5 Reasons Why Your Business Needs Benefits Of ZDDP For Older Engines?

08 Sep.,2025

 

What is ZDDP - Benefits of Zinc in Oil - Speedway Motors

What is ZDDP - Benefits of Zinc in Oil

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Modern engines are vastly different than what the hobbyist racer or hot rodder has in their specialty vehicle. Engines have changed significantly since the s, and mainstream motor oil has followed suit. Today’s parts-store engine oil is engineered for modern engines, not your engine. This means your engine needs specialty oil from a specialty retailer, like Speedway Motors.

For more information, please visit He Ao.

Benefits of ZDDP in Oil

Zinc dialkyldithiophosphate, commonly known as ZDDP or “zinc” is an anti-wear additive that creates a surface layer boundary inside your engine. This zinc additive sticks to metal, minimizing metal-on-metal contact in high load situations, when the oil film thins out. Plus, this boundary layer has the added benefit of minimizing corrosion due to oxidation, so engine internals stay rust-free. As such, ZDDP is great for engines that have more inherent valvetrain, piston and bearing friction, as well as engines that sit for extended periods of time.

Zinc in Oil - Not a Myth

ZDDP was first used in mainstream motor oil in the 's, primarily for its anti-corrosion benefits. Zinc in oil kept the lead-copper bearings of the day from oxidizing, but it was also found to significantly reduce wear. As a result, ZDDP additive levels in mainstream oil gradually increased up until the early s, peaking around 1,200-1,400 parts-per-million.

Starting in the early 's, hot rodders, race teams and automotive enthusiasts began seeing an increase in camshaft and lifter failures, particularly with flat-tappet cams. Issues with flat camshaft lobes became common place. Enthusiasts began scratching their heads trying to figure out why these failures happened. Valve spring pressures were checked, lifters were matched to the cam, everything was put together correctly, and brand-name oil was used - but there was still a failure.

Significantly reduced levels of ZDDP oil additive in mainstream oil were to blame. Looking back, we know these things changed parts-store oil forever:

  • Addition of sensitive emissions equipment like O2 sensors and catalytic converters
  • Better fuel economy via more efficient engines (roller valvetrains, georotor oil pumps, thinner piston rings, etc.)
  • Introduction of ethanol in gasoline (first E10, now E15)
  • Increased levels of detergents, extending oil change intervals

Modern parts-store oil is engineered with all of these things in mind. Obviously, your Eisenhower-era cam-in-block engine has a different set of engineering challenges. It needs different engine oil additives.

Best Oil for Older Cars and Race Engines

Oil composition has changed greatly over the years and while a certain brand/type of oil may have worked great in the past, the reduction of zinc in oil could now spell disaster for your engine. ZDDP additive levels have gradually decreased since the s in ALL mainstream oils, including diesel oils. In fact, the APIs new “SP” oil specification, set for release in , is the first to not have been tested on an OHV pushrod or flat tappet engine.

For certification, API oils are tested on engines with a maximum 215 lbs. (open) valve spring pressure. Typical performance engines are equipped with valve springs over 280 lbs. (open) pressure. If you have an engine with a flat tappet cam, you need to be sure that the oil you use has enough ZDDP in it to create that layer of protection between the cam and lifters.

Motor Oil is Application-Specific

Just like all the parts in your engine, motor oil is designed for a specific usage and operating range. ZDDP additive packages will vary between applications, so be sure to match your oil to your vehicle: break-in oils, classic car oils, racing oils, diesel truck oils, or modern performance oils. Here at Speedway Motors, we’ve done the research for you. Our business is run by enthusiasts who’ve been building, racing and rebuilding engines for 3 generations. We know what motor oil additives you need, and which oils perform best.

See our full line of high-zinc oils, ZDDP oil additives and break-in oils by visiting our engine oil page.

Products Featured in this Article

  • Penn Grade 1 SAE 20W50 Synthetic Blend Performance Engine Oil, 12 Qt. View (35) $119.99

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    For more information, please visit Benefits Of ZDDP For Older Engines.

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  • Champion Racing H Synthetic Engine Oil, 20W50, 12 Quarts View (5) $163.32

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  • Driven Racing Oil XP3 Synthetic 10W30 Motor Oil, 12 Quarts View (4) $247.08

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  • Valvoline VR1 Racing Oil, 10W30, 6 Quart View (33) $53.99

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  • COMP Cams 159 Engine Break-In Oil Additive, 12 Ounce View (35) $19.95

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  • Lucas Oil Oil SAE 10W30 Hot Rod Engine Oil, 5 Quart Jug View (30) $44.79

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  • Royal Purple HPS 10W30 High Performance Engine Oil, 6 Quart Case View (5) $59.94

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  • Redline Cam Break-In Oil Lube Additive View (7) $16.79

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ZDDP for Older Engines (pre-) - Shade Tree Garage

When you own an older vehicle, you want to make sure it is well cared for and that the engine is running its best. At Shade Tree Garage we’ve made a commitment to keeping up with the latest technology. We also take preventative maintenance seriously and give our customers the best advice on how to maintain their car, truck or van for its lifetime. That’s why we recently started distributing a special oil additive for older cars (engines made before ) known as ZDDP (Zinc dialkyl-Ditio-Phosphate).

Why is ZDDP important for my older car engine?

If you have an older car (pre-), its engine design requires the use of ZDDP. Without it, your car could be damaged by the use of the modern motor oils. Remember when they removed lead from gasoline? This was done to protect the environment, but in actuality the older car engines ran better with lead in the gas. In recent years, the oil companies were forced to remove ZDDP from their motor oils because manufacturers must warranty catalytic converters for over 100,000 miles. They found the ZDDP additive shortened the life span of the catalytic converter and would void the manufacturer’s warranty on newer cars. What they didn’t realize is that the removal of the ZDDP would cause engine problems in older vehicles.

So where does this leave the owner of an older car?

It’s very simple. When you bring your older car in to Shade Tree Garage for its periodic maintenance and have its oil changed, we can add ZDDPlus to the motor oil to protect your car’s engine. A single 4-oz. bottle of ZDDPlus provides the proper concentration for a 4- to 5-quart oil change. The minimal cost you will spend on this additive is well worth it when you consider you will be protecting the life and performance of your car’s engine.

The company is the world’s best lubricant additives supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.