The Ford Barn - View Single Post - What should I use for oil in 40 Ford flathead?

VeryTangled · 06-30-2013, 11:24 AM

Welcome to the Forums DP1743.

Those numbers are from the American Petroleum Institute's 'Service Classification' rating system. For starters, ratings beginning with C are for 'compression' engines, and S are for 'spark' engines, current production cars and trucks should take CH-4, CI-4 or CJ-4, or SJ, SL, SM, or SN. More in this .PDF: (don't recognize the .ashx extension, but it opens with Adobe Reader okay), http://api.org/oil-and-natural-gas-o...10_120210.ashx EDIT WRONG INFO: S=Service, C=Commercial as per the "Motor Oil Guide 2010."

It's a good question whether modern oil formulated for high compression, fuel injected, 200k mile engines, would be suitable for engines that originally used single grades not above SAE30 viscosity. As you can tell, there are quite a few perspectives.

-VT/Jeff

06-30-2013, 11:24 AM	#22
VeryTangled Senior Member Join Date: May 2010 Location: (Not far enough...) Outside of DC Posts: 3,387	Re: What should I use for oil in 40 Ford flathead? Welcome to the Forums DP1743. Those numbers are from the American Petroleum Institute's 'Service Classification' rating system. For starters, ratings beginning with C are for 'compression' engines, and S are for 'spark' engines, current production cars and trucks should take CH-4, CI-4 or CJ-4, or SJ, SL, SM, or SN. More in this .PDF: (don't recognize the .ashx extension, but it opens with Adobe Reader okay), http://api.org/oil-and-natural-gas-o...10_120210.ashx EDIT WRONG INFO: S=Service, C=Commercial as per the "Motor Oil Guide 2010." It's a good question whether modern oil formulated for high compression, fuel injected, 200k mile engines, would be suitable for engines that originally used single grades not above SAE30 viscosity. As you can tell, there are quite a few perspectives. -VT/Jeff Last edited by VeryTangled; 06-30-2013 at 07:19 PM.