PLATE-PRESSURE 6E4764 - Caterpillar

3406 ( 90U, 91U, 92U, 70V)The 7N628 Gasket Group has the parts needed to give a better seal to the lubrication oil passages between the cylinder block and cylinder head. This will prevent leakage of lubrication oil into the engine cooling system. If the reason for the engine repair and use of this gasket group is because of engine oil in the cooling system, extra parts will be needed, such as seals for the cylinder liners and cylinder head, and new gaskets. Other extra parts that are needed will be variable according to the engine arrangement, or how much disassembly is done to the engine.The 7N628 Gasket Group can be installed on the above engines that use cylinder head bolts as an oil supply passage for lubrication of the rocker shafts. Installation of this gasket group will give a better seal around the bolt hole oil passages. Before installation of the gasket group, six bolt holes in the original 4N2104 Spacer Plate must be made larger according to the procedure given in this instruction. If the original spacer plate is damaged and cannot be used again, a new 7N624 Spacer Plate is available as a replacement.1 Drain the cooling system and the engine oil pan. Remove the cylinder head, spacer plate and gasket and the cylinder liners. Clean the top surface of the cylinder block.2 Remove all hoses for the radiator. Thoroughly clean (wash) the inside of the cylinder block, cylinder head, the radiator core and any other parts that need to be cleaned, to remove the oil film (thin layer of oil) from all coolant passages.3 Check and clean all cylinder liners. Install new seals on the bottom of the cylinder liners. Check the condition of the seals that are removed. If there is oil on the seals, or the seals show signs of deterioration (wear shown when pieces of the seal are gone), clean the coolant passages in the cylinder head. Inspect the cylinder head; if the cylinder head has cracks or other damage, a new cylinder head is needed.4 Modification to the original 4N2104 Spacer Plate is necessary, according to the procedure that follows. If the original spacer plate is damaged and cannot be used again, install a new 7N624 Spacer Plate. The new spacer plate does not need modification. 5 Thoroughly clean both sides of the 4N2104 Spacer Plate (1). Check the thickness of spacer plate (1); the thickness must be .338" .001" (8.59 0.03). If the spacer plate thickness is correct, use a 31/32" diameter 8 or 10 fluted reamer at a speed of 110 rpm to increase six holes (A) to a diameter of .968" .010" (24.6 0.3). 6 Remove all burrs (rough, sharp edges) at locations (B) of each hole (A). Use a steel stamp to mark the part number 7N624, a minimum of .19" (4.8) high, on the edge of the spacer plate at location (C), to let it be known that the reconditioning has been