Piston: Service and Repair

DISASSEMBLY





1. Also, keep the connecting rods and connecting rod bearing caps with matching numbers together. Be careful to use the proper tools to disassemble and assemble the piston, piston pin, and connecting rod. Extensive damage can result if the wrong tools are used. The piston pins in this engine are interference press fit in the connecting rod. The bearing surface is between the piston pin bore of the piston and the piston Din.





The proper tools for disassembling the connecting rod and piston are contained in Piston Pin Remover/Replacer T81P-6135-A and Piston Pin Tool D81L-6135-A or equivalent.





Assemble the anvil, tube guide, and threaded plug onto the base and press plates of an arbor press.

NOTE: Record or mark the relation of the front "F" mark of the piston to the numbered side of the connecting rod. This is important for correct assembly.

2. Select Insert 39887 (number 5) and place it between the connecting rod and the inside piston pin boss of the piston.
3. Place the insert into the anvil opening with the open end of the insert facing the open side of the anvil.
4. Position the connecting rod and piston onto the anvil and insert with the front of the piston facing down. The anvil and insert should contact as much of the connecting rod pin boss as possible.
5. Adjust the rear support to position the connecting rod in a horizontal position, so the press ram and the piston pin are in line.
6. Position the assembled Piston Pin Remover/Replacer T81P-6135-A onto the top of the piston and under the arbor press ram.
7. Apply press ram pressure and press the piston pin out of the connecting rod and piston. The piston pin should enter the tube guide. Adjust the piston and connecting rod position on the anvil if necessary to align with the tube guide. Keep the piston pin with the piston it came from.

ASSEMBLY
1. Install the threaded plug into the tube guide approximately half of its thread length.
2. Select an appropriate pin guide. Install the spring, body guide, and pin guide into the tube guide.
3. Insert the piston pin into the piston pin bore of the piston. Measure the amount that the piston pin protrudes on each side of the piston. Record that figure.
4. Remove the pin and position the connecting rod and piston on the Insert 39887 (5) and anvil. The insert selected will be one that best fits the piston pin and fills the space between the connecting rod and piston. The spring-loaded pin guide will pass through the piston and connecting rod and align it. Lubricate the piston pin and insert it into the piston.





5. Place the assembled Piston Pin Remover/Replacer T81P-6135-A onto the piston pin and move the piston and pin into position under the arbor press ram. Push the piston pin through the connecting rod until it protrudes the distance recorded in Step 3. Check that the piston is free on the piston pin while installing the pin.
6. When the piston pin-to-piston dimension is correct, keep a slight pressure on the press ram. Thread the threaded plug into the tube guide until it contacts the body guide.
7. Remove ram pressure and check the piston pin-to-piston dimension. Readjust if necessary and reset the threaded plug. The threaded plug is now set to gauge the remainder of the connecting rods and pistons.