<VV> Motor oil shear strenght comparisons - a good article

[Joel McGregor]

There is a huge problem with this test.  It's only on fresh oil which might make the results useful for break in oil you are only going to run for an hour or less but they are pretty much meaningless for an oil you are going to run for 3000 miles.  You might think that if the protection starts out high then it will stay higher than another oil but that isn't always or even often true.
The only test I've read where someone tested oil, ran it and tested it again failed 3 of the 4 oils tested.  The only one that tested good enough to keep running after 750 miles was Mobil1 and it was down 23% in viscosity from where it started.  I think Castrol GTX was 2nd ahead of Honda fully  synthetic oil if I remember correctly.
Joel McGregor
________________________________________
From: virtualvairs-bounces at corvair.org [virtualvairs-bounces at corvair.org] On Behalf Of Mark Durham [62vair at gmail.com]
Sent: Monday, July 16, 2012 4:48 PM
To: Virtual Vairs
Subject: <VV> Motor oil shear strenght comparisons - a good article

Gents, I searched to see what reactions other flat tappet forums are
having about the Defy oil. The Corvette Forum has a article by a classic
car guy who did shear testing on 48 oils, including the Defy 10w30.

540 RAT's results, as you will see, may change the way you look at oils,
but keep in mind his focus is on shear strenght, or the ability to prevent
contact. It really is a good supplement to Richard Widman's article on
oil.

The article has changed my belief that synthetic oil is actually better at
protecting your engine. The Industry standard Amsoils and Mobil 1's did not
come out on top in these independent tests, either, and they are good
oils. Many of todays later generation Dino oils for modern engines did very
well in the shear tests, too. Nor was it consistent that a higher weight
oil did better over a lighter weight oil.

While the author says there are "no bad oils in the group", the oils at the
top outperform those at the bottom in shear strenght by a staggering almost
100% margin. That is significant. I think that from now on I will be making
selections at least in the top 10% of the list for all my cars, and add the
ZDDP to that oil as necessary for the Corvair.  By the way, the Defy 10w30
is in the top 10%, and at 15.64 for 5 quarts, is a great buy.

Enjoy the article.

http://forums.corvetteforum.com/c3-tech-performance/3078239-quaker-state-s-new-defy-motor-oil-lab-test-and-wear-test-data.html

Mark Durham