Charles B. (Charles Brian) Hayward.

Gasoline tractors. A practical presentation of tractor problems and their solution online

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Online LibraryCharles B. (Charles Brian) HaywardGasoline tractors. A practical presentation of tractor problems and their solution → online text (page 10 of 14)
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for weeks at a time and subject it to the severest kind of service
without being called upon to give it more than passing atten-
tion at infrequent intervals, the same amount of care will suffice
to keep the tractor running equally well. The most severe
service to which an automobile can be subjected is trifling com-
pared to what a tractor must undergo in plowing ten hours a
day. No comparison between the two is possible. The atten-
tion demanded in running a tractor is really only comparable to
that required by a marine engine which is run steadily at full

It is naturally impracticable to employ more than one man
to run the average tractor so that the single operator must
assume the combined tasks of the oiler, engine-room attendant,
and engineer on watch in the engine room of a steamer. He
must see that every part is constantly lubricated, must watch
all moving parts in sight from time to time and keep all his
senses on the alert all the time to detect the first indications of
overheating or faulty operation as evidenced by the sounds

Parts Giving Most Trouble. Over two thousand tractor
owners sent in reports in answer to a questionnaire forwarded to
them by the Department of Agriculture. In answer to the ques-
tion "What part of your tractor gives you most trouble?" more
than seven hundred mentioned some part of the motor and of
that number considerably over one-half gave the ignition as the
chief source of delay. A leading tractor manufacturer substan-
tiates this by stating in his instruction book that the motor is
responsible for fully 75 per cent of all tractor troubles and that


70 per cent of the motor trouble is due to the ignition. A
resume of the answers sent in to the questionnaire follows:

Magnetos 299 Cylinders and pistons 61

Sparkplugs 110 Clutch 59

Gears 108 Valves and springs 43

Carburetor 104 Lubrication 29

Bearings 80 Starting 28

The figures given in each case represent the number of tractor
owners who gave the part in question as the chief cause of their
troubles in operation. These figures do not, however, give any
idea of the relative importance of the parts as sources of trouble.
Failure of the magneto, or even of a spark plug, brings the
tractor to a halt, but the trouble may usually be remedied in a
very short time and no damage is caused, whereas a breakdown
due to faulty lubrication, or to the failure of the cooling system,
which is not mentioned at all, will usually involve the loss of
anywhere from a day to a week besides a heavy repair bill.

Supply of Spares Necessary. The cost of an ample supply
of spare parts is small compared with the time that is saved
when the part most needed is right at hand and can be installed
without delay, so that a number of spares of the most necessary
parts should be considered part of the investment and be bought
at the same time as the machine. Unless it be an ocean-going
steamer, there is hardly another piece of machinery that per-
forms such strenuous service so far from a repair and supply
base as does the tractor. It would be just as foolish for the
chief engineer of a steamer to leave port without any spare
parts in the storeroom and still expect to arrive at his destina-
tion, regardless of what happened, as it is for a farmer to pur-
chase a tractor and expect to get through his first, second, or
any other season of plowing or threshing without vexatious delays
unless he has on hand spares of the parts most frequently needed.

Manufacturer's Service Poor. While it would not be just to
generalize by saying that the service rendered the purchaser by
every manufacturer of tractors is poor, this is true in many cases
and must always remain so for the farmer who is located miles
from the nearest dealer representing tbe factory. It is nothing
unusual to waste from half a day to a day, telephoning and


waiting for a part to be sent out or driving in for it. The
dealer may be off for the day in some other part of the county,
making a demonstration or closing a sale, and there may be no
one in his place of business to render the desired service. Mean-
while, the machine is standing idle. There are few replacements
that the experienced driver of a tractor cannot make without
other assistance than that provided by the usual farm shop, so
that if the parts are on hand little time will be lost in getting
the machine under way again.

Parts Needed. While the make of the tractor in question
will determine the character of many of the spares that should
be carried by its owner, there are some that are needed with all
makes. These are valves, valve springs, and small parts needed
in connection with the valves, igniters, or make-and-break plugs
for low-tension ignition systems, also ignitor trip rods, or rather
the small parts which compose the fittings of the rod rather than
the rod itself, since the latter is not subjected to wear. Spare
connecting cables cut to length and fitted with terminals, whether
for high- or low-tension systems, will often be found valuable.
Extra fan belts and spark plugs should hardly be called spare
parts in this connection since they are absolute necessities at
comparatively short intervals. Hose connections between the
motor and the radiator are also in the same class. Where a
motor is equipped with die-cast main bearings or connecting-rod
bearings, a spare set will often prove to be worth many times
its cost in the saving of plowing or threshing time, since even
well-attended machines do suffer breakdowns from burnt-out bear-
ings at times. Extra piston rings as well as an extra piston
and a connecting rod are likely to be called for sooner or later.
The magneto is a pretty expensive piece of equipment and, more-
over, it is usually so reliable that it will continue to work season
after season without giving any trouble. But when it does break
down, it is sometimes beyond the ability of the tractor operator
to make the repair. W T here two or more tractors are operated on
a farm and the same magneto is standard on all of them, it
would pay to invest in a spaiv, though at any time but the
height of the season the laying up of one tractor would probably
not Oanse anv trouble.


The foregoing discussion has been confined to enumerating
motor parts or accessories that should be carried as spares since
they are common to practically all motors. So far as the rest
of the machine is concerned, the owner must either learn from
experience what parts are likely to wear out rapidly and need
replacement at short intervals, or he must depend upon the
manufacturer's representative to give him this information.
Naturally, the maker and his salesmen do not wish to give the
impression that any of the machine's parts will need replacement
in a short time, and in a good many instances they are as much
in the dark as the purchaser is, since it may be that the model
has just been placed on the market and there has been no oppor-
tunity to learn its weak points in actual service.

Both the time spent in getting information of this kind and
the money invested in the necessary spare parts will return very
substantial dividends when the occasion arises to use the parts.
There are some parts that may never be used, such as a steering
knuckle. Get the manufacturer's representative to give you a
frank opinion. Point out your position, when isolated, and do
not content yourself with his first recommendations. Insist on
finding out what are the weak parts of every important unit.
The factory man has a good line on this by the extent of the
demand for certain replacement parts. It will usually be found a
paying investment to purchase a stock of almost all of them
rather than take chances on getting the particular part most
needed at a time when the tractor is worth a good many dollars
an hour to you.


Q. What grade of lubricating oil should be used for a slow=
speed tractor motor; for a high=speed type?

A. Every responsible tractor manufacturer goes to consider-
able expense to determine just what grade of lubricating oil is
best adapted to his own engines. His investigation covers every-
thing from a chemical analysis and flash test of every grade of
oil recommended for his use to actual tests in service extending
over considerable periods of time. The tractor owner should


Accordingly never use anything l>nt llie oil recommended by the

Q. In a motor having any form of splash lubrication, that
is, one in which part of the supply is carried in the crankcase
pan, how often should the oil be drained from the crankcase?

A. The recommendations of different tractor manufacturers
range all the way from every day to once in two weeks, many
giving one week as the maximum period of time the same oil
should be used.

Q. How often should the oil in a circulating system be
completely replaced with a fresh supply?

A. It should he* 1 at the intervals given above for a, splash
system since the service demanded of the lubricant is the same.

Q. Does oil lose its lubricating qualities through use, and
how can this be determined?

A. High temperature and pressure completely change the
character of lubricating oil and destroy its lubricating qualities.
The lubricating quality of an oil depends upon its viscosity, that
is, its body, upon which depends its ability to hold apart surfaces
under pressure by a film of lubricant. Dip the finger ends in
some old oil from the crankcase and rub together under pressure.
The oil will have a thin watery feeling and the finger tips may
be pressed into close contact through it. Try the same experi-
ment with some fresh oil, and it will be noted that a sliding
film is formed between the fingers despite the greatest pressure
that can be put upon them to squec/e it out.

Q. What influence has the effect of high temperature and
pressure on the length of time during which the oil should be
allowed to remain in the crankcase?

A. Both the temperature and the pressure conditions differ
\\idely in different engines so that in some the oil literally nrarx
tmf much faster than in others and should accordingly be replaced
oftener. The tractor manufacturer has learned from experience
the proper period of time for his motors, and his recommenda-
tion is based on a. desire to avoid having his customer pay for
the same experience.

Q. Next to labor and fuel, lubricating oil is the most
expensive item of tractor maintenance. Is it really economy to


replace what appears to be good oil as often as the tractor
manufacturer recommends it?

A. The cost of repairs due to a single breakdown from
failure of the lubrication would usually buy anywhere from one
to five or more 50-gallon barrels of oil, without taking into
account the loss of time due to the tractor being out of service.
It is the highest form of economy to follow the maker's instruc-
tions in this respect; if these are to discard the oil at the end
of every day's service, it will be found far cheaper in the end to
do so. Many tractor owners do not regard it as necessary to
clean out the crankcase more than once or twice a season, but
instead of saving oil they are simply running up repair bills.

Q. What other causes tend to destroy the lubricating quality
of the oil?

A. Another cause is leakage of the fuel past the pistons so
that the supply of oil in the crankcase is thinned out by the
gasoline or kerosene. This is particularly true of kerosene, espe-
cially if the motor be run at a low temperature so that the kero-
sene vapor condenses into a liquid. The admixture of carbon and
dirt with the oil also tends to destroy its lubricating quality.
Compare the color of oil that has been used for some time with
fresh oil; the difference is due entirely to the foreign matter that
has become mixed with it.

Q. What attention does a force=feed lubricator require?

A. The sight feeds should be watched frequently to note
whether oil is constantly passing through them or not. To make
certain of this, dirt should be wiped from the glasses at least
once a day. While this type of lubrication has the great advan-
tage of constantly feeding fresh oil to the bearings almost as fast
as it is consumed, its factor of safety is not so high as that of
the splash or circulating type. In other words, failure of the
part is apt to follow immediately upon a stopping of the feed
since it usually receives no lubrication from any other source.
The lubricator must accordingly be watched closely and the
engine stopped at once if any of the feeds has become clogged.

Q. How often should such a lubricator be supplied with fresh oil?

A. The maker's instructions may be followed but a still
better practice is to get into the habit of keeping the lubricator


constantly filled; that is, of filling it twice or oftener a day, if
necessary, rather than waiting until the supply runs low. A
gage glass on the side of the lubricator shows the amount in it.
The plunder pumps which force the oil to the bearings will
always work better when there is an ample supply.

Q. What other precautions should be taken with a force=
feed lubricator?

A. When it is driven by a belt, close watch should be kept
on the belt to see that it does not become too loose, since any
slackening of the belt slows down the pumps and supplies less
oil to the bearings.

Q. How often should a force=feed lubricator be cleaned out?

A. Two or three times a season should ordinarily be ample,
but this will depend to some extent upon the care that is exer-
cised in handling the supply of oil itself. Unless the oil supply
is kept in a covered oil tank, more or less dust and other foreign
matter is bound to find its way into it. The presence of dirt
in the oil will make itself apparent by clouding the inside of the
sight-feed glasses, making them difficult to read. Oil having
visible foreign matter, such as small specks of grit, short ends of
straw, or chaff, in it should never be put into the lubricator
without straining, as it is liable to clog the pump valves.

Q. How is a force=feed lubricator cleaned out?

A. By disconnecting the leads and flushing it out thoroughly
\vith gasoline or kerosene. The leads should be disconnected at
both ends and also flushed out, blowing through them to see
that they are clear from end to end.

Q. Are some of these leads more apt to clog up than others?

A. Those that supply oil to the pistons are most likely to
clog owing to an accumulation of carbon in the ends opening
into the cylinder. They should be taken off at shorter intervals
and all carbon removed in the tube itself as well as in the open-
ing through which the oil passes through the cylinder wall.

Q. What attention does a circulating system require?

A. A circulating system requires replenishing of the entire
supply after washing out at intervals, as directed in the manu-
facturer's instructions; examination at short intervals of the oil
pump; and l'iv<|iiriit washing oil' of the oil pump screen. Keep


the sight-feed glasses clean and shut down immediately if an oil
stream fails to appear in any of them (some tractors have but
one, others several).

Q. What general precautions should be observed in clean=
ing out a lubricating system of any type and in handling oil?

A. Always avoid the use of waste or rags from which lint
will detach itself in wiping out the crankcase or any part of the
system, since these threads will invariably clog an oil pump or
feeder tubes. All cans or other vessels used in handling oil should
be kept covered to prevent dust falling in them and should be
wiped clean before using. Dust is simply fine grit, and its pres-
ence in the oil converts it into a grinding compound which will
quickly cut away bearing surfaces.

Q. What other lubrication does the motor require?

A. This will depend entirely on the type of motor. Where
it has overhead valves as used on many tractor motors, the rocker
arm spindles and pin should be oiled at least once or twice a
day with a hand oiler. This applies as well to any other external
moving parts not lubricated by the oiling system of the motor.
The grease cups on the fan and on the pump should be turned
down at least once a day. Some tractors are equipped with
gravity oilers for this purpose.


Q. How is the clutch lubricated?

A. On some tractors it is enclosed in the same housing as
the motor and runs in a bath of oil. Where it is not housed in,
grease cups are usually provided on the clutch, and these should
be turned down at least once a day. Xo oil should be allowed
to fall on the facing, as this would reduce the holding power, of
the clutch and cause it to slip.

Q. What attention is required to keep the transmission
properly lubricated?

A. When the transmission is of the enclosed type, running
in oil, it should be kept filled to the height given in the maker's
instructions and with the grade of lubricant recommended. Don't
attempt to use cup grease, or a home-made compound of grease
and oil or graphite, as the different materials will separate, nor


should heavy steam cylinder oil be used, since it contains animal
fats and will become acid, attacking the steel faces of the gears.
The pressure between the gear teeth in a transmission is very
high so that the oil wears out in time and should be replaced at
intervals of two to three months. Watch the transmission hous-
ing for leaks and renew felt washers or other provision for pre-
venting leaks.

Q. How are open transmission gears lubricated?

A. Where gears are run without a housing, they are not
intended to be lubricated and care should be taken to see that
no oil or grease* gets on them as it will hold dirt and grit and
cause the teeth to wear out much faster. The gears should be
kept free of mud and dirt, but an oily rag or waste should never
be used for this purpose. This also applies to the bull pinion
and gear except where completely housed in.

Q. What attention is required to lubricate other moving
parts of the tractor?

A. Grease cups are usually provided on all other moving
parts, and they should be turned down as instructed by the
maker. In some instances the directions are to screw these cups
down as often as twice a day; in others, once an hour.


Q. How long will motor bearings run without developing
sufficient play to require adjustment?

A. This will depend largely upon the motor itself and the
service demanded of the tractor. If it is being run constantly
with an overload, they will need attention much sooner than
when the machine is not called upon to carry more than 75 per
cent of its load for the greater part of the time. In any case
the bearings should be examined at least once a week; some
makers recommend that they be tested for looseness as often as
twice a week when in constant service.

Q* How can the bearings be tested for looseness?

A. They should always be examined just after the motor
has been shut down and is still hot; the amount of play will be


greater when all the parts are cold but some of this will be taken
up by the thickened oil film then present and their condition
cannot be determined as satisfactorily. The connecting-rod bear-
ings are the first to show signs of looseness. Take the handhole
covers off the crankcase and turn the motor until two of the
connecting-rod ends are close to the openings. If there is much
play, it will be evident upon grasping the connecting rod and
attempting to lift it, but this amount would usually cause a
knock in operation. Take a small bar and pry the bearing
upward from below, keeping the other hand on the rod to detect
any movement. Do not confuse the side play of the bearing
with looseness of the bearing itself as a small amount of side
movement is allowed on all connecting-rod bearings. Apply this
test to the other two connecting rods also. A bar may also be
used to detect any looseness of the main or crankshaft bearings.

Q. Will it do any harm to allow a certain amount of play
in these bearings?

A. Nothing will be apt to run up a big repair bill quicker
than running the motor with the bearings too loose. Every
reversal of movement pounds the crankshaft and in time will
cause crystallization of the steel with consequent breakage of the
shaft. The resulting vibration is also detrimental to every other
part of the motor.

Q. How are the bearings adjusted when a test reveals
play in them?

A. Most motor bearings are provided with shims, that is,
small strips of metal placed between the halves of the bearing
and through which the bolts pass to hold the bearing together.
Take off one or more shims on each side of the bearing and
screw down the nuts again tightly. To obtain a proper adjust-
ment, you must be able to set up these nuts as far as they will
go without binding the shaft. Open the pet cocks or the com-
pression release, where one is provided on the engine, and try
the adjustment by cranking the motor by hand. It will be very
difficult to turn the motor over if the bearings are too tight.
They should be adjusted so that the motor turns easily, indi-
cating that there is sufficient space between the bearing halves
and the shaft to permit the formation of an oil film between


them. The shaft should be tested for play, as already described,
to prevent making the adjustment too loose.

Q. When a bearing is too tight, is it good practice to ease
off the nuts and let the shaft run that way?

A. A bearing is not properly adjusted unless the nuts can
be set up hard on the bearing caps, all adjustments being made
by removing or re-inserting shims, or laminations of metal only a
few thousandths of an inch thick. One or two shims should be
removed from each side at a time and the adjustment tested.
Care must always be taken to see that the bearing cap is replaced
on the bearing from which it was taken and that it is put back-
in ihe same way.

Q. Is it ever necessary to adjust the piston=pin, or wrist=
pin, bearing?

A. This is the bearing which holds the upper end of the
connecting rod in the piston and if the motor is properly lubri-
cated with clean oil, it will seldom require any attention. In
some motors the pin is held fast in the sides of the piston and
the connecting rod moves on it, and shims are provided on the
connecting-rod bearing for adjustment. In others the upper end
of the connecting rod is clamped fast to the pin, and the pin
moves in bronze bushings in the sides of the piston or bears
directly on the piston walls. Allowing the big-end connecting-
rod bearings and the crankshaft bearings to become too loose so
that the motor knocks is the chief cause of lost motion in the
wrist-pin bearing. Where the pin bears in the piston walls this
may wear the holes out of round so that they have to be rebored
and bushed to make a good bearing.

Q. When the connecting rod or crankshaft bearings of a
motor require adjustment at frequent intervals, what is the cause
of the trouble?

A. The cause is faulty lubrication: failure to clean out the
crankcase at the proper intervals, with the result that the oil
loses its lubricating qualities and the dirt that becomes mixed
with it cuts away the bearing surfaces.

Q. Where bearings have become worn to the point where it is
no longer possible to adjust them properly, is it practical for the
average operator of a tractor to replace them with new bearings?


A. It is not practical unless he has had experience in the
work, since it requires accurate lining up and scraping in of the
bearings to a close fit. Unless this is carried out properly, such
heavy stresses will be imposed on the crankshaft that it will
break sooner or later. Therefore it is poor economy to attempt
this repair without actually having had experience in making it;
it is one of those ; things that cannot be learned from an instruc-
tion book. It is necessary to see it clone in the shop more than
once and the first attempt should be made under the supervision
of one who has had experience.


Q. What attention is required to keep the valves in good
operating condition?

A. The valve stems must be lubricated one or more times
a day, except on motors provided with special means for doing
this automatically. The clearance between the valve tappet and
push rod, or between the end of the rocker arm and the valve

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Online LibraryCharles B. (Charles Brian) HaywardGasoline tractors. A practical presentation of tractor problems and their solution → online text (page 10 of 14)