Oil for 1947 Plymouth

[skinnyd]

Looking for recommendations for oil for a 1947 Plymouth Deluxe Club Coupe a buddy is purchasing. It has a 217 flat head 6 cyl with dual carbs.

I haven't been able to determine what oil to run in this. I have read things that newer oils are not good for some of the older cars. I have also read they are fine.

What is the consensus is it fine to run a regular oil like Pennzoil (PYB) or should he run some sort of Diesel oil with more zinc?

Unfortunately we have yet to determine what type and weight oil was originally recommended for this car.

I appreciate the help in advance.

 

[skellyman]

Any modern 10w30 will more than protect your engine.
Do NOT buy a ND 30w no matter what !

 

[Bandito440]

Rotella T6 5w-40 and change it annually. It has a robust addative package to keep that old motor happy.

Tractor Supply has it for $16.99/gal right now and there is a rebate on top of that.

 

[46Harry]

Most of the older cars used either an SAE 20 or SAE 30 in the summer and a 10W oil in the winter as multi viscosity oils weren't available. I use an HDEO oil such as Chevron Delo 400 in my old Studebakers and other older cars I maintain as they have more zinc than oils such as PYB. Some people say that the use of an oil with reduced zinc will cause cam failures, but I don't think that an old flat head Chrysler engine cares about reduced zinc levels in the new oils as the valve spring pressure and engine rpm aren't hard on the cam and lifters and many of those engines were operated on non detergent oils in the old days and didn't have cam failures.

 

[Kuato]

Originally Posted By: Bandito440
Rotella T6 5w-40 and change it annually. It has a robust additive package to keep that old motor happy.


That would be my thought also.

 

[Maximus1966]

Rotella Dino 15W40

 

[dave1251]

10W30 of your choice.

 

[Brent_G]

As most have said, any 10w30 will work fine. They are miles ahead of what oil was speced back then.

 

[fraso]

Chrysler only recommended a 40-weight oil when the average daytime temperature was over 90°F, that is, continuously recurring morning temperature of 70-80°F and mid-afternoon peak temperature of 100-110°F.
Chrysler Oil Recommendations

As modern 30-weight oils protect far better than the 40-weight oils of 60+ years ago, I would use a 10W-30 HDEO in your engine, even if you lived in the Mohave instead of MA. Use the grade that keeps your fully-hot oil pressure within the recommended range (or below the blow-off pressure of your relief valve).

See Widman's Corvair Oil article about flat tappet engines for more information.
http://www.widman.biz/uploads/Corvair_oil.pdf

 

[A_Harman]

Thanks, fraso, that's a great link. In 1938, they were talking about the same engine oil issues we do today.

 

[skinnyd]

Thanks guys. I appreciate the info so far. I haven't had time but will check out the links later tonight.

 

[3putter]

Rotella 10w30 would be a logical choice you could run year round with confidence.

 

[SS1970chrysler]

Originally Posted By: 3putter
Rotella 10w30 would be a logical choice you could run year round with confidence.


2nd'ed

 

[skinnyd]

fraso, thanks for the interesting links.

 

[Errtt]

Another Rotella vote.