<VV> oil question

[Chris & Bill Strickland]

Apparently the oils, either dino or synthetic, you want to avoid for the 
older "flat tappet" engine designs, such as the Corvair, 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.

> but may find out when they get some miles on them.
>

That's why this is important to understand, or else you may not "get 
some miles on them"

>> Factory manual says 10W-30.
>>    
>>

Written 50 years ago when oils were rated SA if they were rated at all, 
and 10W-30 was the only multigrade marketed -- this factory manual 
recommendation is just as obsolete as cars we drive.

Nearly all name brand 10W-30 oils today are marketed for New Cars, and 
will carry the dreaded "ENERGY CONSERVING" and ILSAC GF-4 ratings, 
meaning the ZDDP levels are not high enough to reliably get some miles 
on an engine. It seems the ZDDP is very important to new engine break-in 
and subsequent run-in, and perhaps less so in high mileage engines that 
do not have the degree of mechanical wear-in that low mileage engines do.

Single grade oils, and multigrades ending in 40 and 50, do not meet the 
basic new car criteria for high fuel mileage oils and low emissions, so 
may or may not contain adequate levels of ZDDP for flat tappet cam engines.

Bill Strickland