The Dodge Truck V10 Engine (1994-2003)
The V10 had the highest torque and horsepower, with the broadest usable torque curve (1,000 - 4,000 rpm) of any large gas engine in the field, when introduced. Dodge wrote, “It gives the new Ram pickup the ability to outrun all other trucks in its class with manual or automatic transmissions whether unloaded, loaded, or pulling a trailer.”
The bore size was identical to the 360, to cut tooling costs (and probably development time). The direct ignition and crankshaft mounted oil pump reduced its overall size, so it was just 4 inches longer than the 360 despite having one third more displacement.
The V10 had a returnless fuel injection system, rare for the time; most systems sent fuel up the engine bay and then had another line returning the excess. Fuel injectors operated in pairs, injecting half of their fuel during the intake stroke of each cylinder and half at another time. A twobarrel side draft throttle body had a stepper motor air by-pass valve for idle speed control.
Direct (distributorless) ignition system (DIS), rare for the time, helped in acceleration, quick starts, idle quality, and engine simplification, cut the overall engine length, and eliminated ignition timing from maintenance. The V10 was designed for DIS, which requires no distributor, distributor cap, rotor, coil lead nor distributor drive, making it simpler and smaller. The smooth idle came from precise timing control because there was no series of mechanical parts subject to variation; and response times were faster because the powertrain computer got more frequent updates than with a distributor system.
Warren Swaney wrote: This 2000 Dodge Ram 3500 4x4 is still in service [in 2008] with Duck Mountain Ambulance of Kamsack Saskatchewan. It is powered by a V-10 gas engine and gets about 15-18 miles per gallon.
A crankshaft timing sensor and a camshaft reference sensor provided information to the computer. The crankshaft sensor was inserted through a hole in the side of the block, and sensed slots machined on the crankshaft pulse ring. The control module figured out crankshaft position and engine speed from this.
The camshaft sensor was on the front cover module, and sensed slots on the camshaft sprocket; the slots were coded for individual cylinder identification. This made starting quick by determining which spark plugs and fuel injectors to actuate.
Five high-energy ignition coils were mounted above the right cylinder head cover; each coil controlled two cylinders (every other spark was during the exhaust stroke and did no good, but also did no harm). The coils could fire large spark plug gaps consistently and had a rapid rise time to help fire fouled spark plugs.
A Helmholtz resonator intake manifold was tuned to boost torque at 1700 and 3300 rpm. Long primary runners curved over the right cylinder bank to clear the hood. Resonance in the 25-inch primary runners enhanced low speed torque, with peak torque as low as 1200 rpm. Two plenum chambers supplied air to five runners each. Plenum chamber volume was tuned to resonate at 3300 rpm, broadening the torque curve. Passages across the longitudinal center of the manifold fed air from the throttle body to the plenum chambers.
Exhaust manifolds were made of high molybdenum ductile cast iron for durability. A special ribbed design helped control permanent dimensional changes which occurred as a result of thermal cycling. Die-cast magnesium cylinder head covers reduced noise better and were lighter than aluminum while providing a better sealing surface than stamped steel.
The engine-mounted air cleaner element included an oil-wetted foam overlay to increase its dust capacity. The crankcase ventilation system used a fixed orifice instead of the more common variable-area PCV valve.
The pushrod-operated valve train was similar to the 5.2 and 5.9-liter V-8 engines, with 1.6:1 liftratio rocker arms on studs. Tappet bores in the block were aligned with the push rods to minimize pushrod wear, and reduce cold engine tappet noise by keeping air from being trapped. Roller-type hydraulic tappets were the same as used in "Magnum" V-8 engines. Sprockets for the chain-driven camshaft were powdered metal for uniformity and ease of manufacture.
Cast iron cylinder heads had machined top surfaces to provide smooth, uniform sealing surfaces for the cylinder head covers. For durability in heavy-duty service, the heads had high-nickel chromium exhaust valve seat inserts.
The block extended below the crankshaft for added strength and stiffness. The stiffness of this deepskirt or "Y" block configuration helped minimize noise. Extensive research into past and present engine practices was used to determine that the deep-skirt block would be the simplest and most effective way to obtain the desired stiffness. This configuration also provided a continuous flat oil pan sealing surface to minimize potential leakage paths. Finite element analysis guided designers in providing the desired block strength and stiffness properties for this configuration.
Blocks were stress-relieved (annealed) before machining to aid in accurately controlling dimensions and to provide uniform-hardness cylinder walls for low piston and ring wear.
The rear face of the block had the same mounting configuration as the Cummins diesel engine with which it shares transmissions.
Oil pan, pump, and sealing
Holes that allowed oil to return to the pan from the cylinder heads were placed so that oil flowed along the sides of the block to avoid power robbing windage (oil being thrown about by the crankshaft). The shallow portion of the bottom of the pan had longitudinal "U" channels that directed oil to the sump and minimize windage effects, a quarter inch deep in the center, directly under the crankshaft, and three quarters of an inch deep along the sides where there was more clearance to the crankshaft. The formations in the bottom of the pan also stiffened to reduce drumming noise.
The oil pan capacity was seven quarts to help keep oil temperature low during heavy duty operation. It had electro-coated paint to protect against corrosion. A gerotor oil pump in the front cover module, driven directly by the crankshaft, contributed to the compactness of the engine. A unique full-quart capacity severe service oil filter had a patented filter media with a higher capacity to trap and hold contaminants than prior filters.
Molded, radial-lip-type seals at both ends of the crankshaft sealed better than the more common multi-piece units. The oil pan had a flat, continuous gasket surface; both the oil pan and cylinder head covers had state-of-the-art silicone gaskets with steel back bones. The intake manifold had new patented end seals.
Pistons, Rods, and Crankshaft
Die-cast, all-aluminum pistons had a unique "moly" (molybdenum disulfide) coating baked onto the skirts to reduce friction. The coating was particularly effective during engine break-in, but with time the material became imbedded in the cylinder bore walls and continued to reduce friction. Forged steel connecting rods were the same as used on the 5.2-liter V-8 engine.
The cast iron crankshaft had six main bearings. An alternate firing interval balanced harmonic vibrations, minimized engine shake and provided a stable idle. A pulse ring adjacent to the # 3 main bearing had machined slots that provide timing information used by the DIS and fuel injection systems.
Front Cover Module
Camshaft chain and sprocket covering, oil pump and water pump functions were combined in a single cast aluminum front cover module. Oil passages from the oil pickup to the block galleries were cored into the cover. Coolant passages to the block water jackets were also cored into the cover.
The module was cast in a loose sand mold using a consumable Styrofoam® pattern instead of a removable wooden pattern in a compacted sand mold. Molten aluminum entering the mold displaced and vaporized the Styrofoam. While the vaporized Styrofoam was dispersing through the sand, it formed a wall of gas which supported the sand until the aluminum began to solidify. The gas wall kept the surfaces of the casting clean.
Cooling System and Accessories
A heavy-duty truck engine block cooling system and thermostat minimized low-temperature piston wear and oil consumption by allowing the cylinder walls to warm up gradually and expand uniformly. The truck-type thermostat opened in a smooth continuous manner because it had four times the working area of a passenger car thermostat. A conventional thermostat released bursts of chilled water during warm-up that distorted the cylinder walls and caused wear and high oil consumption. The thermostat had a cylindrical valve element with an O-ring seal to assure smooth consistent operation. It was mounted in a molded plastic housing at the front of the engine.
The water pump was mounted on the front cover module and driven by the serpentine accessory drive belt. It had a curved-vane impeller of 40% glass-filled polyphenylene sulfide that required less power to drive than conventional impellers. It also was better balanced than previous stamped impellers.
Accessories were driven by a multi-ribbed serpentine belt that had a torsional automatic tensioner like that used on the 5.9-liter V-8 engine. Accessory locations were the same with and without air conditioning. When air conditioning was added, a longer belt was used.