book (sort of almost, but better) for
modern times.

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