BLOCK AS-MOUNTING 1660690 - Caterpillar

All 3400 Family Of Engines Equipped With Spacer PlatesReference: Special Instruction; Form SMHS8222; "Installation Of 2W3815 Or 5N93 Inserts".A new liner seat insert is available to salvage engine blocks that have damage from fretting, corrosion or a wear step on top of the block under the liner flange. This 9Y3368 Insert is 0.822 mm (.0324") thick and can be used on blocks which have only slight damage.
This insert compliments the other two stainless steel inserts already available. These inserts are 2W3815, which is 1.595 mm (.0628") thick, and 5N0093, which is 2.700 mm (.1063") thick. These inserts are used when fretting, corrosion or cracks are deeper and require more machining to clean up the liner seats.
Caterpillar recommends counterboring only to the depth of the thickest available insert (5N0093). However, if blocks must be counterbored deeper, it is preferred that stainless steel inserts are stacked rather than using a single, thicker cast iron insert. Minor erosion under all liners less than 0.28 mm (.011") can be cleaned up by resurfacing the entire top deck of the block. If measurable erosion is 0.03 mm (.001") or less, no repair is necessary.
Shims (of any material) are not recommended for use on 3400 Family of Engines to adjust liner projection.
The depth setting gage needed to determine the correct machining depth for the 9Y3368 Insert will be available soon and announced in the Tool Guide.