0389471 JOHNSON SPARK PLUG, Champion L78V

Table 1
Required Tools
Tooling Part Number Description Qty
A 7S-9470 Piston Ring Expander 1
B 5P-8639 Hydraulic Press 1
5P-8655 Tool Group 1
1U-5230 Hand Hydraulic Pump 1
8F-0024 Hose Assembly 1
1P-2375 Quick Connect Coupler 1
1P-2376 Quick Connect Coupler 1 Note: Cleanliness is an important factor. Before assembly, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble. Inspect all parts. If any parts are worn or damaged, use new parts for replacement.
Illustration 1 g01003241
Heat connecting rod (1) in an oven to a temperature of 190° 15°C (375° 25°F). Never use a direct flame to heat a connecting rod.
Illustration 2 g01003240
Place connecting rod (1) in position on Tooling (B). Install a new connecting rod pin. Ensure that joint (2) is 90° from the center line through the crankshaft and the bearing bores.
Illustration 3 g01003244
Use Tooling (B) in order to remove the old rod pin bearing and install the new rod pin bearing in one operation.
Use a pin boring machine in order to bore the correct size for the bearing. The bore in the new bearing must be 38.143 0.008 mm (1.5017 0.0003 inch). The maximum permissible worn clearance between the bearing and piston pin must not be more than 0.08 mm (.003 inch).
Illustration 4 g01003245
Place the connecting rod in position in the piston with bearing tab groove (3) and the number identification on the same side as the "V" mark on the top of the piston.
Install piston pin (1) and retaining ring (4).
Check the clearance between the end gaps of the piston rings and the rings in a cylinder liner with a bore size of 120.65 mm (4.750 inch). The clearance of the top ring is 0.51 0.08 mm (.020 .003 inch) and the clearance for the oil ring is 0.46 0.13 mm (.018 .005 inch).
Install the oil ring spring in the oil ring groove of the piston.
Illustration 5 g01003248Note: Install oil ring (6) on the piston. Ensure that the end gap on the oil ring is 180° from the joint on the oil ring spring.
Use Tooling (A) in order to install oil ring (6) on the piston.
Use Tooling (A) in order to install the top piston ring (5) with the side that has the mark "UP" toward the top of the piston.
Check the clearance between the piston ring grooves and the rings. The maximum permissible clearance between all of the rings and piston grooves must not be more than 0.15 mm (0.006 inch). The clearance between the new top ring and the groove must be 0.090 0.020 mm (0.0035 0.0008 inch). The clearance between the new oil ring and the groove must be 0.0635 0.0254 mm (0.0025 0.0010 inch). Before you install the pistons ensure that the end gaps for the top piston ring and the oil ring are 180° from each other. End By:
Install the pistons and connecting rods. Refer to Disassembly and Assembly, "Piston and Connecting Rods - Install" for the engine that is being serviced.