<VV> Selecting an oil

[Tony Underwood]

At 10:58 hours 05/28/2006, TimogensTurbo at aol.com wrote:
>In a message dated 5/28/06 9:32:20 PM Pacific Daylight Time, tonyu at roava.net
>writes:
>
>
> > should have stayed with it to begin with and not even tried the Castrol.
> > ---------------------------------------------------------------
>
>Interesting!  Castrols' big claim to fame was that it DID  have a LOT  of
>anti-foaming  additive!   Always worked well in Sand Buggies...but 
>we used 50 wt
>straight...never a multi in a forged piston engine..



Now:

My disdain with Castrol did *not* extend to their "genuine" race oils 
which were straight-weight, usually 50 or 60 wt.   That stuff was 
tough and never offered up any problems and was oft times the oil of 
choice for 1200 hp Pro-Stock hemi dragrace engines.    It was however 
not a street type oil...  ;)

I ran some of the 50 wt in the "street" 426 in my Plymouth and it did 
OK once it was warm...  but when cold the engine would crank up over 
100 lbs of oil pressure which was often enough to blow the filter off 
the engine if you buzzed it up enough before the oil was warmed, and 
you were using a stock type oil pump pressure relief valve (which I 
was).     I fondly recall having this happen when I ran a straight 50 
wt oil once...  as did a buddy who had a car just like mine... and a 
'64 Max-wedge Superstocker at the Bristol Spring Nats which proceeded 
to empty the pan's contents of racing oil onto the starting line when 
it blew off an oil filter at the line while heating the tires, made a 
puddle 8 feet across by the time it spread out.    Everyone took a 
break while the track crew raked kitty litter...


This sort of thing brings to mind the actual requirements of an 
engine oil for a small lightweight (reciprocating mass) engine like 
the Corvair boxer which doesn't actually load its bottom end the way 
larger V engines do.    Maybe this is why it can get away with less 
than 40 lbs of oil pressure to stay together when that 426 race 
engine needs almost 100...  although it's also making a four-figure 
hp number and turning 9000 rpm.    One can only imagine the forces on 
the bottom end of that engine, trying to shove the crankshaft down 
through the bottom of the pan.


Comes the Corvair engine, with its relatively small rod journals and 
narrow bearings.   It's another sort of loading 
altogether.    There's not as much actual friction on the rod 
bearings as in that larger race V8, which will really heat up the oil 
quick under load... but still the Vair engine is working at a 
disadvantage in that it's gonna keep its engine oil hotter as a mass 
than that race V8.


I'm surprised that a lot of the Vair engines Back When, those pushed 
close to limits and likewise run hard, managed to survive to current 
day, what with oil then being somewhat less substantial than it is 
today.    If nothing else, it's a testimony to the design of the Vair 
engine.



tony..