Ohio 44820
Upon reading the title of this article one may rightfully wonder
why lubricating the cylinders of our restored hobby engines is any
different than it ever was.
The one great difference is in the operating temperature of the
cylinders. The pressure on the aging boilers has been reduced. Many
of our engines are seldom, if ever, pulled as they once were. In
either case the result is the same: there simply isn’t enough
heat to emulsify the oil. The cylinders are working
‘wetter’ which helps to flush away the lubrication that
does exist. Since water is somewhat of a lubricant and the engines
are seldom worked, the poor lubrication most of these engines are
getting is simply not noticed. Some look for milky water emitting
from the cocks and glands. This is about like the ground hog and
his shadow, it may or may not be an indicator of sufficient
lubrication.
The lubricant of most farm engines before 1890 was tallow. It
was a good emulsifier and had satisfactory film strength up to
about 125 lbs. of pressure. As pressures began to exceed this
mineral oil with a 2 or 3% addition of tallow came into use and was
referred to as ‘low pressure steam cylinder oil.’ The
mineral oil was of a dark, straight stock and of a viscosity of
about 160 SSU. Heavier bodied mineral oils without tallow were
generally used at about 200 lbs. pressure of working pressure.
These are not suitable for our engines.
The writer has never run across any commercially available low
pressure steam cylinder oil with over 3% tallow. This oil does not
have enough tallow for our conditions.
An excellent oil can be compounded by taking four gallons of
either low pressure cylinder oil or a straight dark stock 160 SSU
oil. Add one gallon of acid less tallow. Tallow can be obtained by
getting the suet from a butcher shop. This suet lies in the back of
the animal and is practically pure tallow. Any red meat must be
trimmed off as this will produce acid which will destroy the tallow
in time. The writer recently opened a gallon of tallow that was in
excellent condition after 13 years. The suet can be rendered in an
oven at about 250°F. Your wife’s oven will do fine if she is
not home!
While the tallow is hot, strain it through a couple of layers of
cheesecloth or tobacco cloth directly into the oil which should at
least be warm. Next add about a pint of bubble soap that you can
get at nearly any dime store. At times they have this in pint
economy sizes which are much cheaper than the small bottles. Shake
this mixture while still hot. It will settle very little, even over
a long period of time. The viscosity increase will not be
objectionable during the summer months even when poured at ambient
temperature.
The bubble soap is an excellent emulsifier. When your packing
glands are correctly adjusted clusters of oil bubbles will hang
from them. You will find that your engine will roll easier and the
valve gear will be quieter. The writer has used this
‘homemade’ cylinder oil for the past 17 years and has never
had any problems with it.
One more comment: induce the oil into the center of the steam
column. A small copper tube brazed or soldered into the steam line
fitting to carry the oil to the center will do the trick.
