The Straight Scoop on ZDDP (Zinc) Additives

April 27, 2012 by Jeff Ventura

Q:

Hi Rislone. The waters are really muddy right now as far as newer oils without ZDDP, and even with the zinc additive. I have procured gallons of your Rislone with ZDDP trying to protect my older engines. Having some older MGs, I keep up with the latest gossip on a very popular MG forum in the old T car section (TA TC TD TF).

In the latest issue of the New England MG T Register’s Sacred Octagon, there was an article, “Show me the ZINC”: 

“During a conversation with Bob Wagner, owner of Wagner Motor Sports in Atlanta, the question about inc levels in oil came up. I told him I have been using Valvolene 20W–50 VR1 (racing oil) in five of my seven British cars for the past 15 or more years with no problems. Then I said ”on the last Harley engine rebuild I added a zinc additive to the VR1 just for GP."

"He said he has been using racing break-in oil on all of his race engine rebuilds and a mix of racing break-in oil and conventional oil on street engines with great success. He also said he was told by his race oil supplier about the problem that was found by using the additive. The additives are not working because the new detergent oils do not allow foreign matter to stick to engine parts. Zinc being a foreign matter is held in suspension and is not allowed to stick to surfaces such as the lifters and cam lobes Bob and I agreed this sounded reasonable but was it true… we didn’t know.

Since then I have talked with members of the Ford Flat Head Club, a hot rod buddy, a representative from Joe Gibbs Oil and they have all confirmed what Bob Wagner had said. From what I have been told the above oil companies have run test that show zinc additives added to conventional oil offer little or no protection."

The article rambles on, but you get the gist of it.

As an engineer and owner of a hydraulics business, I find this rationale quite illogical. 

First off, if it were added to old nondetergent oil, I’d expect to find it in the sediment on the bottom of the oil pan in no time. Thart fact that detergents keep it in circulation is a good thing. Engines survive on an oil film in a perfect world, but when there’s metal-to-metal contact at startup and often cam lobes/followers, I like the thoughts of zinc there in the crunch. I’ve been known to dump graphite powder in my engines, too.

It sounds like the specialty oil suppliers are trying to scare people into buying their products.

There are a lot of us old codgers out here with money to spend and cost is no object when it comes to oil for our expensive toys.

Jim N.

A: 

Jim, it is very hard to be in this industry and be totally unbiased. It becomes natural for additive companies to push their brand, and for oil companies to push any specialty oil products they produce, which many times sell at a premium price. In our case, we have worked to reduce the cost as much as possible which is why we are releasing a super concentrated version of our ZDDP additive that will be $7.99 or less at most locations starting summer 2012. Until then we have our quart available. Use this additive with your favorite SN-rated motor oil, and it will boost your zinc and phosphorus levels to 1600 to 1800 ppm. We at Rislone work hard to offer product solutions that solve problems. We have been doing it since 1921 and have seen many changes in motor oil tribology, additive chemistries, their solubility and performance. This is no different than the ZDDP (zinc dialkyldithiophosphate) supplement additives we have formulated for the latest problem. Today’s oils are not designed to be run in older engines. The oil companies have worked hard for years to keep oils backward-compatible, but it has finally hit a wall. For the most part, the situation is no different than when lead was removed from gasoline. In older vehicles that were designed run on leaded regular gasoline you either need an additive, or make changes in the engines to adapt them to survive with unleaded fuel.

The product in our bottles is our own proprietary formulation developed from our 90 years of real world experience, along with R&D partners who have developed, formulated and analyzed PCMO’s, HDDEO’s and high performance oils through multiple API Service Categories and OEM performance requirements.

To help understand why there is a need for this product, you need to understand how oils have changed in the past 30 years. Just think back to the SF oil that had nominal levels of zinc and phosphorus at 1500 to 1600 ppm where the current SN oil has a nominal value of 600 to 700 ppm. The reason for this drop was the negative effects phosphorus was shown to have on some emission components, like catalytic converters. Even after all these years, ZDDP is still one of the best additives to prevent wear & oxidation and inhibit rust. The Rislone ZDDP Engine Oil Supplement formulation employs advanced ZDDP technology which has shown no detrimental effects to emission control devices due to its very low volatility.

Today’s engines are designed to run with this lower level of protection, because the sliding metal parts are either designed with rollers or anti-friction coatings to prevent wear. But even today’s engines need some ZDDP to protect internal engine parts, and it continues to work well with the latest oil technology, both regular petroleum and synthetic. This does not help everyone who owns an older vehicle that needs higher levels of ZDDP, especially classic cars, or racing engines that have higher valve spring pressures or those which are not driven daily. History has shown that reducing the ZDDP package has seen increases in premature failure with flat tappet camshafts and other internal engine parts. What can be deceiving is that in many cases, this does not happen overnight, but could take months or even years. This is because the ZDDP provides a sacrificial layer that does get consumed as miles accumulate on the engine.

ZDDP is still necessary in crankcase motor oils and due to its polarity it is in solution, not suspension otherwise solubilized, e.g. scotch & water. The polar zinc migrates and grabs on any exposed surface. The detergent package will not prevent the zinc from bonding with the metal surfaces, nor will it remove the zinc once adhered. These detergents and dispersants keep oxidized particles & soot suspended to be captured by the filter. There is a certain ratio of zinc to phosphorus inside the additive package to make sure this happens. In fact, most ZDDP oil additive packages contain detergents as part of the package.

You can make laboratory type testing show most any results you want to convince consumers that your way of thinking is correct. At the end of the day it is the real world testing and use that everyone needs to count on. Not to sound like a commercial, but Rislone produces the best additives sold worldwide, and as we approach 100 years in business, we’ll continue to create products needed for the ever-changing automobile.