For DRIVERS, MECHANICS & FOREMEN
Page 21
If you've noticed an error in this article please click here to report it so we can fix it.
A 73.1lIZE OF TEN SHILLINGS is awarded each week to the sender of the best letter which we publish on this page ; all others are paid for at the rate of a poany a lime, with an alkiwance for photographs. All notes are edited before being published. Mention your employer's name, in confidence, as evidence of good faith, Address, D., M. and "The Commercial Motor,:' 7-15, Eosebery 4venue, London. E.G. 1.
Lamps Alight.
On Saturday, 28th December, light your lamps at 4.25 in London, 4.46 in. Edinburgh, 4.16 in Newcastle, 4.31 in Liverpool, 4,32 in Birmingham, 4.35 in Bristol, . and 5.14 in Dublin.
Easy Starting.
The sender of the following communication has been awarded the 10s. prize this week.
[1927] "L.V.G." (Worsborough) writes :—" The fol Jowing i are a few suggestions for the starting of engines n winter from cold: they are all based on actual experience. (1) The difficulty, of course, is to get the fuel to vaporize at low temperature, and this applies in particular to the present-day low-grade socalled petrol which is becoming almost universal. " The difficulty is to obtain the first two or three explosions. So soon as the engine has actually started it appears, in most eases to warm up, even in the coldest weather, sufficiently to enable it to continue running, although it may not bentits best, or even good enough to take a. heavy load, for a few minutes. Any driver who has an ordinary acetylene generator and some carbide need not worry. Turn on the water and get the generator gassing freely. Then connect a length of rubber tubing to it,. and, after opening the throttle of the carburetter wade, place the open end of the tube into the main air .intake, and hold it in position by blocking up the reinainder of the area with a piece of rag. Wait a moment or two until the .7 generator has had sufficient time to fill the induction pipe with acetylene gas, then remove the rubber tube and rag, close the throttle to the usual starting position and give the engine a EMMA pull over compression. It will be found that the portion of gas with which the induction pipe has been loaded will enter the cylinders and will fire'immediately.
"I used this method on an Austin lorry for some weeks during a period when I had a damaged arm and was unable to swing the engine. After providing the acetylene gas, I used to place the handle in a starting position and give it a smart push downwards with my foot. This generally sufficed to start the engine, In my opinion, no one need be afraid of damaging the engine by adopting this procedure, as, although, the explosion from acetylene is more violent than that from petrol vapour, it only occurs once or twice "(2) For this the driver must have by him a small blowlamp as used by painters or plumbers. Be should prepare the lamp and get it to the point at which it burns with a nice blue flame. This flame should be held against the inlet pipe just above the carburetter for a short period, sufficient to enable the pipe to be made thoroughly hot. The driver will, of course, take care that there are no sweated or soldered joints any-.
where near the part to which the frame is applied. Now give the engine a good swing. The effect, will then be that some of the petrol escaping from the jet will impinge on the hot inlet pipe and there vaporize, thus providing sufficient mixture to enable a start to be made.
"(3) This one is a modification of No. (2), and may be used as a supplementary method. It has the ad vantage of providing gas upon which the engine will run for a short time, and will overcome the difficulty sometimes met with of an engine stopping repeatedly
every 10 or 20 seconds, when first started, owing to
condensation in the induction pipe. Use the plumber's blowlamp as mentioned in (2), and after filling it with petrol or paraffin, light it. and get the lamp nicely to a red heat. Turn the flame out entirely, and immediately turn' on again the supply of gas from the fuel, but without lighting it. The effect
• is that the petrol or.paraffin comes Irona the lamp in dense volumes of vapour.. Place the lamp so that it is trained into the main intake of the carburetter, and start the engine in the usual way. The driver will find it quite feasible to run theengine for a considerable period on the gases from this lamp, even without any petrol whatever being supplied to the carburetter. A§ stated at the beginning of this letter, I can vouch for all these methods, and have thoroughly tried every one of them."
When Relining Brakes.
[1928] " W.G." (Huddersfield) writes :—" It frequently happens, when relining brake shoes with metal liners, that the new fitting is found not to &inform exactly to the curvature of the shoe.. As generally these liners are riveted in place there is a risk,
especially with cast-iron ones, that if they not bed nicely into position, the operation of riveting may result in breakage of the liner. To bed them down by filing or scraping or other similar method is,Afrom the point of view of economy, out of the question, as it would take too long, and I have found that the curvaturem may very simply and quickly be altered, and with no risk, if a reasonable amount of care is taken.
"I will presume, in the first. place, that the liners in stock or the liners which are supplied are a little ,too large in diameter, that is to say, if they go inside the shoe they will bed on the ends and not in the centre ; or, if they go outside the shoe, as for an expanding brake, they will bed at the centre but not at the ends. In such case, the method is to place a piece of mild-steel bar, about 2i ins. or 3 ins, diameter, in the vice, lay the liner on top of it with (if the liner is east iron) the concave side downwards, and lightly hammer at the outside, taking care always that the blows 'strike the liner only on that portion which is supported by the steel bar. Curiously enough, this method is only satisfactory with cast iron. With other metals, the exact opposite procedure should be earned out, viz., the liner laid upon the steel bar with the concave side upwards, and then tapped with the hammer. In the ease of liners the fault of which is the precise opposite of that stated above, viz., liners which are too small in radius, the opposite procedure should be adopted to that prescribed for the metal of which it is made."