How much zddp

[n2omike]

I've always used Mobil 1 15w50 synthetic in all my flat tappet and air cooled (yard/motorcycle) engines. Have used it for decades. It's the only Mobil 1 grade that has a good ZDDP content at 1300 ppm. Can usually pick it up at Advance Auto. 5 quarts with a Mobil 1 filter is often on sale for around $35. Can sometimes find 5 quart jugs at Walmart for around $28.

There's a few really good "Off the Shelf" oils out there. I don't recommend them, because the large companies have a history of changing an oil's formula, without ever telling anyone. There's a much smaller risk of that happening with a "Not for on-road use" oil.

I believe the reason the Mobil 1 15w50 has escaped the ax as far as ZDDP is concerned... while all of the other standard 'off the shelf' Mobil 1 viscosities got cut to around 800... is that it is not a 'standard' viscosity recommended by any current auto manufactures, and is labeled as 'Racing' on the bottle. It's a great, very affordable oil for flat tappet cams, dirt bikes and various air cooled engines.

One thing I will give you on your statement... is that you are correct that oil formulations can change without warning. It's best to keep an eye on their websites, or to make sure the bottles recommendations do not change.

[BigBlockMopar]

How about the API-ratings. Doesn't anyone look at those?
I thought anything upto API "SL" is still good to use in a FT-engine.
API SM and higher is only to be used for 'stock' cammed/valve-springed flat-tappet engines.

[tenxal]

VR1 has about 1200ppm ZDDP.

Yes, that's correct. Should have had another cup of coffee and I wouldn't have mistyped that!

[Roundybout]

Does ZDDP need to be “replenished” after the initial break in period with a FT cam? I was under the impression during break in heat causes the ZDDP a form a protective layer protecting the surfaces. Is it a sacrificial later that is worn away?

[pdq67]

How about the API-ratings. Doesn't anyone look at those?
I thought anything upto API "SL" is still good to use in a FT-engine.
API SM and higher is only to be used for 'stock' cammed/valve-springed flat-tappet engines.

I thought it was, "SF", but I may be off so please check me.

And as stupid as this sounds, I smell oils and if the one I'm holding smells like 90wt gear lube, I figure that it has a good additive package in it As well as that old, dark, "Teal", color of old.

pdq67

[Mattax]

I'm I placing to much importance on zinc and is there a point that to much is a bad thing.

Yes.
Somewhere above 1,400 ppm can be a bad thing.
1. results in excessive ash
2. can cause damage to the metal surfaces

The latter was not at 1400 ppm, but when concentrations were getting around or above 2000 ppm.

ZDDP does gets depleted through use and turns to ash. So starting a little above 1400 is not something I'd worry about if the oil is going to be run a couple thousand miles. However the reason 1200-1400 ppm became the target in the late 70s was to insure there would be enough ZDDP to remain over 800 ppm up to the next oil change.

As far as grade goes, run whatever grade the engine is built for, balanced against the oil temperatures.
On a related note. Widman has recently (Nov 2019) updated his "Oil for Corvairs"; expanding it slightly to recognize similar needs with other flat tappet engines, and even a couple comments on racing (road).

Generally one advantage of the 40, and 50 multigrades, as well as the tradational single grades over multigrade 30 was the high temperature, high shear (HTHS) performance. But Widman points out there are some xW-40 with as good HTHS as some 20W-50s. It's just that the minimum for qualifying as a 20W-50 is higher than the miniumum for a 10W-40.

He also has a paper on oils for Classic Minis which is interesting to look at because of the gearbox lubrication requirements.

https://www.widman.biz/English/Bulletins/flat.html

n2omike: Limited comments about specific oils but you might find the note about mobile's current 15W-50 on page 24 interesting as its one of the examples of a relatively low HTHS within its grade.

[Mattax]

The documents cited by Widman, as well as Grant are:

“Cam and Lifter Wear as Affected by Engine Oil ZDP Concentration and Type”
Loren G. Pless, John J. Rodgers, Fuel & Lubricants Dept., Research Labs, General Motors Corp. SAE Report 770087, 1977

“How Much ZDP is Enough?” R.M. Olree, (GM Powertrain),M.L. McMillan (GM R&D) SAE Technical Paper Series 2004-01-2986, October 2004

Grant gets more into the additive history. https://mbca.org/sites/default/files/oi ... h_cars.pdf

[pdq67]

I think a guy by the handle of, "540Rat", had a great big oil study on the Boards at one time?

You might want to hunt it up..

pdq67

[Diodedog]

Here's some good videos from Amsoil

[Mattax]

I hope to never see a Rat post ever again.
Might have meant well initially but over the top irrational extrapolation.

[CamKing]

I think a guy by the handle of, "540Rat", had a great big oil study on the Boards at one time?

You might want to hunt it up..

pdq67

NOoooooooooo !

Rat studying oil, would be like me studying electrical pulses from neurons in the brain.
I could study them 24/7 for years, and still have no idea what I was looking at.

[David Redszus]

The amount of ZDDP in an oil is not of great consequence. What matters is having enough anti-wear additive in the oil.
There are several anti-wear additives that can be used in combination with ZDDP.

An oil with a higher level of ZDDP does not provide more anti-wear protection. But it does provide wear
protection for a longer period of operation.

In a race car, how often is the oil changed? How often are the additives replenished?

What other properties of an oil are important in a performance application?

[F-BIRD'88]

The Moly Slip engine oil additive has both zinc and MOLY in it just right for flat tappet cams.
Moly is more important than zinc for initial run in.
www.molyslip.com

don't over think this... ad to a good oil like Shell rotela 15w-40.

[CamKing]

The Moly Slip engine oil additive has both zinc and MOLY in it just right for flat tappet cams.
Moly is more important than zinc for initial run in.
www.molyslip.com

I recommend to never use an oil that has molybdenum disulfide in it. It's corrosive.

[F-BIRD'88]

Ground up cam lobe and lifter face is MUCH MORE CORROSIVE.