[Mgs] ZDDP in oil

[Mike Duvall]

A lot of older, motorcycle, diesel (CI-4) and racing oils have ZDDP  
along with a number of brands. Some people worry about diesel oils  
but some meet diesel and gas standards.  Royal Purple sells a break  
in oil and then recommends standard oils.

I personally am not worried about it the issue.  (I suspect the  
problems are really from using synthetic instead of break in oil)    
There have been studies and publications by API engineers that say  
that SM rated oils are sufficient - see article below. (you can find  
some older rated oils in some parts stores and stations as well).   
Hagerty Insurance this month has a article in their publication.  An  
API spokesperson says that the 800 ppm level of current SM oils is  
sufficient to protect flat tappet engines.

That being said,  they list some alternatives.

Shell (shell.us/views/consumers.html)  & Chevron (chevron.com/ 
products/extramile)  have 1000 ppm.

Valvoline VR1 Racing - 1300 PPM
Castrol Syntec 20/50 1200 ppm
Red LInes oils 1300 ppm
Brad Penn grade 1 racing oil - 1500 ppm
Classic Car Motor oil  (classiccarmotoroil.com)  1500-1600 ppm



How Much Zdp Is Enough?

Document Number: 2004-01-2986

Date Published: October 2004

Author(s):
Robert M. Olree - General Motors Corp.
Michael L. McMillan - General Motors Corp.

Abstract:
Zinc dithiophosphate, or ZDP, for over 60 years has been used as an  
additive in engine oils to provide wear protection and oxidation  
stability in an efficient and cost-effective manner. Unfortunately,  
ZDP contains phosphorus, and phosphorus is a widely known and  
accepted poison of automotive catalysts and other emissions system  
components. Because of this, phosphorus (and ZDP) levels in  
automotive engine oils have been gradually reduced by about 35% over  
the last 10-15 years, and further reductions are likely in the  
future. This paper traces the history of ZDP use in automotive engine  
oils, and addresses the issue of how much (if any) ZDP is actually  
required to provide wear protection in today's, as well as  
yesterday's, engines. The focus in the paper is on wear (including  
scuffing) protection, and not on the other aspects of ZDP  
performance, such as providing oxidation stability of the oil. It is  
assumed that these other functions of ZDP can be provided by other  
ashless and phosphorus-free additives which do not negatively affect  
emissions system performance.

File Size: 4137K
Product Status: In Stock

See other papers presented at 2004 Powertrain & Fluid Systems  
Conference & Exhibition, October 2004, Tampa, FL, USA, Session: Light  
Duty Engine Oils (Part C)