tresamore

Posted in OT also. Wow, I haven't posted here in awhile.

Just a little FYI on some recent changes to motor oil. Apparently the oil companies are pretty much removing the very good stuff called ZDDP (zinc dialkyldithiophosphate) from motor oil (see explanation of the benefit of ZDDP from Amsoil’s website below). We all know as engines wear the oil can get into the combustion chamber through the rings, valve seals, PCV systems, etc… (or if you drive a 928, from the puddle in the bottom of the intake) The phosphorus from the ZDDP that gets into the combustion chamber cannot be processed by the cat and can destroy it over time and is also quite a pollutant. Apparently all this is due to the ever-growing cleaner emissions pressures. Unfortunately I learned all this the hard way last weekend as my Corvette (ya, I know) wiped out the cam. It was an aggressive hi revving solid lifter big block, so it was seeing some hard use, but the engine only had 20K well taken care of miles on it. The latest issue of Hot Rod (Ya, I know again) has a great article explaining the issue. I’m not sure about synthetics, but I would assume the same for them. I am going to a full roller setup (at $1000+, ouch!) which will alleviate the cam issue (still concerned about cylinders though). For those who can’t change setups, they recommend adding a quart of break in lube at each oil change or use Shell Rotella or other oils used by the trucking industry, but they will also lose ZDDP in 2007. They say that any flat tappet cam, hydraulic or solid is at risk.

Amsoil:
Third, the oil's ZDDP (zinc dialkyldithiophosphate) additive is very important in protecting heavily loaded, boundary-lubricated parts, such as cam lobes, valve lifters, piston rings and cylinder bores. Boundary lubrication results when metal-to-metal contact occurs, "which in turn causes the deposition of the antiwear film from ZDDP."

While the antiwear properties of ZDDP will not completely eliminate wear, "they will reduce wear by orders of magnitude so that it will not likely be a limiting factor on engine life," Bergin said.

Phosphorus is an important component of ZDDP and, as well, a poison to emissions systems above certain levels. The auto industry has definite concerns about the use of phosphorus above a certain level, and considers phosphorus above 0.10 percent mass in a motor oil to be an emissions systems threat.

worf928

Calling Doug Hillary!

worf928

The question is - if ZDDP is being removed from oil over the next year what is going to protect the boundary-lubricated parts of new (and old cars?) Or is this one more step to the totally sealed car that you throw away after 20k miles?

BC

There is an additive that has zddp in it.

SharkSkin

Was there no mention of a substitute? I find it hard to believe that they would just drop such an imporant additive without compensating somehow.

worf928

I've been googleing for the last 30 minutes. Other than finding some links from the 2002 to 2004 time frame the mention in passing the need for an alternative wear inhibitor I have found nothing very useful. I found lots of informative stuff and lots of references to how ZDDP is bad for the environment and cats... (But, I did get tired after a little while and figured I'd let someone else dig for a bit...)

Not much came up that actually referenced the pending ZDDP removal's effect on cars. Seems a bit too stealthy for my taste.

http://www.theautochannel.com/news/2...09/158975.html

SharkSkin

Hmmm... interesting article, though it's 3 years old -- even more interesting that they don't mention which of the big 3 is involved. Seems that GM wouldn't mind having people's cars wear out a little faster, given the trouble that they are in right now. Looks like this issue is worth keeping an eye on.

tresamore

From what further info I can find, lower levels began to show in January of 04. There is no set amount so manufacturers levels apparently can vary quite a bit. It looks to be anywhere from .01%-.14% from the few mentions of levels I could find. No one seems to have found a replacement for it yet as Google shows there to be some conferences currently being held around the world that list ZDDP replacement as a topic. I think I'm going to give Valvoline VR1 a try. Looks to be .013/.012 for the levels.

tresamore

I think they've been engineering around it for a while. I know GM uses a proprietary method that joins 2 dissimilar metals together on their lifters. The concern seems to be for all of the cars w/o such engineering.

worf928

Luckily I have 3 cases of 5-year old Castrol 20w-50 dyno juice. Never thought I'd use it....

Doug Hillary

Hi,
oils formulated to API and ACEA quality standards must meet minimum and maximums as mandated. As they are redeveloped every few years they are "normally" backwards compatible

One maximum is the allowable wear in valve train components

Rapid cam wear first came to real notice with engines like the MGA TwinCam and some DOHC engines from Japan. Alfa engines never seemed to have the problem as I recall
It was however most apparent in heavy diesel engines during the 1970s and early 1980s

ZDDP was used as a cheap and available quickfix and has remained a very good additive ever since - sadly its time has come

The first use of better AW additives for cams commenced with API's SF rating for petrol engines in the late 1970s and ZDDP was typically the choice. It is now at SM
For diesel engines the API's rating was CD in the 1950s and this was a rating used by Porsche in 356 and later in 911/912 engines - their oil was Shell's Rotella. Later the diesel rating was upgraded to CE around 1983. It is now at CI-4+

Other more "Modern" anti wear (AW) chemicals have been and are being devised and now do the job very well indeed. In some applications they perform better than Zinc in its various guises. The new additives are rewriting the Tribology rule books as time goes by
(I have had one heavy duty high power diesel engine go over 1m kms (620k miles) on a low ZDDP formulation with no measurable cam or cam component wear)

Some "boutique" oil formulators like Amsoil are believed to avoid obtaining official Licensed approval of some of their products due to the high levels of ZDDP used. Hence they say the oils "Meet" or Exceed" the standards but are not Licensed. Some specific Amsoil oils are now Approved by Benz due to their new reformulation - I expect ZDDP will be minimalised in these products

Mobil 1 0w-40 a low ZDDP formulated oil and the official oil of Benz and Porsche has shown no tendency to any form of excessive wear in any component

Flat tappet engine studies will always show a need for an oil with a high HTHS viscosity (at 150C) above about 3.5cSt. This was also the case with excessive diesel engine cam wear as cam "wiping" pressures increased enormously during the 1980s to meet emission demands

Personally I like an engine oil that is quality rated for both petrol and diesel engines such as API SJ/CH-4 or ACEA A3/B3
I prefer the CI-4/SL quality rating for lubricants along with a HTHS viscosity of at least 4cSt in 928 engines

ACEAs A3/B3 quality ratings still remain viable as a baseline with the correct viscosity in German engines. Official factory Approval and Listing however says it all!

The case is still being written for the "in field" perfomance of API's SM quality oils

Regards
Doug

worf928

Doug, as usual you are a font of information. To summarize - if I understand you correctly - your post: There is no problem as long as you are using CI-4/SL with 4cSt HTHS?

Doug Hillary

Hi Dave,
your question said;

"There is no problem as long as you are using CI-4/SL with 4cSt HTHS?"

Yes that is my opinion on a suitable lubricating oil standard for a 928's engine in good condition and using modern lubricant technology. Of course the HTHS viscosity of >4cSt precludes using any xxW-30 viscosity lubricant. Porsche's minimum HTHS viscosity for Approval and Listing is 3.5cSt.

Using a heavier viscosity non-approved lubricant (say 20w-50 or 25w-50 in Mineral base) than is really needed is counterproductive

Regards
Doug