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The Magnum engine was introduced in the 1992 5.2L V8 and 3.9L V6. The 5.9L Magnum V8 followed in 1993 and the 8.0L V10 followed in 1994. As soon as these engines were released, they were installed in Ram pickups, and they are still going strong in the 2001 models. So, what is a magnum engine, and how is it different from its predecessors?

Magnum engines are V-type lightweight, single camshaft, overhead valve engines with hydraulic roller tappets. They are designed for unleaded fuel only. Engine lubrication system consists of a rotor type oil pump and a full flow oil filter. The cylinders are numbered from front to rear with odd numbers on the left bank and even numbers on the right bank.

The improvements featured in the Magnum series are:

• Sequential multipoint fuel injection (SMPI) delivers fuel to each cylinder through its own injector for immediate throttle response.
• Progressive-bore throttle body increases bore diameter and airflow for more horsepower.
• Intake manifold of durable, lightweight aluminum pulls in huge volumes of air.
• High-flow exhaust manifolds with large cross-sections for maximum exhaust flow characteristics.
• Short-stem valves, so all airflow is quicker into the combustion chamber.
• Powdered metal rocker arm fulcrums increase durability.
• Extra-thick rocker arm covers with silicone gaskets are held in place by additional bolts for better sealing.
• Serpentine accessory belt with an automatic tensioner for less maintenance and reduced engine vibration.
• Heavy-duty spark plug wires increase conductivity and heat resistance.
• High-flow water pump for improved engine cooling.
• Piston and ring package improves power without sacrificing fuel economy.
• Timing chain cover with fluorocarbon elastomer front seal for a tight fit.
• Oil pan gaskets improved 60% through the use of silicone.
• Progressive-bore throttle bodies increase the bore diameter and air flow as the throttle plates are opened.
• Port and combustion chamber configurations optimize air flow and fuel mixture for maximum horsepower.

    The electronic sequential multi-port fuel injection management system gives the engine a distinctive appearance, reminiscent of the high-rise intakes of the muscle cars. These new intake manifolds are tuned to provide wider torque curves, cleaner emissions, and better fuel economy than the older engines.
     Cylinder heads sport larger valves with 5/16" stems. The exhaust ports and manifolds have been enlarged and streamlined for better flow with a rear exit for easier exhaust system installation. Valve trains have roller tappets and fulcrum style 1.6:1 powdered metal rocker arms. Combustion chambers have been optimized to improve fuel burn and flame propagation.  Press-in heat shields reduce the temperatures of the spark plug ends. Interchangeable rocker arm covers are made of thicker stamped steel and wider flanges to improve stiffness, improve sealing, and reduce valve train noise. The number of bolts retaining the cover was increased from five to ten on the V8. Oil deflectors and PCV baffles keep the oil in the engine where it belongs.

    On the front of the engine, the timing chain cover is a one piece of cast aluminum with an improved front seal. A long neck thermostat housing makes servicing easier. Constant tension hose clamps are more reliable and easier to service. A redesigned cast aluminum water pump with an improved impeller, bearing, and seal pumps more than 100 gallons per minute (on the V8) with less engine drag than older designs. A single serpentine accessory belt drive replaces the multiple V belts used on older engines. The serpentine belt aslo uses uses considerably fewer parts for accessory drive support than older engines did (24 vs 85 parts on the V8), and the new belt uses an automatic belt tensioner to reduce belt maintenance.
    The top piston ring groove has been revised and moved 1.2 mm closer to the piston top, and the piston material has been upgraded. Ring land width was reduced from 7.2mm to 6.0mm to reduce internal friction and improve emissions.
    In addition to controlling fuel injection and engine timing, the SMPI engine computer also manages the charging system, cruise control, transmission shifting, and the AC compressor. By treating all engine accessories as a system, the computer can control accessories as needed to improve engine power and efficiency.

This page would not have been possible without the help of Hank LaViers,
who graciously loaned me his extensive Mopar engine library

Last Update: June 19, 2001