Who knows what about Rotella. ZDDP Related.

[vping]

I went to a tech session a week or so ago at a famous engine builders. The subject of ZDDP was brought up and we were told that using Rotella will solve that problem or uning a Zink additive. Since Rotella is $10 a gallon and so is the additive I figured this is easier and I can get it locally. Problem is what grade to use. I normally run 20-50 but the store only carries 30w or 5-40. Are either of this acceptable?

 

[Steve_S]

Diesel fuels aren't the answer. If you put that stuff in a high-mileage engine, the large amount of detergents will knock loose all kinds of crud and you will be very unhappy. Oil formulations are a real science, and the best thing you can use for a gasoline engine is an oil designed for such.

Personally I don't believe in additives either. Motor oils are very carefully balanced to provide the proper amount of each compound within them. Dumping a bunch of extra "stuff" in there upsets this balance, and while it may provide added protection in one area, it could seriously compromise protection in another.

There are oils specifically engineered to protect older engines such as ours, so I prefer to simply use those. DA Super Speed Sport is my current choice. I see Moss is selling "Collector's Choice" and this is an oil I've been planning to look into. I have no experience with it yet though.

 

[ronzi]

I have Rotella in my '64 B now, and so far, so good.

The rap against it I have heard is that it is intended for use in diesel engines and is consequently a very high detergent oil. Diesel engines apparently have a much more elaborate oil filtering system to filter out all the gunk from the oil. Our cars do not have the same kind of filter so .... ? So what? I don't know. Is my engine going to get TOO clean? Is my filter going to get clogged up from all the extra gunk being sluiced out of the motor? I don't know that either.

 

[Silverghost]

According to an article published in the May/June 2008 Flying Lady, the magazine/newsletter of the Rolls Royce Owners Club, on page 8869:

Many have heard that the US EPA is continuing it's mandated ratcheting down of the anit-wear additive ZDDP, even on diesel engine crankcase oil like Shell Rotella. This is due to potential harm to catalytic converters.

The article goes on warn against adding additives because it is hard to know how much zinc and phosphorous are ALREADY in the oil. Too much additive is corrosive to yellow metals and bearing materials. New additives work well in modern cars as modern engines have no copper bearing metals in them. Older engines (the article refers mainly to the engines of Silver Ghosts) can have yellow metals in the timing gears, cam bearings, oil pump housing, oil pump relief valve, and thrust bearings. Anything over .12% ZDDP can be harmful and etch yellow metals.

The Silver Ghost Association has formulated two additives for crankcase oil. One provides better antiwear properties and the other provides increased viscosity.

There is a note at the beginning of this article that expresses that while geared for Silver Ghosts, this is a subject applicable to a much wider audience and is a complex, if not controversial subject.

Most are aware of the changes in gas with ethanol, etc. and there is this issue as well. I thought this information would be useful to the members here. I hope I gave proper and appropriate credit to the source of the information.

 

[Mickey Richaud]

Problem is what grade to use. I normally run 20-50 but the store only carries 30w or 5-40. Are either of this acceptable?

Did you mean 15/40? That's what I'm using. Happy so far.

 

[Steve_S]

I'd use 30W before 5W-40. That's for tighter tolerance engines, such as those found in modern cars.

 

[PAUL161]

I've been around diesel engines most of my life and feel pretty confident that my knowledge of them is slightly above average. This also includes oils used in them. I agree with Steve when he says that you should be very careful when using oil formulated for diesel engines in a gas engine. Don't get me wrong, you can use those oils in a new or newly rebuilt gas engine. But, if it's an old engine with any sludge or foreign particles sticking inside the engine, high detergent diesel oil formulations will break it all loose and it will eventually form at the oil pump screen. I don't think I have to emphasize what will happen then. Because diesels are prone to high carbon deposits in side the block, Super high detergent oils were designed just for them. Why aren't they used in all new gas engines? Because of cost. The zinc measurement in oils is depleting rapidly and there is nothing we can do about it, other than using a replacement. What those replacements are, what are the best, I haven't a clue. I use STP in all my crank case oils and occasionally put in few drops of Marvel Mystery Oil in the gas. Say what you want about this combination, but I've used it for 40 years with good results and never had a problem with any of my engines. So, bottom line, what ever works best for you, use it. But again, be careful using super high detergent oil in an old engine. PJ

 

[Mickey Richaud]

...which is why I'm using Rotella in the TR8. It's a fresh rebuild, so the deposits aren't an issue. Also, I've been told that these engines are prone to becoming pretty dirty, so using Rotella, and changing it often makes sense.

For the B, I'm still using Castrol 20/50.