<VV> Corvair oil choice survey

[Bill Elliott]

Multi-viscosity is always a good idea... at least for the past coupe of 
decades. Previously viscosity modifiers were the first aspects of an oil to 
break down (and the wider the viscosity range the worse the problem was), so 
single viscosity oil generally provided the best protection.

That's no longer true and your engine will be much happier with a thinner 
oil when starting cold.

Since the W (cold viscosity... really "room temperature cold")  number has 
nothing to do with the upper (hot viscosity) number, I recommend getting the 
appropriate upper number for your engine hot viscosity needs and then 
choosing the lowest W number you can find (given other parameters like cost, 
ZDDP content, etc).

Most important thing is to stay away from the "Starburst" economy symbol on 
the oil which guarantees dangerously low levels of ZDDP, etc... common in 
modern 30 weight oils.

I personally like 5W-50 Castrol (for slightly looser and/or older engines) 
and 0W-40 Mobil 1. I've also used Rotella T.

I also like royal Purple, Bran Penn, and Amsoil but generally find them 
cost-pohibitive.

A more expert opinion has been written up by our resident Corvair oil expert 
at:
http://www.widman.biz/Corvair/English/Links/Oil.html

Bill

>>It will soon be time for me to change my oil.  I am not sure if my current
>>oil is a good choice. I currently use Castrol HD 30. It is an SL so I
>>understand that it has ZDDP. I was told that 30 weight is what I should 
>>use
>>in Southern California. The temperatures don’t fluctuate enough to need a
>>multi viscosity oil I was told.
>>
>>