AMSOIL Motor Oil with Zinc for Older Cars

Older vehicles such as classic cars and hot rods should be using motor oil formulated with zinc. What is a motor oil that contains high amounts of zinc? ZDDP, scientifically known as zinc dialkyldithiophosphate is the most commonly used zinc-based additive. Its function is to prevent engine wear.

It is considered an anti-wear agent. Its secondary yet still useful function provides oxidation and corrosion protection. In this blog post, we’ll discuss the best AMSOIL motor oil with zinc for older cars that you can use to get the best possible performance out of your favorite hot rod!

Why It’s Important to Use AMSOIL Motor Oil with Zinc for Older Cars

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Zinc and phosphorous, both components found in ZDDP, were found to be harmful to catalytic converters. Because of their negative effect on catalytic converters, they have been phased out in recent engine oil formulations.

Unfortunately, the vast reduction in the use of ZDDP in modern engines has caused problems for classic car enthusiasts.

AMSOIL Z-ROD® 10W-30 Synthetic Motor Oil.
AMSOIL Z-ROD® 10W-30 Synthetic Motor Oil

Many older vehicles that have been designed with flat tappet camshafts have especially seen abnormal wear. Flat tappet camshafts that also utilize high tension valve springs that create high contact pressures have shown unwanted wear because of this reduction in zinc levels.

Engine builders and motorheads should seek out engine oils formulated with high zinc and phosphorous levels. These higher ZDDP engine oils will provide the best possible protection for flat tappet cams, lifters, and other critical parts during the initial break-in, engine startup, and long-term usage.

If you are looking to give your favorite hot rod/classic car the best performance possible, AMSOIL’s Z-ROD Synthetic Motor Oil is a must. This premium high-performance motor oil comes in two viscosities, 10W30 and 20W50.

The Power of Zinc Additives

How exactly do zinc additives work? Zinc anti-wear agents are activated when exposed to heat. In other words, in areas of increased friction that cause heat, the ZDDP additive is heat activated, thus providing anti-wear protection.

In greater detail, what happens is that as temperatures rise, and as metal surfaces come closer together, the zinc starts to decompose and the resulting chemistry from this decomposition protects the critical metal surfaces.

During engine operation, as these parts move in either a rolling or sliding motion, the moving actions take place either within or on top of the zinc anti-wear film rather than having bare metal-to-metal contact. This strong zinc anti-wear film’s job is to keep these two metal surfaces from contacting each other.

This strong armor-like protective film provided by zinc is especially critical in older classic engines that utilize flat tappet camshafts. Also, any engines that have been modified to create more horsepower can benefit from zinc anti-wear film.

For example, racing engines utilize high tension valve springs, which help to increase the possibility for premature cam wear, thus utilizing zinc in this application can stop any unwanted wear.

Why Are Flat Tappet Cams More Vulnerable to Wear?

What is the difference between roller cams and flat tappet cams and why is one more vulnerable to wear than the other? Flat tappet cams are more vulnerable to wear because of their design. As the name implies, the tappet, or lifter, is actually flat.

AMSOIL Z-ROD® 20W-50 Synthetic Motor Oil.
AMSOIL Z-ROD® 20W-50 Synthetic Motor Oil

As the cam lobe rapidly slides over the flat tappet during engine operation, temperatures and friction are greatly increased.

An engine oil lacking in zinc or having insufficient amounts of zinc could fail and not provide the necessary wear protection, thus causing the flat tappet cam to prematurely wear and also affect valve operation.

Remember, there is only a very thin protective oil film acting as the only barrier that is preventing the cam lobe and lifter from becoming welded together.

If this were to happen, then engine efficiency and power will be reduced because the flat tappet cam is not able to lift the valve sufficiently to properly charge the combustion chamber enough for ignition or to adequately remove and release exhaust gases.

During the classic muscle car era, most of the cars were V8 powered, and these engines were designed with standard flat tappet cams. These hot rod and classic car owners are especially vulnerable to any problems that could occur from using an oil without zinc or not enough ZDDP.

Roller cams differentiate themselves from flat tappet cams because of the rolling contact rather than the sliding contact of flat tappets. Roller cams are more expensive and are ubiquitous to most modern vehicles. It is possible to modify their use into hot rods and classic car engines.

Maximize Engine Performance

It is also important to utilize AMSOIL synthetic motor oil with zinc for older cars if the desire is to improve your chances of engine longevity and to also maintain performance and horsepower. Zinc is critical for minimizing engine wear in older vehicles.

AMSOIL Z-ROD® 10W-40 Synthetic Motor Oil.
AMSOIL Z-ROD® 10W-40 Synthetic Motor Oil

There is a constant cycle of extreme pressure during engine operation that can rupture the oil film whose job exists in preventing metal-to-metal contact and premature wear.

Once this oil film ruptures, the only barrier that is left to protect metal-to-metal contact would be the thin film of ZDDP. It is the most effective anti-wear additive and is required for older classic cars and hot rod engines.

Benefits of AMSOIL Z-ROD® Synthetic Motor Oil

Z-ROD® is built specifically for vintage vehicles. This motor oil contains high levels of ZDDP, rust inhibitors, and top-tier additives that are used to preserve your ride, provide optimum efficiency, and keep your classic car/hot rod engine void of corrosion and rust when in storage.

Flat Tappet Cams are Protected

  • Contains a high concentration of ZDDP to support flat-tappet cams, rockers, lifters, and other parts that are prone to wear
  • The high-phosphorus, high-zinc composition offers the additional wear resistance needed by splash-lubricated parts
  • Combats wear to aid in the prevention of compression failure, allowing for optimum horsepower

Assists in the Prevention of Corrosion and Rust

  • Contains a proprietary combination of corrosion and rust inhibitors to provide optimum security during extended storage
  • Corrosion and rust is inhibited in industry-standard tests (ASTM D1748-10) for outstanding motor safety

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