Oil weight

As Randy mentioned earlier Auburn recommended 40 weight oil in the summer.
From the owner's manual;
"These recommendations come within the range of S.A.E. Viscosity Number 40 down to 32 degrees Fahrenheit , S.A.E. Viscosity Number 20 for 32 degrees Fahrenheit and lower."

I have a gasket set on order. I will be changing everything out after a good cleaning. Thanks for the info! Much appreciated!!

The early oils were non detergent and the filtering system amounted to impurities settling to the bottom of the pan. Thats why the oil pans are pretty accessible as you were to drop them and clean them. 20 weight was recommended except in hotter climates.
ZDDP came about when valve spring pressures became much higher than what our cars came out with. The zinc additive lubes metal to metal contact surfaces due to the higher spring rates for more modern camshaft profiles and higher RPM's.
The question is do engines up to the late 40's and early 50's really need it? Most likely not. I imagine a lot of us use a detergent oil but one should clean the pan and check the inside of the motor for "gunk". If you have build ups I'd stay with non detergent until it cleans up, Change oil frequently and some Lucas additive, I am not aware of an non detergent that has zinc off the shelf.

I do use an oil with ZDDP, Brad Penn or Penn Grade 30 wt.in my Cord, Auburn and other classic and vintage cars. I think some of the Valvoline Racing oils do contain zinc again, back of the bottle usually says. Warmer climates 40wt and if you running in really cold temps 20wt.
The Lucas additive is great also, but not necessary if using an oil with it already in it.
I build flat tappet racing engines and Brad Penn has not let me down. Motors with high seat pressure and 8000 RPM.

If you call the oil manufacturer and ask about the amount of Zinc in there oil they will tell you in PPM. I have done this several times.
CORDiallyMike

Awesome! Very helpful. Thanks!

Here is our Indiana Region CCCA site - we had the oil brewed by DA Lubricants in Indianapolis (they make racing oil). Accompanying such is a few John Klein articles on site (you often see John at ACD Festival with a Tan/Brown Duesenberg Convertible Victoria). This was a well researched project and it has to do more with how much zinc and as far as it goes applies mostly to cars with flat tappets.

inrccca.org/product/classic-car-motor-oil/

I would agree, most people add things to oil not knowing what mixture of stuff they end up having in the crank case. I have a trusted brand (lucas) of ZDDP that I prefer to add to my vintage cars, along with a quality oil. In this case I can control the amount of ZDDP I add. Most oil manufacturers do not disclose the amount of each item in their oil.

I also prefer to make my own 2 stroke gasoline mixture using oil I choose and an octane fuel I prefer rather than buying premixed at the lake.

Sam K

Why the Zinc additive? There are oils available with the zinc already present. When people start adding things to oil they no longer have any idea what brew they are making.
CORDiallyMike

40 wt summer

Hey all, can someone tell me the recommended oil weight for my Auburn 8-100? I'm planning to also add a zinc additive. Thanks! Sam