HINTS ON MAINTENANCE.
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• How to Get the Best out of a Vehicle, to Secure Reliability and to Avoid Trouble.
652.—Taking up Wear in a Halley Oil Pump.
Some users of B35 and 045 Halley vehicles fitted with the Impeller-type oil pump have experienced trodMe with these after much wear has occurred. Now, oil pressure is indicated on the dash by a small button which is flush with the casing that retains it 'when the engine is stationary and projects about.4 in. when the engine is running. This button should offer a good resistance to the finger when the oil pressure is at its highest; that is, when the engine is running at its normal speed during service.
If the button does not project, the usuallwocedure is to examine the oil level in the base, look for a leaking oil pump or remove and clean the filter.
After examining everything and reassembling it is somewhat disquieting to find that still no pressure is registered. This happened in a recent case, and it was noticed that the oil-pump shaft, upon which the engine governor gear is mounted, is poorly supported considering its work. At the lower end, where the shaft enters the pump, there is a packing gland, which, with a narrow neck in the pump casing, forms the only bearing, and after this wears the impeller shaft endeavours to assume a central position in the pump body instead of being eccentric, or else it wobbles about inside the body and causes leakage of oil past the blades of the impeller, thus greatly impairing its efficiency by reducing the output. TO cure the trouble obtain a piece of brass in. thick and bore it eccentric in the manner shown, forming also two Tugs. The inner hole should be a good fit at the bottom end of the impeller shaft, whilst the circumference should be a push-in fit in the bottom of the barrel. Two slots should be cut in the barrel easing, these being in. deep to fit the hugs of the brass eccentric rings. The impeller blades should be shortened by 1 in., whilst a small piece of metal in.
• deep must be fitted into the end of the slot in the impeller shaft.
After making these alterations, and assembling the pump with the eccentric disc in position, it will be 044 found that good oil pressure can be obtained and maintained for a very long period.
Further particulars and a supply of eccentric rings in the rough, ready for fitting, can be obtained from A. Crothers, 36, Prospect Street, Radford, Nottingham.
653.—Rebushing the Water Pump of the Tylor Engine on the A.E.C. Chassis.
The water pump of the Tylor engine has no spindle bush which can be replaced when wear develops, the spindle running direct in the body of the pump. When repairs are necessary, however, it will be found that quite a satisfactory job can be made by boring out the body to take a governor centre bush, the A.E.C. number of which is A42699.
After this, when renewals are required, all that is necessary is to take out the old bush and replace by a new one, carrying out minor machining operations to suit the spindle, which will probably have become worn or scored and must be trued up.
654.—An Oil.level Indicator for the Dennis Engine.
On the majority of Dennis engines the oil level is shown on a dial which is mounted at the upper end of an aluminium standard bolted to the sump. Inside this standard there is a metal float, which runs up and down two brass rods and operates the indicating needle through the medium of a twisted rod passing through the centre of the float.
For a time gauges of this type are usually quite satisfactory, but occasionally, after much service, they become unreliable. If this proves to be the case, the bottom flange of the standard can be drilled and tapped to accommodate a small oil cock, and providing the oil is filled to a height which enables it just to exude from the cock when the tap is turned the oil level will be correct. Care should be taken that this level is maintained by replenishing daily.