Usage:
Disassembly
Cylinder Head and Valve Mechanisms
Removal of Rocker Shaft Assembly
(1) Loosen the adjusting screws on the rockers by rotating each screw about one turn.
Removal of rocker shaft assembly
(2) Loosen the short bolts on the rocker shaft brackets first, then loosen the long bolts to remove the rocker shaft assembly from the cylinder head.
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Incorrect bolt loosening sequence can result in the damage to the rocker shaft brackets. |
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(3) Remove the pushrods.
Disassembly of Rocker Shaft Assembly
Arrange the disassembled rockers in the order of removal, so that the rockers can be reinstalled exactly in the opposite sequence.
This ensures the same rocker shaft clearances as before.
Disassembly of rocker shaft assembly
Removal of Cylinder Head Bolts
Remove the cylinder head bolts from the cylinder head, and lift the cylinder head vertically to detach it from the crankcase.
NOTE: If there is any problem in the cylinder head, before removing the bolts, examine the cylinder head bolt tightening condition by checking the bolt tightening torque with a torque wrench.
Removal of cylinder head bolt
Removal of Valves and lave Springs
Using the valve spring pusher, compress the valve spring squarely, then remove the valve cotter.
NOTE: If the valves are to be reused, mark them to indicate their original installation positions.
Removal of valve and valve spring
Removal of Valve Stem Seals
To remove steam seals, pull with pliers.
Removal of valve stem seal
NOTE: Do not reuse the removed stem seals.
Cleaning of Cylinder Head Bottom Surface
Remove adhered gasket pieces from the bottom surface of the cylinder head, making sure not to scratch the surface.
NOTE: Use a scraper to remove large pieces first, then remove remaining small pieces by using an oilstone dampened with engine oil.
Cleaning of cylinder head bottom surfaces
Measurement of Piston Protrusions
Determine the amount of the protrusion of the piston. If the amount of piston protrusion does not conform to the standard, be sure to inspect and repair each bearing.
(1) Determine the top dead center of the piston with a dial gage.
(2) Attach a dial gage on the top surface of the crankcase, and set the indicator to zero (0).
(3) Check the piston protrusion at three locations on the top surface of the piston, and obtain the average valve. Subtract the amount of piston protrusion from the compressed thickness of the gasket to determine the clearance between the piston top and cylinder head.
Measure of piston protrusion
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Piston protrusion must comply with the standard to ensure proper engine performance and prevent the interference between the valves and pistons. |
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Flywheel
Measure of piston protrusion
Removal of Flywheel
(1) To prevent the flywheel from rotating, have someone hold the crankshaft pulley with a wrench.
Removal of the flywheel
(2) Remove one of the flywheel mounting bolts.
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The person holding the flywheel in place should exercise utmost caution, and communicate with the person removing the flywheel during the removal process to ensure safety. |
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(3) Screw a safety bar (M12x1.25mm) in the threaded hole from which the bolt was removed in the above step, then remove the remaining bolts.
(4) Hold the flywheel securely with both hands, jiggle it back and forth, and pull it straight out.
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When removing the flywheel, be careful not to cut your hands with the ring gear. |
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Removal of Rear Plate
Removal of flywheel housing
Remove the rear plate mounting bolts, and dismount the rear plate together with the oil seal.
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Be careful not to damage the surface of the oil seal. |
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Timing Gears, Camshaft and Oil Pan
Removal of Crankshaft Pulley
Removal of crankshaft pulley
(1) Screw two bolts (M12x1.25mm) into the threaded holes on the back-end of the crankshaft, and put a bar between the bolts to prevent the crankshaft from rotating.
(2) Remove the crankshaft pulley.
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Pay attention to safety. The bar may disengaged from the bolts. |
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Removal of Timing Gear Case
Pull the timing gear case straight out to remove it because it is held in place by right and left dowel pins.
Removal of timing gear case
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Since the front plate is bolted inside the gear case, do not attempt to remove it together with the gear case by tapping it. |
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Measurement of Backlashes
Measurements of idler gear backlash
Measure the backlash of each gear, and use it as a reference in reinstallation.
If the measured valve exceeds the limit value, all gears should be replaced as a general rule.
Measurement of Idler Gear End Play
Measure the endplay with feeler gages or a dial gage, if the limit value is exceeded, replace the thrust plate.
Measurement of idler gear end play
Removal of Idler Gear
Remove the idler gear by turning in the direction of the gear tooth slant.
Removal of idler gear
Camshaft End Play
Measure the camshaft endplay, and, if the limit value is exceeded, replace the thrust plate.
Measurement of camshaft end play
Reversal of Crankcase
Gently lay the crankcase on its side, then turn the crankcase upside down.
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Resting the crankcase with the oil pan on the bottom can cause the oil pan to crack. |
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Reversal of crankcase
Removal of Oil Pan And Oil Pan Gasket
Removal of oil pan and oil gasket
(1) Unscrew the oil pan mounting bolts, and detach the oil pan.
(2) Remove the oil pan gasket.
Removal of Oil Pump
Removal of oil pump
Unscrew the oil pump set bolt, and pull out the oil pump.
Removal of Camshaft
Removal of camshaft
(1) Position the camshaft gear so that the two lightening holes are on the top and bottom, then remove the thrust plate mounting bolts using the socket.
(2) Pull out the camshaft from the crankcase.
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Be careful not to damage the cams and baring sections on the camshaft. |
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Removal of Front Plate
Removal of front plate
Unscrew the front plate mounting bolts, and dismount the front plate (together with the injection pump) from the crankcase.
Pistons, Connecting Rods, Crankshaft and Crankcase
NOTE: When replacing the crankcase, remove all accessories (relief valve and others) carefully from the crankcase, and reinstall them on a new crankcase.
Laying Crankcase on Its Side
Laying crankcase on its side
Gently lay the crankcase on its side.
Measurement of Thrust Clearance on Big-End of Connecting Rod
Measurement of thrust clearance on big-end of connecting rod
(1) Measure the clearance between the big-end of each connecting rod and the crankshaft with feeler gages.
(2) If the measured clearance exceeds the limit value, replace the connection rod.
Weight Difference Among Connecting Rod Assemblies
Weight rank mark on connecting rod
When replacing connection rods, make sure that all connecting rods have the same weight rank mark.
Removal of Connecting Rod Caps
Removal of connecting rod cap
(1) On each connecting rod and cap, put a mark indicating its cylinder No.
(2) Remove the connecting rod caps.
(3) For each removed connecting rod bearing (lower half), indicate the piston No. from which it was removed and the upper/lower identification.
NOTE: Be careful not to damage the bearings. Arrange the removed bearings in such a way that they can be reinstalled in their original positions during reassembly.
Preparation For Removal of Pistons
Preparation for removal of piston
If carbon deposits are present at the upper sections of the cylinders, remove the carbon deposits with sandpaper and a cloth to facilitate piston removal.
Removal of Pistons
Removal of piston
(1) Turn the crankshaft to bring the piston to be removed to the top dead center.
(2) Using the wooden handle of a hammer, push the connecting rod on the cap contacting surface to remove the piston and connecting rod assembly from the top side of the cylinder.
Removal of Piston Ring
Removal of piston ring
Using the piston ring pliers, remove the piston rings
Removal of Piston Pins
Removal of piston pin
(1) Using the snap ring pliers, remove the snap rings.
(2) Pull out the piston pin, and separate the piston from the connecting rod.
(3) If the piston pin cannot be remove easily, heat the piston with a piston heater or in hot water.
Reversal of Crankcase
Reversal of crankcase
Gently stand the crankcase so that the oil pan mounting side faces up.
Measurement of Crankshaft End Play
Measurement of crankshaft end play
(1) With a dial gage positioned at the end of the crankshaft, measure the end play.
(2) If the limit value is exceeded, replace the flanged bearing.
Removal of Main Bearing Caps
Unscrew the main bearing cap mounting bolts, and remove the main bearing caps together with the bearings.
Removal of main bearing cap
NOTE: Be careful not to damage the bearings. Arrange the removed bearings so that they can be reinstalled in the original positions during reassembly.
Removal of Crankshaft
Gently lift the crankshaft to remove it from the crankcase.
Removal of crankshaft
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Be careful not to damage the bearings during the removal of the crankshaft. |
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Arrangement of Bearings
Be sure to arrange the bearings so that they can be reinstalled in their original positions and combined with their matching halves.
Inspection and Repair of Engine Main Parts
Cylinder Head and Valve Mechanisms
Measurement of Distortion of Cylinder Head Bottom Surface
Place a straight edge on the bottom surface of the cylinder head, measure the amount of surface distortion using feeler gages, and, if the limit value is exceeded, reface the surface with a surface grinder.
Measurement of distortion of cylinder head bottom surface
Measurement of Rocker Arm Inside Diameter and Rocker Shaft Diameter
Measure the inside diameter of the rocker arm (bushing) and the diameter of the rocker shaft to calculate the clearance between the rocker arm and shaft, and replace the rocker arm if the clearance is within the limit value. If the limit value is exceeded, replace the rocker arm and shaft.
Measurement of rocker arm inside diameter and rocker shaft diameter
Measurement of Valve Spring Perpendicularity and Free Length
Inspect each valve spring for perpendicularity and free length, and if the limit value is exceeded, replace the valve.
Measurement of valve spring perpendicularity and free length
Measurement of Pushrod Deflection
If the pushrod defection exceeds the standard value, replace the pushrod.
Measurement of pushrod deflection
NOTE: The standard value above is based on dial gage reading.
Measurement of Valve Stem Diameter
Measurement of valve stem diameter
If the stem diameter exceeds the limit value, replace the valve stem. Also replace the valve stem if it is unevenly worn.
Measurement of Clearance Between Valve Stem and Valve Guide
Measure the valve guide bore with and internal bore micrometer.
Because the valve guide wears more rapidly at the upper and lower end, measure the diameter at both ends in two crossing directions. If the limit is exceeded, replace worn parts.
Measurement of valve guide inside diameter
Removal of valve guide
NOTE: Remove carbon deposits from the valve and valve guide before measuring the clearance.
Replacement of Valve Guides
Installation of valve guide
(1) To remove the valve guides, the valve guide remover.
(2) To press-fit the valve guides, use the valve guide installer and a press.
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Be sure to use the valve guide installer in order to drive the valve guide to the prescribed depth. |
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(3) After installing the valve guide, insert a new valve and check the smoothness of the movement.
(4) When the valve guide is replaced, check the contact of the valve with the valve seat.
Inspection of Valve Faces
Inspection of valve face
Coat the valve face lightly with red lead, and use the valve lapper to inspect the valve contact with the valve seat. If the contact is not uniform and the valve is defective, or if a limit is exceeded, correct or replace the valve and valve seat.
NOTE:
(a) Inspect the valve face after the valve guide is inspected or replaced.
(b) When pressing the valve coated with red lead against the valve seat, do not rotate the valve.
(c) After the valve or valve seat is corrected or replaced, lap the valve against the valve seat.
Valve seat contact with seat
Valve contact with seat
Replacement of Valve Seats
(1) Removal of valve seat
Weld a stud or bar to the valve seat, insert a shaft into the valve guide bore from the top of the cylinder head, and drive the seat off the cylinder head.
Removal of valve seat
NOTE: When welding the stud, do not allow spatter to adhere on the machined surfaces of the cylinder.
(2) Installation of valve seat
Valve seat installation dimension
(a) Before inserting a new valve seat, measure the cylinder head bore to which the valve seat is installed to make sure the dimension conforms to the standard.
Installation of valve seat
(b) When installing a valve seat, keep the cylinder head at room temperature and cool the valve seat in liquid nitrogen (approx. -170 °C [-274 °F]) for more than 4 minutes, or heat the cylinder head to 80 to 100 °C [176 to 212 °F] and keep the valve seat chilled in ether or alcohol containing dry ice.
(c) Using the insertion/caulking tool, drive the valve seat into place.
Refacing Valve Faces
If the valve face is excessively worn, reface it with a valve refacer.
Refacing valve face
NOTE:
(a) Reface the valve face to an angle of 30°.
(b) Be sure to ensure the valve margin limit. If the grinding does not result in the conformity of the dimension, replace the valve.
Regrinding Valve Seats
Use the valve seat cutter or valve seat grinder to reface the valve seat. After refacing, grind the seat lightly by inserting #400-grade sandpaper between the cutter and valve seat.
Regrinding valve face
NOTE:
(a) Grind the valve seat as little as possible.
(b) If the seat width exceeds the limit due to wear or as a result of grinding, replace the valve seat.
Lapping Valves Against Valve Seats
Be sure to tap each valve in its valve seat after the valve or seat has been refaced or replaced.
Lapping valve against valve seat
(1) Coat the seat contact surface of the valve face lightly and evenly with a lapping compound.
NOTE:
(a) Do not allow the compound to adhere on the valve steam.
(b) Use a compound of medium coarseness (120 to 150 mesh) for initial lapping, and use a finer compound (200 mesh or finer) for finishing.
(c) Mix a small amount of engine oil with the compound for smooth and even application.
(2) Use the valve lapper to lap the valve in the seat.
(3) Wash off the compound with diesel fuel.
(4) Coat the seat contact surface of the valve face with engine oil, then lap the valve again.
(5) Inspect the valve face for contact.
Replacement of Combustion Jets
Replace the combustion jets only when cracks or other abnormal conditions are found.
Removal of combustion jet
(1) To remove the combustion jet, insert a round rod measuring about 6 mm [0.24 in] in diameter into the glow plug mounting hole, and lightly tap the inside surface of the jet at the perimeter.
(2) To reinstall the combustion jet, point the jet nozzle toward the center of the cylinder, and strike with a plastic hammer.
Installation of combustion jet
Flywheel
Measurement of Flywheel Flatness
Place the flywheel on a surface plate, and run a dial gage on the friction face of the flywheel to measure the flatness. If the limit value is exceeded, refinish the friction surface.
Measurement of flywheel flatness
Replacement of Ring Gear
Inspect the ring gear, and, if missing teeth or abnormally worn tooth surfaces are found, replace the ring gear by following the procedure described below.
Removal of ring gear
(1) Removal of ring gear
(a) Heat the ring gear uniformly using an acetylene torch.
(b) To remove the ring gear, tap the entire perimeter of the ring gear evenly using a rod and a hammer.
(2) Reinstallation of ring gear
Heat the ring gear using a piston heater (to a temperature lower than 150 °C [302 °F], and install the ring gear with the non-chamfered side facing the flywheel.
Timing Gears, Camshaft and Oil Pan
Inspection of V-belt Groove for Wear
Inspection of V-belt groove for wear
Inspect the V-belt groove on the pulley for wear. To judge the amount of wear, wrap a new V-belt around the pulley, and check whether the outside surface of the belt is higher or lower than the edges of the pulley groove.
If the outside surface of the belt extends from the edges of the groove, the pulley can be still used. If the outside surface of the belt is lower than the edges by more than 1.6mm [0.063 in.], the pulley is excessively worn and must be replaced.
Inspection of Oil Seal Contact Surface
Inspect the oil seal contact face of the pulley, and, if the pulley face has been excessively worn by the oil seal, replace the pulley.
Measurement Of Clearance Between Idler Gear Bore And Shaft
Measurement of idler gear inside diameter and shaft diameter
Measure the idler gear inside diameter and the shaft diameter to determine the clearance, and, if the limit valve is exceeded, replace the idler gear or shaft.
Replacement of Idler Bushing
Replacement of idler bushing
(1) To replace the idler bushing, use the idler bushing installer.
(2) Press-fit the bushing into the gear until the end face of the bushing is flush with the boss end face.
(3) After installing the bushing, finish the inside diameter to 36 H7 (+0.0250 mm 0.8 Ra [1.42 H7 (+0.0010in.].
Replacement of Idler Shaft
Removal of idler shaft
Use the idler shaft puller to remove the idler shaft.
NOTE: When driving the idler shaft into the crankcase, make sure that the oil hole in the idler shaft faces the top side of the crankcase.
Measurement of Cam Lift
Measurement of cam lift
Measure the long axis and short axis of each cam with a micrometer, and, if the limit value is exceeded, replace.
Measurement of Camshaft Journal Diameter and Journal Bore Diameter
Measurement of camshaft journal diameter
Measurement of camshaft bore diameter
Measure the camshaft journal and the bore in the crankcase for camshaft, and, if the limit value is exceeded, replace the camshaft.
Measurement of Camshaft Deflection
Measurement of camshaft deflection
Measure the camshaft deflection, and, if the limit value is exceeded, correct the camshaft with a press or replace it.
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With a dial gage set on the camshaft, rotate the camshaft one turn and read the gage indication. One half of the gage indication is the amount of deflection. |
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Removal of Camshaft Gear
Removal of camshaft gear
Use a hydraulic press to remove the camshaft gear.
NOTE: Do not remove the camshaft gear unless the camshaft, thrust plate or gear is replaced.
Installation of Camshaft Gear and Thrust Plate
Installation of camshaft gear and thrust plate
(1) Install the key and thrust plate to the camshaft.
(2) Heat the camshaft gear to a temperature of about 250 °C [482 °F] using a gear heater.
(3) Strike the gear to install it.
NOTE: Before installing the camshaft gear, be sure to position the thrust plate in place.
Pistons, Connecting Rods, Crankshaft and Crankcase
Measurement of Piston Outside Diameters
Measurement of piston outside diameter
(1) Using a micrometer, measure the diameter of each piston in a direction perpendicular to the piston pin at the piston skirt (shown in the diagram). If the limit value is exceeded, place the piston.
(2) The piston weight is stamped on top face of the piston.
Piston weight stamp location
Inspection of Pistons and Piston Rings
Measurement of piston ring groove
(1) Inspection of piston ring grooves
(a) Measure the clearance between each piston ring and the ring groove, and if the limit value is exceeded, replace the piston ring.
(b) If the measurement of the clearance with a new ring still exceeds the limit value, replace the piston.
Measurement of Piston Ring End Gap
Place the piston ring in a gage or reference cylinder to measure the ring end gap. If the limit value is exceeded, replace all the rings as a set.
Measurement of piston ring end gap
NOTE: Using a piston, push the piston ring squarely into the gage.
Measurement of Piston Pin Bore and Piston Pin
Measure the piston bore diameter and piston pin outside diameter, and, if the limit value is exceeded, replace the worn parts.
Measurement of piston pin bore and piston pin
Measurement of Clearance Between Connecting Rod Bushing and Piston
Measure the connecting rod bushing inside diameter and piston pin outside diameter, and, if the limit value is exceed, replace the worn parts.
Measurement of inside diameter of connection rod bushing
Replacement of Connecting Rod Bushings
Replacement of connecting rod bushings
(1) To replace the connecting rod bushing, use the connection rod bushing puller.
(2) Align the oil holes of the bushing and connecting rod. Also position the bushing joint at the location shown in the diagram.
(3) After installation, insert the piston pin, and make sure that the piston pin moves smoothly without excessive play.
Inspection of Connecting Rods For Bend and Twist
Inspection of connecting rod for bend and twist
(1) To inspect, measure value T of C and l, and straighten the connecting rod with a press so that C is 0.05 mm [0.002 in.] or less per 100 mm [3.937 in.] of l.
(2) Generally, a connecting rod aligner is used to check the connecting rod for bend and twist.
Measurement using connecting rod aligner
NOTE: Tighten the connecting rod cap to the specified torque for the inspection of bend.
(3) To inspect the connecting rod installed to a piston, place the piston on a surface plate, insert a round bar having the same diameter as the crankpin, then measure the height of the bar with a dial gage.
Measurement of bend with dial gage
Inspection of Oil Clearance of Connecting Rod Bearing
Measurement of inside diameter of connecting rod bearing
(1) Install the bearing to the big-end bore of the connecting rod, tighten the connecting rod cap to the specific torque, and measure the bearing inside diameter.
(2) Measure the outside diameter of the crankpin of the crankshaft, and subtract it from the above-mentioned bearing inside diameter to obtain the oil clearance of the connecting rod bearing.
Measurement of outside diameter of crankpin
(3) If the oil clearance exceeds the limit value, replace the bearing, and check the oil clearance again.
(4) If the oil clearance still exceeds the limit value, use an undersize bearing (0.25 mm [0.0098 in.], 0.50 mm [0.0197 in.] 0.75 mm [0.0295 in.] undersize. When using undersize bearings, refinish the crankpins to the following undersize dimension. Crankshaft undersize finishing dimension.
Crankshaft fillet finishing dimension (1)
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Inspection of Oil Clearance of Main Bearing
Measurement of inside diameter of main bearing
(1) Install the main bearing to the main bearing cap and crankcase, tighten the main bearing cap to the specific torque, and measure the bearing inside diameter.
(2) Measure the journal diameter of the crankshaft, and subtract it from the above-mentioned bearing inside diameter to obtain the oil clearance of the main bearing.
Measurement of outside diameter of crank journal
(3) If the oil clearance exceeds the limit value, install a new bearing, and check the oil clearance again.
(4) If the oil clearance still exceeds the limit value, use an undersize bearing (0.25 mm [0.0098 in.], 0.50 mm [0.0197 in.] or 0.75 mm [0.0295 in.] undersize). When using undersize bearings, refinish the crankpins to the following undersize dimension. Crankshaft undersize finishing dimension.
Crankshaft fillet finishing dimension (2)
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Inspection of Oil Seal Contact Surface
Inspection of oil seal contact surface
Check the oil seal contact surface of the crankshaft back-end, and, if the crankshaft face has been excessively worn by the oil seal, replace the oil seal and oil sleeve with replacement parts.
(1) Installation of oil seal sleeve
To install the oil seal sleeve, coat the inner surface of the sleeve with oil, and use the crankshaft sleeve installer for driving the sleeve into place.
Inspection of oil seal sleeve
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Be careful not to dent or scratch the outer surface of the oil seal sleeve. |
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When the oil seal slinger becomes worn after engine operation, remove the oil seal sleeve by following the procedure below, and replace it with a replacement oil seal assembly (oil seal and oil seal sleeve).
Inspection of oil seal contact surface
(2) Removal of oil seal sleeve
At three locations on the sleeve end face, hold a chisel at a right angle to the sleeve and strike with a hammer, and remove the sleeve when it becomes loose.
If this method does not allow the removal of the sleeve, hold the chisel in the axial direction and lightly tap to expand and loosen the sleeve.
Removal of oil seal sleeve
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Be careful not to damage the crankshaft with the chisel when removing the oil seal sleeve. |
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Measurement of Crankshaft Deflection
Measurement of crankshaft deflection
Support the crankshaft on its front and rear journals in V-blocks, and measure the runout at the center journal with a dial gage. Compare the amount of runout with the standard. If the runout is small, correct by grinding. If the runout is large, straighten with a press.
If the runout exceeds the limit significantly, replace the crankshaft.
Removal of Crankshaft Gear
Removal of crankshaft gear
Use the gear puller to remove the crankshaft gear.
NOTE: Do not remove the crankshaft gear unless the crankshaft or gear is replaced.
Installation of Crankshaft Gear
Installation of crankshaft gear
(1) Heat the gear to a temperature of 100 to 150 °C [212 to 302 °F].
(2) Install the key to the crankshaft.
(3) Align the gear with key and insert the gear fully.
Measurement of Cylinder Bore
Measurement of inside diameter of cylinder liner
(1) Using a cylinder gage, measure the cylinder bore and cylindricity. If the limit value is exceeded even at one place, bore all cylinders and replace the pistons and piston rings with oversize pistons and piston rings. Measure at three locations each in directions A and B shown in the diagram.
- A: Piston outside diameter measurement (selected oversize piston) mm [in.].
- B: Clearance between piston and cylinder (standard value) 0.03 mm [0.0012 in.]
- C: Honing allowance 0.04 mm [0.0016 in] or less in diameter
- B: Clearance between piston and cylinder (standard value) 0.03 mm [0.0012 in.]
(2) Boring of cylinders
Measurement of piston outside diameter
(a) Since there are two piston oversizes (0.25 mm [0.0098 in.] and 0.50 mm [0.0197 in.] oversize) as indicated above, determine the appropriate piston size to be used based on the largest cylinder bore diameter.
(b) Measure the outside diameter of the piston to be used. The piston diameter measuring points are shown in the diagram.
(c) Based on the measurements of the piston outside diameter, calculate the finishing dimension to be achieved by boring.
(d) Bore the cylinders to the calculated dimension.
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Bore the cylinders in the order of the cylinder numbers to prevent distortion due to the heat generated by the boring operation. |
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(e) Hone the cylinders to the final dimension (piston outside diameter + cylinder clearance).
Measurement of Distortion of Crankcase Upper Surface
Measurement of warpage of crankcase upper surface
Using a straight edge and feeler gages, measure the warpage of the top face of the crankcase at the locations shown in the diagram. If the limit is exceeded, grind the crankcase face.
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The maximum limit of stock to be removed from the crankcase and cylinder head by grinding should be less than 0.2 mm [0.0079 in.]. |
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Inspection of Cam Contacting Surfaces of Tappets
Check the cap contact face of each tappet for wear, and replace badly worn tappets.
Cam contact face of tappet
Measurement of Clearance Between Tappet and Tappet Guide Bore
Measurement of clearance between tappet and tappet guide bore
Measure the clearance between each tappet and the diameter of the tappet guide bore in the crankcase, and, if the limit value is exceeded, replace the tappet.
NOTE: If the tappet guide bores are worn beyond the limit value, replace the crankcase.
Reassembly Of Engine Main Parts
Pistons, Connecting Rods, Crankshaft and Crankcase
Installation of Tappets
Installation of tappet
(1) Apply engine oil to the outside surfaces of tappets, and insert them into the tappet bores in the crankcase.
(2) Make sure the tappets rotate smoothly.
Installation of Main Bearings
Installation of main bearing
(1) Install the main bearings (upper and lower halves) to the crankcase and main bearing caps by inserting them into the lug grooves.
NOTE: Install the bearings with lug groove to the crankcase, and the bearings without lug groove to the main bearing caps.
(2) Install the flanged bearing to the aftermost (No. 5) journal.
(3) Apply a small amount of engine oil to the inside surface of each bearing.
Installation of Crankshaft
Installation of crankshaft
(1) Wash the crankshaft thoroughly with a cleaning solution, and dry it with compressed air. After washing the crankshaft, make sure there is no metal particle inside the oil holes or swelling of the chamfered sections of the oil holes.
(2) Hold the crankshaft horizontally, and carefully place it into the crankcase.
(3) Apply a small amount of engine oil to the crankshaft journals.
Installation of Main Bearing Caps
Installation of main bearing cap
Fit the main bearings, making sure that the front marks (arrow) on the main bearing caps face the front of the engine and the cap numbers are in order from the front to the back.
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Make sure the end faces of the bearing caps No.1, 5 are flush with the crankcase end faces. |
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Tightening of Bearing Cap Bolts
Tighten the main bearing cap bolts alternately to the specified torque.
Installation of main bearing cap bolt
Inspection of Crankshaft for Smooth Rotation
Make sure that the crankshaft rotates smoothly
Inspection of crankshaft for smooth rotation
Measurement of Crankshaft End Play
Measurement of crankshaft end play
(1) Measure the crankshaft end play.
(2) If the end play is too small, loosen the cap bolts, and retighten them.
(3) If the limit value is exceeded, replaced the flanged bearing.
Assembly of pistons and Connecting Rods
Assembly of piston and connecting rod (1)
(1) Assemble the piston and connection rod by positioning the piston weight indication and the connecting rod matching mark face the same direction.
(2) Coat the piston pin with engine oil, and install the pin to connect the connecting rod to the piston.
(3) Install the snap rings in the grooves in the piston using ring pliers. Check the snap rings for tension and proper fitting.
NOTE: The snap ring ends must be positioned toward the bottom of the piston.
Assembly of piston and connecting rod (2)
Installation of Piston Rings
Assembly of piston and connecting rod (1)
(1) Using piston ring pliers, install the compression rings (No. 1, No. 2) and oil ring on the piston.
NOTE: The marks on rings No. 1 and No. 2 must be positioned toward the top of the piston.
(2) Install the oil ring in such a way that its ring end cap is positioned 180° from the joint of the oil spring.
Positioning of oil ring and coil spring
Laying Crankcase on its Side
Laying of crankcase on its side
Gently lay the crankcase on its side.
Preparation for Piston Installation
After cleaning the inside surface of the cylinder with a clean cloth, apply engine oil to the surface.
Preparation for piston installation
Installation of Connecting Rod Bolts and Bearings
Installation of connecting rod bearing
(1) Before installing the bearing, insert the connecting rod bolts so that the notched face of the head is securely positioned.
(2) Install the upper half of the connecting rod bearing to the big-end bore of the connecting rod by aligning the lug grooves, and apply engine oil to the inside surface.
Installation of Pistons
Installation of piston (1)
(1) Apply engine oil to the piston rings.
(2) Set the piston ring end gaps away from one another, also making sure that they do not align with the pin direction, thrust direction or counter thrust direction.
Installation of pistons (2)
(3) Bring the cylinder No. 1 (No. 4) crankpin to the top dead center.
(4) Align the piston guide with center of the cylinder, and hold it at the top surface of the crankcase by hand.
Installation of pistons (3)
(5) Position the "Trigona" mark stamped on top surface of the piston toward the front of the crankcase, and insert the piston and connecting rod assembly into the cylinder using the installer.
NOTE: After inserting the piston, make sure that the direction of the connecting rod big-end bore matches the crankpin direction.
(6) Lightly tap the top surface of the piston with the handle of a hammer to fit the connecting rod big-end bore to the crankpin.
NOTE: Make sure that the connecting rod bearing upper half is in place by feeling with a finger.
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Be careful not to damage the crankshaft with the big-end bore of the connecting rod. |
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Installation of Connecting Rod Caps
(1) Install the connecting rod bearing lower half to the connecting cap by fitting it into the lug groove, and apply engine oil.
(2) Install the connecting rod cap to the connecting rod (crankpin), making sure that the matching mark aligns with that on the connecting rod.
Installation of connecting rod cap (1)
Installation of connecting rod cap (2)
(3) Tighten the connecting the connecting rod cap nuts finger tight.
NOTE: Conduct the above steps for cylinders No. 1 and No. 4 at the same time, and repeat the same steps for cylinders No. 2 and No. 3.
(4) Tighten the connecting rod nuts alternately to the specified torque using torque wrench.
(5) Check the connecting rod end play, if the end play is too small, loosen the cap nuts and then retighten them.
Positioning Crankcase Upright
Positioning crankcase upright
With the oil pan mounting side facing upward, stand the crankcase upright.
Inspection of Crankcase for Smooth Rotation
Inspection of crankcase for smooth rotation
Make sure that the crankcase rotates smoothly.
Timing Gears, Camshaft and Oil Pan
Installation of Front Plate
Installation of front plate
(1) Install the gasket and front plate (mounted with injection pump) to the front face of the crankcase, making sure that the dowel pins enter holes properly.
(2) Tighten the two bolts to the specified torque.
Installation of Camshaft
Application of engine oil to camshaft
(1) Apply engine oil to the camshaft journals and cams.
(2) Insert the camshaft (mounted with gear) into the crankcase.
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Be careful not to damage the journals or cam lobes. |
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(3) Using a torque wrench and the socket, tighten the thrust plate mounting bolts to the specified torque.
(4) Make sure that the camshaft rotates smoothly. Also, move the camshaft back and forth to make sure there is sufficient end play.
Installation of camshaft
Installation of Oil Pump
Installation of oil pump
(1) Insert the oil pump into the mounting hole in the crankcase. Make sure that the oil pump gear engaged properly with the oil pump drive gear on the camshaft.
(2) Install the oil pump set bolt and gasket on the side of the crankcase, and tighten to the specified torque.
Installation of Oil Pan
Installation of oil pan
Clean both gasket contact surfaces and the mating parts to ensure they are free of dirt and grime.
(1) Apply a liberal amount of Threebond 1207 or 1211 to mating surfaces (grooves) of main bearing caps No. 1 and No. 5 and crankcase. A sufficient amount of the sealant should be applied so that a small amount is pushed out when the oil pan gasket is installed.
(2) Install the oil pan gasket to the bottom surface of the crankcase, pushing the curved section into the grooves of main bearing caps No. 1 and No. 2 and the protruded sections into the grooves where ThreeBond was filled.
(3) Install the oil pan and tighten the bolts to the specified torque.
Reversal Of Crankcase
Reversal of crankcase
Gently lay the crankcase on its side, then position the crankcase upright.
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Resting the crankcase with the oil pan on the bottom can cause the oil pan to crack. |
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Installation of Idler Gear
(1) Apply engine oil to the idler shaft.
(2) Align the matching marks on all gears, and install the idler gear to the idler shaft.
Timing gear train
Installation of idler gear
(3) Put the thrust plate on the idler gear, and tighten the bolt.
(4) Move the idler gear back and forth to make sure there is sufficient end play.
Inspection After Timing Gear Installation
When the timing gears have been disassembled and reassembled, be sure to check the gear backlashes after reassembly.
Measurement of timing gear backlash
Installation of Oil Seal
Install a new oil seal to the timing gear case using the installer.
Make sure that the lip section of the oil seal faces toward the inside of the gear case and the oil seal is flush with the gear case face.
Installation of oil seal
Installation of Timing Gear Case
Installation of timing gear case
(1) Install the baffle plate to the crankshaft.
(2) Install the gasket and timing gear case to the crankcase, aligning holes with the dowel pins.
(3) Screw the bolts and tighten to the specified torque.
Installation of Crankshaft Pulley
Installation of crankshaft pulley
(1) Coat the oil seal contact surface of the pulley with engine oil.
(2) Push the pulley onto the crankshaft, making sure that the notch on the pulley is aligned with the key.
(3) By using the bolts holes located of the back-end of the crankshaft, prevent the crankshaft from rotating.
(4) Place the washer and tighten the nut to the specified torque.
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To ensure safety, make sure that bolts and bar for the prevention of crankshaft rotation have sufficient strength. |
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Flywheel
Installation of flywheel housing
(1) Install the oil seal to the flywheel housing.
(2) Coat the contact surfaces of the crankcase and flywheel with ThreeBond 1104.
(3) Align the holes in the flywheel housing and gasket with the dowel pins on the crankcase, and install them to the crankcase.
Installation of Flywheel
Installation of flywheel
(1) Install the flywheel to the crankshaft by aligning the hole with the dowel pin on the back-end of the crankshaft.
(2) Place the washer and tighten the four bolts to the specified torque.
Measurement of Flywheel Runout
Measurement of face runout and circular runout
Measure the flywheel runout with the flywheel installed to the crankshaft. If the standard value is exceeded, check the bolts for tightening condition and the mounting face for adhesion of foreign particles.
Cylinder Head and Valve Mechanisms
Installation of valve stem seal
(1) Apply engine oil to the valve stem, and insert it into the valve guide.
(2) Place a new stem seal on the valve guide.
(3) Using the stem seal installer, install the stem seal to the valve guide, making use of the valve stem as a guide.
Installation of Valves and Valve Springs
Installation of valve and valve spring
(1) Place the valve spring and retainer on the valve guide, and install the valve cotter using the valve spring pusher.
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Excessive compression of the valve spring can cause the retainer to contact the stem seal and damage the seal. |
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Confirmation of secure valve cotter installation
(2) Using a soft-faced hammer, tap the top of the valve stem several times to make sure that the spring and valve cotter are securely installed.
Installation of Cylinder Head Gasket
Installation of cylinder head gasket
(1) Make sure the top surface of the crankcase and piston upper surfaces are clean and free of dust.
(2) Place a new gasket of the crankcase, making sure that the dowel pins on the top face of the crankcase enter the holes in the gasket.
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Do not use a liquid gasket. |
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Installation of Cylinder Head
Installation of cylinder head assembly
Place the cylinder head on the head gasket, making sure that the dowel pins on the top face of the crankcase enters the holes in the cylinder head.
Tightening of Cylinder Head Bolts
Cylinder head bolt tightening sequence
Tighten the cylinder head bolts, following the tightening sequence shown in the diagram two or three times before reaching the specified torque.
Assembly of Rocker Arm and Rocker Shaft Assembly
Assembly of rocker shaft assembly
When installing the rocker arms, make sure that the shaft assembly marks face the front of the engine, as shown in the diagram. After the assembly, make sure that the rocker arms move smoothly.
Installation of Pushrods
(1) Insert the pushrods in the cylinder head through the pushrod holes.
(2) Make sure that the ball end of each pushrod rests securely on the curved surface of the tappet.
Installation of Rocker Shaft Assemblies
Installation of rocker shaft assembly
(1) Install the valve caps.
(2) When installing the rocker shaft brackets, tighten the long bolts first, then tighten the short bolts (reversal of removal sequence).
Adjustment of Valve Clearances
Turning Engine
Confirmation of top dead center on compression stroke for cylinder No. 1
(1) Confirming the top dead center on the compression stroke for cylinder No. 1
(a) By engaging the turning handle on the crankshaft pulley nut, turn the engine in the forward rotating direction (clockwise when viewed from the front of the engine).
(b) Stop turning when the "0" line stamped on the periphery of the crankshaft pulley aligns with the piston on the timing gear case.
(c) Move up and down the inlet and exhaust valve rocker arms of cylinder No. 1 to make sure that they are not being pushed up by the pushrods. The piston in cylinder No. 1 is at the top dead center on the compression stroke when the rocker arms are not being pushed by the pushrods (there is a clearance in each valve). If the rocker arms are being pushed up by the pushrods, turn the crankshaft one more turn.
(2) Adjusting the valve clearances
Adjustment of valve clearance
(a) Insert a feeler gage between the rocker arm and valve cap to inspect the clearance.
(b) Loosen the locknut, and turn the adjusting screw in either direction until the feeler gage is slightly gripped between the rocker arm and valve cap.
(c) After the adjustment, tighten the lock nut securely and recheck the clearance.
(d) Turn the engine, and check the valve clearances on the remaining cylinders. The inspection sequence and turning angle are as follows:
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When adjusting the valve clearances after disassembly, rotate the crankshaft 2 or 3 turns after adjustment, and recheck the valve clearances to make sure that the clearances conform to the standard. |
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