P.O. Box 78 Summit Station, Pennsylvania 17979
I guess everyone who has been collecting engines for a while
eventually makes a buy that they have second thoughts about. In
early 1994 I attended an engine consignment auction, looking for a
project to keep me busy. There was a large selection of engines to
choose from, but I got to the auction later than I had planned and
didn’t have time to look them over as thoroughly as I like to.
When a two horse Nelson Brothers Jumbo came up for bid. I was
pleased to get it for a reasonable price. I had looked over the
engine beforehand and knew it had a split head and some other
problems, but I didn’t notice the cracked and poorly repaired
flywheel until I was loading it onto my truck. The thrill that
usually accompanies a new acquisition was dampened somewhat by this
discovery, as well as the concern that the crankshaft might not run
true, since it was mushroomed on the end with the bad flywheel.
When I got the engine home I stored it in the garage for a few
months, until I finished a two horse Fairbanks-Morse I was working
on. By April I was ready to tackle the Jumbo. Gauging the crank
showed it ran true, despite the damage on the end. When I pulled
the flywheel, it was apparent it was a total loss. My spirits
raised somewhat when I was able to pick up a replacement flywheel
from Hit & Miss Enterprises.
I trued the crank-end by belting the Jumbo to another engine and
working it back into shape with a file and emery cloth. Next, I
pulled the head and took it to the welding shop to have the cracks
repaired. After having the head welded, I filed the weld back to
the original profile of the head and then filled a few weld pits
with a metal epoxy. After priming, it was impossible to detect the
repair. I then ground the valves on the lathe and lapped the seats
with grinding compound.
The side rod was the next headache, because the original had
been replaced with a poorly fabricated one that was bent and
cracked. I turned a new one on the lathe, out of steel bar stock,
and after drilling and tapping the necessary holes had a rod as
good as new. The rocker arm shaft was also missing and had been
replaced with a bolt. Another evening’s work at the lathe
yielded a suitable shaft as near to the original as I could make
it. Additionally, I had to make a new magneto trip rod, a new pin
for the governor assembly, a spark advance lever, a gas cap, and
speed adjustment screw. Parts to repair included the choke, the
needle valves, and an assortment of shims and bushings to take the
play out of a host of worn parts.
After cleaning all the castings I painted and started the
reassembly process. I prefer to leave bolts, springs, and all the
running parts free of paint. Instead of paint I clean them on a
wire wheel then blue them with gun bluing. A coat of wax or boiled
linseed oil helps to further protect them from rust.
While assembling the engine I tried to make all the necessary
timing adjustments as I proceeded. There were no timing marks on
the gears, so I timed them by eye, then set the exhaust valve to
the usual adjustment.
The one bright spot in the restoration was the magneto. The Wico
was like new inside right down to a clean set of points. After
cleaning and polishing the case, and checking the point setting, I
installed the mag and adjusted the ignition timing. I built an oak
skid and mounted the engine to it, and was ready to haul it outside
for a test run.
My daughter helped me move the Jumbo to the lawn and stood by to
watch. I installed an old but serviceable spark plug from the spare
parts cabinet and primed the fuel mixer. I rotated the flywheel to
a comfortable position to give it a spin. As I rotated the
flywheel, the mag tripped and the engine took off! I’m not
usually that lucky, but it was a real treat to see the engine,
which had occupied so much of my spare time for about five months,
up and running. The only adjustment required was to find the proper
Restoring old engines can be frustrating and challenging, but
breathing new life into the old Jumbo taught me how second thoughts
can be turned into fond memories.