Hercules Engine News
Editor’s note: This month, guest writer Kevin Pulver has
written an interesting article on fabricating a cylinder head for
his circa-1915 Champion. A very unusual engine, it was manufactured
for Lininger Implement, Omaha, Neb., by Hercules and based on a 12
HP Model E.
The head (and most everything else) was thrown
away when my 12 HP Champion was converted to a log splitter. I
wanted to cast a water-cooled head as original, but foundry work
was estimated at $3,000. It may have been a Gas Engine
Magazine article about an engine totally made of steel and
welded together that got me thinking about fabricating a head. I’m
not a machinist, but after reading books and dreaming of
do-it-yourself pattern making, sand casting and iron melting, this
method seemed easy by comparison.
A God-given imagination let me see the plan before I ever made
the rough sketches that were our prints. My wife, Maria, encouraged
me to work on it when business was slow. Through Harry’s Internet
engine page (www.SmokStak.com), I met Joel Mosley three hours away
in Omaha, Neb., who re-cast his rocker arm for me, and took me to
measure his 12 HP Economy when I started work.
I should have kept track of time, but I would estimate the
project took 80 hours. My friends Joe Dittrick and Bill Wehrman let
me use their machine tools, and my brother-in-law did most of the
We started with two 1/2-inch thick plates for the top and
bottom. First, I tacked them together, and drilled the five
head-bolt holes. Next, I located where the valves would center and
drilled 1/4-inch holes. The intake port was made up of 2-inch gas
pipe fittings. For the exhaust, I cut 3-inch pipe wedges to get the
tighter radius necessary to fit the available space between the
plates. My friend Bob Clark gave me the idea to first mock up the
ports from PVC pipe. I remembered enough from watching Lyle Clemens
build irrigation risers to get my pipe marked out. After a bit of
trial and error with my DeWalt sliding compound miter saw, I knew
the lengths and angles I needed and copied them in steel on the
I turned tapered valve guides from 1-inch round stock, drilled
1/4-inch. The two ports were drilled on the lathe and mill to
accept the guides, and I used round centering plugs and 1/4-inch
ready rod and nuts to jig them for welding. The same 1/4-inch ready
rod was used to clamp the port/guide assembly to the bottom plate.
Next, 3/4-inch steel pipes were lathe-cut to go over the head bolts
and sandwich between the two plates. They would spread the plates
and seal the water jacket. Slots were milled in the bottom plate to
correspond to water jacket holes in the block.
The plates were cut round on the lathe and a relief was cut for
the 1/8-inch outside band and weld bead to go between the two round
plates. I foolishly cut the corners off with a torch, which
work-hardened the piece. It took lots of bit sharpening and hours
of turning to knock off the high corners and get it round. When I
was almost finished, I figured out my center was off on my 4-jaw
chuck! I had barely enough stock left to clean it up upon
re-centering. The top plate 1/4-inch holes were drilled to 1-inch
to let the valve guides pass through. Thermo-King sheared a piece
of plate for the band, and Hastings Equity Grain Bin rolled it for
After all the pieces were ready, we assembled them on the
engine. We tacked the intake and exhaust ports to the bottom plate
then disassembled and welded them. It took both MIG and stick
welders to reach some tight spots on the exhaust and others. Next,
we reassembled, wrapping masking tape around the 5-head studs to
center the pipes on them for correct fit. We were concerned about
warping, but the top plate with 1-inch holes dropped right over the
valve guides and up against the “spreader” pipes. It was all
clamped tight again and welded. The head had to be pried off the
studs, but when the hot, gummy tape was removed, the head slid on
and off beautifully.
Cardboard templates marked the band to fit around the ports and
a jigsaw cut it out. Homemade hose clamps pulled it tight and it
was welded. We used a hole saw to rough-cut the valve seat holes in
the bottom plate, using the 1/4-inch holes as centers.
Next, the valve guide holes were drilled oversize and reamed to
1/2-inch. A pilot was used in the guide holes for a boring bar to
finish-cut the rough holes that will be our valve seats. Scrap
steel formed the pushrod guide and rocker arm pedestals. Lots of
valve train geometry was studied on the engine before these parts
were welded solid. The bottom plate did warp a few thousandths and
we had the bottom surfaced.
Valves were made of 1/2-inch drill rod and old scrap steel plugs
from hole saw cuts. Center holes were opened up to 1/2-inch,
counter-bored, stems pressed and welded, then chucked on the lathe
and turned down and ground. I couldn’t find 3-inch seat cutters, so
I glued emery cloth to the valve face with weatherstrip adhesive. I
chucked the stem in my cordless drill, pulled it in and spun it
until I had a narrow seat. Then I lapped and blued them, and they
came out pretty good. Lastly, washers were soldered to the head to
resemble the castings where the head nuts go. The engine started
and ran on my birthday, but that’s another story.
Contact engine enthusiast Kevin Pulver at:
Glenn Karch is a noted authority on Hercules engines.
Contact him at: 20601 Old State Road, Haubstadt, IN 47639;
Hercules Engine News
20601 Old State Road Haubstadt, Indiana 47639 Email:
The question comes up frequently in regard as to how to properly
time a Hercules built engine. To set timing properly, three steps
must be taken, and in proper order. The first of these steps is to
set the timing properly. Shown at top right is the explanation
taken directly from the instruction book.
The second step is to set the exhaust valve timing. The exhaust
valve should start to open when the crankshaft is about 45 degrees
before bottom dead center on the power stroke. It should remain
open until the crankshaft is 3 to 5 degrees past top dead center at
the beginning of the intake stroke. This adjustment is made by
turning the screw in or out that is on the end of the exhaust
The final step is then the ignition timing. On all except the
igniter, battery and coil equipped engines, there is a lever with a
retard and run position. For an engine expected to run at rated RPM
and to pull a load, the spark should occur when the ‘spark’
mark on the flywheel is even with the top of the side rod and the
lever set in the run position. On the Webster system, the run
position is when the lever is straight up. On the Wico system, the
run position is when the lever on the trip finger mechanism is in
the down position. With these adjustments, ignition should take
place between 20 and 25 degrees before top dead center depending on
the engine size. When the lever is set in the start position, the
ignition should take place at about top dead center. For show
engines running much slower, reset ignition timing in the run
position to about 4 degrees advance for each 100 RPM.
The run-start position for the Webster system is shown in the
In case you didn’t notice it, I now have an e-mail address
as shown at the top of this article.
HOW TO PUT ON THE CAM GEAR
If it is ever necessary to take off the cam gear or to put on a
new one it must be put on in a certain position, as the cam on the
gear controls the time of the spark and the opening and closing of
the valves, in fact every operation of the engine depends on this
cam being set just right.
To put on the cam gear, hook detent blade back of catch block,
turn flywheels around until the key in the crank shaft is straight
up, as shown by ‘ B ‘ in Figure 5; then set the two teeth
that are just under the indicator ‘ A ‘ on the cam gear
over the one tooth that is just above the Key ‘ B ‘, then
roll the cam gear around to the right until it reaches the position
as shown by dotted gear, being sure to keep the gear teeth
together. Then slip the cam gear pin in place and fasten it with
the lock washer and nut.
Be very careful in putting on this gear to see that it is just
right. One tooth out of the way makes a decided difference in the
way your angina will run.
This is a line drawing of the tripping mechanism showing how it
should be set for proper running. It also shows the timing lever
‘J.’ Be sure when starting the engine that this is pushed
to the right as far as it will go. This retards the spark and
prevents the engine from kicking back when starting
Hercules Engine News
20601 Old State Road, Haubstadt, Indiana 47639
Last month paint recommendations were made for the Hercules and
related engines. Three of the illustrations shown here were taken
from a Hercules S model catalog dated 1926. All of the color
illustrations that I have seen always show red stripes on the
Hercules brand engines. The illustration at top left is of the 1 HP
model S engine. Note that the upper hopper stripe is up on the
rounded hopper edge to allow enough room for the decal. Although
the engine shown here has flywheel stripes, in reality very few had
The next illustration (bottom left) shows a larger size engine
which is most likely a 6 HP. The striping pattern is similar to
that on the smaller engines except the hopper stripes are now all
on the flat surfaces. If you will note care fully, there is a black
stripe across the top and down the sides of the head. In this color
illustration, I believe the artist failed to make it red like the
rest. Flywheel stripes are shown. They were more common on the
larger size engines, but not all had the stripes.
The next illustration (lower right) is that of the model UA
Hercules oil engine. Except for the color, it is the same as the
model UA Thermoil engines.
There was a stripe on the crankguard. It is much like the shape
of a written upside L (see the illustration below).
In the illustrations shown here, it would appear that some
engine parts were left unpainted. That is not the case. Everything
was painted the same color except for the magneto, spark plug and
the oiler, which were covered.
1893 Jigger Details
Read this reader’s letter about a photo of a gas-engine operated jigger.
Answer To Mysterious Engine
Has this reader correctly identified a mysterious engine from a past issue? Read to find out.
Check out this reader’s letter about an photo in the April/May issue.