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Something about the oil!
by
Bill Bollendonk
During the past year, or longer, there has been a major change to the
formulation of the lubricating oils that we have been putting in our MG’s, as
well as other cars that have cams and flat lifters. With these changes comes a
real problem of the ability of current oils to provide ware protection for our
cars.
The problem centers on the reduction of Zinc, ZN and
Phosphorus, P that have been a part of oil for many years. These elements
provide the lubrication for the surfaces between the cam lobes and the cam
followers, without which the rate of ware goes up dramatically.
ZDDP, dialkyl dithiosphosphate has been reduced to extend the life of
catalytic converters, as it clogs
them over time. Modern cars are designed for lower viscosity oil, such as 5W-20
and do not have the metal contact surfaces found in older engines.
There have been many failures of fresh
engine rebuilds noted on the internet due to
the lack of ZDDP in the major oils available. The Zn content of most oils
has dropped from %0.130 (SH grade) in 1996, to %0.087 (SM grade) in 2005.
This may not seem like a major decrease, but it is very significant.
Worse is that the oils, in the near future, will drop to even lower
levels of ZDDP. I personally have seen the results of the lower levels in the
engine that I recently rebuilt for a member of our club; an engine that had less
than 1,500 miles since rebuild. From the literature, I glean that older engines
that have been running for many miles with higher levels ZDDP are less at risk,
but I wouldn’t count on that, so, I have switched to oils that still contain
high levels of ZDDP; in my case Redline racing.
Have a look at www.lnengineering.com.
Click on oil. Good article on the subject. For more info, do some Google
searching on the subject.
The problem is real!
Here is another link for more information: http://www.carbibles.com/engineoil_bible.html
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