Question about motor oil for our old cars, what's best for the really old cars

[Lou McCarrell]

The three cars I have '23, '29 '31 have all come into my possession since the first of the year. I have very little knowledge of their history and I have no experience on anything older than the '60's. I know there are 'restorative' oils, but my concern of such oils is that they may stir up stuff enough to clog the oil passages, etc. Likewise high detergent oils. 

Worse, even if the 'restorative' oils work, would that necessarily be a good thing. 

 

[alsancle]

There are lots of threads on this.   I would suggest Valvoline VR1.  It has zinc.  It gets run in multi-million dollar prewar cars.

[Terry Wiegand]

My personal opinion is to use a very high grade of Mineral Oil (Havoline 20W50 comes to mind very quickly) and stay as far away as you can get from any synthetic stuff.  It wasn't to be had back in the day so why use it now?

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

[Mark Shaw]

     Your cars have relatively low compression engines and do not require Zinc additives.  Any of the least expensive oils today are much better than oils available pre-WWII.  If your cars do not have retrofitted oil filters, and have not been reconditioned, you do not need "detergent oils" to suspend solids.  The large oil pans were designed to settle out heavy contaminants in the form of sludge.  You may only need to remove the sludge if the engines are running ok and do not need to be rebuilt.  

     I run 30 or 40wt non-detergent motor oil in my early cars with no filters.  I change the oil prior to winterizing the cars in the fall so they are ready to drive on the first nice spring day the following year.

     

[28Buick]

Perhaps you should drop the oil pan. You may be impressed by how much sludge is in there. Or maybe you will discover how clean it is as somebody beat you to this bit of housekeeping. While you are in there check the integrity of the screen on the oil pick up, these get holy and not in the religious sense. I have plenty of ZDDP for my 63 and 85 cars but don't add that to my 28 it is not needed. Agree with Terry and others, I run 10W40 mineral oil with no drips. No need for synthetic (stay away from blends that never say what percent).

[Morgan Wright]

I get the standard 30 W which says "for high mileage cars." I have no idea why, but my car has 109,000 on the odometer and millions of miles around the sun.

[EmTee]

I switched to 15W-40 Mobil Delvac for my '38 (and my MerCruiser I/O) about a year ago.  It's API rated CK-4, CJ-4, CI-4 Plus (Diesel) and SP (Gasoline).  I by the 5 gallon pail at Walmart, since the Buick requires 8 quarts for an oil change (and a few more between changes depending upon mileage).  So far, so good.