Why Does Flat Tappet Need High Zinc Oil [Explained]

Wherever the friction is, high-zinc oil is there to fix the issue. Most old car owners (especially those who have flat tappet camshaft) should use a high-zinc additive to reduce the increased stress on the motor produced by metal frictions and high temperatures.

Indeed, high zinc oil provides the ultimate protection against high temperatures produced in the engine compartment and reduces oxidation. All these features of zinc oil ensure the longevity of your car engine and improve overall performance. It’s all in short why does flat tappet need high zinc oil. Now let’s know in detail…

Here Is Why Does Flat Tappet Need High Zinc Oil?

Camshaft in a flat tappet engine is the reason your vehicle engine requires Zinc oil. In other words, the role of a camshaft in an engine makes it indispensable to feed your car engine with Zinc.

During the time the camshaft rotates, it pushes the lobe down to let the valve open. Each part of the camshaft and other components that squeeze against the lobe start rolling along the surface.

In return, it creates pressure on your engine due to the friction between the lobe and the camshaft followers. 

With the increased pressure, the oil starts squeezing out of the camshaft followers and the lobe. Due to the oil loss, it can damage your engine by increasing metal friction or creating wear. 

Regarding this, you should get motor oil that contains an anti-wear additive. The zinc oil sticks with each part of the engine & lube them, and creates an anti-wear coat. In exchange, the zinc oil can resist high pressure, wear, and sludge and let your engine run smoothly. 

To sum up, a flat tappet engine requires zinc oil to protect your engine from high pressure & wear. Therefore, it boosts the overall engine performance by improving fuel efficiency. 

What Motor Oil Is High In Zinc

We found the following oil has the most ZDDP:

i) Valvoline VR1 Racing Oil

Valvoline VR1 Racing oil has 13% zinc containing 1350-1400 ppm zincs and 1250-1300 ppm phosphorus (75% higher than SN or SM motor oil).This high level zincs and phosphorus will protect your flat tappet engine from wear, sludge, and high temperature. 

ii) Castrol GTX Classic Conventional Motor Oil

On the other hand, Castrol GTX Classic 20W-50 conventional motor oil comes with a higher level of zinc (1400 PPM Max) and phosphorus. So, this high zinc oil is also capable of protecting flat tappet engine from extreme wear.

Best Zinc Additive For Flat Tappet Cam

Here is the list of the best zinc additives you can consider for your flat tappet cam.

How Much ZDDP do I Need for a Flat Tappet Cam?

We have spent a crap ton of time researching how much zinc a flat tappet engine needs. After collecting information from oil manufacturers, SAE, and automotive manufacturers, we make our decision. 

According to our research, we found the proper ZDDP level depends on the oil. However, 700-800 PPM of ZDDP level is usually right on. 

We also find two important points. First, extra ZDDP in oil is recommended during a break-in. You need to create a protective layer on the metal, and zinc will help to build that layer. 

Additionally, when you break in, the metal friction will increase. And the extra ZDDP will handle the metal-to-metal contact by lubricating those moving parts. 

The second caveat is high-performance car engines. With the increased rate of crazy RPMs, consistent oil starvation, and cam profiles, extra ZDDP is needed to prevent the damage. 


Is high zinc oil good?

High zinc in oil is good for the high-performance car or the older car models like the car coming with a tappet engine with a camshaft.

Should I add zinc to my oil?

You should add zinc to oil if your car engine is old. The high zinc oil provides ultimate wear protection, and your older car needs it badly. 

Do I need to add zinc to synthetic oil?

Yes, you need to add zinc to synthetic oil for your flat tappet cams if you want to add longevity to your vehicle engine. 

Does diesel oil still have zinc in it?

Yes, heavy-duty diesel oil still contains zinc in it. 

Does Rotella 15w40 have zinc?

Yes, Rotella 15w40 Oil contains around 1200 ppm of zinc.


We hope you get the answer to your question: Why does flat tappet need high zinc oil?

Higher-level zinc in oil will help to reduce metal frictions, handle higher temperatures, and protect your engine against wear. 

Now you can see the effects of high zink oil on your old engines are huge. So, you must pour high zinc oil into your car if you own an older model car with flat tappet cams. 

If you have any questions related to this topic, don’t hesitate to leave a comment below. We are happy to help. 

Read Also: What Type of Oil Does a 5.7 Chevy Take for a Healthy & Safe Engine?

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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