One Good Turn (Deserves Another)

By Staff
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The bore and stroke of the Aermotor measures 3-by-3-1/2 inches, respectively. The flywheel has a 20-inch diameter and 1-1/4-inch face width. The year of manufacture is unknown, but it was likely built in the early teens. Several casting numbers are found
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The photos on this page were taken at the Francis Park Annual Bicentennial Memorial Festival & Celebration in Kewanee, Ill., July 4, 2005. It was the Aermotor’s first public debut.

I own a heating and air conditioning company,
where my friend, Dave, also has a saw sharpening business. We’ve
been collecting and rebuilding hit-and-miss engines for the past 12
years and have accumulated some fairly rare engines along with some
not so rare. We’ve faced some real challenges, but nothing compares
to the engine story about to unfold.


John Montgomery walked into my business three years ago to see
Dave about sharpening some saw blades. He saw a few hit-and-miss
engines in the process of being restored. After speaking with Dave,
he asked me if these engines were mine, so I replied they belonged
to Dave and me. He asked if I could fix a steam radiator from his
house that he had been working on and thought he had ruined. After
explaining what he had done, I gave him a few tips to try. He said
he would prefer that I pick it up and fix it myself.

I went to his home, picked the radiator up, returned to the
shop, spent about 20 minutes fixing it, and returned the radiator.
John asked what I owed him, but since I fixed it and didn’t have
any of my service men run the call, I told him there would be no

He said for the favor he would give me an Aermotor he had. He
had tried to work on it, but was getting nowhere. To say it was in
poor shape would be an understatement. It came from his
grandparents’ farm in Missouri and had been buried in the ground
for approximately 50 years, with only part of the flywheel

I thanked him for the returned favor and headed back to the
shop. When Dave and I put wrenches to the nuts, nothing would
budge. We then got a 55-gallon drum of ATF, affixed a chain to the
engine, dropped it into the barrel and sealed the lid.


Two years later, we pulled the engine out and cleaned it up, yet
to our dismay, we couldn’t move a thing! We had read mention of
electrolysis in an article and searched the Internet until we found
an explanation.

At first, we were unable to find Arm & Hammer washing soda,
so we tried Arm & Hammer baking soda. This started to work, but
after finding the washing soda in Peoria, Ill., the process really
went to town. We used a 24-volt battery charger and unplugged it at
night. After approximately three weeks of eight-hour days, the
parts almost came off with our hands. We were totally amazed.
Everything but the piston, which was at top dead center, broke
loose. Since there was no head to remove (headless), we had a

We made a heavy-duty puller, and while the engine was “cooking”
we tried to move the piston. We applied exterior heat to the
cylinder and pulled. We heated and water shocked while we pulled.
We fabricated 1/4-inch steel block-off plates with gaskets and
sealed off the intake, exhaust and ignition. We filled the cylinder
with Rust Buster, WD-40 – any solvent we thought would work – and
added an air chuck, pushing 150 pounds of air while heating the
cylinder with torches; still no luck. We eventually removed the air
chuck and tapped a grease zerk into one of the block-off plates.
After all the grease the gun would pump, the rod finally moved –
only 1/16-inch, but it took the very last pump to get the top ring
of the piston out of the cylinder!

Internal Analysis

Inspection of the parts found that the rocker arm had been
broken and repaired, but needed further repair, so we brazed it
back together. My brother prepped and nickel rod-welded the
connecting rod cap, as it was broken, too. The cylinder walls were
only slightly pitted, but a honing pretty well took care of that.
The rod babbitt was gone so we repoured. We poured the bearing in
one piece using brass stock, which was 0.010″ under the crank size.
It took five attempts to accomplish this. We then hand sanded and
scraped the babbitt to match the crank size, with the crank shims
in place. We made appropriate shims, then ordered available parts,
such as new valves, rings, needle valve and springs for those parts
available and started to reassemble.

We made a cart from scratch, mounted a Blue Star pump for
recreation purposes, mounted the engine and fired her up. Not being
familiar with an 8-cycle, it took a little bit of thinking, but the
engine runs like a champ! We have yet to find the gear and shaft to
operate the pump or make all the necessary guards and

We started this in November of 2004, and
‘hit-and-missed’ on it during the winter months. I called
the previous owner, as well as other people who watched our
progress and had seen what we started with. On Saturday, April 17,
2005, they all came over with cameras and could not believe that we
were able to breathe life back into this engine. The previous owner
said he was going to Missouri within the next month and would try
to locate the missing pump gear and shaft to give to us.

There is one thing we discovered about the electrolysis cooking
method: It seems as though we lost a bit of tolerance. This only
stands to reason that when two parts are bound together and you
remove the “binding” rust which had them welded, everything is a
little looser. We compensated for this with shim stock, LocTite,

Dave and I never gave up. We had a challenge, but with
perseverance and determination we overcame. There were times the
two of us had our doubts, but the rewards are so much greater when
you accomplish a goal.

Contact engine enthusiast Jeffrey Arch at: 440 Fisher Ave.,
Kewanee, IL 61443;

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