SEAL-O-RING 6V7970 - Caterpillar

3408, 3408B, 3412 Engines In All ApplicationsReference: Engine News: December 1988, Page 4, "New Liner Seat Insert Available" for 3400 Family Of Engines equipped with spacer plates. February 1989, Page 1, "New Head Gasket Available (Used); Head Gasket Replacement Guidelines" for 3406 Family Of Engines.
August 1989, Page 4, "Improved Head Gasket Used; Summary Of Earlier Gaskets And Service Tips" for 3406, 3406B Family of Engines.
Reference: Guidelines For Reusable Parts, SEBF8131, "Spacer Plates For 3406 Family Of Engines."Description of Change: A new 7E7308 Cylinder Head Gasket is used on 3408/3408B Engines and a new 7E7312 Cylinder Head Gasket is used on 3412 Engines in all applications. The new gaskets have the following improvements over the former gaskets. ... A thicker fire ring to compensate for the asbestos-free body material. The thicker fire ring and thinner wrap help to prevent leakage of combustion gases, and give a better "crush" on the liner flange when the head is tightened.... The overlap of the stainless steel fire ring wrap is reduced to give better gasket body loading and minimize the possibility of fluid leaks. The wrap has a tab-style design. This tab design results in a more flexible gasket that requires extra care in handling and storage.... This gasket is NOT coated on the cylinder head side. It DOES have a single layer of black Teflon® (PTFE) on the spacer plate side. The PTFE prevents sticking to the aluminum spacer plate.Adaptable To: The new 7E7308 Gasket is a direct replacement for the former 2W7984 Gasket which has been canceled. The new 7E7308 Gasket is effective with the following engine serial numbers. 3408 Industrial Engine: 67U132263408B Industrial Engine: 6NB7413408B Generator Set Engine: 78Z35923408B Marine Engine: 99U6595The new 7E7312 Gasket is a direct replacement for the former 2W7985 Gasket which has been canceled. The new 7E7312 Gasket is effective with the following engine serial numbers.
3412 Industrial Engine: 38S146233412 Industrial Engine: 7DB4983412 Marine Engine: 60M40563412 Generator Set Engine: 81Z9356 Any time the new head gasket is to be installed, refer to the following topics so that maximum life can be obtained from the new gasket, head, block, spacer plate, and engine block.Liner Projection and Machining the Block and/or Head
Do NOT adjust the liner projection above the block if it measures in the range of 0.03 to 0.15 mm (.001 to .006"). ALSO, make sure that the differences between all four measurements at any one cylinder do not exceed 0.05 mm (.002"). AND, the difference between the average projection of two liners next to each other must not exceed 0.05 mm (.002"). These specifications are in the Service Manuals for these engines.
Wear or erosion under the liner flange will require use of a stainless steel insert. Read the reference article about the new liner seat insert. The head and/or block surfaces may have been damaged if the engine was operated extensively after a head gasket failure.
To prevent entry of debris into the engine when cleaning excess Teflon from the block and head, use a clean Scotchbrite®