Transfer gearsdescription
Drive is transmitted from the clutch to the gearbox by means of three transfer gears. On the end of the crankshaft is the primary gear. When the clutch pedal is depressed the primary gear remains stationary while the crankshaft revolves inside it. On releasing the clutch pedal the drive is taken up and the primary gear revolves with the crankshaft at crankshaft speed.
On early models the bearing inside the primary gear was iubricated from an oilway drilled in the crankshaft. On practice oil frequently found its way past the flywheel oil seat, onto the friction face of the clutch. Self-lubricating primary gear bearings were therefore fitted to later models and the oil hole in the crankshaft blocked. As owners of early models may wish to modify their crankshafts to the later specification, details of how to block the oilway and fit a modified primary gear are given later in the Chapter.
Drive is taken from the primary gear, through an idler gear, to the first motion shaft drivegear which is a splined fit on the nose of the first motion shaft.
Transfer gearsremoval and refitting
To provide access to the transfer gears it will be necessary to remove the engineltransmission unit from the car as described in Chapter 1. The flywheel and flywheel housing must also be removed and full information on this procedure will also be found in Chapter 1.
With the flywheel housingremoved the transfer gears are now exposed. The primary gear can be removed first by lifting off the Ushaped ring and retaining washer and sliding the gear off the end of the shaft. Now slide off the thrustwasher.
Next lift the idler gear out of its needle roller bearing in the transmission casing. Make sure that the thrustwashers (one on each side) are kept in their correct relative positions.
To remove the first motion shaft gear, first extract the circlip (where fitted) and withdraw the roller bearing using a puller or two screwdrivers, from the first motion shaft. Now bend back the lockwasher, undo and remove the nut. To prevent the first motion shaft from turning as the nut is undone, put the transmission in gear and then lock the drive flanges using blocks of wood between the flanges and gearbox casing.
Now lift off the lockwasher and slide the gear off the first motion shaft.
Refitting the transfer gears is the reverse sequence to removal. However, the endfloat of the primary gear and idler gear must be checked and if necessary adjusted as described below before finally refitting the flywheel housing.
Primary gearRefit the primary gear thrustwasher with its chamfered bore against the crankshaft flange. Now slide on the gear and secure with the retaining washer and U-shaped ring. Using feeler gauges measure the clearance between the end of the gear and the thrustwasher (photo). The correct endfloat is given in the Specifications. If the measured endfloat is outside the specified limits, selective thrustwashers are available from your BL dealer.
Idler gearThe endfloat of the idler gear can only be accurately measured with the engine removed from the transmission. If a new idler gear, thrustwashers, transmission casing or flywheel housing are being fitted then this must be done to allow the endfloat to be accurately measured. If however the original components are being refitted it can be assumed that the endfloat will be as before and therefore satisfactory.
To check the endfloat refit the flywheel housing after making sure the mating faces are clean and a new gasket is in position. Tighten the retaining nuts to the specified torque and then using feeler gauges measure the clearance between the thrustwasher and the side of the casing (photo). The endfloat should be as specified. Selective thrustwashers are available from your BL dealer to correct any deficiency. The flywheel housing can now be removed, the engine positioned on the transmission and the transfer gears and housing finally refitted.