znalazłem fajną konwersację na temat oleju i pozwolę sobie zacytować (
http://bobistheoilguy.com/forums/ubbthr ... mber=77945" onclick="window.open(this.href);return false;):
In general, the most common oils used back then were 30w, 10w-30, and 10w-40. A 1973 Petersen's general automotive repair guide I have doesn't even mention 20w-50, only the grades above, plus a few weights which are now obsolete. The 10w-40 grade went out of favor by the 90's due to the increased shearing and burning (a large amount of polymers was required to achieve that particular spread), but modern 10w-40s now use better base oils, so this is no longer an issue.
From the current Chevron/Havoline oil spec sheets:
10w-30: "Recommended for many older vehicles...often those with larger 6 cyl and V-8 engines."
10w-40: "It is often recommended for older model cars that see regular high temperature operation."
20w-50: "Recommended primarily for older engines in high temp and heavy duty operations...towing heavy trailers up inclines...racing and rallying."
The Mobil Drive Clean spec sheet concurs, essentially referring to 10w-30 as a default choice, and 10w-40 "where a higher viscosity oil is preferred and recommended." For 20w-50 they start right off by saying, "MDC 20w-50 is recommended for high-performance engines found in race and rally driving."
Based on this information, it seems to me that 10w-40 would be better suited to your ride than 20w-50, with the former certainly being the much more popular choice, even in hot climates, back in the "old school" days.
