FUEL PRESSURE RELEASE
| CAUTION | Fuel system is under pressure. Fuel pressure MUST be released before servicing fuel system components. |
| CAUTION | Steps 1 and 2 must be performed to relieve high pressure within fuel rail. DO NOT perform steps 3 and 4 to relieve fuel rail pressure as excessive fuel will be forced into cylinder chamber. |
Note. Fuel filler tube has spring-loaded flap below fuel fill cap serving as secondary seal if fuel fill cap is not tightened.
- Remove fuel filler cap. Disconnect negative battery cable. Loosen fuel tank cap to release tank pressure. Press on filler tube flap to relieve any additional tank pressure.
- Remove fuel pump relay from Power Distribution Center (PDC). For location of relay, refer to label on underside of PDC cover. Start and run engine until it stalls. Attempt restarting engine until it will no longer run. Turn ignition switch to OFF position. Fuel rail high pressure is now released.
- Unplug electrical connector from an injector. Attach one end of a jumper wire (18 gauge or smaller) with alligator clips to either injector terminal. Connect other end of jumper wire to positive side of battery. Connect one end of a second jumper wire to remaining injector terminal. CAUTION: Powering an injector for more than a few seconds will permanently damage injector.
- Touch other end of second jumper wire to negative terminal of battery for no more than a few seconds. Place a rag below fuel line. Disconnect quick-connect fitting at fuel rail. See «FUEL LINE DISCONNECT FITTINGS»(ref-98253-S34287325402001051800000) . Install fuel pump relay in PDC.
FUEL LINE DISCONNECT FITTINGS
| CAUTION | Fuel system is under pressure. Fuel pressure must be released before servicing fuel system components. |
CYLINDER HEAD
Note. Removal and installation procedures are same for right and left cylinder head.
CAMSHAFT
| CAUTION | DO NOT use force to rotate camshafts or crankshaft with timing chains removed. Severe valve and/or piston damage can occur. |
Check cylinder head warpage. Repair or replace cylinder head if warpage exceeds specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS.
Valve Springs
Note. Measure valve spring installed height from bottom of spring seat (cylinder head surface) to bottom of spring retainer.
Inspect valve springs for wear. Check valve spring free length, spring pressure, and installed height. Replace spring if not within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.
Valve Stem Oil Seals
Intake and exhaust valve stem seals are same. When installing valves, DO NOT overcompress valve springs, as damage to valve stem oil seal may result.
Valve Guides
Valve guides are not replaceable or serviceable. Manufacturer does not recommend reaming valve guides. If valve guides are worn beyond acceptable limits, replace cylinder head.
Valve Seat
Check valve seat width and runout. Grind valve seat if not within specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS.
Valves
Ensure head diameter, stem diameter, valve face runout, and valve margin are within specification. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.
Valve Seat Correction Angles
Use a 15-degree stone to lower valve seat, and a 65-degree stone to raise valve seat.
ROCKER ARMS & VALVE LASH ADJUSTERS
| CAUTION | If reusing rocker arms and lash adjusters, mark positions before removing. |
Remove rocker arms and lash adjusters. Inspect for wear. Before installing, ensure lash adjusters are filled with oil and plunger has little or no travel when depressed.
Fitting Pistons
See PISTON & ROD ASSEMBLY .
Piston Rings
- Ring gap measurement must be made with ring positioned at least.50" (12.7 mm) from bottom of cylinder bore. Ensure ring gap and ring side clearance measurements are within specification. See «PISTONS, PINS & RINGS»(ref-98253-S07349863522001051800000) table under ENGINE SPECIFICATIONS.
- Position ring gaps in proper location. Compression ring gaps must be staggered so they do not align with oil ring rail gap. Ensure expander ring gap is at least 45 degrees from side rail gaps, but not on piston pin center or on thrust direction. (Scheme 50)
Scheme 50
Rod Bearings
| CAUTION | Connecting rod bolts are torque-to-yield design. DO NOT reuse bolts if loosened or removed. |
- Inspect rod bearings for scoring and bent alignment tabs. Check bearings for normal wear patterns, scoring, grooving, fatigue and pitting. Replace any bearing that shows abnormal wear. Inspect rod journals for scoring, nicks and burrs. Inspect rod bearing caps for scoring, blueing, or severe scratches. If bearing caps show damage, cylinder head(s) must be removed to service piston and rod assemblies.
- Use Plastigage to determine bearing-to-journal clearance. Plastigage should indicate the same clearance across entire width of bearing insert. If clearance varies, check for tapered journal, bent connecting rod or foreign material trapped between insert and cap or rod.
- If bearing-to-journal clearance exceeds specification, determine proper rod bearing service set. See «CONNECTING ROD SERVICE BEARINGS»(ref-98253-S07813095902001051800000) table. Repeat Plastigage procedure to verify proper bearing selection prior to final assembly.
- Apply light coat of engine oil to connecting rod bolt threads before tightening nuts to specification. See «TORQUE SPECIFICATIONS»(ref-98253-S16892144292001051800000) table. Ensure oil clearance and side play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-98253-S30082246452001051800000) table under ENGINE SPECIFICATIONS.
| Service Bearing Mark (1) | Size - in. (mm) | Bearing /Journal Clearance - in. (mm) |
|---|---|---|
| Std. | Standard | 2.0076-2.0082 (50.992-51.008) |
| .025 US | .001 (.025) Undersize | 2.0073-2.0066 (50.983-50.967) |
| .250 US | .010 (.250) Undersize | 1.9984-1.9978 (50.758- 50.742) |
| (1) Stamped on bottom of lower bearing. | ||
| (1) | Stamped on bottom of lower bearing. |
CONNECTING ROD SERVICE BEARINGS
Crankshaft & Main Bearings
| CAUTION | Connecting rod bolts are torque-to-yield design. DO NOT reuse rod bolts if loosened or removed. |
Scheme 51
Scheme 52
Scheme 53
- Check crankshaft journals for excessive wear, taper and scoring. Ensure taper, and out-of-round are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-98253-S30082246452001051800000) table under ENGINE SPECIFICATIONS.
- Use a micrometer to determine maximum journal diameter by measuring 2 locations 90 degrees apart at each end of journal. Compare measured diameter with specification. See «MAIN BEARING GRADE IDENTIFICATION»(ref-98253-S22212970822001051800000) table.
- To check crankshaft end play, mount dial indicator at front of engine. (Scheme 52) Locate probe perpendicular against crankshaft nose. Move crankshaft to rear of it's travel, and zero dial indicator. Move crankshaft to front of it's travel, and read dial indicator. Ensure end play is within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-98253-S30082246452001051800000) table under ENGINE SPECIFICATIONS. If end play is not within specification, inspect crankshaft thrust faces for wear. If no indication of wear, replace thrust bearing, and measure end play. If end play still exceeds specification, replace crankshaft.
- To select main bearings, locate grade identification marks on crankshaft position target wheel. Marks are read left to right, corresponding with journal No. 1, 2, 3, 4 and 5. (Scheme 51) See «MAIN BEARING GRADE IDENTIFICATION»(ref-98253-S22212970822001051800000) table. Select inserts to obtain specified bearing-to-journal clearance. MAIN BEARING GRADE IDENTIFICATION Grade In (mm) Journal Size Usage - in. (mm) A.0004 (.008) Undersize 2.4996-2.4999 (63.488-63.496) B Standard 2.4999-2.5002 (63.496-63.504) C.0004 (.008) Oversize 2.5002-2.5005 (63.504-63.512) CAUTION: DO NOT grind thrust surface of No. 3 main bearing. Journal grinding should exceed.012" (.30 mm) under standard journal diameter. Finish paper or cloth polishing after regrind MUST be done in same direction as engine rotation.
- After grinding, remove rough edges from crankshaft oil holes and clean out all oil passages.
- Apply light coat of engine oil to threads before tightening bolts to specification. Tighten crankshaft bedplate bolts in sequence and to specification. (Scheme 53) See «TORQUE SPECIFICATIONS»(ref-98253-S08964724442001051800000). Ensure oil clearance and end play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-98253-S30082246452001051800000) table under ENGINE SPECIFICATIONS.
Thrust Bearing
Thrust bearing is installed at No. 3 main bearing position. Replace thrust bearing if crankshaft end play is not within specification. See CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS table under ENGINE SPECIFICATIONS.
Cylinder Block
Note. If bore gauge is not available, DO NOT use an inside micrometer.
- Using a dial bore gauge capable of reading in.0001" (.003 mm) increments, measure bore diameter of each cylinder. see scheme 29 Measure inside diameter of cylinder bore at 3 different levels below top of bore. Make first measurement at a point 1.95" (49.5 mm) below top of bore, measuring cylinder bore at 90 degrees to crankshaft. Repeat measurement near middle of bore, then near bottom of bore. Determine taper by subtracting small diameter from larger diameter.
- Rotate dial bore gauge 90 degrees and repeat measurements. Determine out-of-roundness by comparing difference between each measurement. If cylinder bore taper and out-of-round do not exceed.001" (.025 mm), cylinder bore can be honed. If taper or out-of-round exceed limits, cylinder block must be replaced. NOTE: A slight amount of taper always exists when engine has been in service for any length of time.
Oil Pressure
Oil pressure is 4 psi (.3 kg/cm 2 ) at idle, and 25-80 psi (1.7-5.6 kg/cm 2 ) at 3000 RPM with engine at normal operating temperature.
OIL PUMP
Note. Oil pump is serviced as assembly only.