Ford 4.6L 2/3/4v V8 Engine (Specs, Reliability & Issues)
Updated: May 2
The Ford 4.6L V8 engine was initially introduced in the 1991 Lincoln Town Car as the first member of Ford's Modular overhead camshaft engine family. It was a 4.6-liter SOHC eight-cylinder gasoline engine with two valves per cylinder and a 90-degree V-angle.
This engine was eventually utilised in the Mustang GT as the base V8. Ford also produced a 4-valve DOHC variation, which is used in SVT Cobra and Mach 1 cars.
In 1993, the 4.6L Four-Cam V8 32-valve DOHC engine made its debut in the Lincoln Mark VIII. Ford's Small Block 5.0 H.O. engine, which was constructed on pushrods, was superseded by the new Modular 4.6-liter V8 series.
The 4.6L V8 has a deep-skirt aluminium or cast iron cylinder block, depending on the model year and application (Romeo and Windsor castings).
Windsor iron blocks feature "W" lettering and dowel pins on their cross-bolted main caps, while Romeo 4.6 iron blocks have jackscrew cross-bolted main caps with "R" letters (but not all of them). Apart than that, they're the same.
Aluminum cylinder blocks were cast in the Windsor Aluminum Plant, with the exception of early 1990s Teksid blocks, which were produced in Turin, Italy (WAP). On aluminium blocks, the main bearing caps were 6-bolt.
The banks of the cylinders are at a 90-degree angle. The cylinder bore spacing is 3.937 in, and the deck is 8.937 in (227.0 mm) high (100.0 mm). The engine block has a bore-to-stroke ratio of around 1:1 (square design), which reduces noise, harshness, and vibration.
The connecting rod is 5.933 inches long (150.7 mm). In modular engines, six- or eight-bolt crankshafts were employed. Trucks and high-performance applications had steel crankshafts with eight bolts, whereas Romeo blocks under the hoods of passenger cars used six-bolt crankshafts.
All engines have forged pistons and cracked powdered metal connecting rods from the factory.
For the 4.6 engine, there are three types of aluminium cylinder heads: 2-valve (1990-2014) and 3-valve (2005-2010) with single overhead camshaft (SOHC) valvetrains, and 4-valve with dual-overhead-camshaft valvetrain.
In the four-valve form, two timing chains drive single camshafts as well as separate intake and exhaust camshafts (by one for each head).
Their valvetrains all include low-friction roller rocker arms and hydraulic lash adjusters. The three-valve cylinder head has apex-shaped combustion chambers, a centralised spark plug, two intake valves, and one large exhaust valve, all designed to increase velocity and volume.
On the 4.6 3V SOHC engines, Ford's variable camshaft timing (VCT) technology was also offered. On Ford 4.6 2v/3v engines, the intake manifold is made of composite material.
In the 32-valve 4.6L DOHC engines, only aluminium blocks were utilised (except 2003-2004SVT Cobra, which had an iron block with 4-bolt main bearing caps). Each cylinder has two intake and two exhaust valves. On four-valve heads from 1993 to 1998, each intake valve has its own intake port.
Tumble-style intake ports, which feed two intake valves from a single intake port, were added to cylinder heads in 1999. In that year, they also changed the camshaft profiles and swapped out the variable runner-length intake manifold with a fixed runner-length intake manifold.
On modular 4.6L V8s, the ECU and mechanical/electronic throttle body controlled a traditional sequential multi-port fuel injection system. They also had an electrical coil-on-plug ignition system that could be controlled independently.
The 4.6-liter 4-valve V8 engine was on Ward's 10 Best Engines List in 1996 and 1997, while the 3-valve version was on the list from 2005 through 2008 and won multiple accolades. Based on this engine, Ford developed a bigger 5.4-liter engine series, which was likewise a commercial success.
In 2014, the 4.6L Modular engine was taken out of production. A 4.6 2v engine for a Ford E-Series van from the 2014 model year was the line's last powerplant. The replacement engine, the new Modular 5.0L Coyote, had already been in production for three years at that point.
Manufacturer: Romeo Engine Plant in Romeo, Michigan, Windsor Engine Plant in Windsor, Ontario, Essex Engine Plant in Windsor, Ontario
Production years: 1991-2014
Cylinder block material: Aluminium, Cast iron
Cylinder head material: Aluminium
Fuel type: Gasoline
Fuel system: Sequential multi-port fuel injection
Number of cylinders: 8
Valves per cylinder: 2/3/4
Valvetrain layout: SOHC/DOHC
Bore: 90.2 mm (3.55 in)
Stroke: 90.0 mm (3.54 in)
Displacement: 4,601 cc (280.8 cu in)
Type: Four-stroke, naturally aspirated/supercharged
Compression Ratio: 9.0:1 (1990-2000 SOHC 2-valve engine), 9.375:1 (2000+ SOHC 2-valve engine), 9.8:1 (SOHC 3-valve engine), 9.85:1 (1996-1998)
Power: 190-260 hp (142-194 kW) at 4,400-4,750 rpm (2-valve SOHC), 292-315 hp (218-235 kW) (3-valve SOHC), 280-390 hp (209-291 kW) (4-valve DOHC)
Torque: 260-302 ft-lb (353-409 Nm) at 3,250-4,000 rpm (2-valve SOHC), 315-325 ft-lb (427-441 Nm) (3-valve SOHC), 265-452 ft-lb (359-613 Nm) (4-valve DOHC)
Firing order: 1-3-7-2-6-5-4-8
Engine oil weight: SAE 5W-20
Engine oil capacity: 5.7 litres (6.0qts) with oil filter
Oil change interval: 5,000 miles (10,000 km) or 6 months
4.6 2V Applications: Lincoln Town Car (Touring Sedan), Ford F-Series, Ford E-Series, Ford Mustang GT, Ford Crown Victoria, Ford Thunderbird, Ford Explorer, Mercury Mountaineer, Mercury Grand Marquis, Mercury Cougar, MG ZT 260, Rover 75 V8, Mobility Ventures MV-1.
4.6 3V Applications: Ford Mustang GT, Ford Mustang Bullitt, Ford Explorer Sport Trac, Ford Explorer, Ford F-Series, Mercury Mountaineer.
4.6 4V Applications: Ford Mustang SVT Cobra, Ford Mustang Mach 1, Lincoln Mark VIII, Lincoln Continental, Lincoln Aviator, Mercury Marauder, Marcos Mantis (GT), Panoz AIV Roadster, Panoz Esperante, MG X-Power SV, Koenigsegg CC8S, Koenigsegg CCR V8.
Problems & Reliability
Ford's Modular 4.6 V8 has a solid reputation for reliability and longevity among owners. The engine has a range of over 200,000 kilometres of operation. Several taxi companies used Crown Victorias with 4.6 V8 engines until they reached 300,000 or even 400,000 kilometres.
However, there are no ideal engines, and this one has a number of well-known flaws and design flaws.
Breaking in the plastic intake manifold is the first and most typical problem. The 4.6L SOHC 2-valve engines made between 1996 and 2001 are affected by this problem. At the time, Ford used a DuPont nylon composite intake manifold, and this manifold was prone to breakdown without warning.
The intake manifold was unable to sustain the strain on the material caused by millions of heat/cool cycles (expansion and contraction), as well as additional forces/vibrations from the alternator bracket, which was mounted directly into the plastic.
As a result, the manifold, as well as the heater pipe and coolant temperature sensor, may crack and shatter, resulting in an engine coolant leak and vehicle overheating. In late 2001, Ford replaced the all-plastic intake manifold with a revised intake manifold having cast metal failure zones.
The second common problem is spark plug thread stripping in cylinder heads, which is caused by a lack of thread depth in aluminium cylinder heads. When changing spark plugs in a Ford 4.6 V8, be careful not to overtorque them, since this may shred the threads.
To repair a stripped thread, Ford recommends using a threaded insert, and even provides a tool kit that contains one.