Number Four. Part One.
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Although, as a rule, it is as well to "let well alone," it needs care to ensure that all is always well, This is the fourth article of the present series, and we embark upon its compilation with considerable pleasure, in view of the amount or appreciation which has been expressed to us from many qnarters concerning the utility of this " Care
t he Chassis " series generally.
We have chosen a typical Albion machine in the present instance, and the model selected by the direetors of the compane, for treatment in til;.s way, is the two-twiner.
Early in the Field.
The Albion, as a type, needs no introduction, we feel sure, to the vast majority of our readers. It is a model which has borne almost more than its share of the exploitation of the commercial-vehicle market as a whole, and, although so early in the field, those responsible for Albion design have the gratification of knowing that a large number of i he earliest of their productions still continue to do excellent work almost as efficiently, and certainly as reliably, as the later models in which the lessons of many years of hard service have been embodied. Thus from the first has Albion design imele good.
To Ensure Attention to the Designers' Schemes.
We have made it our custom in this ectrieF briefly to repeat in each article the principal reasons which have. actuated us in preparing particulars of the kind which we are presenting to our readers. We do this in order that the tieatment of each, machine may be quite complete in itself, and in view of the fact that makers, as a rule, desire, subsequent tO publication in this journal, to give these descriptions etill further publicity on their own aceonnt.
We may repeat, therefore, that, during a number of years of experience of utility vehicles of all kinds, and of their use and misuse, we have been forced to tho conclusion that the skill and forethought whic1. is lavished on the design and product km of up-to-date commercial vehicles is in far too many instances lost when once the machine is handed over to the user. Carefullycompiled handbooks are, it is true, issued by the principal makers, Albion included, in an endeavour to insure that the precautions for which they have made provision are effective in service. Good as these are in their way, it TIMM be remembered that they are produced by makers and designers to whom the internal mechanism of
their own chassis is an open book, containing few, if any, secrets.
We Know the Machine but Not the Designer.
The information we desire and endeavour to give in these " Care of the Chassis " articles is much on the lines of that which is found in these handbooks, but with this most important difference : that, familiar though we are with all types of machines, we are sometimes unawar€. of the reasons which have conduced to the embodiment of many wellintended details.
We therefore are engaged in an endeavour to produce the equivalent of a handbook based on a representative model from each of the more important works, the information in each of which is built up from a detached, although, we trust, not ill-informed, examination of a cheseis for which we ourselves have not been responsible. In that way we feel confident that we are doing our share to ensure that the labour and strivings of designer, works manager, experimental chief, head tester, and perhaps chief salesman, shall receive as much appreciation in actual practice as is possible.
What We All Want to Know.
Such 'propaganda do not necessitate any cut-and-dried description in full detail, and in what often unavoidably is catalogue style, of the chassis as a complete machine. We confine ourselves to a brief summary of the principal components, in order to indicate the class of vehicle of which they go to form the whole. Our detailed writing need, therefore, only concern those points of design on which we ourselves, after careful examination, have felt that we should like more information, and our method of acquiring the necessary particulars has been to assume, so far as possible, that we knew nothing of the chassis, and to ask endless questions as to the why and wherefore of individual parts. Whether the results of such crossexamination, as set forth in the pages which follow, will prove useful to those who would know more about Albion construction as a whole, we must leave to the judgment and discrimination of our readers.
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The 2-ton Albion Chassis in Brief.
The 25 hp., two-ton Albion is a plain, straightforward job, but it hears evidence in its latest form of careful and considered pruning in the designing stage ; its simplicity tells that tale quite effectively. We reproduce elsewhere a line drawing that has been prepared from a specially-taken photograph that affords an excellent bird's-eye view of the complete machine. For its load capacity, platform area, wheel diameters and other particulars necessary for buyers we refer our readers to the maker's published lists and pamphlets. Suffice it to write, at the moment, that a four-cylinder engine, with a bore of 4 in. and stroke of tV, in., magneto-ignited and pump-cooled,
and with forced lubrication throughout, generates power that is transmitted through the Albion type of single-disc plate clutch, thence through a short propeller shaft to a capacious yet compactly-designed gearbox, which includes three forward and reverse-gear engagements, and the worm-gear reduction to the differential shafts. The final drive is by side chains cased effectively in the manner shown by one of our illustrations.
Grouping the Mechanism.
For general convenience we will group the components, under certain headings, and will analyse collectively in each case what we consider are the points which call for information in the present instance. We will leave the lubrication of the chassis—that ail-important feature of its eare—to the latter part of the article, and deal with the chassis for that purpose as a.whole. In the meantime, our groupings may usefully be as follow : the engine, with its carburation and petrol-supply, ignition and cooling accessories ; the clutch and propeller shaft ; the gearbox complete and the final-drive arrangements; the steering gear and the engine and gear-change control ; and, finally, the wheels, axles and brake mechanisms.
The Engine and its Accessories.
First of all we will consider that part of the chassis which is more or less "under the bonnet." The engine as the power producer riaturally calls for more care and more frequent adjustment arid inspection than any other part of a modern petrol-driven chassis, and we may again sub-divide its details under the headings : valves and valve. gear ; magneto and ignition details ; carburetter and petrol supply ; and cooling arrangements, including pump, fan and radiator,
Modern Engines Need Little Watching.
A modern engine, of any type similar in general construction to that which we find on the Albion chassis that is under consideration, requires, for itself as an engine, ve.ry little further care than systematic lubrication and periodic overhaul at long intervals. With the exception of the valves, the need for care in respect of other engine adjustments will concern only the acceeseries and not the engine itself— that is to say, it is very seldom that anything goes wrong with the pistons, crankshaft, camshaft., con_ fleeting rods and main hearings.
When a Knock Develops.
If trouble does arise, it is almost invariably detected by engine "knock," and, even then, it is not certain that, such knock arises of necessity from the big-end or the top-end of the connecting rod : a loose flywheel, a tight piston, preignition, and several other wellknown causes will yield similar evi
dence of need of attention. If wear is taking place at the gudgeon-pin end of the connecting rod, it is certain to be due to the fact. that the lubricant intended for it is not reaching the bearing surfaces. That means to say that the hole in the gudgeon pin, through which the oil finds its way from the walls of the cylinder, is probably
choked. Similnrly, a well-fitting big-end beating will give no trouble unless something has gene wrong with the lubricating system. The amount of wear and tear which shows at either end of the connecting rod, even after long periods, if lubrication be satisfactorily attended to, is almost negligible.
Piston Rings.
With regard to the wear and tear of piston rings, once now arid again a piston ring may break, but this is a mast unusual occurrence in modern engines. Should such a thing happen, it is possible that the engine will run quite satisfactorily without giving any evidence of the broken ring for a long period. Piston rings, naturally, will wear after a long period of running, hut it will he sufficient if they be examined when the anneal overhaul takes place. The best evidence upon which to go in order to decide as to the advisability of replacing them is to test the compression of the engine by pulling up the starting handle with the ignition switch off. If the valves be seating properly, the rings should, if in good condition, hold compression perfectly.
The Valves Must Be Taken Care Of.
The chief parts of the engine itself which require systematic inspection and periodic adjustment are the valves. On the Albion 25 Imp, engine, the valves, both inlet and exhaust, all of which, of
course, are mechanically operated; are placed on one side. The valve operation is that universally adopted, viz., by cam and tappet.
Our Valve Di.kgratn.
The efficiency of the engine as a prime mover, both in respect of work done and of fuel consumed, depends upon the correct setting of the valves to a very large extent indeed. The best results all round, and taking into consideration the many varied conditions under which an engine of this class is called
upon to work, are achieved if the valves be set in accordance with the positions shown on the special diagram which we reproduce on the lira page of the present article. These are the results of many years experience, and may be taken as the best authoritative compromises that are attainable.
The Albion factory turns out all • its engines with their flywheels most carefully marked and lettered, so that it is an easy matter not only to take the setting of the valves on any particular engine whenever it is desired to do so, but also, if the engine has had to be dissembled for any purpose, to reset them afresh,
This valve-setting diagram is one of the series which we. have specially contrived on lines which we assume will be most useful to the user and repairer. It is self-explanatory, and we may perhaps leave our readers to examine it with care, and to use it if they find it. necessary.
Exhaust Valves Want Watching.
Of inlet and exhaust valves of the mushroom type, it is the latter which requite the more attention. The passage of the hot gases between the seats and the faces of these valves results in the pitting of their surfaces, and this gradually increases. The suction valves are but little. subject to the same action, The exhaust valves, moreover, if not attended to, may from time to time stick, owing to the fouling of their stems and the jamming of the latter in the guides. A general falling off in power and a decided loss of compression, are the normal symptoms for which to look in order to ascertain that the valves are likely to require grinding in. With the ordinary chassis, covering normal mileages, it will be found advisable to inspect the valves at intervals of not more than 1000 miles of running. It will then, as a rule„ be found that they will be the better in operation for being slightly rubbed down on to their seatings again ; this applies especially, as we have said, to the exhaust valves ; the inlets very seldom require it.
When to Adjust the Tappets.
After several treatments of this kind, it is obvious that each valve as a whole will seat lower on its seat than it did previously, and this will have the immediate effect of reducing the clearance between t]ie. end of the valve stem and the top of the tappet, and if this be hot correct, the result will obviously be that the clearance will disappear entirely. So that, when the tappet is lowered completely by the cam, the valve will not. quite have seated—a circumstance which will have very serious results on The engine's running. The tops of the tappet rods are fitted with the usual nut and lock, and should be kept adjusted so that the clearance hetween valve stem and tappet approximates .007 in. Care should
t, taken that this adjustment is made when the engine is properly warmed up.
In connection with this all-important subject of valve adjustment, it should be remembered that the valves must not, as a practice, be set by the altering of these adjustments, but the latter must be effected in order to accommodate the proper setting: i that means to say, that f the camshaft has not beer tampered with since it left the maker's works, and if 114) wear has taken place on the cams themselves, the setting of all the valves is bound to be correct if the camshaft is put in its proper position, awl the timing gearwheels are meshed in accordance with their marks, just as they left the erectors.
File Away the Ridges.
When the valves have been ground properly and good seats are showing, any ridge on the valves should be remedied with care by filing. The emery powder which has been used in the course of the grinding operation must be removed with The utmost care before the engine is again running. When the valve plugs are being replaced, they should be screwed into position with just sufficient tightness to make good joints. The copper and asbestos washers should be replaced, when they have become hardened by compression after a considerable interval—as they are likely to do.
Magnetos: Murray and Bosch.
Amongst the special features of Albion machines for many years, the Murray special form of magneto e as a noticeable one and for long enough it has yielded consistently satisfactory results.
Ilhe engine of the chassis with which we are dealing at the moment has a ZI74 Bosch magneto, as is die case on so many other indus trial vehicles of to-day. It is driven by spur pinion from the timing gear, and a neat flexible (-wilding is embodied ; this allows for any lack of alignment in the setting of the magneto, and it permits of slight alteration to the time setting, should this become necessary, by the use t f differentlyplaced holes in the loather links. We illustrate this little device.
So far as the magneto itself is concerned, this is now so perfect a piece of mechanism that, providing its lubrication be systematically performed, nothing is at all likely to go wrong with it in ordinary service. We remark elsewhere upon the necessity for remembering that the Bosch magneto requires but very little oil. Our lubricating diagram indicates this as being a few drops only once a week, or, say, every 500 miles—an amount that, although small, is necessary.
Leave the Magneto Alone.
This is not the occasion on which to attempt anything in the nature of a concise description of the functions of a magneto or of its constructional features : in its modern form it is a piece of apparatus which requires very little watching. Users cannot do better than to leave it alone as a rule and to refrain from interference with its assembly. The only exceptions to this rule are that the contactbreaker platinum points should be inspected occasionally, in order to ensure that they are clean and flat. It is important to see that no oil of any kind is allowed to get on to them, as, should this happen, there will be a tendency for the points to burn away very quickly ; oil is a non-conductor, and obviously would tend to insulate the contacts from one another. Secondly, the distributor disc should be removed when the contact breaker is being inspected, and any carbon dust which may have accumulated should be carefully cleaned away.
We recommend all users of 25 h.p. Albions to procure for themselves one of the Bosch Magneto Co.'s capital little handbooks, which deals with the ZU4 arc-light magneto. The company's address is 204, Tottenham Court Road, London, W.
The Care of the Plugs.
It is perhaps hardly neces sary to remind our readers that the ignition leads should be kept clean and free from oil and dirt. The only other ignition details which require occasional inspection are the plugs ; the correct gap for their points is between .5 nun. and .6 mm., or approximately 1-50th in. It is advisable to inspect the plugs at least once a week, in order to insure that they are free from soot deposit.. If it be desired to test them for firing;
this should be done when the plugs are screwed home in the cylinders under compres sion. A plug will often fire in the open air, but may re fuse to do so under compres sion. The ignition installation may be neutralized by the use of the in-and-out switch, which will he found on the dashboard below the petrol tank.
Now, with regard to the carburetter and petrol-supply installation, the Albion has a unique equipment. The patent carburetter in itself differs from any other type that is on the market. The drawing which we reproduce will serve to indicate the general constructional features. Broadly speaking, it will be seen that. the throttle mechanism is jointly under the control of the Murray governor, which is mounted on the. front end of the crankshaft, and of the hand-control gear.
The Special Albion Carburetter.
The main throttle valve is primarily set by hand, and the governor mechanism, by an in genious arrangement of levers combined with a movable fulcrum, can overrun it The fulcrum for the lever which effects the control of the throttle by the action of the governor is moved by the setting of the hand-throttle lever. The main double-beat throttle valve admits the rich mixture of air and petrol, which conies via the choke tube from the jet, and it will be noticed that it has two seatings. In the centre of this valve there is a small relief or pilot valve, which is just left open when the hand throttle is closed—that is to say, in such a position that it will pass only enough mixture to keep the engine running light at a low speed. file lift of this valve is permanently set at about 1-32nd in. ; there is no actual adjustment provided, although, of course, the governor control-lever itself varies •it.
Reference to the illustrations of the carburetter will show that provision is made for the Nosing of the lowest air-supply port by means of a handle in front of the radiator,
cc which is operated when it is desired to start the engine. Another device to assist engine starting is a half • compression exhaust-cam-sliding arrangement, which is a feature of other Albion models.
Two Useful Self-explanatory Illustrations.
It will suffice on the present occasion if we draw our readers' attention to the sectional elevation of the carburetter proper, and indicate that it is of a class of construction in which the first mixture is brought along to the throttle valve in a state in which it contains too large a proportion of petrol and a very limited amount qf air, the subsequent refinements of it being effected by the operation of one or more special valves which are part and parcel of the device. One of these is controlled from the dash, and is intended to dilute the mixture for certain varying .atmospheric conditions or different
densities of fuel. As a rule, it is well to run with this valve furnishing as much air as possible.
To Enable the Governor to Act.
Although, perhaps, this Albion carburetter may not seem so simple in its construction as other types, yet from ,experience we have no hesitationiin testifying to the fact that it requires very little attention. The various joints of the levers in the governor gear and the hand control gear should be kept quite free, as, obviously, it is necessary that the control should above all be sensitive, and capable of giving effect readily to the control movements for which they are intended.
With regard to the float chamber, jet modification or float adjustment should only be undertaken at the
instance of an expert. Stoppage of a jet, or the puncture of the float are2 however, mishaps which can be easily diagnosed and quickly rectified.
On the near side of the engine there is a clamp to the induction pipe which is intended solely to support it as well as the fibre block for the electric leads.
The Provision of Filters.
The petrol tank itself is situated, as some of our illustrations show, on the dashboard, and the feed is by gravity. A large hand hole is provided on the near side of the top of the tank, and if a filter be furnished at this point, it should, of course, systematically be kept clean. Amidships at the
bottom of the tank is a cast outlet, from which the main petrol pipe runs direct to a filter, and thence to the float-feed chamber in the usual way. This outlet casting also has a plug on it by which the tank itself may be drained. The Albion people are not altogether in favour of the use of a filter in the main petrol tank ; they rather prefer to ensure that a funnel shall be used with a good gauze in it whenever the tank is being filled. There is a drain cock on the filter itself, and the filter should, of course, be kept clean ; it is in an accessible position, and, therefore, there is no reason why it should not receive regular attention.
Cork-lined Petrol Cocks.
An interesting evidence of the Albion care for details is the fact that the cocks in the petrol-supply pipes are lined with cork, and under any circumstances work freely and yet keep nice and tight.
(To be continued.)