The biggest news for 2004 is the new 5.4-liter SOHC Triton V-8 featuring 3 valves per cylinder, along with variable cam timing, electronic throttle control, and a trick new spark plug that will be setting the standard for all Ford products to come. The result is an engine that produces 300 horsepower at 5,000 rpm and 365 lb-ft of torque at 3750 rpm. That’s a 40-hp and 15 lb-ft bump over the current model.
The engine features an all-new aluminum cylinder head and cast iron block, and the highlight is the 3-valve design: two intake and one exhaust. The new 5.4 also is the first Ford modular V-8 to use variable cam timing. Ford claims it’s the industry’s first mass application of dual-equal variable cam timing, where the intake and exhaust valve timing shifts together.
In order to make the 3-valve system work, Ford had to reengineer the spark plug, which now resides in a center position surrounded by the valves. The plug is longer, narrower, and features a fixed-gap U-shaped terminal at the electrode end, which means no more adjustments needed. The spark plug in the center provides the shortest path for the flame to travel, providing efficient combustion.
Although a four-valve design is preferable, Ford acknowledges that the setup requires dual cams that add weight, cost and parts. The engineers achieved many of the same benefits of the four-valve design, but in a more compact, less complex design, with the added benefit of reduced weight. Because of the dual intake valves, breaking is improved by 40 percent over the old 5.4-liter, with peak airflow at 350 cu ft per minute versus 250 in the old engine. The redesigned intake port aids in airflow improvement as well. The three-valve head design is dimensionally smaller than the old 5.4 head, but offers more rigidity and strength. In addition, Ford notes that it is easier to manufacture, with simpler drilling angles and straight-machined surfaces.
The variable cam timing feature allows the cams to operate at different points during the combustion cycle, allowing the engineers to tailor the performance for specific engine speed and loads. The cam timing is altered via oil flow in the hydraulic cam timing mechanism, which is controlled by the powertrain control module (PCM). In milliseconds, the unit can shift between fully advanced and full retarded timing points. The result is improved efficiency under no or low-load conditions, as when idling or cruising, and more power on demand for speed or heavy load.
By using the variable timing, the engineers also were able to create a higher compression level in the chamber than in the two-valve engines, again contributing to increased performance and efficiency.
Another first use for Ford is the Charge Motor Control Valves (CMCV), which features electronically controlled metal flaps at the ends of the intake runners to add air when needed for power, and run economically when under normal driving conditions.
One of the biggest changes is the addition of an electronic throttle control system, standard on all Ford trucks. The ETC is another segment first, and has no mechanical linkage between the accelerator pedal and the throttle control. The linkage is replaced by an accelerator position sensor in the cabin and an electronic control circuit and actuator at the throttle valve on the engine. Using algorithms, the current operating status of the engine and ambient conditions are taken into account, and throttle output is delivered instantly, as requested by the driver.
The advantages to the ETC system include consistent response, improved fuel economy, and better communication between engine operating systems. Tip in should be smooth and driveline lash should be non-existent. Imagine how nice this will be when towing. In off-road situations, the engineers have provided a special calibration for low-range throttle input. This will help modulate the engine more accurately for perilous rock climbing excursions. Only the Range Rover SUV offers the same system.
For safety, the ETC features redundant sensor and double return springs on the throttle pedal, as well as and other software for fail-safe operation and limp-home modes.
As far as reducing NVH, the new 5.4 features vibration-resistant ribbing and reinforcements in the composite intake manifold, reshaped pistons with longer side skirts to reduce slap, smaller cylinder heads that reduce radiant noise, roller-finger cam followers that are quieter than non-rollers, and new magnesium cam covers for vibration resistance.
The engineers did make sure the V-8’s engine produced the good sound quality that drivers who mash the pedals want to hear. The exhaust note from the F-150 is tuned to sound like a “tough truck,” and Ford insists it is not the same sound as generated by a Mustang or even a Thunderbird.