This Haynes 28012 - Datsun Repair /Service Manual covers 1970-1978 Datsun 240Z, 260Z and 280Z, all models including 2+2, with 2.4, 2.6, and 2.8 liter engine, manual and automatic transmission.
A Haynes manual is based on a complete teardown and rebuild of the actual car models referenced. Photographers, technicians and writers work through the teardown and rebuild to document service and repair steps in great detail so that even an inexperienced mechanic can do the work necessary to complete the service or repair action. Detailed photography throughout the manual enhance the step by step instructions so that you can tackle service and repairs on your 1970-1978 Datsun 240Z, 260Z & 280Z with confidence.
Book Excerpt: 1970-1978 Datsun 240Z, 260Z, 280Z Repair Manual
VALVES AND VALVE SEATS | EXAMINATION AND RENOVATION
SUSPENSION AND STEERING
- Examine the heads of the valves for pitting and burring, especially the heads of the exhaust valves. The valve seatings should be examined at the same time.
If the pitting on valve and seat is very slight the marks can be removed by grinding the seats and valves together with coarse, and then fine, valve grinding paste.
- Where bad pitting has occurred to the valve seats it will be necessary to recut them and fit new valves. If the valve seats are so worn that they cannot be recut, then it will be necessary to fit new valve seat inserts.
These latter two jobs should be entrusted to the local Datsun agent or engineering works.
In practice it is very seldom that the seats are so badly worn for replacement, and the owner can easily purchase a new set of valves and match them to the seats by valve grinding.
- Valve grinding is carried out as follows:
Smear a trace of coarse carborundum paste on the seat face and apply a suction grinder tool to the valve head.
With a semi-rotary motion, grind the valve head to its seat, lifting the valve occasionally to redistribute the grinding paste.
When a dull matt even surface finish is produced on both the valve seat and the valve, wipe off the paste and repeat the process with fine carborundum paste, lifting and turning the valve to redistribute the paste as before.
A light spring placed under the valve head will greatly ease this operation.
When a smooth unbroken ring of light gray matt finish is produced, on both valve and valve seat faces, the grinding operation is completed.
- Scrape away all carbon from the valve head and the valve stem. Carefully clean away every trace of grinding compound, taking great care to leave none in the ports or in the valve guides.
Clean the valves and valve seats with a paraffin soaked rag and then with a clean rag, and finally, if an air line is available, blow the valves, valve guides and valve ports clean.
RACK AND PINION ASSEMBLY | DISMANTLING AND REASSEMBLY
- Secure the unit in a vice fitted with jaw protectors.
- Remove the bellows clamps.
- Disconnect the track rod-ends and draw off the bellows from both ends of the unit.
- Disconnect the ball-jointed end fittings from the rack, extract the spring seats and springs.
- Release the locknut and then unscrew and remove the retainer adjusting screw.
- Extract the retainer and retainer spring.
- Pry out the oil seal.
- Remove the set screws, the pinion housing cover and the shims (260Z models). On 240Z models the pinion assembly is secured with a circlip.
- Withdraw the steering pinion assembly.
- Withdraw the rack from its housing.
- Pry out the pinion lower bearing which is located at the bottom of the housing (260Z models only).
- Press the pinion out of its upper bearing.
- Inspect the rack for shipped teeth and distortion, also the pinion for worn teeth.
- Replace the pinion bearings and oil seal.
- Check the rack end fitting balljoints for wear or shake, and replace if necessary.
- On 260Z models only: Commence reassembly by fitting the pinion bearing to the rack housing (seal of bearing is towards interior of housing).
- On 260Z models: Insert the pinion complete with its new bearing. Fit the pinion housing cover complete with the necessary shims to provide the correct turning torque when the cover bolts are tightened to 20 lb/ft (2.8 kg/m).
The correct turning is 5 lb/in (2.4 kg/cm) measured with a spring balance and a piece of cord wound round the pinion splines. Shims are available in the following thicknesses: 0.0020 in. (0.05 mm), 0.0394 in. (1.00 mm).
- When the correct pinion preload has been established, remove the cover and pinion assembly.
- On all models: Smear the rack with multi-purpose grease and insert it into the pinion assembly into the housing so that it meshes correctly with the teeth of the rack.
Subject: 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978 Datsun 240Z, 260Z, 280Z service, maintenance, repair. ISBN-10: 0856962066 | ISBN-13: 9780856962066 | Haynes 28012