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Politically correct.
'09 SRT 440 HEMI
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11,170 Posts
Discussion Starter #1
Here's a bit of info on ZDDP anti-wear additive in engine oils.

From a recent Amsoil article:




"Do modern motor oils formulated with reduced zinc and phosphorus anti-wear additives provide adequate engine protection? It’s a question some industry insiders, auto enthusiasts and motorists have been asking for years. And as engine builders and classic-car owners continue to experience engine failures they attribute to reduced zinc and phosphorus motor oils, the debate seems to intensify. Arriving at an answer, however, first requires some background information.


What is ZDDP?

Zinc dialkyldithiophosphate (ZDDP) is the most commonly used anti-wear additive in motor oils. It contains both zinc and phosphorus components that work together to provide anti-wear protection and minimize lubricant breakdown. ZDDP also exhibits mild extreme-pressure protection.


How ZDDP Works:

As temperatures rise and surfaces come closer together, ZDDP decomposes, and the resulting chemistry protects critical metal surfaces. When parts move during operation, any sliding or rolling motion takes place on top of or within the ZDDP anti-wear film, which reduces metal-to-metal contact. This is especially important in modified engines with flat-tappet camshafts because the engine is creating more horsepower than it was designed for, which puts more stress on the engine. High-tension valve springs, often used in racing applications, also increase the potential for cam wear and require added ZDDP.


Negative Effects of ZDDP:

Since all engines benefit from oils with superior anti-wear properties, it seems obvious to formulate all motor oils with high levels of ZDDP. Generally, high levels of ZDDP results in volatile phosphorus being transferred from the combustion chamber to the catalytic converter. Phosphorus can blind over the catalytic reaction sites in the converter, making it less efficient in turning carbon monoxide (CO) into carbon dioxide (CO2). The EPA mandates that catalytic converters operate as designed for more than 100,000 miles. As a result, phosphorus is limited for newer motor oil specifications.
Despite the limitations, there is no evidence to suggest modern engines using today’s lower-ZDDP oils are suffering widespread wear. A properly formulated oil that meets API SN and ILSAC GF-5 is more than capable of delivering reliable wear protection in stock engines.
When it comes to older engines – particularly those equipped with flat-tappet cams – and engines modified for increased performance, the challenges to delivering adequate wear protection become more pronounced. The design of flat-tappet cams makes them especially vulnerable to wear. As the name indicates, the tappet – or lifter – is flat. During operation the surface of the cam lobe slides rapidly over the surface of the tappet, producing high friction and temperatures. The camshaft and lifters are responsible for triggering the precisely tuned movements of the valvetrain. Without the protective film barrier provided by ZDDP, the cams and lifters wear from the force of operation, negatively affecting cam and valve operation. Because most V-8 engines of the muscle-car era came standard with flat-tappet cams, the problem is especially prevalent to classic-car and hot-rod owners.
In these applications, modern oils, such as AMSOIL synthetic motor oils, are capable of providing adequate wear protection after the engine has been broken in."


:3-smoke:
 

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What's Old is New Again!
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39,566 Posts
Thanks, John! I think the most important statement here is the last sentence.

"In these applications, modern oils, such as AMSOIL synthetic motor oils, are capable of providing adequate wear protection after the engine has been broken in."
 

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Premium Member
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21,684 Posts
We banged this around a while back.
Most important for the older hot rods but still a good wear additive and only a few of the top end oils have a good amount in them.
 

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Politically correct.
'09 SRT 440 HEMI
Joined
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11,170 Posts
Discussion Starter #4
I agree guys!

I liked that article because it's easy for the average car enthusiast to understand. Not much technical mumbo jumbo. :smileup:
 
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