Oil

[Wm Steed]

Motor oil is another item like women, everyone has a different idea of what is best...
Modern engine lubricants can also be compared to the controversy surrounding unleaded fuel in engines made prior to the introduction of unleaded fuel in the early 1970'.
Many people are running around like chickens with their heads cut, fretting about the reduction of zinc in engine oil. Reputedly the reduction of zinc in oil will have an effect on the life of "flat tappet engines", therefore if you have an overhead cam engine, there is nothing to worry about.
The mechanics whose opinion I respect are telling me that if the oil is approved for use in diesel engines, then it is good for older engines, providing the engine is in good condition. If the engine is worn out, heavy weight oil might quiet it down, however, it is not a magic potion that will rebuild the engine like a mechanic in a can.
I have had older engines, pre-unleaded, rebuilt in the past, the re-builder told me I needed new valves and valve seats to cope with the unleaded fuel. I posed the question to the re-builder... what happens if we don't replaces the valves/seats? The valves will only last about 50,000 miles.... At 2,000. per year, that being high mileage for an antique car, I will have to rebuild the engine in 25 years... Hmmmmm? ???
I learned a long time ago that additives for modern multiple viscosity oil is like the old patent medicines, they do nothing but separate you from your hard earned money....Bill

[Fr Mike]

Why not use molybdenum sulphate as an additive to cut start up wear? There is a molecular bonding so that friction is reduced and metal to metal contact is prevented.  A small amount is added to the engine oil only about every 10k miles.  

[TodFitch]

Lots of conflicting information on ZDDP... The most authoritative source that I've come across indicates that there was a little zinc in the oil as far back as the late 1930s but that they increased it in the 1950s to deal with cam/lifter wear in the then new high performance V8 engines. Then increased it a bit more to deal with a sludge issue in the 1960s engines. Other additives now deal with sludge and the latest standards reduce zinc to the levels needed to deal with cam/lifter wear (new amount same as that found needed in the 1950s). So ZDDP additive should not be needed for any production car, much less one built with low performance cams in the 1930s. However your Internet searches may turn up different information... And if you are using a non-standard cam, you needs may vary.

I use a multi-weight oil in my 1933 even though we don't have a real winter where I live either. But I think it circulates faster so it should cut start up wear especially when starting after the car has been sitting a week or more. I usually go for a 20w-50 store brand oil. Seems to me like any oil meeting modern standards is far better than what was available when the engine was designed.

[plym_46]

so if the W in 15 W stands for winter, and you don't have any winter, and the viscosity modifiers thin the oil when its gets cold, to the 15 rating, whats the difference at 70+ degrees at the high end of the viscosity rating????


And if the ZDDP was not in the oil formulary when your car was manufactured,(most sources say that it was added to oil after the introduction of multi viscosity some time in the 60's) how does it's presence or lack there of rated in parts per million in new oil make any difference?

[DENNIS P NOLAN]

I have read allot of the articles posted here about oil. I especially like the info on the ZDDP product to help in the lubrication process.
I have a '39 P-8. I live in the southwest (very Hot)-don't drive the car much, and am thinking about a straight 40W oil- to quiet the 'mechanics' down a bit. I am currently using 15W40 Rotella-T.
So, I am serching for: Your thoughts on the best (what do you suggest for these old cars) Brand and suggested weight....D