SECTION M Cooling System The engine is cooled by water circulation through passages in the cylinder block and cylinder head. Cir- culation is by thermo-syphon action, assisted by an impeller type water pump, belt driven from the crank- shaft pully. To Remove the Fan Belt 1. Slacken the generator adjusting lever setscrew. 2. Slacken the generator to bracket mounting bolts. 3. Pivot the generator towards the cylinder block. 4. Turn the engine slowly by hand and work the fan belt off the water pump pulley. 5. The belt can now be lifted from the generator and crankshaft pulleys and removed from the engine. 6. Examine the belt for signs of fraying or cracks in the rubber and renew if necessary.
FAN BELT To Adjust the Fan Belt Fan belt adjustment is achieved by altering the posi- tion of the generator as detailed below. 1. Slacken the generator adjusting lever setscrew. 2. Slacken the two generator to bracket mounting bolts. 3. Move the generator either towards or away from the engine to either slacken or tighten the belt. 4. Lock in the desired position by tightening the ge:1erator adjusting lever setscrew. To Refit the Fan Belt Refitting the belt is just a reversal of the removal operation. Adjust the belt tension as previously detailed under the heading "To Adjust the Fan 8elt". If a new belt ha'. been fitt0d refer to the note given after the details on fan belt adjustment. 5.
Belt tension must be adjusted so that, without undue pressure, the belt can be depressed '% in (10 mm) with the thumb at the centre of the longest free length (see Fig. M 1). 6. If the tension is correct tighten the two generator to bracket mounting bolts. NOTE: When a new belt is fitted, it is advisable to recheck the adjustment after only a comparatively short running period. This is to allow for the initial stretch which is common to new belts, once this initial stretch has taken place the belt may be checked in accordance with Periodical Attentions. WATER PUMP General Two different types of pump are used, depending upon the application.
In one type of pump the impeller shaft is supported by two separate bearings, as shown in Fig. M.3 and in the other the bearings are combined with the shaft to form one assembly, as shown in Fig. M.4. The lastest pumps of both types incorporate a stationary seal that registers on a ceramic counterface revolving with the impeller. Earlier pumps incorporate a revolving seal that registers on a stationary counter- face fitled in an insert fixed to the pump body, as shown in Fig. M.5. In earlier pumps to the type shown in Fig. M.5, the seal registers directly on to the insert. To Remove the Water Pump 1.
Tap back the locking tabs, remove the fan securing setscrews and remove the fan (and adaptor where fitted) . 2. Remove the fan belt as previously detailed. 3. Unscrew the four setscrews securing the water pump and back plate to the cylinder block. 4. Remove the water pump and backplate.