Engine Lubrication, Let's Talk

Let's have a discussion on the lubrication requirements of our old Horses. I have religiously used Mobil 1 in my tractors with good results, however, I recently learned that our government now requires oil companies to reduce the amount of zinc, ZDDP (Zinc dialkyldithiophosphates) in our gasoline engine oils to below recommended levels for flat tappet engines because it "may be harmful to catalytic converters". Here's the Wikipedia description of ZDDP:

The main use of ZDDP is in anti-wear additives to lubricants such as greases, gear oils, and motor oils, which often contain less than 1% of this additive. It has been reported that zinc and phosphorus emissions may damage catalytic converters and standard formulations of lubricating oils for gasoline engines now have reduced amounts of the additive, though diesel engine oils remain at higher levels.[4] Crankcase oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat tappet camshafts and lifters which undergo very high boundary layer pressures and/or shear forces at their contact faces, and in other regions such as big-end/main bearings, and piston rings and pins. Roller camshafts are more commonly used to reduce camshaft lobe friction in modern engines. There are additives, such as STP(R) Oil Treatment, and some racing oils such as PurOl, Brad Penn and Valvoline VR-1, which are available in the retail market with the necessary amount of ZDDP for engines using increased valve spring pressures. The same ZDDP compounds serve also as corrosion inhibitors and antioxidants.

Here's my take on this, Kohler engines used in our tractors are flat tappet engines with stiff valve springs thus requiring a zinc additive. B&S on the other hand have very weak springs which would not suffer from the new Federal oil requirements. At this time I am inclined to add some Lucas TB Zinc-Plus Engine Break-In Oil Additive to all of my Horses to restore the proper amount of zinc protection to the engines.

What say you?

I agree Geno, it's a can of worms but worthy of discussion. This is the same government that took away tetraethyllead additives in our fuels and added ethanol.

I guess I'll use an additive. It can't hurt..

I'm with you Motor. The more I read on the subject the more convinced I am that an additive will extend the lives of these engines. 1200 PPM of zddp appears to be the bare minimum recommended amount where as the new oil mandates are less than 900 PPM, typically. Any API tested oil is required to adhere to these standards, the exception are oils rated for diesel engines. If an oil is labeled "Energy Conserving" it will have a low zddp content. This issue isn't exclusive to cams and tappets but includes cylinder bores, wrist pins, crankshaft journals, all wear surfaces, you get the picture.

Here is a good article from Hemming's on the subject zddp content.

http://blog.hemmings.com/index.php/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/