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>>>>Straight 30 weight? I usually use 10W30 or 10W40, as
per the manual on my '70.? Why would these be considered the wrong oils? Is it just because
this car is worn? I don’t have a manual from a'70, but what you say surprises me.? 10W30 is very thin oil, especially for a car with 35 years of use on
it.?? I use SAE30W in all my old cars, but my choice is somewhat influenced by
where I live.? Our temps almost never go below 32 degrees, and SAE30W was the
recommended oil for that environment, even when the cars were new.? A more worn
engine requires heavier oil to maintain proper oil pressure.? See what the
factory says about this - - - The following is quoted verbatim from the 1972 FSM (the capital letters
are theirs, not mine!):? "IMPORTANT:?
If the vehicle is to be used for maximum performance service (very high speed
or very rapid acceleration), the engine requires heavier than normal lubricating
oil.? This is due to the high speed, loads, and temperature of moving parts
developed in these engines during this type of operation. "FOR BEST PROTECTION OF THE ENGINE UNDER THESE
CONDITIONS, THE HEAVIEST AVAILABLE ENGINE OIL OF SD OR SE QUALITY SHOULD BE USED
THAT WILL PERMIT SATISFACTORY COLD STARTING. [these are obsolete
quality ratings, today we would say SJ or SI] ? SAE 30 AND SAE 40 ARE RECOMMENDED
[then it goes on to discuss multigrade oils, which are also permitted, if 20W40
or 20W50 is used, with a special "high performance" additive (STP?). For many years, some car manufacturers, and most heavy equipment
manufacturers advised against using multigrade oils (the viscosity index improvers
are not lubricants - My understanding of the reason is that they are simply thickening
agents, so when the lubricant is under great stress (high temp, high loads),
the coefficient of friction is higher than with straight weight oils.? I also
have some antique heavy equipment (dozer, backhoe, skiploader etc), and those
manuals are very emphatic about it. In my modern cars, I don’t agree with the recommended 5W30 oil
either.? I believe the car manufacturers specify very thin oil in an attempt to
satisfy the CAFÉ requirements - they don't give a hoot how long the engines
last, as long as they go beyond the warranty period.? I switch to 10W30 after
the first oil change - and when the cars get older, I'll probably go to a still
heavier oil. I do use multigrade in the new cars, because I know they were
designed to tolerate it better. Enough of my biased opinions - suit yourselves, guys. Dick. -----Original Message----- >From: "Dick Benjamin" <dickb@xxxxxxxxx> >There are other possibilities, such as the wrong oil being used
(you should >be using at least either straight SAE30W or 15W40, depending on
where you >live, low oil quantity, or a worn oil pump. > -----------------? http://www.imperialclub.com? ----------------- This message was sent to you by the Imperial Mailing List. Please reply to shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm |
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