1932-01-21 — Page 3

THURSDAY, JANUARY 21, 1932.

STORY

OF THE CAMSHAFT

AN EXAMPLE OF FORD PRECISION

The three

THE

CHINA MAIL.

bear-

an inch. inga must have the right diameter within a thousandth; they must be concentric with each other within a thousandth; they must be concentric with the shaft within a thousandth; the diameter Proper design, manufacture and semi-circular heel of the cam, red of the dowel pin holes in the flange operation of the camshaft are as and valve are stationary, and the to which the timing gear is attached important to engine performance as valve is closed. Then as the cam must be accurate within one-half of ignition. While the timing of the revolves, the push rod is moved up a thousandth of an inch, or five ten- spark may be changed at swiftly to take up the .010/.013 inch thousandths, and so forth.

the will of ing entirely non-adjustablo,

A

the

the

Maintenance of such strict. stan- is Decessitated partly unusual design of

surface

and part-

the driver, tim- clearance between it and the valve

is made stem. Just as the rod touches the dards of the valves

in Atom, section of even

by CRM To make certain is reached which has a much the com .of the utmost, unchangeable ac gentler slope, 80 that the ly by the fact that the Ford curacy, the calculations of the shape upward motion la slowed down valves are not adjustable. If an of the cams have been carried out considerably. Instead of hit-adjustment were provided in the

service work.

to ten-thousandthe of an inch. ting the stem a hard, noisy blow, the valve push rod, as is common prac- It is the camshaft which operates rod is laid gently and quietly against tice, it would be possible to compen- sate somewhat for minor imperfec- the valves at the proper time, open-it.

ing the intake valves to admit a As soon as this is done, the rod tions in the cams. However, it is a fresh charge: closing them when the reaches a section of the cam with a basle Ford principle to make the maximum charge has been allowed greater alope, and the valve is push valves nonadjustable; for any ad- to enter: allowing intake and ex-jed open against the resistance of the Justment must in time get out of likelihood would haust valves to remain closed during valve spring as swiftly as possible. order, and this the compression and firing strokes:When the point, or nose, of the cam lessen the reliability of the car. opening the exhaust valves to allow is reached the valve is wide open; Furthermore, an adjustment is an the burnt gases to escape:

and here the shape is such as to slow invitation to tinker, whereas valve closing them when the cylinder has down the motion considerably, hold-operation is so vital to engine per- been cleared as much as possible. ing the valve open for a predeter-formance that it should not be pos- sible to change it. The Ford cam- If the valves were not opened and mined time. closed at exactly the correct time, The push rod then commences shaft, push rod and valves, are made not enough fresh gas would be ad-to follow the opposite face of the right once and for all.

Early Opening. Late Closing. ⚫mitted, or not enough of the burnt eam, allowing the valve spring to

It might be thought that the gas would be expelled. Then the force the valve swiftly downward, to engine would not operate properly close it as rapidly as it was opened. valves should be opened and closed and with maximum power. Ita per- However, just as the valve reaches an dead centre: that is, that the formance would be unsatisfactory. Its seat

second B

ance.

A

section intake valve is opened when the reach-piston is exactly at the top of the motion stroke, ready to start downward, con-nnd closed when the platon is exact-

In valve timing a difference of a of lessened alope la thousandth of a second in time of ed on the cam. Valve opening and closing can make a is thereby blowed down tremendous difference in perform-siderably. Instead of hitting the ly at the bottom and about to start!

seat with a bang, the valve is laid up: also that the exhaust valve is opened at the exact bottom of the That is why the Ford camshaft is gently and quietly on it. designer and made with auch re- Then there is a sudden increase 'explosion, stroke, and closed at the markable precision. It is without in cam slope, allowing the push rod exact top.

Actual practice is far from this. doubt the most complicated single to fall away from the valve stem!

begin to part of the engine; yet it is made until the heel is reached, where the The Ford intake valves

open seven and a half degrees before of a single piece of forged steel rod is at rest once more. So perfectly does it function that That is the cycle of eight changes the crankshaft reaches upper dead few motorists are even aware of its in motion provided by the Ford centre. This is for the reason that Here is the order in which it takes a definite veriod of time to existence.

cam.

The camshaft is located on the the rate of motion changes: ac- open the valve, and it is desired to right side of the engine, above and celeration, de-acceleration (slawing have the valve as wide open ns is! to the right of the crankshaft. It down), acceleration, de-acceleration, practical by the time suction ac- is driven at one-half crankshaft acceleration. de-acceleration, actually starts to draw a fresh charge; speed by means of a genr that celeration, de-acceleration, to rest. into the cylinder. mcahea with a gear on the crank- shaft.

The camshaft gear, mnde of 2 composition

purpose of quiet operation.

the cam.

timing

one

fourteen-thousandth

short A

of A

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Telephone 30228.

33, WONG NEI CHUNG ROAD, HAPPY VALLEY.

PETROL PUMPS.

Home Counties to the Rescue.

The intake closes forty-eight and Timing of Every Cam Tested,

a half degrees after lower dead cen- When the engine is developing tre has been passed. This seemns material, has helical teeth for the its maximum horsepower of 40, at very late, for by that time the piston! 2,200 revolutions per minute, this is well started upward. and one! cycle takes place in only 1/866th of might think that some of the fresh For each valve there is a cam, a second, which seems

gas would be driven back out of the forged integrally with the shaft and enough period of time. But con-eylinder. As a matter of fact, the machined to exactly the right shape. sider this: each of the two sections incoming gas, drawn into the cylîn- What is called the valve push rod of the cam where the slope is lessen der with considerable velocity, has bears constantly on the cam; this ed and the push rod is laid gently so much Inertia that when the valve is merely a short rod, Its lower end againat the stem, or the valve has been left open for this length of expanded into

a flat, mushroom brought quietly into its seat, oc-time some additional gas la allowed shape. The upper end of the push cupies only nine degrees on to crowd itself into the cylinder. rod bears against the valve stem. the cam. At 2,200 revolutions Thus the maximum charge is allow When the valve is closed there is a

minute per

It takes only ed to enter, for maximum power. clearance of .010 to .018 of an inch)

Production in the new assembly

Two more counties are taking maximum between rod and stem second for the push rod to pass Afty-one and a half degrees before at Buffalo, New York, was started or so to regulate their design that The exhaust valve starts to open plant of the Ford Motor Company steps to suppress ugly petrol pumpa, The thirty-six pound pressure of the over this vital section of the cam. lower dead centra is reached-again on September 1 when, in the pre- they "shall not offend the beauty valve spring makes the rod follow What happens in that infinitesimal for the reason that it takes time to sence of more than fifteen thousand of the scenery." It is proposed to the cam, and thus the position of period of time is what makes the oven it fully, and time for the was interested spectators, the plant was prohibit them altogether within a the valve is governed at all times by Ford valves quiet.

to get started through the manifold. formally opened as the latest addi-mile of Stonehenge, So accurate are the cam-grinding The exhaust closes four and a half tion to the Ford family. All this is conventional practice in machines that it might be supposed degrees after upper dead centre is

By-laws drafted under the Petro- Following so closely on the recent leum (Consolidation) Act of 1928 the automobile industry. But be necessary to test only an occasional passed, being closed late to take ad opening of a plant on fore the introduction of Model A a shaft, on the theory that a shaft vantage of the Inertia of the escap Coast at Richmond, California, the shire County Council. They give the the West are being considered by the Wilt- great improvement was made in the chosen at random would be the avering gas, which pulls out more than Buffalo ceremonies gave another de- Council power to regulate the site, design of Lincoln cams, which bet-age of an hour's or a day's produc-would be removed if the valve were monstration of the company's pro-design, materials and colour of all terment was carried over to the newition. Ford practice, however, is to closed exactly on the too centre. gramme in carrying forward build-petrol-filling stations to be erected Ford. The purpose of the change test the timing of every cam on was to silence the valve.

every shaft; for it is known that valves themselves might serve as

Perhaps a few words about the ing operations, furnishing employ- in the future, while established sta- It is generally recognised that only thus can there be certainty that atting conclusion

ament to labour and expending money tions are given two years grace to this article. for materials. It was the fourth within which to conform to the Ford valves are unusually quiet. every shaft meeta Ford standards The valves in the Model A motor are new plant to be opened by the com-standard design and colour: This quietness has been obtained of accuracy, and that thus every en- unfoue in that they are entirely pany during the past year.

The Council is recommended to not by merely inclosing the valves to gine will have its valves solid throughout.

Each being free "I know of no better expression prohibit entirely the erections of muffle them, but by minimising the timed, allke дя the design of any drilled hole, or slot, made of confidance in the future of our petrol stations in four areas; within source of the noise.

era intend, to the smallest necessary to the ordinary engine country," declared Edsel Ford in a mile of Stonehenge, within half a The shape of an ordinary cam is fraction of A second

To test valve to accommodate a valve spring telegram read at the opening, than mile of the centre of the village of such, that, as it rotates, the push the timing, each shaft is put in a keeper (to hold the spring cap in the large investment in modern Averbury, within half a mile of rod is thrown swiftly up against the Ford-designed timing machine, in place), they are correspondingly facilities which we have made at Silbury Hill, on the London-Bath end of the valve stem. It hits the which it is supported by its three stronger.

Buffalo. We are firmly convinced road, and within a mile of Old stem a bard blow, thus producing a bearings, exactly as it will be in definite click. And likewise, the the engine; it is then ratated while they produced this wholly solid belief in high quality and low conta

In fact, it has been said that when that by adherence to our well-known Sarum. valve is allowed Lo drop swiftly an indicator giving a reading to one-

In Devon petrol pump regulations into its seat. It hits the seat with half of one-thousandth of an inch valve, Ford engineers accomplished and by the maintenance of our for the rural areas have already a bang, and there is another click is applied to each cam in turn.'

the most important single advance traditional standards of service, we been adopted. Conferences are now In a four-cylinder engine there can Every cam must pass this test yet made in valve design in an shall be prepared to meet the next being held with a view to similar period of American Industrial acti- action in urban districts. It is ex be eight of these clicks for each re- with an accuracy of one-thousandth internal combustion engine. volution of the crankshaft,. What a of an inch, or the entire camshaft

The freedom from the usual vity with manufacturing resources plained to the local authorities that source of noise!

is rejected.

piercing was gained by forging the adequate to the greatness of the op- the county has power to define any valve with a bottom or foot, portunity."

ares as a beauty spot where no The new Buffalo assembly plant is filling station may be erected, or to

It was realleed that the noise came 3,500 Miles in. Fifteen Seconds. terminating with a mushroom and.. frora metal hitting metal at high) speed. Yet good design required| To complete the silencing of the The valve spring is held in place by located on the Hamburg Turnpike compel the removal from it of exist the valves to open and close camshaft, the gear in the middle of a retainer, shaped like a ring, which and projects out into Lake Erie ing stations, and the local auther- as quickly AB possible; the centre bearing, which drives the reats upon the mushroom. The face harbour, occupying ground that has ities are being asked to formulate

the ideal valve would spring wide of pump and distributor, le of the mushroom contacts with the been filled in. The platform where proposals for Imitation, prohibition, open instantaneously, and close burnished, or run in, after it has bush rod and is unusually wide, the exercises were beld was, Httle or removal as they think ft. just as quickly. Though this been cut. The shaft is placed in a being about one-half inch in dis- more than a year ago, a patch of "Petrol stations, are springing up ideal cannot be realised, it must be Ford-designed burnisher, in which meter. It presents an exceptional water in the outer harbour, like mushrooms all over Devon, and approached as closely as possible. it is held by its bearings. Three amount of wearing surface, which The luncheon preceding the formal there is no necessit "för half of The problem then was seen to be hardened steel master gears are works in oil. The oil bath in the opening was attended by one thou them,” was a statement made at the that of reducing the force of the pressed firmly into the camshaft valve chamber acts as a enshian be- sand civic, Industrial and business first of these confere blows of push rod and valve without gear; the shaft is then rotated at tween the surface of the mushroom leaders and officials of state, county Honiton changing the speed with which the the rate of 820 revolutions per min- face and the end of the push rod and city John J. Bennet, fun, In both Devon and Wil valve is opened.

ute for fifteen seconds, half the Among the advantages gained are Attorney

pressed the but agreed that the motor, time in one direction and half In a stronger valve, especially at the top setting the machinery in motion, isations are loyally coo Cam Provides Eight Motions. the other. The motion polishes the foot; simplicity of construction and andz

Charles Roesch, of the task of preserving. After much study, the problem helical teeth, running them in so assembly elimination

of the amenities from the imy was solved by developing a new that from the moment the engine is for atting to contact

филтр. ahape for the cam The greatly im- started the gear will operate silent rodno possibility proved cam is found on all Model Aly. This burnishing process is the burring over and camshafts

equivalent of three thor and to four Considering!

When you look at this cam it pre- thousand miles, of actual running tire

sents no unusual feature to the eye; in

It seems to be just an

looking like a pyramid

circular base. Yet the shi

the push rod is in contact, wWIN

tests and Inspočel of čita hard the camshaft)

and other

BUYERS' GUIDE

MOTOR. CARS.

ARMSTRONG SIDDELEY.-Hongkong Hotel Garage, Queen's

Road. Tel. 24759.

BUICK-The_Dragon, Motor Car Co., Ltd., 88, Wong Nei Chung,

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21759.

FIAT MOTOR CAR-A Goeke & Co., China Bldg., 7th floor.

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* MARQUETTE--The Dragon Metor, Car Co., Ltd., 28, Wong Net.

Chung Road, Happy Valley, Tel. 80228. MORRIS.-Hongkong Hotel Garage, Queen's Road, Tel. 24759. OLDSMOBILE-The Dragon Motor Car Co., Ltd., 88, Wong Noi

Chung Road, Happy Valley. Tel. 80228. ROLLS-ROYCE-Hongkong Hotel Garage, Queen's Road. Tel.

24759.

STUDEBAKER,-Hongkong Hotel Garage, Qupen's Boad. Tel.

24759, WILLYS-KNIGHT & WHIPPET MOTOR CARS.--Gilman & Co..

Ltd., 4a, Des Voeux Rd. C. Tel. 28011,

MOTOR TRUCKS AND TRACTORS. CHEVROLET.—Hongkong Hotel Garage, Queen's Road. Tel.

24769.

6M.C. The Dragon Motor Car Co, Ltd, US, Wong Nói Chung

Chung Road, Happy Valley, Tel. 80228. DODGE-South China Mótor. Car Co., 88, Des Voeux- Road: C.

Tel. 25644,

MORRIS, Hongkong Hotel Garage, Queen's Road. Tel. 24759.; STUDEBAKER--Hongkong Hotel Garage, Queen's Road.

24759.99

Tel.

WILLYS-KNIGHT & WHIPPET TRUCKS-Gilman & Co., Ltd,

da, Des Voeux Road C. Tel, 28011,

MOTOR CYCLES.

B.S.AThe Sincere Co., Ltd., Des Voeux Road. Tel. 27767. NORTON The Sincare Co., Ltd.. Des Voeux Road C. Tel

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TYRES AND ACCESSORIES, ACCESSORIES-Hongkong Hotel, Garage, Bueen's Road.

#2476992

ACCESSORI The Daro Motor Co., Nathan Road, Kowloon.

FISK TYRES, Gilman & Co., Ltd. da, Des Voeux Ed

R. Loxley Co., York Bldgs ESA. Goeke & Co. China Bidg

INDIA

MICHE