Ford 4.6L DOHC Engine

Engine Electronics

Description and Operation

The electronic engine controls for Project COBRA'33 and our Ford 4.6L DOHC engine consist of the following.

1.   Power-train Control module (PCM)

2.   Throttle Position (TP) Sensor

3.   Idle Air Control (IAC) Valve

4.   Engine Coolant Temperature (ECT) Sensor

5.   Cylinder Head Temperature Sensor

6.   Camshaft Position (CMP) Sensor

7.   Crankshaft Position (CKP) Sensor

8.   Mass Air Flow (MAF) Sensor

9.   Intake Air Temperature (IAT) Sensor

10. Heated Oxygen Sensor (H02S)- Front

11. Wide Band Heated Oxygen Sensor (HWO2S)

12. Transmission Output Speed Sensor (OSS)

13. The Barometric Pressure (BP) Sensor

14.   Vehicle Speed Sensor (VSS)

15.  Manifold Absolute Pressure Sensor (MAP)

The 4.6L (4V) (281 CID) Cobra engine is a V-8 with the following features:

• Inter-cooled supercharger
• Dual overhead camshafts
• Four valves per cylinder
• Sequential multi port fuel injection (SFI)
• An aluminum intake manifold
• Aluminum cylinder heads
• A cast iron, 90-degree V- cylinder block
• Individually chain-driven camshafts with a hydraulic timing chain tensioner on each timing chain
• The electronic ignition system with eight ignition coils

Identification

Always refer to these labels when replacement parts are necessary or when checking engine calibrations. The engine parts often differ within a CID family. Verification of the identification codes will ensure that the correct parts are obtained. These codes contain all the pertinent information relating to the dates, optional equipment and revisions. The Ford Master Parts Catalog contains a complete listing of the codes and their application.

Code Information

The engine code information label, located on the side of the valve cover and the front side of the valve cover, contains the following:

• Engine build date
• Engine plant code
• engine code

Exhaust Emission Control System

Operation and necessary maintenance of the exhaust emission control devices used on this engine is covered in the Power-train Control/Emissions Diagnosis (PC/ED) manual.

Induction System

The sequential multi port fuel injection (SFI) provides the fuel/air mixture needed for combustion in the cylinders. The eight solenoid-operated fuel injectors:

• are mounted in the lower intake manifold.
• meter fuel into the air intake stream in accordance with engine demand.
• are positioned so that their tips direct fuel just ahead of the engine intake valves.
• are connected in series with the fuel pressure sensor.
• supply fuel from the fuel tank with a fuel pump mounted in the fuel tank.

A constant fuel pressure drop is maintained across the fuel injectors by the fuel pressure sensor. The fuel pressure sensor:

• is positioned upstream from the fuel injectors on the fuel injection supply manifold.

Valve Train

The valve train operates as follows:

• ball-tip hydraulic lash adjusters provide automatic lash adjustment.
• roller followers ride on the camshaft lobes, transferring the up-and-down motion of the camshafts to the valves in the cylinder heads.

Positive Crankcase Ventilation System

All engines are equipped with a closed-type positive crankcase ventilation system recycling the crankcase vapors to the upper intake manifold.

Lubrication System

The engine lubrication system operates as follows:

• oil is drawn into the oil pump through the oil pump screen cover and tube in the sump of the oil pan.
• oil is pumped through the oil bypass filter on the left front side of the cylinder block.
• oil enters the main oil gallery where it is distributed to the crankshaft main journals and to both cylinder heads.
• From the main journals, the oil is routed through cross-drilled passages in the crankshaft to lubricate the connecting rod bearings. Controlled leakage through the crankshaft main bearings and connecting rod bearings is slung radially outward to cool and lubricate the cylinder walls as well as the entire connecting rod, piston and piston rings assembly.
• The left cylinder head is fed from a drilling into the supply passage feeding the main gallery at the front of the cylinder block. The right cylinder head is fed from a drilling into the rear of the main gallery. Main gallery pressure is reduced as it enters the cylinder head galleries through fixed serviceable orifices located at the upper part of the feed passages. It is this reduced pressure in the cylinder head galleries which feeds the camshaft journals, the hydraulic lash adjusters and the primary and secondary timing chain tensioners.
• The camshaft lobe and roller followers are lubricated by splash created through valve train operation.

Oil Pump

The lubrication system of the 4.6L (4V) engine is designed to provide optimum oil flow to critical components of the engine through its entire operating range. The heart of the system is a positive displacement internal gear oil pump using top seal rotors. Generically this design is known as a gerotor pump, which operates as follows.

• The oil pump is mounted on the front face of the cylinder block.
• The inner rotor is piloted on the crankshaft post and is driven through flats on the crankshaft.
• System pressure is limited by an integral, internally-vented relief valve which directs the bypassed oil back to the inlet side of the oil pump.
• Oil pump displacement has been selected to provide adequate volume to ensure correct oil pressure both at hot idle and maximum speed.
• The relief valve calibration protects the system from excessive pressure during high viscosity conditions.
• The relief valve is designed to provide adequate connecting rod bearing lubrication under high-temperature and high-speed conditions.

Cooling System

The engine cooling system includes the following:

• Radiator
• Water pump
• The electric cooling fan motor and fan blade, activated by the variable control module
• The degas bottle, which aids in maintaining the correct volume of engine coolant
• Water thermostat
• Upper radiator hose
• Lower radiator hose
• heater water hoses

Engine — Cobra 4.6L (4V)2003-2004

General Specifications

Item	Specification
Lubricants and Sealants
Motorcraft Premium Engine Coolant VC-4-A (In Oregon VC-5, In Canada CXC-10)	ESE-M97B44-A
Motorcraft Premium Gold Engine Coolant VC-7-A (In Oregon VC-7-B)	WSS-M97B51-A1
SAE 5W-20 Engine Premium Synthetic Blend Engine Oil XO-5W20-QSP	WSS-M2C153-H
Metal Surface Cleaner F4AZ-19A536-RA	WSE-M5B392-A
Silicone Gasket and Sealant F7AZ-19554-EA	WSE-M4G323-A4
Pipe Sealant with Teflon® D8AZ-19554-A	WSK-M2G350-A2
Threadlock 262 E2FZ-19554-B	WSK-M2G351-A6
Engine
Displacement	4.6L (4V) (281 CID)
Number of cylinders	8
Bore	90.2 mm (3.55 in)
Stroke	90.0 mm (3.54 in)
Firing order	1-3-7-2-6-5-4-8
Oil pressure	138-310 kPa
Oil capacity	6 ± 0.25 a
Compression ratio	8.5:1
Cylinder Head and Valve Train
Cylinder head gasket surface flatness	0.10 mm (0.004 inch) max. overall
Combustion chamber volume	52.6 ± 0.5 cm
Valve arrangement (front to rear) b Intake (left hand):	S-P-S-P-S-P-S-P
Valve arrangement (front to rear) Exhaust (left hand):	E-E-E-E-E-E-E-E
Valve arrangement (front to rear) Intake (right hand):	P-S-P-S-P-S-P-S
Valve arrangement (front to rear) Exhaust (right hand):	E-E-E-E-E-E-E-E
Valve guide bore diameter	7.015-7.044 mm (0.2762-0.2773 in)
Valve stem diameter—intake	6.975-6.995 mm (0.2754-0.2746 inch)
Valve stem diameter—exhaust	6.949-6.970 mm (0.2744-0.2736 inch)
Valve stem-to-guide clearance—intake	0.020-0.069 mm (0.00078-0.00272 inch)
Valve stem-to-guide clearance—exhaust	0.046-0.094 mm (0.0018-0.0037 in)
Valve head diameter—intake	37 mm (1.46 inch)
Valve head diameter—exhaust	30 mm (1.18 inch)
Valve face runout	0.05 mm (0.002 in)
Valve face angle	45.5 degrees
Valve seat width—intake	1.8-2.2 mm (0.071-0.086 inch)
Valve seat width—exhaust	1.8-2.2 mm (0.071-0.086 inch)
Valve seat runout	0.05 mm (0.002 inch)
Valve seat angle	45 degrees
Valve spring free length—intake	42.16 mm (1.6598 inch)
Valve spring free length—exhaust	42.16 mm (1.6598 inch)
Valve spring squareness	2 degrees
Valve spring compression pressure—intake	711.47 N @ 26.19 mm (159.9 lb-ft @ 1.031 inch)
Valve spring compression pressure—exhaust	711.47 N @ 26.19 mm (159.9 lb-ft @ 1.031 inch)
Valve spring installed height	36.14 mm (1.4228 in)
Valve spring installed pressure—intake	289.1 N @ 36.14 mm (64.99 lb-ft @ 1.4228 inch)
Valve spring installed pressure—exhaust	289.1 N @ 36.14 mm (64.99 lb-ft @ 1.4228 inch)
Roller follower ratio	1.8:1
Hydraulic Lash Adjuster
Diameter	16.000-15.988 mm (0.6299-0.6294 inch)
Clearance-to-bore	0.018-0.069 mm (0.000709-0.002717 inch)
Service limit	0.016 mm (1.0006299 inch)
Hydraulic leakdown rate c	5-25 seconds
Collapsed lash adjuster gap	0.80-1.20 mm (0.0315-0.0472 inch)
Camshaft
Theoretical valve lift @ 0 lash—intake (primary and secondary)	10.0 mm (0.3937 inch)
Theoretical valve lift @ 0 lash—exhaust	10.0 mm (0.3937 inch)
Lobe lift	5.54 mm (0.218 in)
Allowable lobe lift loss	0.130 mm (0.0051 in)
Journal diameter	26.962-26.936 mm (1.0615-1.0605 inch)
Camshaft journal bore inside diameter	27.012-26.987 mm (1.0635-1.0625 in)
Camshaft journal-to bearing clearance	0.025-0.076 mm (0.00098-0.002992 inch)
Runout	0.025 mm (0.0010 in)
End play	0.025-0.165 mm (0.00098-0.00649 inch)
Cylinder Block
Cylinder bore diameter	90.2-90.239 mm
Cylinder bore maximum taper	0.016 mm
Cylinder bore maximum out-of-round	0.016 mm
Main bearing bore diameter	72.402-72.422 mm
Head gasket surface flatness	0.15 mm (0.006 in) max. overall
Crankshaft
Main bearing journal diameter	67.493 mm
Main bearing journal maximum taper	0.05 mm
Main bearing journal maximum out-of round	0.05 mm
Main bearing journal-to-cylinder block clearance	0.023-0.055 mm
Connecting rod journal diameter	52.983-53.003 mm
Connecting rod journal maximum taper	0.004 mm (0.0002 in)
Connecting rod journal maximum out-of-round	0.004 mm (0.0002 in)
Crankshaft maximum end play	0.130-0.301 mm
Thrust bearing journal diameter	67.493 mm
Thrust bearing journal maximum out-of round	0.05 mm
Thrust bearing journal maximum taper	0.05 mm
Thrust bearing journal length	17.725-17.775 mm
Piston and Connecting Rod
Piston diameter	90.180-90.191 mm
Piston-to-cylinder bore clearance	-0.010/+0.026 mm
Piston ring end gap — compression (top)	0.30 mm
Piston ring end gap — compression (bottom)	0.50 mm
Piston ring end gap — compression (oil ring)	0.65 mm
Piston ring groove width — compression (top)	1.53-1.549 mm
Piston ring groove width — compression (bottom)	1.519-1.539 mm
Piston ring groove width — oil ring	3.031-3.055 mm
Piston ring width — compression (top)	1.47-1.49 mm
Piston ring width — compression (bottom)	1.47-1.49 mm
Piston ring width — oil ring	2.854-2.984 mm
Piston ring-to groove clearance — compression (top)	0.04-0.079 mm
Piston ring-to groove clearance — compression (bottom)	0.029-0.069 mm
Piston ring-to groove clearance — oil ring	0.047-0.201 mm
Piston pin bore diameter	22.0042-21.998 mm
Piston pin diameter	21.991-29.994 mm
Piston pin length	61.60-62.03 mm
Piston pin-to-piston fit	0.0058-0.0132 mm
Connecting rod-to-pin clearance	0.018-0.033 mm
Connecting rod pin bore diameter	22.012-22.024 mm
Connecting rod length	150.7 mm
Connecting rod maximum allowed bend	0.038 mm per 25 mm
Connecting rod maximum allowed twist	0.050 mm per 25 mm
Connecting rod bearing bore diameter	56.866-56.886 mm
Connecting rod bearing-to-crankshaft clearance	0.027-0.069 mm
Connecting rod side clearance	0.15-0.45 mm