Zinc Levels in Engine Oil - Tech Tip

One of the more frustrating technical enquiries we answer from both retail and trade is questions about the amount of zinc in engine oils.

It seems the so-called “Forum Experts” still manage to scare both consumers and mechanics into thinking that “Zinc” is the saviour of engines from the evils of wear, breakage, poor fuel consumption, noise and every other problem associated with an internal combustion engine. In most cases, it couldn’t be further from the truth!

Zinc in oil, is used as an anti-wear agent. It is put into the oil with phosphorus in a chemical known as ZDDP  (Zinc dialkyldithiophosphates) or ZDTP (zinc di-thiophosphate). This has been the additive of choice for many engine oils over the years due to its cost and chemistry effectiveness. It is a sacrificial wear agent used to prevent wear in the rings, camshaft and valve train of the engine.

We hear frequent stories where customers have been told – by a so-called “Expert”, that they HAVE to get a High Zinc Oil otherwise their engine will suffer premature wear or even failure. 

What the customer has not been told is - 
1)    What constitutes a High Zinc Oil? 
2)    How much Zinc do they need? 
3)    Why they need Zinc? 
4)    What other specifications do they need?

In fact, only a very minor percentage of the total population, actually know what a standard zinc level would be in a full SAPS engine oil. The same again for why zinc in oils are at this level, how this relates to specification and what really constitutes a high zinc oil. So what constitutes a high Zinc oil? Normal standards for a Full SAPS (Sulphated Ash Phosphorus and Sulphur) engine oil is above mid and low SAPS levels which are under 1000 PPM in Zinc. So anything above that number could be considered to be Full or High Zinc oils.

Another question we get asked frequently is about using zinc additives when breaking in a new engine. Many are told it is a “MUST” for the camshaft to allow it to bed in properly during the running in period. Some manufacturers and marketers even put warranty guidelines on their parts where they tell the customer that if they don’t use their particular zinc additive, it will void warranty. Again, what these companies don’t tell the consumer is that once an additive is placed into an oil, it effectively wipes any warranty with the engine oil as they have changed the chemical constitution of the oil.

Another consideration that the so-called “Experts” don’t  understand or explain, is that for zinc to act as an anti-wear or sacrificial agent, it needs to be exposed to heat and load. When running in a camshaft on an engine, it takes the engine oil approximately 5 - 10 minutes to reach operating temperature. So what happens to the protection during this most critical period? Once it has reached operating temperature and the oil placed under load, then Zinc can start working. Extra Zinc will not work any faster or provide any more protection during the initial start-up period of a new or rebuilt engine. During a 20 minute dynamometer run in, The zinc or zinc additive is not going to provide a massive level of extra protection. A camshaft or engine assembly lube is a much better option.

Click here to find out more about Zinc Myths & Legends.

Further details on our products are available on their respective product page found on the Penrite web site: www.penriteoil.com.au/

Looking for more Technical Information? Please click on "Technical" at the top of the page. To talk to the Tech Team call 1300 PENRITE (M-F 7:00am - 5:30pm AEST) or email tech@penriteoil.com.au

Posted on: 19 Dec, 2017