Quote:
Originally Posted by 767Jockey
Are the higher Zinc/ZDDP levels important in hydro or solid roller lifter engines or are they only important to flat tappet engines? |
They tend to be a positive for all engines, Dave. The engines with the most to gain are the freshly built flat tappet engines. Even after a successful break-in the higher
Zinc/ZDDP levels provide an extra margin of protection for the flat tappets.
The roller tappets either hydraulic or solid do not have the same susceptibility to break-in or operation failures that flat tappets have in low
zinc/zddp environments. That said the higher zinc/ZDDP level lubricants do not do any harm to the roller style lifters.
The higher viscosities in the 40 / 50 /60 weight lubricants provide additional protection in high temperature, high load environments that the lower viscosity oils can not duplicate. A lower HP (say below 400) engine driven as a daily driver would load the bearing surfaces less than a large displacement 550 or 600HP engine capable of generating 600 or so ft/lbs of torque at 4000 to 5000 rpm.
That kind of torque can be impressively destructive in a hot engine at lower speeds with a low viscosity
oil that is also skinny in the zinc/ZDDP categories. No need to take on additional risks if it is not necessary.
Ed