Engine Oil/Brand?

[Bruce Adams]

I have voted for the 15W-40 Rotella, figuring that the ZDDP which has been around for 75 years in our oil kept engines running for those years since the mid 1930s and the 15 wt at zero C is around what Henry suggested for winter, and the 40 viscositi number at 100 C is around what Henry sugggested for summer use.
The SM grade oils are lacking in the ZDDP zinc additive.

[Joop]

Quote


>Zinc is only need for engines with very stiff valve springs, not what you find in the A<

[Joop]

Here is an article from a Model A newsletter

..

Tech tip....

(

editors note: Much has been written on the subject of ZDDP
in motor oil. The removal of ZDDP from oil has been
deemed responsible for cam damage in flat tappet engines,
especially those with high valve spring pressure. Here is
some more “borrowed” from the Shade Tree A’s. Food for
thought....fg)

MOTOR OIL REVISITED

Jim McPherson

Shade Tree A’s News, Volume 39, No. 11, November,

Additional information is available on the value of
ZDDP (zinc) in motor oils, this time from an engine
rebuilder. In engines with a flat tappet cam-shaft, like our
Model A, camshafts can be ruined in the first few minutes
of operation. They need maximum lubrication during this
time while the lifters mate to the cam. During break-in,
the engine must be run between 1800 to 2400 RPM for 20
to 30 minutes. Do not let the engine idle any what-so-ever
during this time. This keeps the oil splashed onto the cam
lobes. Change the engine RPM frequently. It is important
for the engine to start as soon as possible. Turning the
engine by hand, or excessive starter spinning will result in
wiping the assembly lube from the cam lobes. While this
in-formation is general, and not specific for our Model A
engines, it is good advice for the initial starting and
break-in of our engines.

It is very important to use a motor oil or additive
that contains ZDDP. The current "SM" oils do not
contain sufficient amounts of ZDDP (600-800 PPM) to
protect your rebuilt engine, especially during break-in.
Do not use oils with less than 0.14% (1400 PPM)
ZDDP, and 0.16% is best. Do not use a synthetic oil for
break-in, even if it con-tains ZDDP. Rotella, other
diesel oils and Val-voline VR1 Racing oil are better
than "S" rated car oils, but do not contain 0.14% ZDDP.
Do not use "SA" through "SE" rated oils. We have
discussed it and many of you are using Classic Car
Motor Oil in your Model A. It is produced by the
Indiana Region of the Classic Car Club of America and
D-A Lubricant Co. to contain the optimum amount of
ZDDP and oil additives for our engines. The information
presented here is from Carolina Ma-chine Engines
in Johnston, SC, which now sells correct oils and additives
for break-in and everyday use and Classic Car
Motor Oil.
THANKS to Don Cerefin for supplying the information

for this Tech Tip.

[marc hildebrant]

The Texico Chart is interesting. Notice that they call for 50W above 70 degree's F.

The owners manual didn't call for 50 W. Anyone know the reason for the difference ?

Marc

[Jeff M]

Thanks for the replies guys, I think I'll try Castrol GTX 20w50.

[Glen in Hillman MI]

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Originally Posted by John Stone

If I don't use 40 wt. I use Wallyworld 20w50. Price is right and good oil.

I also use this oil. I chang anytime from 1500 to 2600 miles. [over 28,000 in 3 yeaars with no wwork on the engine.

[Joop]

Is someone using Penn Grade 1 High Performance Oils!



..

[Mike V. Florida]

Like I said as long as the oil is the slippery kind it will work fine in the Model A engine.