# ZDDP and VW



## joezeeuw (Feb 23, 2003)

I've been hearing a lot about ZDDP and engine oil lately. Apparently oil now does not contain enough zinc to protect our older VW's with flat tappet valve trains. 

Has anyone had any failures that can be attributed to a lack of ZDDP? 

Is anyone adding any additives or running special racing oil to make up for the ZDDP deficiency? If so which do you use?


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## saaber2 (Jul 15, 2008)

A. ZDDP. This is true that API specs are causing lower amounts of ZDDP to be used than in the past. ZDDP is the most typically seen anti-wear additive. It's possible that some formulations can compensate for some of the loss of ZDDP with other anti-wear additives, but most recommendation still say a minimum of 1200ppm zinc is what is needed for flat tappet cams. 

Here is a very good article on ZDDP as it relates to flat-tappet cams: 

http://www.corvetteactioncenter.com/tech/oil/ 

B. Regarding failures. browse the 2.O FSI engine forum for tons and tons of photos of failed flat-tappet fuel pump cam followers. There are tons of them. Most are using 502 oils with lower amounts of ZDDP. There aren't that many people yet who make a concerted effort to use an oil with high enough anti-wear additives (such as ZDDP) to protect flat tappet cams. I'm not saying ZDDP is the only thing to look for when choosing an oil to protect cams because base oils, viscosity moditifiers, and other additives all make up the finished oil, but it is one thing to look for. 

Also keep in mind that the type (quality) and amount (quantity) of viscosity modifiers also heavily influences the oil, in particular how it stands up to fuel dilution. An oil that has been run too long or is impacted by fuel dilution can have depleted additives (such as ZDDP) or that has sheared heavily can heavily influence wear. Look for an oil with good quality viscosity modifiers. Look for oils that have naturally multi-grade base stocks such as Group V esters which means less of these viscosity modifiers are needed. Unfortunately these oils will cost more because the ingredients are much more expensive. 

Also the amount and quality of viscosity modifiers may greatly impact valve deposits on direct injection cars. Think of it this way, as the long-chain viscosity modifiers are "chewed up", or sheared, their remaining remaining smaller molecules are volatile (the resulting volatility can be similar to gasoline) and can be evacuated through the pcv system to the valves. Again, better base stocks allow the formulator to use less viscosity modifiers, and oil brands vary in the quality of viscosity modifiers used. Better base stocks and better Vis modifiers cost more unfortunately. 

C. Re: additives. i would suggest keeping these 2 things to keep in mind: 

(1) oils are formulated so that all the additives are balanced. adding an additive to a finished oil could possibly disrupt that balance and do more harm than good. you can also have reactions between the oil and additives and that too may do more harm than good. 

(2) too much zddp can be harmful to your engine. Above about 1600ppm seems to be the most commonly used "maximum". So if using an additive you are taking a guess that you are not adding too much. 

So rather than play "chemist" to a formulation which was carefully thought out, you are better off IMO to just use a good oil with over 1200ppm zinc or one that has high anti-wear additives. There are some great oils out there such as ester-based oils that use a strong anti-wear package.


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## joezeeuw (Feb 23, 2003)

Thanks for the great response. I just read through the linked article, good info there. I'm thinking I will go with the Valvoline VR1.


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## slowbluVW (Oct 15, 2002)

joezeeuw said:


> I've been hearing a lot about ZDDP and engine oil lately. Apparently oil now does not contain enough zinc to protect our older VW's with flat tappet valve trains.
> 
> Has anyone had any failures that can be attributed to a lack of ZDDP?
> 
> Is anyone adding any additives or running special racing oil to make up for the ZDDP deficiency? If so which do you use?


Use Shell Rotella Syn 5W40 and put all of your worries to rest.


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## cryption (Mar 28, 2006)

I swear by the Valvoline MST 5w-40. You can get it on amazon. High zinc for an American oil


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## TechMeister (Jan 7, 2008)

Testing seems to indicate that 1% zinc is the preferred choice for flat tappet engines. Significantly more or less zinc seems to cause wear and other issues. If your engine does not have a flat tappet cam then you really have no need for zinc as there is no other application in the engine that requires the anti-wear properties associated with zinc.


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