We personally have been doing our own research on currently available
motor oil quality & additives & have come to this conclusion
which is to be construed as my opinion only.
Due to the lack of enough of or any at all zinc based additives
in currently available name brand it is prudent, if not a
must, to add Richard's ZDDP additive not only to flat tapped
cam engines. But also to any car (regardless of cam type) that
is driven hard even if not raced.
Not only does ZDDP protect the flat cam / lifter engines,
but also other "impact" / scuff prone engine components such as wrist pins,
rocker arms, valve lifters (flat & roller), push rod ends, &
thrust bearing areas. All these areas are also protected
by ZDDP.
My opinion is not based upon or meant to be a sales pitch
or infomercial. Both my GNX (flat tappet) & GN (roller)
will not be run without this additive in it.
As a side note on both cars I fill the crankcase with a 50/50
blend of Mobil 1 & Mobil 5k mineral oil. ( any other major brand
of these types of oils will work just fine also) My reasoning is synthetic
oils are not as forgiving to the intrusion of amounts gas & coolant
while mineral oils tend to be. Therefore you have a combination
of the best of both oil type protection. Have been doing this for
nearly 10 years with absolutely no adverse effects.
I only mix the same brand maker's oils. Reason:
I think motor oils of the same brand probably contain the same
mix of additives. Don't know if that makes a difference but
thats the way I do it along with other T/R owners I remain
in contact with.
Plus the oil change cost becomes cheaper.
To repeat, this is my opinion only.

Ron J.
GS Nats. PR Director


Last Edited By: RonsAuto 05/01/09 17:11:24. Edited 2 times.