Joined
·
2,290 Posts
AMC Eagle: American 4x4 Pioneer
Subaru claims to have the "first sport utility wagon," but the AMC Eagle pre-dated it by 17 years.
While the Eagle started out with an NP203 transfer case, based on Jensen FF technology, the car soon moved to a state of the art, 42-disc New Process Gear NP119 transfer case. Both transferred power to the wheels with the most traction. The full time four wheel drive system, dubbed "Quadra-Trac," was co-developed by AMC/Jeep and Chrysler's New Process Gear.
Power went through the rear driveshaft and was sent to the left using a Morse Hy-Vo chain to the front of the car. Differential action was aided by a velocity-sensitive viscous coupling, which also limited slip. The silicone-based fluid in the coupling had high shear and heat resistance, keeping its viscosity through a wide temperature range (starting at 40°F below zero and going over 400°F). The system provided some anti-skid protection, by the way it worked to equalize driveshaft speeds - whether or not the car was moving under power.
Bob Sheaves wrote that the NPG119 was created to solve issues that cropped up on the NPG203, and was the first modern style (low drag, low fuel milage penalty) transfer case.
The big advance of the NPG119 was the Dow Corning silicone fluid, which had a high shear force. The NPG203 (and the later 242) used a conventional differential with a manual locking feature to control the speed difference between the front and rear outputs of the transfer case.
The AMC Eagle was rooted in the 1978 AMC Concord, itself an upmarket version of the compact AMC Hornet. Concord sold as a sedan, hatch, and wagon, with a four-cylinder, two straight sixes, and a 304 V8. The car was an immediate hit (for AMC), with 121,293 cars sold in its first year, easily beating every other AMC car combined.
The 4x4 version of the Concord was given a completely new name - Eagle - and a three-inch lift, with minor sheet metal and trim changes, and standard 15-inch wheels (Concord used 14s). Buyers could choose between two or four door sedans, or a four door wagon. It used recirculating ball steering rather than the trendy rack and pinion, and front disc brakes with rear drums.
The AMC Eagle was only sold with the 258 straight six (4.2) with a Carter two-barrel carburetor, coupled to a Chrysler 998 TorqueFlite (or "Torque Command") transmission controlled by a T-handle floor shifter.
The standard final drive ratio was 3.08:1, with an optional 3.54:1 ratio mandatory with the high altitude and medium trailer towing packages. P195/75R15 radials were standard, along with power steering and brakes.
The Eagle used an independent front suspension for better cornering and tire wear, one of the first 4x4 cars to use an independent front suspension (the 1964 Jeep Wagoneer was the first). The car was unit-body, so the differential and axle tube were attached to the engine rather than the body. The basic design of the front suspension was similar to Concord, with higher spring rates.
Buyers could get an optional heavy duty suspension, with a heavier front roll bar (going from 0.94" to 1.06" diameter), a 0.63" rear roll bar, upgraded front shocks, and thicker rear leaf springs. A Delco automatic load leveling system was optional, using air shocks and an electronic height sensor. The transfer case and front end had skid plates.
While the Eagle started out with an NP203 transfer case, based on Jensen FF technology, the car soon moved to a state of the art, 42-disc New Process Gear NP119 transfer case. Both transferred power to the wheels with the most traction. The full time four wheel drive system, dubbed "Quadra-Trac," was co-developed by AMC/Jeep and Chrysler's New Process Gear.
Power went through the rear driveshaft and was sent to the left using a Morse Hy-Vo chain to the front of the car. Differential action was aided by a velocity-sensitive viscous coupling, which also limited slip. The silicone-based fluid in the coupling had high shear and heat resistance, keeping its viscosity through a wide temperature range (starting at 40°F below zero and going over 400°F). The system provided some anti-skid protection, by the way it worked to equalize driveshaft speeds - whether or not the car was moving under power.
Bob Sheaves wrote that the NPG119 was created to solve issues that cropped up on the NPG203, and was the first modern style (low drag, low fuel milage penalty) transfer case.
The big advance of the NPG119 was the Dow Corning silicone fluid, which had a high shear force. The NPG203 (and the later 242) used a conventional differential with a manual locking feature to control the speed difference between the front and rear outputs of the transfer case.
The AMC Eagle was rooted in the 1978 AMC Concord, itself an upmarket version of the compact AMC Hornet. Concord sold as a sedan, hatch, and wagon, with a four-cylinder, two straight sixes, and a 304 V8. The car was an immediate hit (for AMC), with 121,293 cars sold in its first year, easily beating every other AMC car combined.
The 4x4 version of the Concord was given a completely new name - Eagle - and a three-inch lift, with minor sheet metal and trim changes, and standard 15-inch wheels (Concord used 14s). Buyers could choose between two or four door sedans, or a four door wagon. It used recirculating ball steering rather than the trendy rack and pinion, and front disc brakes with rear drums.
The AMC Eagle was only sold with the 258 straight six (4.2) with a Carter two-barrel carburetor, coupled to a Chrysler 998 TorqueFlite (or "Torque Command") transmission controlled by a T-handle floor shifter.
The standard final drive ratio was 3.08:1, with an optional 3.54:1 ratio mandatory with the high altitude and medium trailer towing packages. P195/75R15 radials were standard, along with power steering and brakes.
The Eagle used an independent front suspension for better cornering and tire wear, one of the first 4x4 cars to use an independent front suspension (the 1964 Jeep Wagoneer was the first). The car was unit-body, so the differential and axle tube were attached to the engine rather than the body. The basic design of the front suspension was similar to Concord, with higher spring rates.
Buyers could get an optional heavy duty suspension, with a heavier front roll bar (going from 0.94" to 1.06" diameter), a 0.63" rear roll bar, upgraded front shocks, and thicker rear leaf springs. A Delco automatic load leveling system was optional, using air shocks and an electronic height sensor. The transfer case and front end had skid plates.
1980 AMC Eagle |