Benefits Of ZDDP For Older Engines

As vehicles age, maintaining engine performance becomes increasingly challenging. This is especially true for older engines that rely heavily on well-formulated engine oils to keep them running smoothly. One of the most important additives for these engines is Zinc Dialkyl Dithiophosphate, or ZDDP.

As vehicles age, maintaining engine performance becomes increasingly challenging. This is especially true for older engines that rely heavily on well-formulated engine oils to keep them running smoothly. One of the most important additives for these engines is Zinc Dialkyl Dithiophosphate, or ZDDP. But what exactly is ZDDP, and why is it so crucial for older engines? In this article, we’ll explore the benefits of ZDDP for older engines, how it works, and why it should be an essential part of your engine care routine.

What is ZDDP?

ZDDP stands for Zinc Dialkyl Dithiophosphate, a chemical compound commonly used as an additive in engine oils. ZDDP has long been known for its ability to protect engine components against wear, particularly in high-stress areas like the valve train. The compound works by forming a protective layer on metal parts, reducing friction, and preventing damage caused by metal-to-metal contact.

Advantages of ZDDP in Oil

Zinc dialkyldithiophosphate, commonly referred to as ZDDP or simply “zinc,” is an anti-wear additive that forms a protective surface layer within the engine. This zinc additive adheres to metal surfaces, reducing metal-on-metal contact during high-load conditions when the oil film becomes thinner. Additionally, this boundary layer helps prevent corrosion caused by oxidation, keeping engine components free from rust. Therefore, ZDDP is particularly beneficial for engines with higher inherent valvetrain, piston, and bearing friction, as well as for engines that remain idle for extended periods.

Why Older Engines Need ZDDP

Older engines, especially those with higher mileage, are prone to increased wear and tear. Over time, the internal components of the engine, such as the camshaft, lifters, and valves, can become worn, leading to decreased performance. ZDDP is vital in these situations because it provides the lubrication necessary to prevent further damage.

How Do Zinc Additives Impact Old Engines?

If vintage vehicle's engine relies on a flat tappet lifter, it will require engine oil containing zinc or a zinc substitute additive. Zinc in the engine oil helps prevent premature wear of the lifters and camshaft.
Engines built before the 1980s commonly featured camshaft designs with flat tappets, which generated substantial friction. Modern roller cam designs have reduced this friction, but older vehicles with flat tappet engines still need zinc oil additives for protection.
Without protection, the friction in a flat tappet engine can cause significant damage, such as overheating and reduced efficiency and performance due to cam wear.
As engine technology advanced, modern oil companies phased out zinc additives like ZDDP and ZDTP from standard motor oils. Consequently, using modern oils in classic engines is often unwise, and specialized zinc additives are needed for older cars.
Though zinc additives are less common in newer engines, some companies still produce them or their replacements. When selecting motor oil, look for products with appropriate levels of ZDDP (1,000–1,400 ppm) and ZDTP, or specialized zinc replacements that offer equivalent or better protection.

Why Use Zinc Replacement Additives?

Zinc replacement additives provide a similar level of lubrication and coating without the negative effects of ZDDP. Zinc can harm the catalyst when it gets on it, resulting in the catalytic converter having a shorter service life and increased emissions. Due to these effects, the OEM engine manufacturers and the EPA have both directed companies to reduce the level of ZDDP in their motor oils and other products.

Though there’s no doubt these measures are important for protecting consumers’ cars from premature damage to catalytic converters, the regulations do leave older engines in a tough situation. They need zinc for the anti-wear protection they provide, but they also need to follow regulations and protect their catalytic converter. While the new regulations are great for reducing environmental impact and keeping engine components safe, any non-roller cam-designed or high-performance engine is left without the wear protection it needs.

The right zinc engine replacement additives will take the zinc and phosphorous out of the oil, while still providing the same high level of protection you’ve come to expect from a zinc product.

While using the product, you can be certain that any rocker arms, lifters or cams you apply the product to will be kept safe without any significant wear problems. As the product doesn’t use phosphorous or zinc, you’ll also be able to use it without fearing that you’re hurting the environment or harming your catalytic converters.