Questions and Answers

Nissan Laural Has Some Valve Noise Q. Vincent, My car have just got a top overhaul. It is now giving me chatting valves noise. Can you recommend any additives that I can add to reduce the noise and lubricate these sticky valves? Car specification: 1994 Nissan Laural, automatic transmission, 2.0 liter RB20 engine and fuel injection. Thanks, Paul

A. First thing I would do is check the valve clearance. Even though this engine uses Hydraulic Lash Adjusters (HLA) to maintain a valve clearance of zero +/- 0.0010", if the clearance between the rocker arm guide and the valve shim is greater than 0.0010", you need to select and install a new shim.

1. When replacing valve, cylinder head, shim, rocker arm guide and/or valve seat, select a new valve adjustment shim as follows:
   1. Install dial gauge stand tool No. KV10115700, or equivalent and a suitable dial indicator onto cylinder head.
   2. Measure the distance between the sliding surface of the rocker arm guide and valve stem end. When measuring, pull lightly on the dial gauge stand tool to eliminate any play in the tool .
   3. Shims are available in 17 different thicknesses ranging from 0.1102" to 0.1260". Select a suitable shim to obtain a zero clearance +/- 0.0010" between valve shim and rocker arm guide.

2. Check hydraulic lash as follows:
   1. Push on the rocker arm assembly, Fig. 12.
   2. If the rocker arm can be moved 0.04", air is trapped in the high pressure chamber.
   3. Remove the HLA and dip it in a container of clean engine oil.
   4. While pushing the plunger, lightly push check ball using a thin rod. Air is completely bled when the plunger no longer moves, Fig. 13.

Fig. 12

Fig. 13

If the adjustment is good then you can try this; drain the engine oil and replace the oil filter with a new one. Then refill the engine replacing one quart of oil with one quart of transmission fluid. Drive it for about 3,000 miles and do it again if the noise is still there. Do this up to three times. If the noise is still there, you will need to replace the HLAs.