I knew how a hot bulb engine worked, so I
figured it wouldn’t be too hard to start it on my own. The more I
thought about it though, I figured I would read the section in
Dusty Erickson’s book (Mietz & Weiss, New York, America’s First
Successful Oil Engine) to be sure I got it right the first
time.
A hot bulb or oil engine is not the same as a hot tube engine.
Although a hot bulb engine also uses heat to light the charge, it
is a totally different system. On a hot bulb engine, the engine
head has a bulb or protrusion on the head of the engine that is
heated red hot with a torch. On the intake stroke, only air is
drawn into the engine cylinder. At the proper time, during the
compression stroke, fuel is introduced into the bulb via the fuel
injector where it vaporizes, mixes with the air in the combustion
chamber and flashes into flame, providing thrust against the
piston.
Like a diesel engine, the timing and the duration of the
injection of fuel determine the power and speed of the engine. Oil
engines are sometimes called semi-diesels. The major difference
between the true diesel and the hot bulb engine is the compression
ratio. A true diesel engine operates by compressing the air in the
cylinder at fantastic pressures. This pressure generates heat,
which in turn ignites the fuel as it is injected into the
combustion chamber. Some of the lower compression diesel engines
need a glow plug to provide enough heat for starting in cold
conditions, but once started, the glow plug cools off and the
engine runs on compression alone. Diesels run most efficiently
between 18-to-1 and 22-to-1 compression ratio. The typical oil
engine is nowhere close to that. My Charter-Mietz, for instance,
has a compression ration of only 5.5-to-1. Once a hot bulb engine
starts, the preheating flame can be removed as the heat supplied by
engine combustion provides enough heat to maintain ignition.
I was told that the small Bunsen burner I was given was used to
start the engine, so I hooked it up to a new 14 ounce propane
bottle and prepared to heat the hot bulb. I had read in Dusty’s
book that you had to open the shutter in front of the hot bulb
chamber in order to allow the flame to travel around the bulb. I
tried to open the door in front of the head by gently tapping on
it, but it was frozen fast. I then used a large pair of channel
lock water pump pliers and the door finally moved. It took the
mounting bolt with it! I put the bolt in my vice, poured a lot of
Liquid Wrench on it, heated it bright red and then allowed it to
cool until it was no longer red. The bolt then came loose
easily.
Next, I decided to inspect the heating chamber to see if there
were any unwanted guests. I found some! There were two mud dauber
nests, a yellow jacket’s nest (with bees to boot) and a lot of
spiders. A load of Berkbile 2+2 carburetor cleaner and the air
compressor took care of the critters.
I reinstalled the cleaned door assembly onto the hot bulb
chamber and then opened the door. I lit the Bunsen burner and let
it burn under the hot bulb for about 10 minutes. I then tried to
roll the engine over to start it, but I could not get it to go over
the compression stroke. I opened the compression release and tried
again. This time the engine rolled over, but still gave no hint of
trying to start. I let the burner burn another five minutes until
it almost went out and tried again. Still no luck. I had totally
used up the bottle of propane. I decided that more heat was
needed.
I got out my plumber’s acetylene torch and lit the hot bulb.
After a few minutes I noticed a lot of white vapor coming out of
the compression release port. I tried rolling the engine over and
got great plumes of vapor out the compression release and the
exhaust port, but no hint of ignition. I closed the compression
release and tried pulling the engine over with no success. Then I
remembered a trick I had pulled when I was a kid. I was trying to
remove a stuck piston from a 2 HP Witte headless engine and had
loaded the cylinder with kerosene and heated it. As vapor was
escaping from a removed plug in the head, I decided to pass a lit
torch over the vapor plume. The resulting explosion blew the piston
and connecting rod clean off the engine and through the garage
door! That was a hard one to explain to Dad. I decided to try this
maneuver now.
As the piston and rod were attached to the engine this time,
there was a different result. I rolled the engine over a few more
times and held the lit torch near the compression release port. The
thick white vapor lit with a WOOSH and the flywheels turned a
little bit under their own power. But as soon as the exhaust port
was uncovered, all hell broke loose. The stored up vapor in the
2-inch exhaust pipe lit with a loud bang of an after-fire
explosion. Orange flames shot out of the exhaust pipe and the
compression release. I could smell that a couple of spiders did not
survive that experience very well.
I put the torch back under the hot bulb for a few more minutes,
and when I again saw the white vapor, I closed it. I pulled the
engine up against the compression stroke with the flywheels turning
toward the head of the engine, over the top. I had only gotten a
little compression when the flywheels were pulled out of my hands.
The crankshaft rolled clockwise against compression and the engine
fired with a dull thud. The flywheels reversed direction, hit
compression, fired and reversed again! This firing and crank
rotation reversal went on for about 15 rockings before the
flywheels finally got enough inertia to carry over the compression
stroke. After that, the rest is history.
The engine began to belch a heavy mixture of white and gray
smoke, so thick that I could not see past 10 feet. I decided the
engine was flooding so I held the fuel pump drive primer lever
forward, stopping the pump. The engine did not stop though. It
continued to accelerate even faster, so I opened the compression
release to slow the engine. It continued to fire for several
minutes, even though the compression release was wide open, before
it finally quit. The compression release was so hot I could not
touch it or turn its handle with an adjustable wrench. The
Charter-Mietz actually ran though, for the first time in over 25
years!
My second attempt at starting went better. I pulled the primer
lever twice, heated the head with the plumber’s torch and after
five minutes or so, rocked the engine. This time, when I saw the
white vapor, I closed the release and rocked the engine hard
against the compression stroke in the opposite direction I wanted
the engine to turn. It fired, carrying over the compression stroke
the first time and the engine sped up to governed speed and stayed
there. What sweet music to my ears! As the engine ran, I noted that
the exhaust note seemed muffled and kerosene was leaking from the
injector piping at both ends at the solder joints. I shut off the
fuel valve and let the engine coast to a stop.
The next afternoon, I took the injector supply pipe off and
cleaned it with electrical contact cleaner. I blew the pipe out
with air and heated the brass fittings in order to remove them, as
I also had to clean and re-solder them. The repair of the one at
the pump end went well, but the one at the injector end was another
story. The brass fitting had split up the side and as the area was
still dirty, solder would not take. I had some Muriatic acid left
from a cleaning job, so I placed a small amount in a plastic
container and put the brass adapter in the cup, slowly. After
several minutes, I removed the adapter and put it into another
container that had baking soda and water in it to neutralize the
acid. I dried off the fitting, blew it off with air, re-cleaned the
piping bore with the drill and emery, and again soldered the
fitting onto the tubing. This time the solder took and sealed the
crack as well.
I took the remaining acid and poured it slowly into the other
container (the one with the baking soda) in order to neutralize all
the acid waste. (Never pour anything into acid because it can
generate tremendous heat and can cause an explosion. Always pour an
acid into the neutralizing solution. It will remain cool and will
not harm you if it is spilled.) With the repairs to the fuel
injector piping finished, I polished the brass fittings, and
installed the piping assembly and tested it by using the priming
lever on the primary pump. No leaks!
The cooling system
In speaking to Dusty and Fred, they both told me the Mietz
&Weiss engines liked to run very hot. A lot of owners do not
even put water in the engines! I did not feel comfortable running a
kerosene-burning engine for a long time with no cooling –
especially a hot bulb type. The heat build up would be tremendous!
As the engines like to run hot, I decided to make the cooling
system as minimal as practical, yet allow the engine to run for
several hours without a lot of maintenance. I decided to make a
water reservoir out of a piece of 4-inch K copper pipe I had in the
garage. I measured the distance between the 3/4-inch pipe nipples
already on the engine and added 8 inches to the measurement. I cut
the pipe to length, which turned out to be about 2 feet long and
soldered a sweat cap to what would be the bottom of the water
reservoir. This done, I held the reservoir next to the nipples
mounted on the engine and scribed marks onto the side of the
container, double checking the locations. Once I was sure the
locations were correct, I used my drill and a Vari-bit to open the
holes to about 3/4-inch in diameter.
I used a 3/4-inch pipe tap to make threads into the side of the
container. I installed two brass nipples into the wall of the
copper vessel and then put brass unions onto them. The unions were
used in order to make any necessary adjustments in the length of
the piping and to make it easier to remove the reservoir in case
the engine had to have the water drained. I also replaced the
broken thermometer with a 260-degree thermometer I purchased from
my local hardware store.
Thankfully, I got the alignment of the 3/4-inch piping on the
reservoir right on the first try. Since this engine operates on a
thermosyphon cooling operation, I filled the reservoir with water
so that it was about 3 inches over the upper piping. I started the
engine, and after about 30 minutes the water temperature was only
about 200 F and the water level had hardly dropped.
Exhaust pipe
I decided at this time to make an exhaust pipe for the engine,
as the original open pipe was pretty loud. I put a 2-inch diameter,
90-degree elbow on the exhaust pipe nipple that was originally on
the exhaust tee and turned the open end up. I soldered a male
fitting, by sweat adapter, onto a 4-foot piece of 2-inch copper
tubing and installed it onto the upturned “L.” After another test
run, I now figured the engine was ready to take to a show.
I had learned from Fred Pritchard that the Mietz & Wiess, as
well as the Charter-Mietz engines, originally used a Hauck kerosene
torch as the heat source for the hot bulb. This torch was made
especially for starting these engines, as the actual torch head
operated in an upright position.
I located a Hauck Model 10 starting torch on eBay. However, for
now I will continue to use the acetylene torch, as using the
original requires up to 15 minutes to generate enough heat to start
the engine! My acetylene setup only takes four minutes – tops.
The show
The Denville, N.J., Historical Society has an annual show at the
historic Ayers/Knuth Farm. The North Jersey Antique Engine and
Machinery Club runs a display there every year, and we demonstrate
engines and tractors at work. I decided this was the perfect
setting for the engine’s first public display, so off we went! I
ran the engine for eight hours that day and discovered some
problems.
First was the water reservoir. After eight hours of running, I
noticed that the water was steaming more than it was earlier in the
day. A quick check on the water level had me scrambling for a paper
cup and a lot of water! The water level had fallen to about halfway
down the side of the cylinder. I soon had the water over the upper
pipe again, but two hours later, it was another scramble to get
water. I needed something to tell me the water level.
Second was the upturned exhaust. Although the engine made some
beautiful smoke rings when she started, she also had the nasty
habit of chucking quite a few drops of nasty, black, used 50-weight
motor oil into the air along with them. The ground for about 20
feet around the engine was covered with 1/4-inch black dots. Then
again, so was anybody who stood near the engine for any length of
time.
Third and most important, the fuel pump was losing kerosene at a
prodigious rate. I soaked an entire roll of paper towel during the
course of the day due to a leak at the primary fuel pump shaft
packing. I tightened the packing gland many times, sometimes tight
enough to jamb the pump, only to have it start leaking again five
minutes later. The eight-hour show took 2-1/2 gallons of fuel!
Fourth was the fact that the cast iron fuel tank lid practically
vibrated itself off the tank due to the fact that the engine is not
well balanced internally. The Charter-Mietz engine is meant to be
permanently mounted on a concrete pad. The sheer weight of the
engine precludes that it will not move much on the cart, but move
it does.
Remedies
I decided to add a boiler sight glass to the water reservoir so
I could see the engine water level without having to peer into the
top of the reservoir itself. I purchased an old NOS unit with a
12-inch sight glass. I scribed two marks on the reservoir where I
wanted to mount the boiler gauge and removed the reservoir from the
engine. I drilled the 1/4-inch pilot holes and re-drilled the holes
this time making the pipe holes 1/2-inch to fit the gauge mounts. I
tapped the holes 1/2-inch NPT and then installed the gauge mounts
and the glass. Finally, the two copper glass protectors were
dropped in place.
The exhaust work got a little more extensive then I bargained
for. When I removed the 4-foot pipe and the elbow, I found the tee
on the exhaust manifold was loose. I decided to tighten it, as I
had the tools out already. I took the exhaust manifold clean off
the engine and stuck it in my big vice. At this time, I was
interested in seeing what the heat exchanger actually looked like,
so I tried to remove it from the tee while it was in the vice. I
could not budge the heat exchanger with a 2-foot pipe wrench! I
ended up using a 3-foot pipe wrench with a 3-foot piece of 2-inch
copper as a cheater bar on the wrench handle to finally break the
fitting loose – loose, but not out. I had to use the 2-footer to
turn the exchanger fitting out of the tee. At last it was free, but
the exchanger would not come out of the pipe threaded opening.
After about two hours of turning, twisting and banging the poor
exchanger, it finally fell out of the tee.
It was a mess! At first I could not tell what the exchanger was
made of or how it was constructed. The heat exchanger is made of
3/8-inch OD copper in a tightly wound double coil that was
approximately 2-1/2 inches in outside diameter by 3-1/2 inches
long. If it were to be stretched out, there would be about 3 feet
of 3/8-inch tubing. It was so badly caked with carbon that I was
surprised the engine ran with it in place. I also cleaned out the
tee, tightened it in the manifold and cleaned the exchanger itself.
I used a piece of oak scrap, a brass wire brush and a couple of
screw drivers as well as two cans of 2+2 carburetor cleaner to
clean the caked material. I reinstalled the tee and the manifold,
and changed the route of the exhaust piping. Instead of turning up,
I removed the 2-inch screw elbow and the mounting nipple, and
screwed the 2-inch male adapter and attached pipe into the exhaust
tee. I cut off the excess pipe with my trusty Porta-Band saw and
attached a 2-inch sweat, 90-degree elbow looking down toward the
ground with a self-tapping screw. As the exhaust pipe now sticks
outside the side of the cart, I wanted the outside part to be
removable, in case I had to get the cart into a tight place.
I did some research on the engine fuel routing. In looking at
the ratchet wheel pump drive, I concluded this engine was set up
for multiple fuel usage. The poorer quality fuels were run through
the heat exchanger and through the secondary pump mechanism, then
to a second injector on the engine cylinder next to the primary
injector. Fuel mixture on the secondary pump is made with a set
bolt and locking nut mounted within the guide block pushrod mounted
before the pump. The primary pump guide and pushrod do not have
this feature and I believe the primary pump’s adjustment is
actually made with the governor. The primary guide does have a
priming handle though the secondary does not. I made up a set of
fuel lines for the heat exchanger and installed them. One line is
connected to the engine mount next to the manifold as a way to
anchor the exchanger in position. The other end goes to the
secondary fuel pump inlet check valve. As the secondary injector is
not mounted in the engine, the connection was mocked up for
appearance sake by soldering part of a 1/4-inch compression fitting
onto the brass plug in the injector mount hole and piping to the
secondary pump discharge.
Then I tackled the primary fuel pump leakage. I had to remove
the primary fuel injector piping as well as the fuel line from the
kerosene tank before I could remove the pump body from the transfer
cover-pump mount. I took apart the pump again in order to see why
the fuel was leaking past the packing gland nut. Upon close
inspection, I found the fuel pump piston had a rough surface due to
the rust that formed when the pump had water in it. I had cleaned
it earlier with some emery paper, but I guess the pitting was too
deep. I tried again to clean the shaft, but did not bother to
install it, as a lot of pits could still be felt. I decided a new
pump piston needed to be built. I ended up buying two bolts, a
5-1/2-inch and a 6-inch. I cut the threads off the two bolts and
tried them for fit in the pump housing. I ended up using the 6-inch
after profiling the end that was in the pump, to match the
original. I also polished the bolt shaft and assembled the pump,
installing new packing while I was at it.
The last repair was made to the fuel tank lid. As the lid sits
directly on the tank, I had to devise a way to make the lid stay
put. I ended up putting a solid rubber bungee cord onto the tank,
wrapping it around the lid-lifting knob. This effectively made the
lid quiet, but I’ll have to find a more sightly remedy in the
future.
Back at the show
The next show I attended was the Hudson Valley Old Time Power
Assn. show in Hudson, N.Y. As I drove onto the show grounds, I
gathered a good sized crowd of people. Many started asking if I was
going to start it and I answered, “As soon as I?get it out.”
I had plenty of help getting the monster off the trailer. I
filled the kerosene tank 3/4-full of fuel, opened the gas to my
acetylene torch, lit it and began heating the bulb. After answering
all kinds of questions about the engine, I opened the compression
release valve, turned on the fuel valve and pulled the primer
handle on the primary pump a few times. I then gently pulled on the
flywheel. A lot of white vapor came out of the compression release
port so I closed it. I turned off the torch and rocked the engine
crankshaft flywheel against compression. The people stood
mesmerized by the engine’s flywheel rocking antics! It must have
reversed eight times before it got up enough inertia to carry it
over the compression stroke. When it finally carried over, it ran
up to full speed and then quit.
As it was spinning down, I noticed the pump plunger was not
moving. It took a second to realize the plunger was stuck. I tapped
the plunger with my finger and it started pumping again. By this
time, the flywheels had lost enough speed that the engine was going
to stop altogether. I gave the primer a double pump and the engine
fired, reversed and kept on running. You should have seen the
people jump! It was quite a show for the first 15 minutes. The
engine ran all day, hardly missing a beat.
As it was running at about 210 degrees Fahrenheit, I had people
asking if it was a steam engine! I must have given the hot bulb’s
operation speech a dozen times that day. The Charter-Mietz used a
little more than a gallon of kerosene in eight hours of running.
One of my twin sons, John, had come with me and during some spare
time he began polishing some piping on the engine. He told me the
fuel pumps were made of brass, too. I took a look and lo and
behold, he was almost right. Both fuel pumps were made of bronze.
The rust I saw on the surface of the paint must have come from
something resting on the engine some time in the past and it
rust-stained the paint. Now I had another project.
While I was cleaning all the brass and bronze, I was looking
over the engine’s general appearance. I decided to leave the paint
as found, as it was about 95 percent there. While I was looking, I
again noticed the 3/8-inch pipe-threaded hole above the rear air
intake on the engine subbase. This hole actually generated more
vacuum than the engine induction on the intake stroke. I remembered
a hole on the transfer port, near the piston oil inlet, but further
toward the top of the port. I did not see where it went. I opened
the compression release and blew into the pipe connection with air
and it came out the combustion chamber.
As there was only one item this engine was missing, compared to
the regular Mietz & Weiss engines, that being the water-steam
induction, I decided to install one on my engine. I connected a
3/8-inch specialty tee to the female connection on the block of the
engine and installed a 3/8-inch flare male adapter on the tee. I
left one end of the tee open so if water should condense in the
piping, it would have a place to escape instead of being trapped in
the line. I routed the 3/8-inch OD tubing to the top of the water
reservoir, and drilled and tapped a 1/4-inch pipe thread into the
side of it. I threaded an old bronze gas cock into the reservoir. I
flared the 3/8-inch tubing and attached it to the valve and the tee
in the block. The steam induction piping works fine!
Coolspring
Recently, I took the engine to the Coolspring show in
Pennsylvania, and started the engine many times to the amusement
and entertainment of quite a few people. One of those people in
attendance was Dusty, the gentleman who wrote the book about Metz
&Weiss engines!
I was setting up my display and I noticed a man looking at the
engine with great interest. I asked him if he wanted to see it run,
and his face lit up with a big smile as he asked, “Could you?” I
lit the acetylene torch, opened the fuel and compression release,
and gave the Madison-Kipp a few turns. I continued setting up my
display, which included a copy of the July 2006 Gas
Engine?Magazine, with the first part of this artival in it, as well
as the Hauck no. 10 ignition torch. Three minutes later, I pulled
the primer handle on the primary injector pump a few times. The
engine responded with a loud bang out the exhaust port that made
both of us jump!
I closed the compression release, rocked the engine on
compression, and again hit the priming lever. The engine lit right
off and ran as pretty as a picture. The gentleman just stood there,
watching the engine intently. After several minutes, I demonstrated
all the injector pumping options, and turned the fuel selector off.
As the engine rolled to a stop, it rocked between compression
strokes. I re-opened the fuel valve and the engine rocked, firing,
and then started in the opposite direction, belching out a huge
cloud of blue-white smoke.
After another two-minute run, I shut the engine down, as I had
not yet put water in the reservoir. The man walked up to me, held
out his hand, and said, “The photos you sent me do not do the
engine justice, I’m Dusty Erickson. It is one thing to see
pictures; to see this engine in person, well, this is an
experience,” he said. “I have never seen another like it; it is so
the same, yet so different. This is fantastic!” He thanked me for
running the engine for him, and asked me several other questions
about its operation and how it runs.
For instance, it likes to run reversed better than forward and
it uses about one quart of fuel in 10 hours. Unloaded it weighs
1,500 pounds without the cart and uses about a cup of water an
hour, as steam is taken into the engine to prevent knock. We
exchanged some more information and he took a few photos of the
engine. Dusty shook my hand, said thanks again, and went on to see
the rest of the show.
Final adjustments
I have mounted a no. 6 turbo tip acetylene torch to the engine
hot bulb assembly. This will allow me to provide the heat for the
hot bulb exactly where it is needed, consistently. It used to be a
guessing game as to how long and where to heat the bulb for quick
starts. With the turbo tip, I get good heating results and starting
availability in less than four minutes. I also painted the hot bulb
housing with Krylon Hi Heat semi-flat black paint to prevent
rust.
In general, here are the unusual characteristics about my
Charter-Mietz engine: While normal flywheels are two, 42-inch
wheels, weighing 225 pounds each, mine are twin 24-inch wheels
weighing 325 pounds each. Second, there is no steam dome or water
feed assembly on the outside of the engine cylinder, nor are there
provisions for one. Third, the Madison-Kipp oiler; although Dusty
has advertisements about the Charter-Mietz and M&W engines
having these oilers, this was the first time he had seen one
mounted. The same went for Fred Pritchard. Fourth were the dual
fuel pumps and the ratcheting assembly. The left hand primary pump
is definitely M&W design; however, the timing ratchets,
camshaft and the secondary pump have never been seen or mentioned
before. Fifth, the heat exchanger is unique to this engine; no one
has seen the like on this puppy either. Sixth, the engine serial
no. is at least 1,000 higher than the next known engine. (As a side
note, Dusty is compiling a worldwide registry of all the M&W
and Charter-Mietz engines, of which mine seems to be unique out of
more than 70 M&Ws in over 13 countries so far.) Seventh, the
two-position fuel valve, not known on any other Charter-Mietz
engine. Eighth, the steam inlet passage location is different from
the standard as well. Ninth, the engine weight is extremely heavy
for its size. Tenth, the main bearing supports have four external
buttressed supports. This also is not a regular Charter-Mietz
feature and probably was done to support the extra-heavy
flywheels.
I would like to extend a special thanks to Bill Popalell, the
previous engine owner, without whose trust and faith in my ability
and honor, none of this would have been possible. And to my wife
Mary, who has been so patient through the years, my special thanks
and my love. Thanks also to my twin sons Richard and John for their
help.
Contact Andrew?Mackey at 26 Mott Place,?Rockaway Boro, NJ
07866-3022; mackmotr@aol.com