Brumbach

Does anyone know how the minimum requirement of 1200 ppm was determined?

Mike Ward

All the oil company engineers spend their days reading CF and design the products accordingly. I thought that was obvious.

Brumbach

Maybe but to a novice like me it’s not. I’ve read hundreds of opinions from users stating ZDDP should be equal to or greater than 1200 ppm. And other user opinions stating that too much ZDDP is bad. I’ve read dozens of oil mfg claims that their product is for flat tappets and their spec sheets demonstrates >1200ppm. And then folks have published independent lab tests disputing the claims of the oil mfg. But I’ve never seen anything published from car mfg (or cam mfg) stating the minimum required ZDDP. Where did the 1200 measurement come from? I’m sure it’s been substantiated. Just curious.

Plasticman

And I am sure that as the pressure loading goes up (think race cam valve springs), that the number becomes a moving target...........your 1200 might be fine, whereas mine with a heavier spring will be a disaster.

Plasticman

Vetterodder

I suspect that was a typical amount before it was reduced.

MiguelsC2

At the risk of controversy.

Stick with Shell Rotella and forget about it.

MiguelsC2

Isn't all of that decided by SAE?

After hundreds of opinions. Looks to me, that you have uncovered about all there is.

Did you read the insane oil sticky here on the Forum?

babbah

Way too much detergent in that diesel oil, but you already have heard that.....Read Read Read.....

MikeM

The standard was established in 1953-54 at around 850-900 ppm. This reserch was done AFTER the new OHV engines of the period experienced cam/lifter failures. Open some old automotive books and you can read all about it from 60 years ago.

That standard would have been good for any flat tappet cam Detroit put out for street engines that they warranted. Like Plasticman says, it's probably a moving target, depending on a number of factors. With your L-79 engine and stock valve train, that's all you need.

I have no idea where the 1200 ppm figure came from.

1snake

Hundreds of thousands collector car owners (myself included) do exactly that and they/I have ZERO problems.

Jim

Godholio

I recently sent a sample of new Mobil Delvac 1300 to Blackstone. Unused oil, purchased a few weeks ago locally.

Zinc 1024
Phosphorus 881

ren

I used to add ZZDP plus to Castrol 10W/40W. Been using Rotella for the last 2 yrs. Just became aware of a zinc additive made by Risolone. Anybody use this product?

Frankie the Fink

Why not just buy a good oil with the zinc and phosphorus already added ?
I've been running synthetic Mobil One 15W-50W for two years -- no issues and no additives.
Here is the spec sheet for their oils.

65tripleblack

A very important factor for your consideration: ZDDP is consumed as the cam and lifters rub against each other. It is not so much a matter of how much is enough, but how long can you use the oil before ZDDP consumption drives the concentration down to dangerous levels. If for example, your oil has 500 ppm ZDDP content, that might be fine for a full race flat tappet cam so long as the oil is changed after every race, whereas, for a mild flat tappet cam like ANY of the vintage 1950's - 1960's cams, then frequency of oil changes would be less often than if you were running a cam requiring higher spring loads.

65tripleblack

Frankie............

It is great oil, and I have been using it for the last couple years as well. I need full synthetic because of elevated oil temps during extended highway cruising due to a 3/4 filled block.

The only trouble is, is that I can't keep it IN the engine and OFF the garage floor. One piece oil pan gasket, and well sealed valve covers notwithstanding. Damn stuff comes out of the damnedest places! I'll have to put up with it until next year when I install the ROD 6 speed with .76:1 overdrive, at which time I'll go back to the Brad Penn Racing oil which also has 1500 ppm ZDDP.

vt65

not sure about Rislone but GM stores sell EOS (engine oil suppliment) said to be a good zinc and phosphorus source, that's what i have been adding to my oil changes

Frankie the Fink

I've been lucky the only oil leak (other than easily fixed valve cover, self-induced leaks) is a small drop under the car after it sits for a week or more. I'm not tearing anything apart for that very minor nuisance !