<VV> oil question, here's an answer

[Tony Underwood]

At 11:01 PM 4/14/2011, Mark Durham wrote:

>Chevy built the engine to use a oil in a specific viscosity range and
>with a ZDDP PPM of around 1200 each.
>
>The 30 weight derivities , 5 W30, 10 W30 and plain 30 wt fit the bill.
>The 5 w40 and 10 W40 synthetics while slightly higher in viscosity
>also are just above the viscosity range. If you get too heavy a oil,
>you get startup damage, and the engine may run hotter if a
>conventional oil, because it will not flow as fast in the engine;
>however, we have guys on this site that use mobil 1 15W50 with no
>issues, and have for many years.



It is at this point that I shall point out that just about every 
Corvair engine in existence started out using engine oil that was 
MUCH less capable than what's available now, and many of them went 
200,000 miles (or more) on that antiquated oil and the house brand 
oils that followed it.   There are guys that use Advance Store house 
brand 10W40 oil in older cars with no issues, and have for many years.

My point is that ultra-modern engine oils may well be just a tad bit 
overkill and the point of diminishing returns has been reached 
already.   Advancing towards those 10 buck/quart oils won't really 
give you that much of an advantage over a 5 buck/quart oil, 
considering that those engines started out on oils that were quite 
inferior to just about anything available today unless you buy 
nondetergent bulk stuff.

...and I've seen people back in the day use that stuff in those 
engines... used to be carried by mom&pop gas stations, in racks out 
front, shipped in glass bottles.  They used to call it bulk motor 
oil.  They lasted through it.

There are still a lot of Corvair engines out there that are running 
their original rings and bearings.   Who knows what sort of Family 
Dollar Store cutrate engine oil they absorbed for a decade or more 
along the way?  And they did it while owned by some ditz with no respect.

Not a Luddite... nothing wrong with using high tech space-age 
synthetic engine oil in a Corvair.   But...   ;)



tony..