2005 Mustang Engine Information – 281 cubic inch V-8 (4.6 L Ford Modular V8)

Ford’s Modular 4.6L SOHC V8

While the modular V-8 still displaced 4.6 liters, the engine block was now cast out of lighter aluminum rather than iron; saving 75-pounds and featured a deep skirt for added strength. Inside the block was a set of short skirt aluminum pistons with an antifriction coating and wrapped with high-tension piston rings for longer life and better oil control. Once again, the cracked-powdered-metal connecting rods were used after proving their durability in past modular motor Mustangs.

Bolted to the top of the aluminum block was a pair of new cylinder heads that were taken from the 5.4-litre Triton truck engine. These aluminum three valve-per-cylinder heads allowed the engine to breath better at high engine speeds since they allowed the incoming air a more direct, port-style path to the two intake valves. The new heads allowed engineers to raise the compression ratio to 9.8:1 while still being able to safely run on regular grade fuel. Operating the valves was the camshaft lifted directly from the 5.4 Triton engine along with another innovation that was a first for any Mustang; Variable Camshaft Timing.

Variable Camshaft Timing (VCT) allows for better engine performance, increased fuel efficiency and reduced emissions by electronically adjusting the camshaft timing. The system works by directing high pressure oil through electronically controlled hydraulic valves into the camshaft phaser cavity. When the Powertrain Control Module (PCM) requires a change in cam timing, depending on factors such as engine load and RPM, it will send a signal to the hydraulic valves to regulate oil flow to the phaser cavity. This in turn causes the camshaft to rotate slightly from its initial orientation thus resulting in the camshaft timing being advanced or retarded depending on the needs of the PCM. Since the Mustang employed a single overhead cam design the VCT system operated both the intake and exhaust valves simultaneously.

Crowning the improved V-8 was an all new intake system featuring an intake manifold with tuned runners. At the end of these runners was another new feature to the Mustang called a charge motion valve. These flaps would close at light loads and low engine speeds causing the air entering the engine to speed up and induce a tumble effect in the combustion chamber allowing fuel and air to mix more thoroughly and burn efficiently. When the driver put their foot down on the accelerator and engine speeds rose or when under heavy loads these flaps would then open fully allowing maximum air flow into the combustion chamber. Throttle control on the V-8 was controlled electronically just as it was with the 4.0-litre V-6.

Engine Specs

Engine Torque Specifications

All torque specifications provided in this table are those recommended by FORD. If you use special bolts, follow the torque specifications provided by the manufacturer. I recommend that you use the 3 step torque technique where you torque down the bolts in three equal steps. Once you have reached the maximum recommended torque setting, go around one more time. Do not torque in a circular pattern. Always torque cross to cross or pattern specified by FORD. Many specs are given in inch pounds. 12 inch pounds is equal to 1 foot pound. The use of a inch pound torque wrench is desirable because it is more accurate at most lower settings.