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88v8
Ivor Duarte
Gloucestershire UK
(487 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
TR6 74 2.5 injection six

Another slant on oil & zddp levels
Posted by: 88v8
Date: July 02, 2017 04:34AM

Some interesting comments in this thread
[forum.dloc.co.uk]
where owners of the Daimler hemi, and others, are discussing zddp levels.

In particular
In the 1950s, ZDDP was at a level of about 800ppm. In the '60s and '70s it was increased to higher levels, not to counter wear but as a cheap anti-oxidant in the newer higher pressure engines in which the oil would otherwise turn to sludge and become too thick to pump. As other anti-oxidants were then introduced, the levels of ZDDP were reduced back to just over the 1950s levels. What is the ideal level? No one really knows for sure. In the 1950s and again in the 1970s General Motors experimented with levels of 600ppm and found no adverse effects.

Any views on this observation? And on the other comments about the merits of synthetics?
Perhaps this is all old hat, in which case apologies.

Ivor


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