Genuine 1985 Nissan 300ZX Cylinder Head

1985 Nissan 300ZX Cylinder Head Parts Questions & Experts Answers

• Q: How should the Cylinder Head be prepared for reassembly after valve servicing on 1985 Nissan 300ZX?

  A: Even if the head may have been sent to an automotive repair shop for valve resurfacing, the head must be free of grime when one is reconstructing it. If head has been removed for valve to be serviced,tot eh area related with the valves and the adjuncts would already be in position hence commence with the setting up process as directed below. Place new seals on all of the valve guides using seal installation tool or a deep socket of the correct size to fit the guide and gently seat each one of the seals in its right place. Some of the practices that should not be followed while installing the guide seal include; do not bang on the guide seal once seated and do not twist or cock the seals while setting up. Be very gentle with the new valve guide oil seals when installing the valves and set the valve spring shim(s) around the valve guide boss and put the keepers and retainer in place. Check the installed spring height by adjusting the retainer upwards to the valve sealing and compare the height to the standard installed height and put shims if there is a gap. After the correct height is set, all the keepers and retainers have to be removed for the valve springs to be fitted with the outer spring having the narrow pitch side towards the cylinder head. To compress the springs and keepers you need a valve compressor which should be inserted and the keepers place on after pouring a little grease which will help keep it there until you release it. Using a small ruler verify the installed height of the valve spring for each valve is within the limit and add one more valve spring seat shim, if necessary. Coat the camshafts with engine oil followed by gentle tapping of the camshafts into the heads while ensuring that the lobes do not come into contact with the cylinder head casting. Place the plate and camshaft retaining bolt and tighten them to the required torque limit. While the intake plate is bolted to the head check camshaft end play with this plate in place by first zeroing a dial indicator and comparing the reading to the recommended amount of end play; if adjustment is needed use the next larger size of plate. Bolt on the cylinder heads, timing pulleys, and timing belt, then the hydraulic valve lifters and each lifter guide assembly must be placed in the original position of its bores; they are held by rubber bands while tightening the bolts. Last but not least, get rid of the rubber bands and set the rocker shafts with the rocker arms; tighten the bolts of the rocker shafts in stages, up to the recommended torque.