DAMPER AS 2163358 - Caterpillar

3500 Engine History
Times are continually changing. Part of this change includes demands placed on diesel engines. These demands include things such as higher horsepower to weight ratio, better fuel economy, and lower emissions. To meet these demands, 3500 engines have undergone a series of iron changes. The 3500 engine has evolved through the following three basic "PHASES":
Changes that took place with the two piece pistons (see Chart A) were raising the top ring and higher cylinder pressures. The higher top ring decreases crevice volume (space between the top ring, top of piston, and cylinder wall). Other changes in the combustion system (fuel injection pressure and fuel nozzle spray angles) along with this crevice volume reduction, have been used to reduce emissions and improve performance. These changes have allowed more partially burned fuel (soot) to be mixed with the oil on the liner. This soot laden oil is pulled into the sump by the higher ring position and thus the soot level in the oil is increased. Equally important, the higher ring position also creates a higher operating temperature for this ring.
Chart AOil History
Oil technology must keep up with changing engine technology! Engine oil technology of the past will not provide optimum life and performance for current and future engines. Engine oil has been forced to undergo changes to meet the increasing demands all engines are placing on it. This change is best tracked by the American Petroleum Institute (API) service category, which has been in existence for many years. The API CA category typifies the oils of the 1940's and 50's. The oils were upgraded for operation with poorer quality fuel in 1949 with the CB category. In 1951 API CC oil was released to handle moderate or severe duty engine applications which included turbocharged engines. All of these categories are now obsolete. The API CD category was introduced in 1955. It was adequate for most diesel engines and applications for many years. However, as engine technology changed, some diesel engines needed a better class of oil by the mid 1970's. This forced the development of another category of oil, titled API CE oil, in 1983. As engine performance continued to develop, improvements to engine oil continued, resulting in the newer API CF-4 category release in 1990. A new rating is in the development stages and will be the new oil standard in a few years (see Chart B).
Chart BAPI CD And CE Verses CF-4 Oil
What is the difference?
1. The API "CD" category is a very broad classification. This means that there can be a wide variation in the performance level from one API CD or CE oil to another. The API CF-4 oil category requires more performance tests, to higher and stricter standards. This means API CF-4 oils have a narrower performance band within the API CF-4 range than API CD oils do. API CF-4 oils also have a higher average performance rating than API CD or CE oils.2. The API CF-4 oil qualification test includes new