FUEL PRESSURE RELEASE & FUEL LINE CONNECTIONS
| WARNING | Fuel system is under pressure. Release pressure before servicing fuel system components. |
- Remove fuel cap to release fuel tank pressure. Connect EFI Pressure Gauge (T80L-9974-B) to relief valve on right rear corner of fuel rail. Release pressure using valve on pressure gauge.
- Before disconnecting fuel lines, disconnect negative battery cable. To disconnect fuel lines, remove retaining clip from outside of fuel line coupling.
- Install Spring Lock Coupling Remover (D87L-9280-A for 3/8" line; D87L-9280-B for 1/2" line) on fuel line coupling so it enters cage opening. (Scheme 108)
- Push spring lock coupling remover into cage opening to release female fitting from garter spring. Pull couplings apart. Remove spring lock coupling remover.
- When installing fuel lines, fit new fuel resistant "O" rings (Brown) on fuel lines. Before installing, lightly coat "O" rings with clean engine oil. Clean fittings, and replace garter spring (if necessary).
- Install female fitting to male fitting and push until garter spring snaps over flared end of female fitting. Ensure lines lock together and garter spring is over female fitting flared end.
- Install retaining clip. Install Black retaining clip on fuel supply line and Gray clip on fuel return line. Ensure horseshoe portion of clip is over coupling. DO NOT install retaining clip over rubber fuel line.
Scheme 108
VALVE COVERS
Note. Pickup valve cover removal and installation procedure is unavailable from manufacturer.
FRONT CRANKSHAFT SEAL
| WARNING | The electrical power to air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. Air suspension switch is located behind right kick panel. Failure to do so can result in inflation or deflation of air springs, which may cause vehicle to shift during these operations. |
CAMSHAFT
| CAUTION | DO NOT remove camshaft before removing camshaft followers. Camshaft will bend and be damaged from side loading. |
| CAUTION | DO NOT rotate engine at any time when cylinder heads are installed and timing chains are removed. Severe piston and valve damage will occur. |
OIL PAN
| WARNING | The electrical power to air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. Air suspension switch is located behind right kick panel area. Failure to do so can result in inflation or deflation of air springs, which may cause vehicle to shift during these operations. |
Cylinder Head
Check cylinder head for cracks or damage. If maximum warpage exceeds .004" (.10 mm), replace cylinder head.
Valve Springs
Inspect valve spring free length, out-of-square and pressure. Replace valve spring if not as specified. See VALVES & VALVE SPRINGS table under ENGINE SPECIFICATIONS.
Valve Stem Oil Seals
Use Seal Installer (T91T-6571-A) to install oil seals.
Valve Guides
- Valve guides may be reamed for oversize valves if stem-to-guide oil clearance exceeds specification. See «CYLINDER HEAD»(ref-54508-S22915666762001011700000) table under ENGINE SPECIFICATIONS. Valves are available in .015" (.38 mm) and .030" (.76 mm) oversize.
- Valve guides may also be replaced with a NEW guide if oversize valves are not available or guide is damaged. Ream valve guides until proper stem-to-guide clearance exists.
Valve Seat
Ensure valve seat angle, seat width and seat runout are within specification. See CYLINDER HEAD table under ENGINE SPECIFICATIONS. Valve seats must be ground when valve guide is reamed or replaced. Replacement information is not available.
Valves
| CAUTION | DO NOT remove more than .010" (.25 mm) from valve stem when resurfacing tip. |
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
If seat width is too wide after grinding seat, use a 75-degree stone to remove stock from bottom of valve seat (raise seat) or a 30-degree stone to remove stock from top of seat (lower seat).
Fitting Pistons
- Standard service pistons are coded 1, 2 and 3 on dome of piston. Measure piston skirt diameter at 90-degree angle to piston pin, 1.62" (42.0 mm) below piston top. Replace piston if piston diameter is not within specification. See «PISTONS, PINS & RINGS»(ref-54508-S15456848612001011700000) table under ENGINE SPECIFICATIONS.
- Measure cylinder bore at .50" (12.7 mm) below top of piston travel and .50" (12.7 mm) above bottom of piston travel. Ensure piston clearance is within specification. See «PISTONS, PINS & RINGS»(ref-54508-S15456848612001011700000) table.
- If piston clearance is not within specification, choose a selective fit piston to bring piston clearance within specification. See «PISTONS, PINS & RINGS»(ref-54508-S15456848612001011700000) table, for selective fit piston sizes.
- If piston clearance cannot be corrected using a selective fit piston, bore all cylinders to nearest oversize.
Piston Rings
Ensure ring end gap and side clearance are within specification. See PISTONS, PINS & RINGS table under ENGINE SPECIFICATIONS. Position oil control ring expander with gap positioned straight forward and rails with gaps 180 degrees apart, aligned with piston pin. Install compression rings with gaps staggered, so ring gaps do not align.
Rod Bearings
| CAUTION | Mark connecting rod and cap for reassembly reference. Components are not marked at factory. Install NEW bolts in connecting rods. DO NOT reuse bolts. |
- Ensure piston and connecting rod are installed in engine with arrow on top of piston toward front of engine.
- Check bearing clearances using Plastigage. Ensure bearing oil clearance and side play are within specification. See «CRANKSHAFT, MAIN & CONNECTING ROD BEARINGS»(ref-54508-S14344752562001011700000) and «CONNECTING RODS»(ref-54508-S21875165762001011700000) tables under ENGINE SPECIFICATIONS. If oil clearance exceeds specification, grind crankshaft to fit undersize bearings. Tighten connecting rod bearing cap bolts to specification. See «TORQUE SPECIFICATIONS»(ref-54508-S28386032862001011700000) table.
Note. When checking bearing clearances using Plastigage, side bolts and side adjusting screws do not need to be installed.
Crankshaft & Main Bearings
- Measure main bearing clearances using Plastigage. Main bearing caps are marked for location, with No. 1 at front and No. 5 at rear of engine. Arrow on main bearing cap must point toward front of engine. Lubricate bearing shells with assembly lube or heavy oil before installation.
- Install main bearing inserts in cylinder block. Lay crankshaft into cylinder block. Push crankshaft rearward. Roll thrust washer into cylinder block, ensure coating on bearing is facing crankshaft thrust surface.
- Install main bearing caps using NEW bolts, do not fully tighten. Using a pry bar push crankshaft forward to seat thrust washer. While holding crankshaft forward, evenly pry No. 5 main bearing cap rearward. DO NOT cock bearing cap. Tighten main bearing cap bolts to specification in 2 steps using proper sequence. (Scheme 109) See «TORQUE SPECIFICATIONS»(ref-54508-S28386032862001011700000) table.
- Tighten side adjusting screws against cylinder block to specification in 2 steps using proper sequence. (Scheme 109) Side adjusting screws have left-hand threads. Tighten side bolts.
Scheme 109
Cylinder Block
- Using a feeler gauge and straightedge, inspect cylinder block deck for warpage. If not within specification, resurface or replace cylinder block. See «CYLINDER BLOCK»(ref-54508-S41969969142001011700000) table under ENGINE SPECIFICATIONS. CAUTION: DO NOT machine more than .010" (.025 mm) from original cylinder block head surface.
- Check cylinder bore diameter, out-of-round and taper. Cylinder bore is measured at .50" (12.7 mm) below top of cylinder block head surface and .50" (12.7 mm) above piston when at bottom of cylinder bore.
- Bore cylinder block if measurements are not within specification. See «CYLINDER BLOCK»(ref-54508-S41969969142001011700000) table.
Oil Pressure
| Application | Psi (kPa) |
|---|---|
| New | (1) 24 (165) |
| Broken-In | (1) 18 (124) |
| Maximum Pressure | (2) 100 (690) |
| (1) With engine speed at 650 RPM and engine temperature at 200°F (93°C). (2) With engine temperature at 200°F (93°C) and engine speed at 4000 RPM. | |
| (1) | With engine speed at 650 RPM and engine temperature at 200°F (93°C). |
| (2) | With engine temperature at 200°F (93°C) and engine speed at 4000 RPM. |
OIL PRESSURE SPECIFICATIONS
OIL PUMP
Note. Disassembly and inspection procedures are not available.