It can be time consuming and the end result may not be desirable if you haven't done it before.
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The following is just a sample of what to do once the engine is torn down:
Pistons and Connecting Rods
- Before installing the piston/connecting rod assembly, oil the pistons, piston rings and the cylinder walls with light engine oil. Install connecting rod bolt protectors or rubber hose onto the connecting rod bolts/studs. Also perform the following:
- Select the proper ring set for the size cylinder bore.
- Position the ring in the bore in which it is going to be used.
- Push the ring down into the bore area where normal ring wear is not encountered.
- Use the head of the piston to position the ring in the bore so that the ring is square with the cylinder wall. Use caution to avoid damage to the ring or cylinder bore.
- Measure the gap between the ends of the ring with a feeler gauge. Ring gap in a worn cylinder is normally greater than specification. If the ring gap is greater than the specified limits, try an oversize ring set.
Fig. 5: Checking the piston ring-to-ring groove side clearance using the ring and a feeler gauge
- Check the ring side clearance of the compression rings with a feeler gauge inserted between the ring and its lower land according to specification. The gauge should slide freely around the entire ring circumference without binding. Any wear that occurs will form a step at the inner portion of the lower land. If the lower lands have high steps, the piston should be replaced.
Fig. 6: The notch on the side of the bearing cap matches the tang on the bearing insert
- Unless new pistons are installed, be sure to install the pistons in the cylinders from which they were removed. 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 engine or cylinder to another, new bearings should be fitted and the connecting rod should be numbered to correspond with the new cylinder number. The notch on the piston head goes toward the front of the engine.
- Install all of the rod bearing inserts into the rods and caps.
Fig. 7: Most rings are marked to show which side of the ring should face up when installed to the piston
- Install the rings to the pistons. Install the oil control ring first, then the second compression ring and finally the top compression ring. Use a piston ring expander tool to aid in installation and to help reduce the chance of breakage.
Fig. 8: Install the piston and rod assembly into the block using a ring compressor and the handle of a hammer
- Make sure the ring gaps are properly spaced around the circumference of the piston. Fit a piston ring compressor around the piston and slide the piston and connecting rod assembly down into the cylinder bore, pushing it in with the wooden hammer handle. Push the piston down until it is only slightly below the top of the cylinder bore. Guide the connecting rod onto the crankshaft bearing journal carefully, to avoid damaging the crankshaft.
- Check the bearing clearance of all the rod bearings, fitting them to the crankshaft bearing journals. Follow the procedure in the crankshaft installation above.
- After the bearings have been fitted, apply a light coating of assembly oil to the journals and bearings.
- Turn the crankshaft until the appropriate bearing journal is at the bottom of its stroke, then push the piston assembly all the way down until the connecting rod bearing seats on the crankshaft journal. Be careful not to allow the bearing cap screws to strike the crankshaft bearing journals and damage them.
- After the piston and connecting rod assemblies have been installed, check the connecting rod side clearance on each crankshaft journal.
- Prime and install the oil pump and the oil pump intake tube.
- Install the auxiliary/balance shaft(s)/assembly(ies).
OHV Engines
CAMSHAFT, LIFTERS AND TIMING ASSEMBLY
- Install the camshaft.
- Install the lifters/followers into their bores.
- Install the timing gears/chain assembly.
CYLINDER HEAD(S)
- Install the cylinder head(s) using new gaskets.
- Assemble the rest of the valve train (pushrods and rocker arms and/or shafts).
OHC Engines
CYLINDER HEAD(S)
- Install the cylinder head(s) using new gaskets.
- Install the timing sprockets/gears and the belt/chain assemblies.
Engine Covers and Components
Install the timing cover(s) and oil pan. Refer to your notes and drawings made prior to disassembly and install all of the components that were removed. Install the engine into the vehicle.
Engine Start-up and Break-in
STARTING THE ENGINE
Now that the engine is installed and every wire and hose is properly connected, go back and double check that all coolant and vacuum hoses are connected. Check that your oil drain plug is installed and properly tightened. If not already done, install a new oil filter onto the engine. Fill the crankcase with the proper amount and grade of engine oil. Fill the cooling system with a 50/50 mixture of coolant/water.
- Connect the vehicle battery.
- Start the engine. Keep your eye on your oil pressure indicator; if it does not indicate oil pressure within 10 seconds of starting, turn the vehicle OFF.
WARNING
Damage to the engine can result if it is allowed to run with no oil pressure. Check the engine oil level to make sure that it is full. Check for any leaks and if found, repair the leaks before continuing. If there is still no indication of oil pressure, you may need to prime the system.
- Confirm that there are no fluid leaks (oil or other).
- Allow the engine to reach normal operating temperature (the upper radiator hose will be hot to the touch).
- At this point any necessary checks or adjustments can be performed, such as ignition timing.
- Install any remaining components or body panels which were removed.
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