HINTS ON MAINTENANCE.
Page 68
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Saving Oil on the Leyland. Why Boiler Tubes Leak. Dismantling the F.W.D. Gearbox. Crankcase Cleaning. Obviating Oil Leakage on a Bean.
Improving Oil Retention in the Leyland Engine Fr HE oil-retaining device at the rear end of the crank-1shaft on most Leyland engines consists of a brass ring grooved to take a felt washer and cut into halves. If an ordinary ring of felt be employed, this may soon
pack down into the groove and permit oil to pass between it and the face of the crankshaft. To avoid this a felt ring slightly larger in diameter should be employed, and this also should be cut into halves so that each end is left protruding about in. out of its section of the ring. Then, when the sump is bolted down, the pressure on the halves of the gland ring will force the felt washer against the crankshaft and ensure a good joint.
Causes of Tube Leaks in Boilers.
LIKE most of the other leaks in boilers, those in tubes are essentially caused by unequal ,contraction or expansion due to difference in temperature of the water as between one part of the boiler and the other.
The method of introducing feed water does not appear to be thoroughly satisfactory, particularly if great care be not exercised by the driver. It has been demonstrated that the side of the boiler at which the injector is situated often cools twice as quickly as the opposite side. This is due to working the boiler while the wagon is stationary and, as a general rule, tube leak occurs more readily at the injector side.
To avoid the trouble, drivers should keep boilers full during running, so that they can inject as little as possible when standing. Water in a boiler carrying 200 lb. pressure is at a temperature of nearly 400 degrees F., and the water entering from the average White injector is at approximately 175 degrees F., which means that over 200 degrees F. must be added to the water immediately it enters. If this be done, the boiler will be maintained at a uniform temperature; if not, the cooler water settles to the bottom, thus lowering the temperature of the tubes at that point and causing them to contract, Dismantling and Reassembling the Gearbox of the F.W.D.
WHEN it is necessary to dismantle the gearbox of an F.W.D. difficulty is sometimes experienced in taking off end replacing the silent chain.
What appears to be the best way to overcome the difficulty is first to remove the plate that is screwed on to the top of the gearbox over the chain, then disconnect the two universal joints at each side of the main differential case; next remove the two flanges and push the differential, together with the chain, up into the
c46 case so far as it will go, an3 pack it up with a block of wood. It will then be found an easy matter to pull the chain up through the hole in the top of the gearbox and remove the pin.
To replace the chain, the pin should be inserted and riveted, after which a bar can be passed through the centre of the differential so that it can be held in its proper place while the flanges are replaced. This method permits a big saving in time and temper and enables the operator to do in an hour or so what might otherwise take the best part of a day.
Cleaning the Crankcase.
AFTER a season's work the crankcase will retain
a large amount of sediment, and it is advisable to drop the lower half so that it can be thoroughly cleaned with petrol, using a stiff brush. While removing it the oil strainer should also receive attention, in order to avoid the danger of the oil lead becoming congested and causing burnt-out bearings.
Plenty of petrol or paraffn should be employed to remove every particle of oil that may have congealed in the case, and the oil-level gauge should be inspected to make certain that it functions correctly.
The operator should make certain that every trace of petrol or paraffin has been removed before refitting the bottom half, as even a small quantity will con_ taminate the new oil. In replacing the lower. half, care should be taken not to damage the gasket that lies between the halves.
Preventing Oil Leakage from the Timing Case of a Bean Engine.
ONE of our readers has a number of Bean 25-30-cwt. vans under his care. He found that after these had been running some time an oil leak developed in the timing case and was found to be from the gland near the fan and pump-shaft couplings.
In the bearing which supports the pump shaft is an oil-way which, in the course of normal running, should allow any excess oil to run back into the timing case. This oil-way was, however, found to be inadequate, so two more holes were drilled, one being situated each side of that casting.
Experience with Westinghouse Brakes.
One of our readers would like to learn from users regarding their experiences with Westinghouse brakes and of any hints in connection with their maintenance. Suitable matter received will be published and payment made at our usual rates.