The Hornsby oil engine works on the Otto Four Cycle, i.e., one explosion for
two revolutions of Crank. The oil is converted into vapour by being
sprayed into the hot Vaporiser. The explosion is obtained by the
compression of fresh air along with the vapour already in the hot
A separate plan is supplied with each Engine giving particulars
for erection and diameters of pipes required.
The Vaporiser Cap End is heated by lamp before starting and is
kept hot by the explosions.
The Lamp is required for starting only.
The Speed is regulated by governor acting on relief valve (see
Vaporiser Valve Box, p. 15), a portion of oil delivered from pump
escapes and flows back to Oil-tank, thus reducing the quantity
sprayed into Vaporiser, and consequently reducing the force of
The Engine must be set level and square to its drive, bolted to
a block of good hard concrete.
MANUFACTURED BY: RUSTON & HORNSBY Ltd.
Engineers: LINCOLN, England
Works at Lincoln and Grantham
Section of Hornsby Oil Engine
The Tank for Cylinder cooling water may be placed to suit
building, but not lower relative to Engine height. Rain or soft water should be used; if water is hard, the lime
deposit must be cleaned frequently from the vaporiser and cylinder
water jackets. The tank must be filled well above inlet “T” value, “U” open, cock “V” shut. The
water coming from top of Cylinder should be not less than 100°, nor
more than 140° Fahrenheit. Quantity of water not less than 44 gallons (7
cubic feet) per brake h.p. In hot countries more may be
The pipe for adding cold water to the tank should be taken
within 3in. of the bottom, and the overflow pipe should be at the
top above the water circulating pipe.
The Exhaust Pipes and Silencer should be at least one foot from
all woodwork, not buried, but arranged in trenches for easy
The Lubricating Oil for piston is most important; inferior or
unsuitable Oils cause Engine to work badly by fouling the Cylinder.
Oil must never be used a second time. For Great Britain R. & H.
supply and strongly recommend their S.C.L. brand of Gas Engine
Cylinder Lubricating Oil, and ask all users not to obtain any other
quality except under their advice.
The best Engine Bearing Oil should be used for all other working
Ring Oiled Crank Shaft Bearings (where
The oil reservoir of these must be filled to the indicated level. Care should be taken that the oil is kept clean by
regularly removing the sediment out of the oil wells. Examine all
ring oil bearings to see the rings are working properly.
Minor adjustments of compression to suit local conditions or
variations of oil can be made by moving the roller on end of
exhaust lever (using the plain washer supplied). If the oil
requires a higher compression or the Engine tends to cool down by
the scavenging effects of the exhaust arrangements then the roller
can be advanced from a central position to a forward position. If the oil
requires a lower compression or the Vaporiser gets too hot through
back pressure in the exhaust arrangements, the roller can be
adjusted to a back position.
To adjust the Engine to suit different
Oils.Only one Vaporiser is used on each size of Engine of
1 b.h.p. to 4 b.h.p. inclusive. For each size of Engine 5 b.h.p.
to 30 b.h.p. we make two different vaporiser cap ends, one marked “O” and the other marked “P.” The former has
more heating surface than the latter, and gives a higher
compression. Each Engine is sent out fitted with the vaporiser cap
end best adapted to the use of the class of oil specified by the
customer at the time of ordering. If no indication of the class of
oil to be used has been received, then Engines for Great Britain
are set to use American Refined Oil. For abroad, that vaporiser cap
end is supplied which is most commonly required for the country to
which Engine is going.
If customers wish to change their vaporising oil, R. & H.
strongly recommend a sample (not less than 5 gallons) be sent them
to test, when they will advise customers what alterations and
adjustments are required to get the best possible results from
When vaporiser cap ends are fitted with cleaning doors the studs
or screws securing these in position should be lubricated on the
threads with a mixture of black lead and tallow each time the door
is removed. The same treatment should be given to all studs that
get hot when Engine is working.
In Frosty Weather, after stopping Engine, close
cock “U” open cock “V” to empty pipes and
cylinder jacket. Engines 5 b.h.p. and above, also open cock
To prepare for starting Engine. Fit proper
worsted wicks in oil cups where fitted on crank shaft bearings, and
crank end of connecting rod, and fill with oil. Oil
the following parts: Piston end of connecting rod, bearings
of side shaft, skew gearing, rollers and pins on valve levers,
lever bearings, governor and spindle and joints, bevel wheels and
pins of levers to relief valve.
To trim the lamp, fill the reservoir of lamp
through plug “A” level with plug “B,” replace plugs “B” and “A,” then turn
cock “C” to position “STOP.” Pump air into reservoir, then
pour oil on cup “D” under coil, put a piece of asbestos wick in it,
and light it. When well alight, turn cock “C” to position ‘
START,’ and regulate until Oil in cup “D” burns with a clear
flame. After oil has burnt out in cup D, turn cock C to position “WORK,” and regulate it so as to obtain a. steady clear
flame. Should the flame burn unsteadily, or on one side, clean the
spray hole out with the pricker supplied, pump more air into the
reservoir, and re-adjust cock “C.” Occasionally take out plug in
bottom of coil and allow air (under pressure) from the reservoir to
blow through and clean interior of coil.
To Heat the Vaporiser, take the lid off Vaporiser cover, place
lighted lamp underneath; according to size of Engine, 5 to 15
minutes should heat Vaporiser enough. Oil the Engine whilst
Vaporiser is being heated.
To Stop the Lamp turn cock “C” to position ‘ START ‘ and
allow air to blow through coil; this will help to keep it clean.
The thorough heating of Vaporiser is most important, otherwise
Engine is sure to work badly, and may stop altogether. Better
double the time for heating than start with an insufficiently
heated Vaporiser.To Start the Engine
In small Engines slide exhaust roller to the right to engage
with double part of cam. In large Engines slide exhaust cam in
direction “TO START,” to engage double part of cam with
roller. Set Oil Pump to give a slightly shorter stroke than No. I
gauge, and put starting handle to position “SHUT,” and work the pump lever up and down until oil passes
freely from the overflow valve. Then turn the handle to position
“OPEN,” work the pump lever again once or twice ; then
give the flywheel one or two smart turns, and the Engine should
start readily.; The Engine can also be started by turning the
flywheel backwards till it compresses the air in the Cylinder. An explosion will generally be obtained which will start the Engine
forward. When Engine has got to half speed, in small Engines slide
exhaust roller to the left to engage with single part of cam, and
in large Engines slide exhaust cam in direction “TO WORK”
to engage single part of cam with roller. After putting load on
Engine, adjust stroke of oil pump to suit.
To stop the Engine, turn handle to position “SHUT.”
Self-starter may be applied when ordered for Engines 26 b.h.p. and
When a Self-starter is used see that the valve “A” on the receiver
is open, and also the cock “B” on the pipe leading from the hand air
pump. Put the starting lever in the quadrant at the position marked “SHUT”‘ and pin it there. Pump air into the receiver by
the hand air pump to the pressure of say 60 or 70 lbs. to the
square inch. Then close the cock B on the air
pump pipe, withdraw the pin in the starting lever and get the
Engine ready for starting as previously described. Place the crank
a little over the dead centre in the impulse stroke in whichever
direction the Engine is intended to run and then suddenly push the
starting lever forward to the end of the quadrant. The Engine
will start. Pull the lever right back immediately to “SHUT”
position and screw down the valves on the receiver.
Before stopping the Engine at any time, pull the lever back and
pin it in the hole marked “TO CHARGE,” open the valve “A” on
the receiver, and allow the Engine to pump air into the receiver to
80 or 100 lbs. pressure; put the lever to the end hole marked
“SHUT” and pin it there; screw down the valve on the
receiver and the air pressure in the receiver will be retained for
the next start. If an air pump is not provided, the Engine must be
started in the usual way the first time, by pulling round the
flywheel, and the receiver afterwards filled each time before
stopping. Periodically blow out receiver through the drain cock at
bottom. The air receivers are constructed for a working pressure
170 lbs. per square inch; this must not be exceeded.
When Engine is working at full power, part stamped “I”
on OIL PUMP GAUGE must fit between the two round flanges “A” and “B” on
pump plunger; parts marked “2” and “3” are used for
adjusting pump for medium and light loads respectively. Should oil
leak from pump gland it should be re-packed. Use nothing but well greased asbestos
packing should be used for this
purpose. Pump Plunger must work freely in its packed gland. On no
account must the Engine be worked with greater oil pump stroke than
No. I gauge. A continued over-supply of oil induces carbon deposit.
See that the oil pipe from pump to Vaporiser has a gradual rise from
Running light or nearly so for long
periods. When Engine is to run light for long periods the
stroke of pump must be reduced so that governor occasionally acts
on the relief valve. The vaporiser thus gets a small charge of oil
each time and prevents it from cooling without reducing speed of
Engine. The cock “U” can also be partially closed, to keep
the Cylinder warmer. On Engines 5 b.h.p. and upwards the cock
“O” may be closed. Above remarks do not apply when work is
Skew Gearing. If the crankshaft is taken out,
be sure that the Skew-wheel Gearing is afterwards put together. If the Air or Exhaust Valves open or close at
the wrong time, take off the nut, which should be screwed up tightly
on end of cam shaft, and see that the chisel cuts on the shaft and
skew-wheel are opposite.
Engines must not be overloaded nor the Oil
reduced so much that they run below the speed they are set
for. This causes pre-ignitions, and the Vaporiser gets too hot,
causing the Engine to lose power. Where Engines are driving dynamos
charging accumulators, suitable resistances must be arranged in the
shunt circuit so that the above may be carefully observed.
Air and Exhaust Valves should be ground with
flour of emery and water if air leaks past. The cam rollers should
not quite touch the cams when the projections are on the top. In
replacing the Air Valve, take care to tighten the Nuts equally. Apply air valve seat gauge and make the space between
flanges equal all round.
Vaporiser Valve Box contains the vertical
relief valve regulated by governor as explained above, and a
horizontal back-pressure valve. If, on pressing down the relief
valve by hand, vapour should issue from the overflow pipe, the
horizontal valve leaks. The cap must be removed and valve turned on
its seat a few times to dislodge any dirt. If it still leaks it must
be ground with a little of the finest emery and water, and great
care must be taken in replacing it.
Clean the Filter occasionally: it may become
clogged with dirt or gummy oil. Should level of oil get below the
filter, pump will draw air in, and Engine stop working. After
refilling oil tank, work pump by hand for sever minutes, holding
open relief valve to expel the oil remaining in pump and pipes. Cock
on filter is to be use only for testing filter.
Cylinder and Piston. Should the piston become dirty or sticky by using unsuitable
lubricating oil, or should there be a leakage of gas from it, it
should be taken out and cleaned thoroughly.
Piston Rings should not be taken off for cleaning purposes, but the piston end should be allowed to
stand all night in a bucket of Petroleum. If a ring is set fast it
can be released by pouring methylated spirit into groove. If
necessary to remove a piston ring, lift the point of ring, then
take a piece of thin flat steel or tin and push it under the ring,
slide it round the piston; then slip in another piece, following on
until four pieces are under the ring, when the ring will have
sprung to the size of piston and will easily slide off.
To Fit New Rings. Before fitting rings on the
Piston, ease the plain end of ring with a file until it goes into
the Cylinder, as rings are always sent slightly large to allow for
any wear that may have taken place in the Cylinder. Ring should
then be put on Piston in usual way.
Do not pump too much oil when starting Engine, it cools
Vaporiser unduly. Use lamp again if Engine does not start
To test compression, turn flywheel forwards. If
elastic resistance due to compression of air continues to be felt
then air and exhaust valves and piston rings are not leaking.
When spray holes become partly blocked up,
clean with rymers in tool box, but do not enlarge them. This is most important. Also frequently remove deposit out of
beck under spray pad. Generally see that Engine is kept clean and
free from dirt.
Take off Vaporiser cap end occasionally to ascertain that it,
and the neck through which the Oil is injected as well as back part
of Engine, are clean inside.
See that Crank end of piston is clean outside and properly
lubricated. If dirty at that part, it should be taken out for
cleaning the rings.
To test spray.
Detach valve box from Vaporiser, but not from the pump delivery
pipe, then work pump by hand. If no oil is discharged the filter
cock should be opened to see if the filter is choked and
consequently needs cleaning. If filter is clear then take down the
vaporiser valve box and test the pump. After pumping vigorously for some time in order to
expel any air from the pump or pipes, the slightest movement of the
pump plunger ought to cause a corresponding delivery of oil past
the thumb held over the mouth of the pipe. If the pump still fails
then the gland packing should be looked to and the valve examined
and re-seated if necessary, or if corroded must be renewed. The Oil
Spray is correct when it works without dribble and ceases
immediately when the plunger comes to rest.
Governorjoints and spindle must be clean and able to move freely. It will not
work properly if pump gives irregular supply of oil. It is working properly
when it is constantly moving slightly up and down.
If Engine Thumps, tighten Connecting Rod on Crank Bearings.See that the flywheel
keys have not worked loose.
Spare Parts: When ordering, the letters and figures on the castings should be
given. If forgings or springs without marks are required, a
description and slight sketch will prevent mistakes. The size and
number of the Engine and date supplied should always be given.