The gear pump used on the Halley is a double-sided positive displacement gear pump. The oil pump drive shaft drives the CAM gear train through the case and passes into the back of the oil pump body. Two sets of gear drive shaft keying: thick setting and thin setting. Thin setup provides high capacity, low pressure oil engine oil system. The thick set, or return set, draws the exhaust valve and forces it through the oil filter and back to the tank of oil.
Locate the drive keyway of the drive shaft close to its exit case. Insert the key slot and ensure that it nests completely evenly in the groove, without cockfighting. Slide into the thin drive gear shaft and engage the gear keys into its groove drive gear.
Place it on the back of its mounting bolt thin driven gear oil pump body and fix it in place. The positioning bolts on the case are placed into the new inner pump gasket and slide into the drive shaft pump body. The driven gear rotates until the drive and drive gear nest together, making the pump body slip tightly against the case. Exit the pump body before the drive shaft is inserted into a key. The thick transmission gear slides on the shaft and participates in its groove gear transmission gear keys. Slide the mounting bolts onto the thick driven gear and rotate the gear until it nests with the thick drive gear square on the positioning bolts of the pump cover gasket. Slide the pump cover to the locating bolt and tighten the cover bolt with the mounting finger. Cover bolts are tightened to outgoing specifications and manufacturer in approved mode Settings. The return oil line is installed to the socket on the pump and a new factory crimp tool clamp is installed.
