Hercules Engine News

By Staff
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20601 Old State Road Haubstadt, Indiana 47639

This article will cover the procedure necessary to rebuild the
head on the l to 2 HP Hercules built engines. Valves, valve guides,
rocker arm support mountings and pin and the side rod support hole
are all possible areas that may need repair. Although the following
remarks are intended for the engines mentioned, many of these same
principles can be applied to other sizes and brands of engines.

If parts are rusted and stuck, disassembly should be done
carefully. If the exhaust rocker arm pin does not come out easily,
it is likely stuck in the rocker arm hole. Proceed with caution so
you don’t break off one of the rocker arm support arms. Tap
gently. If that doesn’t work, heat the rocker arm and then
continue to tap gently on the pin. It may require a slow cooling
and reheating several times. If that doesn’t work, take a hack
saw and saw off the rocker arm pin on the end where the biggest gap
is between the rocker arm and the support. This will allow enough
gap to saw off the other end of the pin. You now may put the rocker
arm in a vise or other suitable support and become more vigorous in
trying to punch out the pin; however, it is still possible to split
the rocker arm wide open. Heat again if necessary. Once the pin
begins to move, apply a penetrant and tap the pin back and forth
until it is free. Once the rocker arm pin has been removed, a new
one can be made from inch rod. If the holes in the support arm are
quite loose, I ream them and the rocker arm hole out to
26/64 inch and make a new pin to fit.

If a rocker arm support is broken off, I use the set up as shown
in the picture to line up and hold parts steady for welding.

The procedure is somewhat the same with stuck valves. Tap the
stem gently so the valve guide doesn’t split. If the valve
doesn’t move, apply heat to the guide. Once the valve moves,
apply penetrant and tap it back and forth until it will come out.
If the end of the stem becomes mushroomed or bent from hammering on
it, saw it off flush with the end of the guide. Continue to heat
and with a hammer and punch continue the tapping process.

The valve stems are 5/16 inch in diameter.
Once they are removed, if needed, they can be replaced with new
valves or if usable, new stems can be put on the valve heads. If
the guides are badly worn, I have a nearby automotive shop ream the
guides to 11/32 inch. Valves from 350
Chevrolet engines have 11/32 inch steins.
These used valves are usually available in abundance at auto repair
garages. The heads are turned down to the proper size and faced.
The stems are sawed off to the proper length. The protruding stem
can be turned down to 5/16 inch so it looks
original from the outside. A 3/32 inch hole
is drilled for the cotter pin. Refer to the accompanying diagram
for details.

The last point of repair is the side rod support hole.
Originally this hole was about 33/64 inch in
diameter. Another 64th of an inch play probably doesn’t hurt,
but if it is worn more than that, the inside of the hole should be
built up and filed to a more original size. The hole could also be
reamed out and be fitted with a thin bushing.

The next article will deal with the side rod and possible
repairs that it may need. It seems like a simple part, but a lot of
the engine functions depend on it.

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