Zinc compounds in oil.

[Simon TR4a]

I am posting this in the hope that someone can educate me on this subject.
A group of TR racers to which I belong has recently been discussing the merits of Kendall GT1 oil, saying that it still has zinc compounds which have beneficial lubricating properties removed from more commonly available engine oils in order to comply with the latest SM specification.
As a result the Kendall meets the older SH spec but not the new standard, but is said to be a good choice for older cars like ours.
I think I understood the removal of the zinc had something to do with emissions.
Can someone explain this, please?
Thanks, Simon.

 

[swift6]

Simon,

Here is a synopsis of what I have learned over the last few months on this subject.

The zinc additives (known as ZDDP in the formulas) is an extreme pressure lubricant. Those additives have been found to foul and shorten the lifespan of catalytic converters, thus affecting the emissions. This lubricant, or lack thereof, has been blamed for early camshaft failures on solid lifter engines. The most likely cause for the early failures are bad lifters as a few years ago the market was flooded with poor quality cheap lifters. Racing specific oils are supposed to still contain appropriate levels of ZDDP (Kendall, Valvoline R etc...) as emissions are not a concern for race vehicles. Many diesel oils still have ZDDP but are slated to reduce their ZDDP content in the near future for emissions related reasons as well. Castrol has stated that for standard/stock prepared engines with solid lifters (like most of our LBC's) that Castrol 20W50 is still 100% backward compatible and tested to a higher standard than previous formulations as well. They do however, recommend using racing formulas for engines with aggressive camshaft profiles.

Hope that helps some.

Shawn

 

[70herald]

It is true that the zinc content is being reduced in oils however, modern oils have MANY components to them, and zinc is only one of them. There are MANY different ways to achieve the same results. Fortunately ANY oil available today is significantly better than whatever was available when our cars were built.

It does seem that many people are starting to use Diesel oils for older engines. This is because diesel oils have higher levels of detergents than current formulas for gas engines. Indecently, the detergents in oil don't clean anything. They simply keep the soot which is trapped in the oil floating around.

If you want an interesting education in oil take a look at the forum at “bob is the oil guy”

 

[JerryB]

"""" Fortunately ANY oil available today is significantly better than whatever was available when our cars were built""""

Thats true. But.."older" cars use flat tappets...which slide not roll....thus having problems, especially at higher rpms (cam lobe speed) and higher spring pressures (loading).


"""""""I think I understood the removal of the zinc had something to do with emissions.
Can someone explain this, please?
Thanks, Simon"""""""

Simon...this has been kicked around a bit in this forum and others in the last 2 months. (do a search). Heavy metals are being removed from everything. That means Zinc, Phosphorus, Boron, Magnesium and more have been removed or lessened in motor oil. EXCEPT some diesel motor oil, made/formulated for over the road truck use.

Short answer...use an oil that is flat lifter compatible or an additive such as General Motors EOS.

 

[prb51]

The ZDDP and other additives were removed to extend the life of catalytic coverters. It seems they tend to degrade them (internal crumbling of material) and the new regs are meant to extend the coverter life to 150k.
Even though Castrol says their 20w-50 is completely backward compatible they have reduced the Zinc content by almost 50% to .075 and .10 is the recommended minimum content.
I understand that Valvoline VR1 racing 20w-50 has the correct ZDDP and Phos etc. required and is also API street rated (has the detergent etc. not found in pure racing oils).
Question on additives. When adding up to a quart of additive aren't we changing the chem composition of the primary oil greatly. Hasn't this lead to foaming/frothing by reducing these agents below the required level thru dilution? I'e seen some web sites where they demonstrate the negative effects of quantity additive use in this respect.
Any engineers out there please weigh in.

 

[70herald]

[ QUOTE ]
The ZDDP and other additives were removed to extend the life of catalytic coverters. It seems they tend to degrade them (internal crumbling of material) and the new regs are meant to extend the coverter life to 150k.
Even though Castrol says their 20w-50 is completely backward compatible they have reduced the Zinc content by almost 50% to .075 and .10 is the recommended minimum content.
I understand that Valvoline VR1 racing 20w-50 has the correct ZDDP and Phos etc. required and is also API street rated (has the detergent etc. not found in pure racing oils).
Question on additives. When adding up to a quart of additive aren't we changing the chem composition of the primary oil greatly. Hasn't this lead to foaming/frothing by reducing these agents below the required level thru dilution? I'e seen some web sites where they demonstrate the negative effects of quantity additive use in this respect.
Any engineers out there please weigh in.

[/ QUOTE ]

I am not a Tribologist, but as an ME (and working on an additional degree in Materials), this is an area which interests me.
I believe that the main problem with metals in the oil is that the tend to coat the surfaces of the catalytic converter. Basically the cat has a huge surface area covered with an extremely thin layer of catalyst material. The calatlyst itself does not play a direct role in the reactions, but its presence is important. It does not get "used up" rather it eventually is coated with other materials and is no longer effective.

While it is true that modern engines ussually don't have solid lifters, they work under significantly higher internal pressures and temperatures than old engines.

I have also seen the tests where is shows how some of the additives cause foaming. Personally I think that modern brand name oils are very well engineered, and I would not mess with their composistion. As an engineer, I understand that there are many comprises which go into a product, but I doubt that any additive I randomly add to a profesionally designed product will really improve it.

 

[Simon TR4a]

Thanks to all of you for your responses.
I have done a little more research and have found that the main area where problems are likely to arise is in camshaft and lifter wear, and is associated with flat tappets like ours.
Other indicators are high lift camshafts and stronger valve springs, both of which I have in my car, because of the increased pressure, which on race tuned big displacement V8s can reach 200,000psi.(No idea how that compares with a Triumph, but it sounds like a lot of pressure.)
Race oils DO contain appropriate additives, and are specified for off-road use only because they shorten the lives of catalytic converters, and at least some diesel oils
also still retain ZDDP. Shell Rotella, which many people apparently use as a break-in oil, has ZDDP but will apparently be reformulated in 2007, as will many diesel oils as diesel emission standards are tightened and cat converters come into use.

Again, thanks to all who replied, Simon.

 

[70herald]

Simon
Race oils are not necessarily formulated for a long lifespan. What I would look for is an oil with a high molybdenum percentage. Moly tends to stick to steel and is a very good lubricant in sliding applications. Like the lifters. Basically it works because it attaches itself to the steel, but is in the form of slippery plates. The slide very nicely against each other or other metals.
I am using "Liquid-Moli" brand oil (German) with added Moly in my cars now. Funny grey color from the Moly. Moly paste is what is used in CV joints because of its slip properties. Not quite sure what to recommend in the US though.

 

[jlaird]

Man, you a long way off. Glad to see someone from the other side of the world, well almost.

 

[Dave Richards]

??? ...see "New Oils, Bad for Old Cars" this same area!

 

[JerryB]

PRB51 wrote............
Loc: Arizona Re: Zinc compounds in oil. [Re: JerryB]
#291730 - 12/12/06 05:54 AM Edit Reply Quote Quick Reply



""""""The ZDDP and other additives were removed to extend the life of catalytic coverters.""""""""

Thats correct...as well as all the other problems associated with heavy metals.


"""""""Even though Castrol says their 20w-50 is completely backward compatible they have reduced the Zinc content by almost 50% to .075 and .10 is the recommended minimum content."""""""""

Well there not gonna say the ARE NOT backwards compatible.....any thing to make a sale!

""""""I understand that Valvoline VR1 racing 20w-50 has the correct ZDDP and Phos etc. required and is also API street rated (has the detergent etc. not found in pure racing oils)."""""""

You might want to readthe lable on the bottle again.....


"""""""""Question on additives. When adding up to a quart of additive aren't we changing the chem composition of the primary oil greatly. Hasn't this lead to foaming/frothing by reducing these agents below the required level thru dilution? I'e seen some web sites where they demonstrate the negative effects of quantity additive use in this respect. """"""""

Your right. I wrote that "such as GM EOS". I should have wrote "use GM EOS ONLY. 1/2 can per 5 quarts in break in and 1/4 can per oil change. There may be another decent additive other than EOS but I don't know what it is. I have heard that EOS is being discontinued ...thats only a rumor. Most oil additives that claim this or that are mostly snake oil.


70herald wrote............
""""While it is true that modern engines ussually don't have solid lifters, they work under significantly higher internal pressures and temperatures than old engines. """

And are designed for higher temp/pressure .......roller lifters, low drag ring packages, EPDM and Slicone gaskets and hose etc.

"""""""""". Personally I think that modern brand name oils are very well engineered, and I would not mess with their composistion. """"""

Absolutely right.....EOS is an exception to the rule.

""""""""Race oils are not necessarily formulated for a long lifespan. What I would look for is an oil with a high molybdenum percentage""""""

An thats what EOS does. BUT...too much moly is bad thing. MoS2 paste for example...use in assembly of flat lifter followers/cam lobes and thrust/wear plates in engines....not for extended use and is best flushed with the initial oil change at the first opportunity if you use a lot of it....like a 16 cylinder lump with 32 lobes.

"""""Not quite sure what to recommend in the US though. """"

Sound similar to EOS. Try a search..General Motors (GMPD) EOS.

 

[RomanH]

There may still be appropriate oil that we can use in our flat tappet engines. It seems that certain Exxon Superflo oils are not API SM certified "Energy Conserving" and are only rated to the API SL standard.
This is from Exxon's site:
Superflo 10W-40, 20W-50, SAE 30 and SAE 40 viscosity grades meet API SL requirements.
Their web site does not list zinc content or ZDDP content but since it not rated to the newest standard might there be hope for it?