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Originally Posted by Sensei I'm sure alot of you may already be aware of this, but I am surprised by how many people, even full time mechanics that pride themselves on keeping up to date that have not heard yet. The EPA recently required oil companies to remove the zinc from motor oils as it damages catalytic converters. Zinc is a lubricant that roller tappet engines can do without, but flat tappet camshafts are getting wiped left and right. Shell Rotella T oil (made for deisel trucks) and Valvoline racing oil still have zinc. Other than that, you need an additive. God bless, Sensei |
The above blanket statement is, IMO, irresponsible.
It is true that oil refiners and blenders have, over the last decade or so, been forced by EPA regulations to remove and/or reduce the amount of certain extreme pressure (EP) lubricants from engine oils. Examples of these EP additives are zinc, molybdenum and calcium, however, not all of them have been banned/removed.
It is, also, true that there are a number of engine oils out there, including the above mentioned Shell Rotella and Valvoline Racing Oil, which still have very robust EP additive packages. Generally these engine oils are sold to the heavy duty market or for motorsports.
It's irresponsible to post "Other than that, you need an additive" because that statement is false. Further, even if it were true, it's ridiculous to post such as statement but not also post some specific information as to what "additives" (if there really are any containing the right ingredients in the correct amounts) can supplement the reduction in certain EP additives in engine oils currently available to consumers today.
The above says nothing about what oil refiners have used to replace zinc...afterall, zinc is not the only EP additive. The above also supplies no data to support the implied belief that wide-spread failures of flat tappet camshafts is taking place--which it's not. Contrary to what many think, the entire auto industry has not converted to roller tappets. There are many engines, especially those with overhead camshafts, which use flat tappets so there is an installed base of tens of millions of late model engines which use flat tappet cams. Do you think oil refiners have simply begun to ignore the needs of those engines, many of which are still under warranty?
Not even.
Now, where those with flat tappet camshafts need to be concerned is the following circumstances in combination: 1) tendency to buy cheap oil and 2) use of significantly higher than stock valve spring pressures to control the valve train when a more radical cam profile is used or the engine runs in a higher rpm range.
What are the solutions?
Better oil than some of the mass marketed stuff many people insist on using.
Some examples of excellent petroleum-base oils are:
Shell Rotella
Chevron Delo 400
Valvoline Racing Oil.
Shell Aero oils
A good synthetic with an EP additive package which is still pretty good:
Mobil 1 15W50
An outstanding, ester-based synthetic which contains a high quantity of an extremely robust EP additive package:
Red Line Race Oil (any viscosity)
It's important to note that any of the above will decrease catalytic converter life, especially in an engine with high oil consumption. For example, if you have a Vette which has been modified with both an aggressive flat-tappet camshaft, high tension valve springs and forged pistons but also has a cat converter(s) and you use a diesel engine or racing oil to lube the camshaft, you're headed for trouble as the increase oil consumption common in forged piston engines coupled with the oil containing a lot of EP additives is going to degrade the catalytic reactant in the converters more quickly. The solutions are either 1) a roller cam 2) finding a better oil choice such as a premium synthetic intended for street use, like Red Line 10W30 or 10W40, which has less or different, but still robust EP additives or 3) changing your engine configuration to reduce oil use and decrease valve spring pressure.
Those with older engines running stock or near stock camshafts with profiles having modest velocities and stock or near stock spring pressures can continue to use mass-marketed engine oil which meets modern API specs and comes from a reputable refiner and have no worries about durability. You also don't need to start spending a lot of money on an oil additive, either. The idea that an additive is required is ridiculous. In a few cases, an additive might be useful but, even then, you'd better understand what's in the additive and that seldom is discussed by the snake oil....er.... additive maker.
Lastly, oil changes--do them at the oil change interval specified in your Owner's or Service Manual. For normal duty cycles the so-called "3000-mile oil change" is pure propaganda by the "quick-lube oil change" business. Not only that, 3000 mile oil changes are wasteful and environmentally irresponsible.
Art
Attention all with flat tappet cams 
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