Piston and Connecting Rod

Tools Required:

• Piston Pin Remover/Replacer T68P-6135-A
• Rotunda Piston Ring Compressor 014-00290
• Rotunda Cylinder Ridge Reamer 014-00292

Disassembly

1. Remove any ridges and/or deposits from the upper end of the cylinder bores as follows.

    CAUTION: Never cut into the ring travel area in excess of 0.8mm (1/32 inch) when removing ridges.

   Turn the crankshaft until the piston to be removed is at the bottom of its travel and place a cloth on the piston head to collect the cuttings. Remove any ridge and/or deposits from the upper end of the cylinder bores. Remove the cylinder ridge with Rotunda Cylinder Ridge Reamer 014-00292 or equivalent.

2. Ensure all connecting rod caps are marked so that they can be installed in their original positions.

3. Turn the crankshaft until the connecting rod being removed is down.

4. Remove the connecting rod nuts and cap.

    CAUTION: Avoid damage to the crankshaft journal or the cylinder wall when removing the piston and rod.

5. Push the connecting rod and piston assembly out the top of the cylinder with the handle end of a hammer.

6. Remove the bearing inserts from the connecting rod and cap.

7. Install the cap on the connecting rod from which it was removed.

8. Remove the piston rings using a suitable piston ring expander.

9. Mark the piston and pins to ensure assembly with the same rod and installation in the same cylinders from which they were removed.

10. Using an arbor press and Piston Pin Remover/Replacer T68P-6135-A or equivalent, press the pin from the piston and connecting rod.

Assembly

1. If new piston rings are to be installed, and no visible cross-hatch marks remain on the cylinder wall, remove the cylinder wall glaze using a spring-type tool. Follow the instructions of the tool manufacturer. After honing, clean the cylinder walls with a detergent and water solution.

    CAUTION: Be certain to install the pistons in the same cylinders from which they were removed or to which they were fitted. The connecting rod and bearing caps are numbered from 1 to 4. The numbers on the connecting rod and bearing cap must be on the same side when installed in the cylinder bore. If a connecting rod is ever transposed from one block or cylinder to another, new bearings should be fitted and the connecting rod should be numbered to correspond with the new cylinder number.

2. Oil the piston rings, pistons and cylinder walls with recommended quality engine oil. Check the fit of a new piston in the cylinder bore before assembling the piston and pin to the connecting rod. The piston pin bore of a connecting rod and the diameter of the piston pin must be within specification.

3. Assemble the piston to the connecting rod with the oil squirt holes on the side of the connecting rod and the arrow in the piston positioned as shown.
   
   
   
   

4. Start the piston pin in the piston and connecting rod (this may require a very light tap with a mallet). Press the piston pin through the piston and connecting rod until the pin is centered in the piston.

5. Install piston rings using a suitable piston ring expander. Check the end gap and spacing of all piston rings. They must be within specification. Refer to Section 03-00.

6. Check the ring side clearance as outlined in Section 03-00.

7. Install Rotunda Piston Ring Compressor 014-00290 or equivalent on the piston. Push the piston in with a hammer handle until it is slightly below the top of the cylinder Be sure to guide the connecting rods to avoid damaging the crankshaft journals.

    CAUTION: Install the piston with the indentation notch in the piston head toward the front of the engine.

   
   
   
   
   

8. Ensure the bearing inserts and the bearing bore in the connecting rod and cap are clean. Foreign material under the inserts will distort the bearing and cause a failure. Install the bearing inserts in the connecting rod and cap with the tangs fitting the slots provided.

9. Check the clearance of each bearing. Refer to Section 03-00.

10. After the bearings have been fitted, apply a light coat of engine oil to the journals and bearings.

11. Turn the crankshaft throw to the bottom of its stroke. Push the piston all the way down until the connecting rod bearing seats on the crankshaft journal.

12. Install the connecting rod cap. Tighten the nuts in two steps: 34-41 Nm (25-30 lb-ft), then 41-49 Nm (30-36 lb-ft).

13. After the piston and connecting rod assemblies have been installed, check the side clearance between the connecting rods on each crankshaft journal.