Originally Posted by JRWooden
(I don't want to make valve lash another oil thread either)
I'm used to working on "old school" cars where clearances "ALWAYS" increased ... leading me to bias my adjustments to the low side so that they could "grow through" the range.
What we have here is yet another opportunity to toss another tried-and-true technique into the dustbin when it comes to these hi-tech cycles...........................
Older car engines gained clearance due to all the wear in the poorly lubricated valve train. Lifters wore, pushrods wore, rocker arms wore at the tips and the pivot, even the valve stem tips wore. All those wear points added up to more wear than the little bit on the valve seats and faces and led to increased clearances. Modern OHC engines have fewer valve actuation components to wear, and have better lubrication with better lubricants. The valve seats and faces are the most significant contributor to changing clearances now, but even that is less than on the older stuff.