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

[Ulli Dittmar]

I am driving a modern VW Van "Bus" and I have a recommended oil change interval of 25.584 miles or every 2 years - the oil VW is using on the change is Shell Helix. But I would never have an interval that long on an air cooled engine.

Regards
Ulli

---------------------------

61 Monza 900 Sedan
65 Monza 110 Coupe
66 Corsa Convertible
86 Porsche 356 Speedster Kit Car
91 Porsche 964, C4
62 VW Split Window Bus
65 VW Split Window Bus

Am 18.07.2012 um 20:36 schrieb Ron:

> Mercedes recommends Mobil 1 for the Crossfire with a 7000 mile change 
> interval so they must have a lot of confidence in it.
> RonH
> 
> ----- Original Message ----- 
> From: "Joel McGregor" <joel at joelsplace.com>
> To: "Virtual Vairs" <VirtualVairs at corvair.org>
> Sent: Wednesday, July 18, 2012 11:20 AM
> Subject: Re: <VV> Motor oil shear strenght comparisons - a good article
> 
> 
>> 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
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