Engine System-General Information: Other Lincoln Aviator I

Material

MATERIAL SPECIFICATION

Engine Oil Leaks

Note. When diagnosing engine oil leaks, the source and location of the leak must be positively identified prior to repair.

Prior to carrying out this procedure, clean all sealing surface areas with a suitable solvent to remove all traces of oil.

Engine Oil Leaks-Fluorescent Oil Additive Method

Use the UV Leak Detector Kit to carry out the following procedure for oil leak diagnosis.

1. Add gasoline engine oil dye. Use a minimum 14.8 ml (0.5 ounce) to a maximum 29.6 ml (1 ounce) of fluorescent additive to all engines. If the oil is not premixed, fluorescent additive must first be added to crankcase.
2. Run the engine for 15 minutes. Stop the engine and inspect all seal and gasket areas for leaks using the UV Leak Detector Kit. A clear bright yellow or orange area will identify the leak. For extremely small leaks, several hours may be required for the leak to appear.

Leakage Points-Underhood

Examine the following areas for oil leakage

1. valve cover gaskets
2. intake manifold gaskets
3. cylinder head gaskets
4. oil bypass filter
5. oil filter adapter
6. engine front cover
7. oil filter adapter and filter body
8. oil level indicator tube connection
9. oil pressure sensor

Leakage Points-Under Engine-With Vehicle on Hoist

1. oil pan gaskets (6710)
2. oil pan sealer
3. oil pan rear seal (6723)
4. engine front cover gasket
5. crankshaft front seal (6700)
6. crankshaft rear oil seal (6701)
7. crankshaft main bearing cap side bolts
8. oil filter adapter and filter body
9. oil cooler, if equipped

Leakage Points-With Transmission and Flywheel Removed

1. crankshaft rear oil seal
2. rear main bearing cap parting line
3. rear main bearing cap and seals
4. flywheel mounting bolt holes (with flywheel installed)
5. camshaft rear bearing covers (6266) or pipe plugs at the end of oil passages

Oil leaks at crimped seams in sheet metal parts and cracks in cast or stamped parts can be detected when using the dye method.

Compression Pressure Limit Chart

COMPRESSION PRESSURE LIMIT REFERENCE

If one or more cylinders reads low, squirt approximately one tablespoon of engine oil on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.

Cylinder Leakage Detection

When a cylinder produces a low reading, use of the Engine Cylinder Leak Detection/Air Pressurization Kit will be helpful in pinpointing the exact cause.

The leakage detector is inserted in the spark plug hole, the piston is brought up to dead center on the compression stroke, and compressed air is admitted.

Once the combustion chamber is pressurized, a special gauge included in the kit will read the percentage of leakage. Leakage exceeding 20 percent is excessive.

While the air pressure is retained in the cylinder, listen for the hiss of escaping air. A leak at the intake valve (6507) will be heard in the throttle body (9E926). A leak at the exhaust valve (6505) can be heard at the tail pipe. Leakage past the piston rings will be audible at the positive crankcase ventilation (PCV) connection. If air is passing through a blown head gasket to an adjacent cylinder, the noise will be evident at the spark plug hole of the cylinder into which the air is leaking. Cracks in the cylinder block or gasket leakage into the cooling system may be detected by a stream of bubbles in the radiator (8005).

Excessive Engine Oil Consumption

The amount of oil an engine uses will vary with the way the vehicle is driven in addition to normal engine-to-engine variation. This is especially true during the first 16,100 km (10,000 miles) when a new engine is being broken in or until certain internal engine components become conditioned. Vehicles used in heavy-duty operation may use more oil.

The following are examples of heavy-duty operation

1. trailer towing applications
2. severe loading applications
3. sustained high-speed operation

Engines need oil to lubricate the following internal components

1. cylinder block cylinder walls
2. pistons and piston, pin and rings (6102)
3. intake and exhaust valve stems
4. intake and exhaust valve guides
5. all internal engine components

When the pistons move downward, a thin film of oil is left on the cylinder walls. As the vehicle is operated, some oil is also drawn into the combustion chambers past the intake and exhaust valve stem seals and burned.

The following is a partial list of conditions that can affect oil consumption rates

1. engine duty cycle
2. operator driving habits
3. ambient temperature
4. quality and viscosity of the oil

Operation under varying conditions can frequently be misleading. A vehicle that has been run for several thousand miles on short trips or in below-freezing ambient temperatures may have consumed a "normal" amount of oil. However, when checking the engine oil level, it may measure up to the FULL or MAX on the oil level dipstick due to dilution (condensation and fuel) in the engine crankcase. The vehicle might then be driven at high speeds on the highway where the condensation and fuel boil off. The next time the engine oil is checked, it may appear that a liter (quart) of oil was used in about 160 km (100 miles). This perceived 160 km (100 miles) per liter (quart) oil consumption rate causes customer concern even though the actual overall oil consumption rate is lower.

Make sure the selected engine oil meets the current recommended API performance category with SAE viscosity grade as shown in the vehicle Owner's Guide. It is also important that the engine oil is changed at the intervals specified. Refer to the vehicle Owner's Guide.

Valve Train Analysis-Engine Off-Valve Cover Removed

Check for damaged or severely worn parts and correct assembly. Make sure correct parts are used with the static engine analysis as follows.

Valve Train Analysis-Engine Off, Rocker Arm

1. Check for loose mounting bolts, studs and nuts.
2. Check for plugged oil feed in the rocker arms (6564) or cylinder head.

Valve Train Analysis-Engine Off, Camshaft Roller Followers and Hydraulic Lash Adjusters, Overhead Camshaft

1. Check for loose mounting bolts on camshaft carriers.
2. Check for plugged oil feed in the camshaft roller followers, lash adjusters or cylinder heads.

Valve Train Analysis-Engine Off, Camshaft-Engines

1. Check for broken or damaged parts.

Valve Train Analysis-Engine Off, Push Rods

1. Check for bent push rods (6565) and restricted oil passage.

Valve Train Analysis-Valve Springs

1. Check for broken or damaged parts.

Valve Train Analysis-Engine Off, Valve Spring Retainer and Valve Spring Retainer Keys

1. Check for correct seating of the valve spring retainer key (6518) on the valve stem and in valve spring retainer (6514).
2. Check for correct seating on the valve stem.

Valve Train Analysis-Engine Off, Valves and Cylinder Head

1. Check for plugged oil drain back holes.
2. Check for worn or damaged valve tips.
3. Check for missing or damaged guide-mounted valve stem seal.
4. Check collapsed valve tappet gap.
5. Check installed valve spring height.
6. Check for missing or worn valve spring seats.
7. Check for plugged oil metering orifice in cylinder head oil reservoir (if equipped).

Static checks (engine off) are to be made on the engine prior to the dynamic procedure.

Valve Train Analysis-Engine Running

1. Start the engine and, while idling, check for correct operation of all parts. Check the following

Valve Train Analysis-Engine Running, Valves and Cylinder Head

1. Check for plugged oil drain back holes.
2. Check for missing or damaged valve stem seals or guide-mounted valve stem seals.
3. Check for a plugged oil metering orifice in the cylinder head oil reservoir (4.6L engine only).

If insufficient oiling is suspected, check oil passages for blockage, then accelerate the engine to 1,200 RPM with the transmission in NEUTRAL and the engine at normal operating temperature. Oil should spurt from the rocker arm oil holes such that valve tips and camshaft roller followers are well oiled. With the valve covers (6582) off, some oil splash may overshoot camshaft roller followers.

Valve Train Analysis-Engine Running, Camshaft Lobe Lift-OHC Engines Check the lift of each camshaft lobe in consecutive order and make a note of the readings.

Scheme 330

1. Remove the valve covers.
2. Remove the spark plugs.
3. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of indicator is on top of the camshaft lobe and on the same plane as the valve tappet.
4. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retainer bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
5. Zero the dial indicator. Continue to rotate the crankshaft until the (1) high-lift point of the camshaft lobe is in the fully-raised position (highest indicator reading).
6. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the (2) base circle is reached. The indicator reading should be zero. If zero reading is not obtained, repeat Steps 1 through 6.
7. Remove the Dial Indicator Gauge with Holding Fixture.
8. Install the spark plugs.
9. Install the valve covers.

Valve Train Analysis-Engine Running, Camshaft Lobe Lift-Push Rod Engine

Check the lift of each lobe in consecutive order and make a note of the readings.

Scheme 331

1. Remove the valve covers.
2. Remove the rocker arm seat bolts, rocker arm seat (6A528) and rocker arms. Typical Engine With Push Rods
3. Make sure the valve tappet is seated against camshaft (6250). Install (1) Dial Indicator Gauge with Holding Fixture so the ball socket adapter of the indicator is on top of the valve tappet or (2) Dial Indicator Gauge Adapter is on top of push rod and in same plane as valve tappet push rod movement.
4. Remove the spark plugs.
5. Connect an auxiliary starter switch in the starting circuit. Crank the engine with ignition switch in OFF position. Bump crankshaft over until valve tappet is on base circle of camshaft lobe. At this point, valve tappet will be in its lowest position. If checking during engine assembly, turn crankshaft using a socket or ratchet.
6. Zero the dial indicator. Continue to rotate crankshaft slowly until valve tappet is in fully-raised position (highest indicator reading).
7. Remove the Dial Indicator with Holding Fixture, Dial Indicator Gauge Adapter, and auxiliary starter switch.
8. Install rocker arm seats, rocker arms and rocker arm seat bolts.
9. Install valve covers.
10. Install spark plugs.

Valve Train Analysis-Engine Running, Valve Tappet

Valve tappet noise can be caused by any of the following

1. excessive valve tappet gap (collapsed)
2. incorrectly functioning valve tappet
3. air in lubrication system
4. excessive valve guide wear
5. low oil pressure

Excessive collapsed valve tappet gap can be caused by loose rocker arm seat bolts/nuts, incorrect initial adjustment or wear of valve tappet face, or worn roller valve tappets, push rod (6565), rocker arm (6564), rocker arm seat or valve tip. With valve tappet collapsed, check gap between the valve tip and the rocker arm to determine if any other valve train parts are damaged, worn or out of adjustment.

Scheme 332

1. Inspect the timing chain/belt and the sprockets. Look for worn or cracked sprocket teeth, cracked or missing timing belt teeth, or cracked, split or worn timing chain links. Install new components as necessary. Refer to «ENGINE FRONT COVER, TIMING GEARS, CHAIN AND T»(ref-193002-S18500445112005092300000) for the procedure.

An incorrectly functioning valve tappet can be sticking, caused by contaminants or varnish inside the tappet. The tappet can have a check valve that is not functioning correctly, which can be caused by an obstruction, such as dirt or chips that prevent the check valve from closing, or a broken check valve spring. A tappet with a leakdown time out of specification can cause tappet noise. If no other cause for noisy valve tappets can be found, the leakdown rate should be checked and new valve tappets installed if found to be out of specification.

Assembled valve tappets can be tested with Hydraulic Lash Adjuster Leakdown Tester to check the leakdown rate. The leakdown rate specification is the time in seconds for the plunger to move a specified distance while under a 22.7 kg (50 lb) load.

Air bubbles in the lubrication system will prevent the valve tappet from supporting the valve spring load. This can be caused by too high or too low an oil level in the oil pan or by air being drawn into the system through a hole, crack or leaking gasket on the oil pump screen cover and tube.

Camshaft Journal Clearance - OHC Engines

Special Tool(s)

Scheme 333

Note. The camshaft journals must meet specifications before checking camshaft journal clearance.

1. Remove the camshaft bearing cap and lay Plastigage across the surface. Refer to «ENGINE»(ref-193002) for the procedure.
2. Position the camshaft bearing cap and install the bolts. Refer to «ENGINE»(ref-193002) for the procedure.
3. Use Plastigage to verify the camshaft journal clearance. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Camshaft End Play - Push Rod Engines

Special Tool(s)

Scheme 334

Scheme 335

1. Remove the valve tappets. Refer to «ENGINE»(ref-193002) for the procedure.
2. Use a Dial Indicator Gauge with Holding Fixture to measure camshaft end play.
3. Position the camshaft to the rear of the cylinder block.
4. Zero the indicator.
5. Move the camshaft to the front of the cylinder block. Note and record the camshaft end play. If the camshaft end play exceeds specifications, install a new camshaft thrust plate. Refer to «ENGINE»(ref-193002) for the procedure.

Camshaft End Play - OHC Engines

Special Tool(s)

Scheme 336

Scheme 337

1. Remove the roller followers. Refer to «ENGINE»(ref-193002) for the procedure.
2. Use a Dial Indicator Gauge with Holding Fixture to measure camshaft end play.
3. Position the camshaft to the rear of the cylinder head.
4. Zero the indicator.
5. Move the camshaft to the front of the cylinder head. Note and record the camshaft end play. If camshaft end play exceeds specifications, install new camshaft and recheck end play. Refer to «ENGINE»(ref-193002) for the procedure. If camshaft end play exceeds specification after camshaft installation, install a new cylinder head. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 338

1. Inspect camshaft lobes for pitting or damage in the contact area. Minor pitting is acceptable outside the contact area. If excessive pitting or damage is present, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Camshaft Lobe Lift

Special Tool(s)

Scheme 339

Scheme 340

1. Use a Dial Indicator Gauge with Holding Fixture to measure camshaft intake/exhaust lobe lift. Rotate the camshaft and subtract the lowest indicator reading from the highest indicator reading to figure the camshaft lobe lift. Refer to «ENGINE»(ref-193002) for the procedure.

Camshaft Runout

Special Tool(s)

Scheme 341

Scheme 342

1. Use a Dial Indicator Gauge with Holding Fixture to measure the camshaft runout. Rotate the camshaft and subtract the lowest indicator reading from the highest indicator reading. For additional information, refer to the «SPECIFICATIONS»(ref-193002-S15836854152005092300000) . If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Crankshaft Main Bearing Journal Clearance

Special Tool(s)

Scheme 343

Note. Crankshaft main bearing journals must be within specifications before checking journal clearance.

Scheme 344

Scheme 345

1. Remove the crankshaft main bearing caps and crankshaft main bearing.
2. Lay a piece of Plastigage across the face of each crankshaft main bearing surface.
3. Install and remove the crankshaft main bearing cap.
4. Verify the crankshaft journal clearance. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 346

1. Measure each of the crankshaft main bearing journal diameters in at least two directions. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 347

1. Measure each of the crankshaft main bearing journal diameters in at least two directions at each end of the main bearing journal. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Crankshaft End Play

Special Tool(s)

Scheme 348

Scheme 349

1. Measure the crankshaft end play. Use a Dial Indicator Gauge with Holding Fixture to measure crankshaft end play.
2. Position the crankshaft to the rear of the cylinder block.
3. Zero the indicator.
4. Move the crankshaft to the front of the cylinder block. Note and record the crankshaft end play. If crankshaft end play exceeds specifications, install a new crankshaft thrust washer or crankshaft thrust main bearing. Refer to «ENGINE»(ref-193002) for the procedure.

Crankshaft Runout

Special Tool(s)

Scheme 350

Scheme 351

1. Use the Dial Indicator Gauge with Holding Fixture to measure the crankshaft runout. Refer to «ENGINE»(ref-193002) for the procedure. Rotate the crankshaft and subtract the lowest dial indicator reading from the highest dial indicator reading to figure the crankshaft runout. If it is out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 352

1. Measure each of the crankshaft connecting rod journal diameters in at least two directions, at each end of the journal. The difference in the measurements from one end to the other is the taper. The difference in measurements perpendicular to each other is the out of round.
2. If the diameter, taper, or out of round measurement is out of specification, install new parts as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 353

1. Measure the crankshaft connecting rod journal diameters in two directions perpendicular to one another at each end of the connecting rod journal. The difference in the measurements from one end to the other is the taper. The difference in the measurements perpendicular to each other is the out of round. Verify the measurements are within the wear limit. If either measurement is out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 354

1. Measure the cylinder bore at the top, middle, and bottom of piston ring travel in two directions as indicated. Verify the cylinder bore is within the wear limit. The difference indicates the cylinder bore taper. Bore the cylinder to the next oversize. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 355

1. Measure the cylinder bore in two directions. The difference is the out-of-round. Verify the out-of-round is within the wear limit and bore the cylinder to the next oversize limit. Refer to «ENGINE»(ref-193002) for the procedure.

Piston To Cylinder Bore Clearance

1. Subtract the piston diameter from the cylinder bore diameter to find the piston-to-cylinder bore clearance.

Piston - Selection

Note. The cylinder bore must be within the specifications for taper and out-of-round before fitting a piston.

Scheme 356

Scheme 357

1. Select a piston size based on the cylinder bore.
2. Choose the piston with the correct paint color. Refer to «ENGINE»(ref-193002) for the procedure.

Piston Ring End Gap

Note. Cylinder bore must be within specification for taper and out-of-round.

Scheme 358

Scheme 359

1. Use a piston without rings to push a piston ring in a cylinder to the bottom of ring travel.
2. Use a feeler gauge to measure the top piston ring end gap and the second piston ring end gap. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 360

Scheme 361

1. Inspect the piston for ring land damage or accelerated wear.
2. Measure the piston ring-to-groove clearance. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 362

1. Measure the piston pin diameter in two directions at the points shown. Verify the diameter is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Connecting Rod Cleaning

1. Mark and separate the parts and clean with solvent. Clean the oil passages.

Scheme 363

1. Tighten the bolts to specification, then measure the bore in two directions. The difference is the connecting rod bore out-of-round. Verify the out-of-round is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 364

1. Measure the inner diameter of the connecting rod bushing, if equipped. Verify the diameter is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 365

1. Measure the connecting rod bend on a suitable alignment fixture. Follow the instructions of the fixture manufacturer. Verify the bend measurement is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 366

1. Measure the connecting rod twist on a suitable alignment fixture. Follow the instructions of the fixture manufacturer. Verify the measurement is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Connecting Rod Bearing Journal Clearance

Special Tool(s)

Scheme 367

Note. The crankshaft connecting rod journals must be within specifications to check the connecting rod bearing journal clearance.

Scheme 368

Scheme 369

1. Remove the connecting rod bearing cap.
2. Position a piece of Plastigage across the bearing surface.
3. Install and tighten to specifications, then remove the connecting rod bearing cap.
4. Measure the Plastigage to get the connecting rod bearing journal clearance. The Plastigage should be smooth and flat. A changing width indicates a tapered or damaged connecting rod or connecting rod bearing. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 370

1. Inspect the roller for flat spots or scoring. If any damage is found, inspect the camshaft lobes and valve tappet for damage.

Scheme 371

Scheme 372

1. Inspect the hydraulic valve tappet and roller for damage. If any damage is found, inspect the camshaft lobes and valves for damage.

Scheme 373

Scheme 374

1. Measure the diameter of each intake and exhaust valve stem at the points shown. Verify the diameter is within specification. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Valve Stem to Valve Guide Clearance

Special Tool(s)

Scheme 375

Note. The valve springs must be removed before checking valve stem to valve guide clearance.

Note. Valve stem diameter must be within specifications before checking valve stem to valve guide clearance.

1. Install a Valve Guide Clearance Gauge on the valve stem and install a Dial Indicator Gauge with Holding Tool. Lower the valve until the Valve Guide Clearance Gauge contacts the upper surface of the valve guide.
2. Move the Valve Guide Clearance Gauge toward the indicator and zero the indicator. Move the Valve Guide Clearance Gauge away from the indicator and note the reading. The reading will be DOUBLE the valve stem-to-valve guide clearance. Valves with oversize stems will need to be installed if out of specification.

Scheme 376

1. Inspect the following valve areas: the end of the stem for grooves or scoring the valve face and the edge for pits, grooves or scores the valve head for signs of burning, erosion, warpage and cracking the valve margin for wear

Scheme 377

1. Measure the inner diameter of the valve guides in two directions where indicated. Refer to «ENGINE»(ref-193002) for the procedure.
2. If the valve guide is not within specifications, install a new cylinder head assembly.

Scheme 378

1. Use a hand-reaming kit to ream the valve guide.
2. Reface the valve seat.
3. Clean the sharp edges left by reaming.

Scheme 379

1. Measure the installed length of each valve spring. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 380

1. Measure the free length of each valve spring. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 381

1. Measure the out-of-square on each valve spring. Turn the valve spring and observe the space between the top of the valve spring and the square. Install a new valve spring if out of square. Refer to «ENGINE»(ref-193002) for the procedure.

Valve Spring Strength

Special Tool(s)

Scheme 382

Scheme 383

1. Use a Valve/Clutch Spring Pressure Gauge to check the valve spring for correct strength at the specified valve spring length. Refer to «ENGINE»(ref-193002) for the procedure. If out of specification, install new components as necessary. Refer to «ENGINE»(ref-193002) for the procedure.

Valve and Seat Refacing Measurements

Scheme 384

1. Check the valve head and seat. Check valve angles. Check margin width. Refer to «ENGINE»(ref-193002) for the procedure. Be sure margin width is within specification.
2. Inspect for abnormalities on the valve face and seat. Install a new cylinder head assembly if abnormalities are found.

Scheme 385

1. Measure the valve seat width. If necessary, grind the valve seat to specification. Measure the intake valve seat width. Measure the exhaust valve seat width. Recheck the valve spring installed length after the seats have been ground, and shim the valve springs as necessary to achieve the correct installed spring length. Refer to «ENGINE»(ref-193002) for the procedure.

Scheme 386

1. Use the Valve Seat Runout Gauge to check valve seat runout.

Cylinder Head Distortion

Special Tool(s)

Scheme 387

Scheme 388

1. Use a straight edge and a feeler gauge to inspect the cylinder head for flatness. If the cylinder head is distorted, install a new cylinder head.

Cylinder Block Distortion

Special Tool(s)

Scheme 389

Scheme 390

1. Use a straight edge and a feeler gauge to inspect the cylinder block for flatness. If the cylinder block is distorted, install a new short block assembly.

Cylinder Bore Cleaning

1. Clean the cylinder bores with soap or detergent and water.
2. Thoroughly rinse with clean water and wipe dry with a clean, lint-free cloth.
3. Use a clean, lint-free cloth and lubricate the cylinder bores. Use clean engine oil meeting Ford specification.

Spark Plug Hole Thread Repair

1. There is no authorized repair for spark plug hole threads. If the threads are damaged, install a new cylinder head.

Scheme 391

Scheme 392

Scheme 393

Scheme 394

Scheme 395

Scheme 396

Scheme 397

1. Inspect the spark plug for a bridged gap. Check for deposit build-up closing the gap between the electrodes. Deposits are caused by oil or carbon fouling. Clean the spark plug.
2. Check for oil fouling. Check for wet, black deposits on the insulator shell bore electrodes, caused by excessive oil entering the combustion chamber through worn rings and pistons, excessive valve-to-guide clearance or worn or loose bearings. Correct the oil leak concern. Install a new spark plug.
3. Inspect for carbon fouling. Look for black, dry, fluffy carbon deposits on the insulator tips, exposed shell surfaces and electrodes, caused by a spark plug with an incorrect heat range, dirty air cleaner, too rich a fuel mixture or excessive idling. Install new spark plugs.
4. Inspect for normal burning. Check for light tan or gray deposits on the firing tip.
5. Inspect for pre-ignition, identified by melted electrodes and a possibly damaged insulator. Metallic deposits on the insulator indicate engine damage. This may be caused by incorrect ignition timing, wrong type of fuel or the unauthorized installation of a heli-coil insert in place of the spark plug threads. Install a new spark plug.
6. Inspect for overheating, identified by a white or light gray spots and with bluish-burnt appearance of electrodes. This is caused by engine overheating, wrong type of fuel, loose spark plugs, spark plugs with an incorrect heat range, low fuel pump pressure or incorrect ignition timing. Install a new spark plug.
7. Inspect for fused deposits, identified by melted or spotty deposits resembling bubbles or blisters. These are caused by sudden acceleration. Install new spark plugs.