CYLINDER GP-BUCKET 2054846 - Caterpillar

(4YC),
785 (8GB),
789 (9ZC) Off-Highway Trucks;
776B (6JC) Off-Highway Tractors;
D11N (74Z) TractorsThe 9Y-2100 Piston Body Assembly was previously manufactured with an anodized layer on the top of the crown and a phosphate-graphite coating on the skirt. The anodized layer is a chemical surface hardening process for aluminum. The phosphate-graphite coating is a dry lubricant.
The purpose of the anodized layer is to protect the combustion bowl against excessive heat and pressure. The purpose of the phosphate-graphite coating is to protect against piston scuffing during the break-in process.
Due to recent structural improvements to the oil galley and the piston crown, the anodized layer is no longer necessary. Field and laboratory data have also demonstrated that there is no need for the phosphate-graphite coating.
As a result, the 9Y-2100 Piston Body Assembly is now manufactured without the anodized layer and the phosphate-graphite coating. This piston is adaptable to the above Caterpillar Machines which are powered by 3500 MUI Engines. The new piston without the anodized layer and phosphate-graphite coating can be interchanged with the earlier made piston that contains these two features. There is no noticeable difference between the coated and uncoated pistons other than a difference in color. The color difference has no effect on the usability of the pistons.