<VV> Fw: Multi-Grade 10W-40 Motor Oil in Corvairs ?

Charles Lee Chaz at ProperProPer.com
Sun Oct 25 05:10:16 EDT 2009

OK, 10W40 means 10 when cold, and 40 when hot, right ?  ("W" means "winter" 
? Why ?)

 Seems like they all prefer high viscosity in the 'cold' part and higher in 
the 'hot' part, but I've heard that multigrade oil breaks down faster (lose 
viscosity) when hot, which Corvairs do on occasion (most of the time, 
actually ?)

 So, single grade is still better ?  Recommended ? What ?

 Thanks again,

> ----- Original Message ----- 
> From: "Chris & Bill Strickland" <lechevrier at earthlink.net>
> To: <Chaz at ProperProPer.com>
> Sent: Sunday, October 25, 2009 1:38 AM
> Subject: Re: <VV> Multi-Grade 10W-40 Motor Oil in Corvairs ?
>>>Can we use modern Multi-Grade oil (10W-40 Motor Oil) in our 
>>>high-temperature, air cooled Corvair engines ?
>> Anything that is *not*  ILSAC GF-4 rated, and nearly all, in not in fact 
>> *all* 10W-40's  ain't  (it's the 5W30 stuff and 0W-40 and things like 
>> that, new car oils that are bad for old engines)
>> now, for the generic more long winded set of references --
>> Periodically, some Corvair or Porsche guy asks, and here is the latest 
>> version of my reply --
>> This was big stuff a couple years ago when nobody knew much about what 
>> was happening, but now, lots of people have done/are doing the research 
>> and there are numerous web sites, each with their own opinion. Also most 
>> of the manufacturers address the issue on the corporate web sites, but 
>> can you trust them to tell the corporate secrets?
>> Perhaps the oldest one is here, frequently updated, by a guy that sells 
>> Nickisil cylinder barrels  --
>> http://www.lnengineering.com/oil.html
>> >From the 356 Porsche folks, who have engines a lot like the Corvair --
>> http://www.356registry.org/tech/modern_oil_in_the_356.html
>> Richard Widman is an oil importer in South America restoring and old 1960 
>> Corvair -- laws down there prevent him from buying a nice one in the 
>> states and importing it -- has to work with what is already there --
>> http://www.widman.biz/uploads/Corvair_oil.pdf
>> then there are these folks in addition to whatever shows up when you 
>> Google for Oil Zinc --
>> http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/index
>> http://www.compcams.com/Base/pdf/FlatTappetCamTechBulletin.pdf
>> http://bobistheoilguy.com/
>> Apparently the oils you want to avoid for the older "flat tappet" engine 
>> designs have an ILSAC GF-4 rating in the fine print on the back of the 
>> can, and they say "ENERGY CONSERVING" in the little SAE circle logo 
>> identifying the oil rating.
>> Godspeed!
>> Bill

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