Before making adjustments, you need to check and record the clearances of each and every valve.
After recording, remove the shim and measure the thickness with a micrometer.
All shims must be related to each cylinder it comes out from and add the shim thickness to the clearance of the particylinder valve.
Whatever valve clearance you desire is deducted from the total clearance and the balance is the shim thickness you need to fit in.
Usually not all valve would be out of specs so you need only to adjust those necessary.
You would need special tools for pushing the job.
As Roy mentioned, oil pressure and related concerns might cause the problem so you need to check them as well. If the noise is intermittent, it could be from the VVTi control soleanoid due to inefficient oil pressure, a result of clogged oil strainer at bottom of oil pan, If engine is heavily sludged, you would get this problem with intermittent flashing of the oil pressure oil indicator.
Sunday, April 15th, 2012 AT 6:04 AM