http://lucasoil.com/images/documents/TDS_Break-In-Additive.pdf
3750
In December, 2007, the publication GM Techlink
, distributed to GM dealers, contained an
article by a GM lubrication guru, Bob Olree,
of the GM Powertrain Fuels and Lubricants
Group. As well as debunking cert
ain other erroneous
ideas about oil, he
addresses the ZDDP
question in detail. In that arti
cle, he flatly calls the concer
n about ZDDP a “myth,” citing the
extensive testing of modern oi
ls for scuff resistance. One pa
ragraph is espe
cially worth
repeating here:
A higher level of ZDDP was good for flat
-tappet valve-train scuffing and wear,
but it turned out that more was not
better. Although break-in scuffing was
reduced by using more phosphorus,
longer-term wear increased when
phosphorus rose above 0.14%. And,
at about 0.20% phosphorus, the ZDDP
started attacking the grain
boundaries in the iron, result
ing in camshaft spalling.
I would not use more than 1400.
At 2000 it is dangerous according to GM Cheers.
http://www.nonlintec.com/sprite/oils_and_zddp.pdf