THURSDAY, FEBRUARY 26, 1931.
"PINKING.”
Harmful Effects on Engines.
VALVE GRINDING.
Some Points That Must Be Looked to
THE CHINA MAIL.
THE REAR AXLE.
Adjustments Necessary for Silent Running.
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Neglect carelessness, and over- Recently there was brought under The back axle on a motor car la with a very bad¦n most importanḥ part of the trans- cautiousness are without doubt, my notice a car
compression leak In one cylinder. mission system, and its develop-| responsible for over 90 per cent. of it proved to be due to a burnt out ment to its present-day state of failures in cur engines and trans-exhaust valve, the valve itself be-¦ perfection has been almost an epic missions. There may be many ing unfit for further use, and the in engineering. The transmission motorists who will dispute the cylinder seating so damaged aa to of widely varying pressures under require a cutter before a new valve adverse conditions, and over a big laller cause. Neglect and careless could be ground in. This car had range of speeds is a problem that nuss ure easily understood as pos- been compuratively recently over
has taken years to solve success- aible cause9 of trouble, but one hauled by the owner, and he was fully, and the engineer, the naturally thinks that too much naturally very curious as to why the chemist, and the metallurgist have care cannot be taken. To a cor valve burnt out as it did. After all had their share in bringing the tain extent they are right, but, and inquiries as to one point and an- complete mechanism to the it sounds paradexical, there is a other, the reason was fairly evident.derful pitch of efficiency that It limit to caution, beyond which it The owner had ground in all the has reached to-day. merges into abuse. I have in mind valves-not before they needed it, No mechanism so delicately ad- several cars that have come under-and had refitted without, having¦justed can run continuously with- notice during the past few months afterwards readjusted the clear-out some care and attention, and that have been practically wrecka¦ance.
at some time actual adjustment of after having done only between Now, when a valve is ground in the gears will be required. 7,000 and 8,000 milen. In every the stem end is naturally lowered Adjusting Bevel Drives. case these cars had been driven more or less, according to the In the case of the bevel drive, ‹ over "give and take”, roads, and Infamount of metal removed from the whether of the straight tooth
two cases had not been driven over cylinder seating and valves; it is the helical tooth type, devices are 20 miles an hour. In spite of this possible to grind away so much of provided in all up-to-date designs the engines were in a bad state and the seatings that when they are for making adjustments to the the transmissions wanted renewing cleaned and the valve resented the depth of meshing of the pinion completely, before quiet unning atem actually rests on the top of with the crown wheel. Generally could be obtained.
the tappet, preventing the valve this is provided in the forward Consistent slow driving, particu- ' seating. Result-a compression member, which carries the radial larly in hilly country where the leak, and a badly burned seating in and thrust ball (or roller) bear- engine is allowed to get to the less than a hundred miles of run-ings, which support, the shaft of last gasp before geur changing igning if the valve is an exhaust, and, which the bevel pinion is usually attempted, places, un- enormous if, as is usually the case, the atempan integral part. strain on the bearings and 18-xpands as the engine warms up. The radial bearings will not, mission. at is actually more Indeed, it should not be forgotten under normal service. conditions, harmful to the car than if it were that a valve that may clear when require any attention (probably driven at 10 miles an hour con cold may, if the clearance is in for the life of the car) if proper, tinuously. In addition to this, a sufficient, be held off its seating care, is taken with the lubrication - slow-running motor usually means when lengthened by the heat. of the unit. The thrust bearing
an overcool one, and for that
may, however, develop sufficient renson dilution and cylinder wear
wear to put the crown wheel and are excessive. in every case the owners of these curs claimed that every care had been taken (greas-
on the
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1
or
Checking Valve Clearances. Them, too, grinding with a coars abrasive to remove deep pitting pinion out of perfect mesh with leaves a series of ridges on theach other, and the meshing of the even though there teeth to the correct depth is a vital ing and plug points were fault-seatings, and
point in a bevel gear, if we are to less), and blamed prior construc- may be a slight clearance tion and material as the source of valve tappet, and a fair compres avoid noises, either of the grind their trouble Actually they had sion when the job is finished, theng, growling type, or of the rat- ling, knocking description. If a over-stepped the limit of caution, rst ten or twenty miles of running and had arrived at the point where will flatten out those ridges, allowar axle develops the former type ng the valve to drop so that its of noise it is generally after an the extra care simply meant abuse.
overhaul when those responsible One thing I noticed particularly stem has no clearance at all. with these drivers was that when the other case, a compression leak for the adjustment have been too
the engine was dying out on д hill, just pricr to changing to a lower gear,
it was allowed to. "pink" badly. This alone puts a
As is
and a burnt-out valve may follow.
enthusiastic and make the mesh
a little too close. If the noise is
will
Invariably, after grinding in theanly a slight one this may be a valves, clearances should be check- ed with a feeler gauge, and, unless good fault and the trouble very heavy strain on the bearings, past experience with the same ea- probably disappear after a short
tine has indicated to the contrary,
&c.; and a it is a fairly commoni fault with drivers a brief outline should be assumed that when the
period of running. This is not always so, however, and if the noise persiste it is a wise plan to
of the cause and effect of "pink-ngine becomes hot the clearance have the adjustment slackened off
ing" will not be amiss.
and this knock must not be con-
fused with knocks emanating from
worn engine parts or other mechanical defecta.
Some types of engines more readily than others.
114" Wheelbase Buick Models 118" Wheelbase Buick Models 124" Wheelbase Buick Models 132" Wheelbase Buick Models
G$1,530 to G$1,655 G$1,820 to G$1,930 G$2,160 to G$2,195 G$2,160 to G$2,705
THE DRAGON MOTOR CAR CO., LTD.
Telephone 30228.
33, WONG NEI CHUNG ROAD, HAPPY VALLEY.
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will be reduced by from two to five a little. A good adjustment for the castellated ends, so that the sleeves Under certain conditions any e..
one-thousandths of an inch. There
Average rear axle is, after the may be screwed up or back to is no uniformity in thin respect. gine will knock or produce the
In either. metalic noise known as "pinking," however, among various engine de-bearings have been adjusted so make an adjustment.
that there is no perceptible end case both sides must be adjusted. In most, the clearance is signs.
play, to allow a backlash or move-In the case of the washers, if one reduced with an increase in engine ment between the meshing teeth of is taken out of the left side it must temperature, while in a fair num-
004in., or the thickness of a piece be replaced in the right side, and ber it remains almost unchanged.
of ordinary writing paper.
vice versa. If a thrust sleave is knock allow rather more
It is a good plan, therefore, to
From the above it will be realis-screwed up one notch, the other clearance than Even the instruction book calle for after little care, and it would not be too notch. This is necessary, in order
ed that the adjustment calls for acne must be slackened off two identical engines may differ the valves have been ground in, greatly in this respect. The reason leaving the adjustment much to any that many a sound to maintain the bearing adjust- Hles in the nature of the exploalone after any, a hundred miles ha
and carefully assembled rear axle meht after the crown wheel has in the cylinders, and the nature covered.
been ruled, so far as the been shifted. In either case a de After this dista
el drive is concerned, by carry-licate appreciation of the amount out an adjus.ment without that of movement to be made is neces- ce shade of appreciation for fine sary. Idjustment and accurate location of parts. The
of these explostors, mechanical while the engine is warm,\ considerations being equal, is con- the clearances to those recoiti; trolled by the petrol employed.
the
com-
ed by the manufacturer.
LONDON REFUSE.
Ford Has a Use For It.
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Worm Drives.
Worm drives are more simple and from the user's point of view, and clanking, rattling. knocking noises in rear axles are do not often require adjustment. almost invariably due to the fact Nor is there much (if any) adjust- that the mesh of the teeth is not ment provided by the maker's to deep enough either through wear shift the worm nearer to the worm or through maladjustment.. Owing wheel. But since there is not, so to the relative angles of the teeth much need for extremo accuracy, wheel of the bevel pinion and the crown once the worm and worm
wear in the have been run in, a little leeway, wheel, very little
reversing or picking up the load Lubrication is a great point to
after a change of gear.
A charge of air^saturated ̧with petrol vapour ls. drawn into cylinders, the ring piston presses it, and when compressed the spark ignites it and it ex- plades, or, more correctly, it burns rupidly and expanda, forcing the piston down and developing a power stroke. Engine builders en-; deavour to obtain the utmost power from any given sized engine and
You have heard that the only
case of a arrange for the greatest expansion thing wasted in the Chicago pack-thrusts of the wheel will make for can be allowed in the of the charge after it is ignited. ing-houses is the squeal.
shallow meshing, noise, clatter, worm which would make a bevel To do this it is necessary to draw It seems that another extreme in and backlash waen running light, toothed drive very noisy.
Lubrication. the greatest possible charge into the anti-wastefulness is to be operated cylinder and to compress it into at the new Ford factory at Dagen the smallest possible space before
In many cases this thrust ad- be watched, especially in the case aam. England. igniting it. For these reasons we
justment for the crown wheel can of the worm drive, and users of The furnaces of the huge power- find a tendency to increase engine house are to be fired by the refuse not be made without taking down ears generally err on the side of compression and the development
of London. Boats will deliver the axle, while the adjustment Into too infrequent changing or of the device called the super 1,000 tons a day, the Fora Co, be (or out of) mesh of the pinion is lenishing of the axle charger. There are very definite ing haid 3s. a ton for taking it off Very often provided in a manner The lubrication in a worm drive limits to which compression can be the hands of the various local au-that makes it cany of accomplish-axle will require more constant at- raised, because, if the charge fo
ment without taking down or dis- tention than in the case of a bevel thorities. too highly compressed, it burns
assembling any part. Under these driven axle, but the smoothness But Ford would not confine • too rapidly, produces too much feat to one-way service on the trip conditions one is apt to take the and silence of running which heat, and makes the engine knock back to London the ships will carry the adjustment by setting up the ensure is worth the small extra line of least resistance, and make good, full-bodied lubricants, will and actually lose power..
Knocking is caused by
bevel pinton nearer to the crown cost entallad to keep it supplied wheel.
with good quality oil not used too charge itself, for instead of the flame
long before renewal. On the other? of
Mesh. igaltion spreading through the whole mass compara-
Owing to the alight angle of the hand, it is important not to add tively evenly it develops so violent-i
bevel pinion it must be moved too much oil, as this may cause a ly, and in such concentrated form,
considerably endwise to get a very leakage from the axle ends on to as to push ahead waves of unburnt
slightly deeper meshing of the the brakes. charge which are so highly com
teeth, and sometimes this end pressed as to produce a real knock
movements sufficient to allow the
tho
coal.
BRITISH CARS OVERSEAS.
A Hint As To Australian Requirements.
only come to earth and give Auslap the teeth of the bevel. This
re-
lubricant.
ESSEX CARBURETTER. when they impinge upon their con- If British manufacturers will teeth of the crown wheel to over-
Smoother operation. at low fining cylinder walls and head.
The speed and also the time of tralians a large chassis with an results in a ridge of wear on the speeds, quick warming-up in cold combustion have to be brought engine of at least 20 h.p., with teeth of both wheels, at the wide weather, high fuel economy and under control "pinking" under floppy, "comfortable" springs, end of the crown wheel and at the minimum heat at high speeds are arduous conditions is to be avoid plenty of chromium plating, pretty narrow end of the bevel pinion. A all made, possible by the two jot ed. One way to do this is to re-louvres in the bonnet, a "neatly situation is then created in which expanding automatic, beat control used KA standard fard the spark, and on cars that grouped instrument board, hub, the full length of the teeth are not carburetter are fitted with a manual control caps like saucepan Hds, to sell at meshing, and If there is any end equipment on the Esser Chal- This carburetter, when the ignition should be retarded about 4200, they needn't worry play, so that the teeth can move lenger.
the Just enough to prevent the knock about the number of crankshaft up to the worn ridges, we get an properly adjusted, enables On cars that are fitted with | bearings, Twrites-- an Austrian intermittent grinding and hom- driver to use low-test fuels. Locat governed Ignition, providing an correspondent of the Autocar), ・・ ming, making altogether a very ed within the cylinder block itself, the Essex manifold ensures a automatic advance and retard, the The majority have an idea that noisy transmission.. only thing to do to get over the the crankshaft is a device for con- This can only be avolded by ad- uniform distribution of gasified knock in to reduce the load and trolling the supply of petrol voltage justing both wheels (the crown fuel to all cylinders. This factor, compression by changing down to from the rear axle.
lower gear. This practice is one!
that is really preferable to retard-
ing the spark, in that in addition
wheel very slightly and the bevel added to the size of the carburet pinion a little more), so that the ter, results in high volumetric relativa position of the teeth has efficiency at all speeds. A unique not been altered, although there is silencing feature is the placing of A to reducing the load on the engine tion, much damage can be done if a slightly deeper meal.
the cylinder head in such a way It eases the strain on the trans- the correct remedy is not taken Same designs of rear axles pro- that the mixture entering the inlet mission to a very large extent. Gear changing in modern cars is vide washers of varying thick valve is made fo flow across the An engine that "pinks" is an en- esey, and a little practice will go aheases behind the ball thrusts, and exhaust valve, thereby preventing gine that is being overloaded, and long way in 'adding to the life of the so make provision for adjustment. detonation, as the exhaust valve is as the engine overload is transmitt car as well as to the pleasure of In the other cases screwed Internal the hottest point, and combustion ed to the rest of the car in propor- motoring.
sleeves are provided with large takes place there Immediately.
11
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DODGE BROTHERS
SOUTH CHINA MOTOR CAR CO.
33, Des Voeux Road Central.
Tel. 25644.
Tel. 25644.