At 04:28 AM 12/13/2006 -0800, Dan DiBiase wrote:
>I don't know of anyone that puts more mileage on his MG(A) than
>Barney Gaylord. Here is what he says -
>http://mgaguru.com/mgtech/engine/of104.htm
I appreciate the referal, and I still stand by the information
content in that article. But as written it has not much to do with
recent developements under the current topic of discussion.
I have been intentionally avoiding this discussion, because it has
the appearance of a religious war not well founded in scientific
fact. It is my humble opinion that oil formulations are driven by
auto manufacturers' demands, and each successive oil formutation is
superior to the predecessor. When a change of oil formulation might
be driven by environmental demands, the oil companies will find a way
to substitute compound B in place of compound A to achieve the same
effect, possibly at some increase of expense, but never allowing any
reduction of oil performance.
One thing we should get from these discussions is that as of about 15
years ago there is a different approach to lubrication of modern
engines. New engines are built with tighter manufacturing tolerances
and smaller clearance gap for oil film in the bearings. This allows
them to use lower viscosity oil for reduced friction and (a little)
better fuel economy. The new cars can thrive on 5W30 oil, but you
should never put 5W30 oil in your vintage MG engine, because the
older bearings with larger clearances cannot survive long with very
low viscosity oil.
Above all, you need to use the right type of oil for your vintage
engine design. You should by now have noted that the new oil
furmulation that seems to have folks worried is applied to 10W30 and
lighter grades of oil used in modern engines. If you stick to using
20W50 or 10W40 (and in some cases older spec 10W30), your vintage
engine should be happy as a lark. For a new cam and tappets follow
long standing practice of heavily greasing the cam, or use assembly
lube where recommended, especially if it makes you feel better. Also
follow proper run-in procedure with higher engine speed for 20
minutes while you assure that the tappets do rotate.
As to the recently reported spate of cam failures, I have seen no
scientific documentation to indicate that this is any different,
better of worse, that it has been for the past 50 years. It may
simply be a matter of perception resulting from better modern
communication spreading the stories around. I have no personal
concern whatsoever for the intergity of modern motor oil. I have
never had a premature cam failure, but then I'm stilll running the
cam I installed six years ago (with high lift and heavy duty valve
springs), so I cannot profess to have any experience with new cam
run-in using very recent oil formulations.
Since I am not an expert on motor oil formulation or oil testing, my
opinion is worth about as much as most folks, ....
$.01,
Barney Gaylord
1958 MGA with an attitude
http://MGAguru.com
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