The Series 60 engine can be configured with or without a mechanical tachometer drive. A camshaft drive gear access cover mounted to the gear case cover and a slotted head camshaft bolt must be used with the mechanical tachometer drive option. See Figure
1. Attaching Bolts
4. Camshaft Drive Gear Access Cover
2. Tachometer Drive Adaptor
5. Tachometer Drive Shaft
3. Tachometer Drive Unit
Tachometer Drive and Related Parts
The tachometer drive is driven off the head of the camshaft drive gear retaining bolt, which must be of the slotted configuration, and mates with the blade of the tachometer drive unit. The tachometer drive unit is driven at half crankshaft speed. A tachometer drive adaptor is attached to the drive. See Figure
Tachometer Drive Adaptor
A grease fitting on the tachometer drive adaptor is supplied for lubrication. The tachometer drive adaptor should be greased any time the vehicle chassis is lubricated.
Repair or Replacement of Tachometer Drive
To determine if repair is possible or replacement is necessary, perform the following procedure. See Figure
Flowchart for Repair or Replacement of Tachometer Drive
Removal of Tachometer Drive Adaptor
Remove the tachometer drive adaptor as follows:
Disconnect the tachometer drive cable from the tachometer drive adaptor by unscrewing the bezel nut and pulling the cable straight out of the unit.
Unscrew the nut that retains the tachometer drive adaptor to the tachometer drive in the camshaft drive gear access cover.
Remove the tachometer drive adaptor.
Loosen and remove the five bolts that secure the camshaft drive gear access cover to the gear case cover.
Tap the cover with a rubber mallet or plastic hammer to break the gasket loose.
Remove the camshaft drive gear access cover/tachometer drive unit from the gear case.
Remove the tachometer drive shaft from the access cover.
Cleaning of Tachometer Drive Adaptor
Clean the tachometer drive prior to inspection.
Clean all of the gasket material from the mating surfaces of the camshaft drive gear access cover and the gear case.
Inspection of Tachometer Drive
Inspect the tachometer drive as follows:
Visually inspect the drive shaft for galling, scoring, or wear.
If the drive shaft is damaged or excessively worn, replace with new part. Refer to section
Lubricate the drive shaft with clean engine lubricating oil.
Install the drive shaft into the bushing in the access cover.
Using a new gasket, install the camshaft drive gear access cover tachometer drive unit to the engine by indexing the tachometer drive blade with the slotted camshaft drive gear retaining bolt. See Figure
Tachometer Drive Unit Installation
Install the camshaft drive gear access cover retaining bolts, and torque the bolts to 30-38 Nm (22-28 lbft) using the pattern as shown in the illustration. See Figure