REMOVAL & INSTALLATION
See Figures 1, 2, 3, 4 and 5
When draining coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.
Although, in most cases, the pistons and connecting rods can be removed from the engine (after the cylinder head and oil pan are removed) while the engine is still in the vehicle, it is much easier to remove the engine from the vehicle.
- Disconnect the negative battery cable.
- Drain the cooling system and engine crankcase of fluids.
- Remove the engine from the vehicle.
- Remove the cylinder head(s), oil pan and front cover (if necessary).
Mark the connecting rods and bearing caps so they can be installed in the proper cylinders.
- Remove the connecting rod bearing caps and bearings.
Because the top piston ring does not travel to the very top of the cylinder bore, a ridge is built up between the end of the travel and the top of the cylinder. Pushing the piston and connecting rod assembly past the ridge may be difficult and may cause damage to the piston. If necessary, ridge ream the top of the cylinder sleeve before removing the piston assembly.
- Push the piston assembly out of the cylinder.
If new piston rings are to be installed, remove the cylinder wall glaze. Follow the instructions of the tool manufacturer. Clean the cylinder bores with soap and water solution after deglazing or honing. Properly dry and oil the cylinder walls immediately after cleaning.
- Oil the piston rings, piston and cylinder walls with clean engine oil.
- Position the piston ring gaps approximately 90 degrees apart.
- Install a suitable piston ring compressor on the piston and 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. Install the piston with the "NOTCH'' on the piston toward the front of the engine.
- Check the bearing clearance. After the bearings have been fitted, apply a light coat of clean engine oil to the journals and bearing.
- Push the piston all the way down until the connecting rod bearing seats on the crankshaft journals.
- Install the connecting rod cap and bearings. The oil squirt hole in the bearing must be aligned with the squirt hole in the connecting rod. Tighten to specifications.
- Install the oil pump pickup, oil pan, cylinder head and front cover as necessary.
- Install the engine in the vehicle.
- Fill the crankcase with the recommended engine oil. Fill and bleed the cooling system.
- Connect the negative battery cable.
- Run the engine and check for leaks.
CLEANING AND INSPECTION
- Use a piston ring expander and remove the rings from the piston.
- Clean the ring grooves using an appropriate cleaning tool. Exercise care to avoid cutting too deep into the piston.
- Clean all varnish and carbon from the piston with a safe solvent. Do not use a wire brush or caustic solution on the piston.
- Inspect the pistons for scuffing, scoring, cracks, pitting or excessive ring groove wear. If wear is evident, the piston must be replaced.
- Have the piston and connecting rod assembly checked by a machine shop for correct alignment, piston pin wear and piston diameter . If the piston has collapsed it will have to be replace or knurled to restore original diameter. Connecting rod bushing replacement, piston pin fitting and piston changing can be handled by the machine shop.
Check the cylinder bore for wear using a telescope gauge and a micrometer, measure the cylinder bore diameter perpendicular to the piston pin at a point 2.5 in. (63.5mm) below the top of the engine block. Measure the piston skirt perpendicular to the piston pin. The difference between the two measurements is the piston clearance. If the clearance is within specifications, finish honing or glaze breaking is all that is required. If clearance is excessive a slightly oversize piston may be required. If greatly oversize, the engine will have to be bored and oversized pistons installed.
PISTON RING REPLACEMENT
See Figures 6 and 7
- Take the new piston rings and compress them, one at a time into the cylinder that they will be used in. Press the ring about 0.98 in. (25mm) below the top of the cylinder block using an inverted piston.
- Use a feeler gauge and measure the distance between the ends of the ring. This is called measuring the ring end-gap. Compare the reading to the one called for in the specifications table. If the measurement is too small, when the engine heats up the ring ends will butt together and cause damage. File the ends of the ring with a fine file to obtain necessary clearance.
If inadequate ring end-gap is utilized, ring breakage will result.
- Inspect the ring grooves on the piston for excessive wear or taper. If necessary, have the grooves recut for use with a standard ring and spacer. The machine shop can handle the job for you.
- Check the ring grooves by rolling the new piston ring around the groove to check for burrs or carbon deposits. If any are found, remove with a fine file. Hold the ring in the groove and measure side clearance with a feeler gauge. If the clearance is excessive, spacer(s) will have to be added.
Always add spacers above the piston ring.
- Install the ring on the piston, lower oil ring first. Use a ring installing tool (piston ring expander) on the compression rings. Consult the instruction sheet that comes with the rings to be sure they are installed with the correct side up. A mark on the ring usually faces upward.
- When installing oil rings, first, install the expanding ring in the groove. Hold the ends of the ring butted together (they must not overlap) and install the bottom rail (scraper) with the end about 25mm away from the butted end of the control ring. Install the top rail about 25mm away from the butted end of the control but on the opposite side from the lower rail. Be careful not to scrap the piston when installing oil control rings.
- Install the two compression rings. The lower ring first.
- Arrange the rings in a staggered order such that the ends do not overlap on top of each other. Install a ring compressor and insert the piston and rod assembly into the engine.
PISTON PIN REPLACEMENT
- Matchmark the piston head and the connecting rod for reassembly.
- Position the piston assembly in a piston pin removal tool.
- Following the tool manufacturers instructions, press the piston pin from the piston.
- Check the piston pin bore for damage, replace defective components as required. Check the piston pin for damage, replace as required.
- Installation is the reverse of the removal procedure.
ROD BEARING REPLACEMENT
- Remove the engine from the vehicle. Position the engine assembly in a suitable holding fixture.
- Remove the oil pan. Remove the oil pump, as required.
- Rotate the crankshaft so that you can remove the rod bearing cap. Matchmark the rod bearing cap so that it can be reinstalled properly.
- Remove the rod bearing cap. Remove the upper half of the bearing from its mounting.
- Carefully remove the lower half of the bearing from its mounting. It may be necessary to pull the piston down in the cylinder chamber to gain more access to the bearing and complete the procedure.
- Installation is the reverse of the removal procedure.