ZDDP is in itself a good additive. What you have to ask yourself, is that
when you have oil analysis performed, and it shows a certain PPM of Zinc,
are you sure that that Zinc is in a form of ZDDP? The answer to how it
shows in the analysis and at what PPM is going back to the Chemistry of
chelators and ligands. I'm no Chemist.
I will add that both Crane and Castrol have, when pressed on older cars,
recommended or suggested that using a diesel rated oil or something for
4-cycle motorcycles, is the way to go. Almost all have flat tappet cams and
very high rate lifts. Motorcycles for power and diesels because there is
nearly zero valve overlap.
See, diesel engines have such high pressures at the wristpin that they need
it to survive at all. The newer diesels with pump injectors had to minimize
the cam lobe thickness to fit the lobe for the injector actuations. That
leaves them with a very high pressure contact area. Adding moly to oil is
great when there is ZDDP already there in the proper concentration, because
the moly bonds to the Zinc and is very slippery. But, add too much moly and
the effectiveness of both additives is greatly reduced. How much is too
much...the answer is in PPM. How accurately can you pour?
That's why I say run a diesel rated regular or synthetic oil. As long as it
is not the 0W30 or other energy conserving variety, you can be sure that it
has the proper additives in it. I think one of the best is the Schaeffer
9000, but I have never personally used it.
On my list of diesel rated oil contenders suitable for flat tappets:
From: Michael Salter [mailto:email@example.com]
Sent: Sunday, May 20, 2007 5:20 PM
To: 'Chris Masucci'; firstname.lastname@example.org
Cc: 'Gary TR4A Fitzgerald'
Subject: RE: OIL - beware
Dose this mean that ZDDP can be in different forms not all of which will
provide the tappet/cam protection that we need?