In a message dated 10/30/2006 10:58:00 A.M. Eastern Standard Time,
amcewen2@cogeco.ca writes:
Hes had a couple of conflicting expert opinions from diesel mechanics,
Cummins says not to use synthetic oil on
any engine with solid lifters. Neither one of us can figure out why that
would matter.
Any ideas?
ZDDP is the Zinc compd that's been phased out of gasoline engine motor oils
over the last 10 years - during this time engine builders and cam makers have
found, the hard way, that the absence of ZDDP causes early cam failure in
solid lifter engines - engines with hydraulic lifters and roller cams (which
I'm
guessing includes all modern gasoline engines) are not similarly affected by
the absence of ZDDP - apparently the ant-scuff properties of ZDDP are vital
to the life of the cam in solid lifter engines.
What Cummins means is don't use oils missing ZDDP in solid lifter engines -
that would include ALL current gasoline engine oils - synthetic or not -
except some racing and marine synthetics with additive packages including ZDDP
Diesel engine oils (like Shell Rotella T) still have ZDDP
Cheers
Jack Mc
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