ClassicCar

Almost any modern motor oil will be acceptable.

If the engine oil has not been changed for many years (if, for example, the car has just come out of storage for 20 years) you may want to remove the oil pan and clean out any sludge or oil build-up, before putting in new oil.

One consideration: some folks believe that -- if a car's engine is really "used" and has a lot of sludge build-up throughout the engine, you should use a NON-detergent type oil, lest the modern (detergent) oil loosen the sludge and get it into circulation. This would be bad because large hunks of the sludge could get caught in oil passages and stop the oil from circulating. Some folks debate that whole notion. (Generally, you can only find non-detergent oil in a straight weight like 30W, if you can find it at all. You can't get 10W-40 for example, in non-detergent.) But if your engine's pretty clean inside, don't worry and just use a standard multi-viscosity modern detergent type oil.

One more caution: There is an ongoing controversy about the amount of zinc in today's oils. There used to be a lot more, and its traditional purpose was to lubricate the cam lobes in cars with flat tappets, but modern cars use roller tappets so this became increasingly unnecessary. Then catalytic converters came along and it was discovered that the zinc in the oil fouled up the converters, so the zinc has gradually been reduced. Trouble is, a great number of older cars that have flat tappet (versus roller tappets) and without the zinc, the cam lobes may (or may not, depending on your opinion) be damaged. The safest thing is to use an oil with a good amount of zinc additive (or a zinc additive alone, in your crankcase). One of these is Shell's "Rotella T", which is really a diesel oil but has more zinc than most oils. (Look for the "CI4" or "CI4+" symbol on the can.) I myself use Brad Penn racing oil and I get it by the carton so it comes out being just a bit more than standard oil. You have to find a Brad Penn distributor to get this, and I have a distributor near me. The whole thing may turn out to be an old wives tale but I have heard enough horror stories (mostly from people who race cars with the older flat-tappet engines) of cams being ground down when no zinc is in the oil. So, see if you can find some Rotella T with the CI-4 or CI-4+ marking, and try using that. This is a modern oil with the detergent, so if you

By the way, you may want to place your future messages in the "Hudson" Forum, which is at http://classiccar.com/index.php?option=com_kunena&func=showcat&catid=13&Itemid=129 . You will probably get a much better response there, than you do in the "General" Forum, which is for all automotive marques.