WAYS AND MEANS.
Page 69
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Useful Contributions from Our Driver and Mechanic Readers.
Precautions Against Frost.
SOME remarks in connection with the danger of frost, and some suggestious as to how precautions can be taken, arc sent us by "H.M.," of West Bromwich. He points out that water when at 39 deg. F. is at its greatest density, and that at all other temperatures, either lighter or lower, it expands to a greater volume. When water turns into solid ice it increases in volume to the extent of Si per cent.
The force of expansion, especially in freezing, where the water expands and the surrounding metal does not, is practically irresistible, and added to this there is the fact that most metals become more brittle at low temperatures, so it will be easily seen why such parts as radiators and the jackets of cylinders will crack in frosty weather.
There is a popular fallacy that pipes, etc., crack when the thaw sets in, but this is entirely wrong; the burst occurs when the water turns to ice and this is not often seen until the water thaws.
Our correspondent, " all.," goes on to suggest several remedies and means for the prevention of damage to motor vehicles in cold weather.
He says that some drivers use sis-cerine, calcium chloride, alcohol, etc., in solution with the water, which has the effect of lowering the freezing point of the water and preventing it from freezing under ordinary conditions, and goes on to say that a solution of 5 per cent, alcohol added to the water will lower the freezing point to 25 deg., while SO per cent. alcohol will lower it to 9 deg, below freezing point, which is 32 deg. F. . For temporary stops, such as for meals or while loading in cold weather, a rug or some sacks over the radiator will mostly have the desired effect, unless the vehicle he standing in an exposed position when a cold wind is blowing, in such circumstances it is wise to restart the engine for a few miffutes now and then.
For leaving the• vehicle all night it is always best to run off the water, as lamps under the bonnet may prove dangerous unless handled by experienced persons. Even when the water is run off there is a risk that a film of water may remain between the impeller and the casing of the pump, and when the pump is gear-driven this may result in a pump spindle, being twisted off, so it is wise to run the engine for a few minutes after the water has been allowed to run out, as this will ensure the pump being emptied.
Holding Big-end Bolts From Turning. A HINT in re-assembling the engine of a Dennis lorry is sent us by " J.A.11.." of Camelot.). Our correspondent points out that in these engines there is no provision to prevent the big-end bolts from turning while the nuts are being tightened up, and he has had considerable trouble when reassembling owing to this.
To overcome the inconvenience he has designed and made a special screwdriver so that the bolts can be held from beneath, as it is not always convenient to hold them from above.
The tool consists of a piece of
by 1-in. steel bent to the shape hown in the sketch. By pressing the body of the screwdriver, against the wail of the engine case he is able to hold the bolts securely while tightening up the nuts.
Trouble With Oil Rear Lamps. A DRIVER of a 5-ton lorry, " of London. seems to have had a lot of trouble with his back lamp, which would not keep alight. He procured an old railway lamp which had a spring back attached ; this, however, does not seem to have answered, so he took off the spring back and fixed the lamp rigidly to his bracket, but still without success. He then took the spring out of the back arrangement so that it merely formed a hinged back, with a parallel-ruler action; he then attached a spring to the top of the lamp and connected the other end to the frame, as shown in sketch. Since then he seems to have had no more trouble.
Curing a Magneto Trouble.
THE following is an experience of . "H.H.," of Shrewsbury, and we give it in his own words :----" I have learned • many reliable tips from this page, and it is always the first to which I turn when the journal arrives.
"I recently had trouble on the road with a sticking contact breaker, on a Bosch Z4 magneto. It was caused by a swollen bush on the rocker pivot. A reamer was not available, so I was at a loss to know what to do until I noticed that the centre pin which holds the contact breaker to the armature was the same size as the rocker pivot. This pin was removed and screwed into the bush until all the thread had passed through ; it was the a taken ous again, "On replacing the rocker I found it to be a nice fit in the bush."
Electric Rear Lamp Troubles.
IN spite of the attention which has been given to rear electric lamps, there still seems to be trouble experienced with those drivers who have much night driving to do. " of Bolton. seems to have found a way, not only of preventing the breaking of his rear lamp, but of detecting failure in the case of anything happening to it.
In the Ford car which he drives, he tells us, he has led a long piece of thick wire from his headlights to the rear of the chassis near the number plate, but before fixing his rear lamp holder he fastened a piece of rubber to the chassis, and then fixed his lamp holder to the rubber in such a way that vibration was prevented, and thathe has had no trouble since.
As a means of detecting faults, he has fixed a small lamp, visible from the seat, in series with this wire, so that should his rear lamp fail the visible lamp will fail also. He has painted the top of this lamp black so that he is not dazzled by it.