Often for older cars using solid lifters Zn (ZDDP or
zinc-dialkyldithiophosphate) aids in wear. There are also version in conventional
oil and others in
synthetic.
What Zn
oil do you use? Lucas, Shell, Enos, Royal Purple,
Amsoil, Valvoline VR or other?
Also type: Conventional or
Synthetic
What is your experience?