Valvoline on Zinc and Flat Tappet Wear

[Jaymus]

http://www.valvoline.com/downloads/2008-003a.pdf

I mainly happened to notice this yesterday when looking for any information on how long Valvoline VR1 is recommended to be ran. It's about Zinc and flat-tappet wear.

"Many hands-on car enthusiasts and engine experts believe the lower levels of zinc in SM engine oil is causing excessive wear in older style push-rod and flat tappet engines. This is despite the fact that all new engine oil classifications are intended to be backward compatible. This has resulted in the widely accepted belief that modern engine oil is not adequate to protect older engines."

I trust Valvoline. I mean, they are a huge, multi-$$$$$$ company. They have some great products. They seem to do 'tests' to advertise with.

But this sounded like something straight off Royal Purple. You would think that a company like Valvoline would do a real test, unless it came back with results that would not be beneficial in their advertising. They have a page about Zinc that is based off of hearsay. I just think that's odd considering the day and age we live in.

This is the most information you can find on the web. It's killing me that there are no facts about zinc/flat tappet wear that I can find.

 

[river_rat]

I can't find the link to youtube now, but a Valvoline spokesman was on Motorweek or one of those shows. He stated something about that Valvoline SM was fine even for older flat tappet engines for daily use but to use VR1 or a zinc additive for break-in on it. Then go to regular SM.
Sorry I can't find the link right now.

At least Valvoline and others will tell you how much ZDDP is in their SM oil on the website or by responding to email.
Castrol thinks it's a trade secret. Wouldn't tell me when I emailed.
I don't trust products that are "secret" with basic info like that.
Nobody is going to copy their product based on knowing ZDDP content from the Web. It makes my think Castrol SM oils have too little or none and they don't want me to know it.

 

[ADFD1]

There are certain cases where an oil might be backward compatible, but not necessarily the best oil for our engine. The addition of a good additive like RL Break In Oil Additive is just plain better. We pay a lot for our cars and modifications we make to them, the cost of the additive is good insurance in my book. A 12 ounce bottle can easily work for 2-3 oil changes, depending on the dose of ZDDP you're looking for.

AD

 

[1bolt]

There's a tremendous amount of info on the ZDDP thing out there, the best of it is SAE papers that are expensive and hard to dig up.

The basic reality of the matter are that car/engine enthusiast community's that tend to use flat tappet cams have and are experiencing oddly high numbers of lobe and lifter failures (dished) and have been for some time. Even in applications where high spring pressures aren't the norm.

For example The Jeep engine forum I'm a part of has seen a remarkable number of dead cam lobes and lifters worn concave often one lobe goes while others are relatively normal (but often pitted) leading me to believe that the lower ZDDP exposes weakness and flaws in the iron of the cam or lifter face... these flaws in the grain structure of the iron "grab" and walla dead lobe or two with 5 or 4 others that just look "beat up" for lack of a better word.... BTW these are cast iron cams and the Jeep 4.0 is well known for high iron levels in UOA's Coincidence?

One of my favorite links that had (haven't looked lately) all sorts of good links to SAE papers was a Porche enthusiast site.
http://www.lnengineering.com/oil.html

Here's a snippet:

How did you determine the recommended 0.12% Zn and P level (ZDP, a.k.a. ZDDP)?

There are many excellent SAE technical papers on the subject, but the one I found most interested was from 1977 titled "Cam and Lifter Wear as Affected by Engine Oil ZDP Concentration and Type." There is some background that is needed to shed light on their results. First of all, there are different types of ZDPs. There is an Aryl ZDP which is the most stable form. There is also an Alkyl ZDP which although is not as stable, exhibits the best wear protection.
[end snippet]

I would look for and pay SAE for that paper.

That site used to contain a great deal of SAE text, and the SAE is like a rabid dog with copyrights, so I don't know if he still has it but he had much of the text of that study that directly showed ZDDP levels lower than 10% caused steeply increasing wear levels. and that even the recomended 11 to 12% levels aren't enough for spring pressures that are higher than average OEM's use.

 

[wannafbody]

Is this an issue with roller cams?

 

[GT Mike]

Originally Posted By: wannafbody
Is this an issue with roller cams?
No. Roller cam engines won't have a problem.

 

[1bolt]

Weeeeeelllll... that's not entirely correct. While the flat tappet Cam and lifter interface is the most important/large area that requires an EP additive that forms a sacrificial layer; there are many others.

Any where that metal touches metal and doesn't have a hydro-wedge of pressurized oil, is protected by a sacrificial layer formed from ZDDP and extreme pressure and heat. I expect the reason that the EPA hasn't had ALL ZDDP removed, is that it is quite good at this type of protection even in the most modern rollerised overhead cam engines. Not just pushrod engines.

Just to give you an idea:
Any gears/meshing rotors inside the engine
Such as the Oil pump
Distributor gear
Timing chain and gears
Any surface that rubs back and forth or rotates metal on metal...
Valve stems
Valve tips
Lifter nose on valve tip (if not roller tipped)
Lifer on lifter bridge/rocker or pivot.
(but not shaft rockers which are oiled with pressure and have a hydro-wedge like rod/main/Cam bearings do)
Push rod tip at rocker interface and the other end at the lifter cup.

These are all commonly only oiled by splash or flow (drips drabs whatever happens to overflow or get carried onto the surface) and commonly are metal touching metal... so they will all wear at higher rates without the sacrificial film deposited where ZDDP meets heat and pressure. It may be that the 6-8% ZDDP levels in current spec oils is good enough for these much smaller less critical surfaces... but for me whats good enough (11-12%) for the cam lobes is what I want for critical components like the timing gears, and valve stems and tips.

Also there's a misconception that ZDDP is only needed at break in. This is wrong according to SAE papers I've read (link above had many of the links, not sure if they are still there). The sacrifical layer wears off,... as the name implies it gets sacrificed... thus after a while without sufficient ZDDP in the oil to "repair" (as one SAE paper put it) the layer, the layer goes bye bye.