Kelley's Works in Progress

AMC 258ci I6 Engine Specifications

Second most popular of the AMC sixes (it follows the 242/4.0L,) the 258 enjoyed a long and useful life. It still survives in rigs to-day, as well as donating its crankshafts to the legions of 242 owners looking for a little more low-end torque (cf. "stroker.")

The 258 fell out of use in 1991, when it was replaced by the 242. The two overlapped production for four years - the 242 was an option in the Cherokee/Wagoneer and Comanche (XJ & MJ,) while the 258 was an option in the Wrangler (YJ) and standard in the Grand Wagoneer (along with the AMC360V8 - both produced until 1990, and replaced by the MOPAR 360 starting in 1991 as an option in the Grand Cherokee/ZJ.)

Bolt Item Bolt Size "Install To" Torque "Service Recheck" Torque
Air Injection Tube to Exhaust Manifold Special 20 pound-feet 15-20 pound-feet
Air Pump Adjusting Strap to Pump --- 20 pound-feet 15-22 pound-feet
Air Pump Brackets to Engine --- 25 pound-feet 18-28 pound-feet
Air Pump to Bracket --- 20 pound-feet 15-22 pound-feet
Alternator Adjusting Bolt --- 18 pound-feet 15-20 pound-feet
Alternator Mounting Bracket to Engine --- 28 pound-feet 23-30 pound-feet
Alternator Pivot Bolt/Nut --- 28 pound-feet 20-35 pound-feet
Alternator Pivot Mounting Bolt to Cylinder Head --- 28 pound-feet 20-35 pound-feet
Engine Block Heater --- 20 pound-inches 17-25 pound-inches
Camshaft Sprocket --- 50 pound-feet 45-55 pound-feet
Carburettor Holddown Nuts --- 14 pound-feet 12-20 pound-feet
Clutch Housing Spacer to Engine Block --- 12 pound-feet 9-15 pound-feet
Clutch Housing to Engine Block, Bottom --- 43 pound-feet 37-47 pound-feet
Clutch Housing to Engine Block, Top --- 27 pound-feet 22-30 pound-feet
Coil Bracket to Cylinder Head --- 14 pound-feet 10-18 pound-feet
Connecting Rod Bolt Nuts --- 33 pound-feet 30-35 pound-feet
Crankshaft Pully to Damper --- 20 pound-feet 15-25 pound-feet
Cylinder Head --- 85 pound-feet 80-90 pound-feet
Valve Cover --- 28 pound-inches 25-31 pound-inches
Distributor Holddown Clamp --- 13 pound-feet 10-18 pound-feet
EGR Valve Mounting --- 13 pound-feet 9-18 pound-feet
Exhaust Manifold --- 23 pound-feet 18-28 pound-feet
Exhaust Manifold to Downpipe --- 20 pound-feet 15-25 pound-feet
Viscous Fan Clutch to Idler Pully --- 18 pound-feet 12-25 pound-feet
EGR Tube Nuts --- 30 pound-feet 25-35 pound-feet
Flywheel/Flexplate to Crankshaft Bolts --- 105 pound-feet 95-115 pound-feet
Engine Mount Bracket to Engine Block --- 35 pound-feet 25-40 pound-feet
Engine Mount Cushion to Bracket --- 33 pound-feet 27-38 pound-feet
Engine Mount Cushion Bracket to Frame --- 37 pound-feet 30-45 pound-feet
Fuel Pump Mounting --- 16 pound-feet 13-19 pound-feet
Idler Arm Bracket --- 50 pound-feet 35-60 pound-feet
Idler Pully Bracket to Front Cover Nut --- 7 pound-feet 4-9 pound-feet
Idler Pully Bearing Shaft to Bracket Nut --- 33 pound-feet 26-38 pound-feet
Intake Manifold Coolant Fittings --- 20 pound-feet 15-25 pound-feet
Intake Manifold Heater Screws --- 7 pound-feet 5-9 pound-feet
Intake Manifold --- 23 pound-feet 18-28 pound-feet
Crankshaft Main Bearing Caps --- 80 pound-feet 75-85 pound-feet
Oil Sump Pan Drain Plug --- 30 pound-feet 25-35 pound-feet
Oil Sump Pan Screws 1/4"-20 x 3/4" 7 pound-feet 5-9 pound-feet
Oil Sump Pan Screws 5/16"-18 x 3/4" 11 pound-feet 9-13 pound-feet
Oil Pump Attaching Screw, Long --- 17 pound-feet 12-20 pound-feet
Oil Pump Attaching Screw, Short --- 10 pound-feet 8-13 pound-feet
Oil Pump Cover Screws --- 70 pound-inches 60-80 pound-inches
HEGO Sensor to Exhuast Manifold Special 35 pound-feet 32-38 pound-feet
Power Steering Pump Adapter Screw --- 23 pound-feet 18-28 pound-feet
Power Steering Pump Bracket Screw --- 43 pound-feet 37-47 pound-feet
Power Steering Pump Mounting Screw --- 28 pound-feet 25-35 pound-feet
Power Steering Pump Pressure Hose Nut Special 38 pound-feet 30-45 pound-feet
Power Steering Pump Pully Nut --- 58 pound-feet 40-65 pound-feet
Rocker Arm Assembly Screw --- 19 pound-feet 16-25 pound-feet
Start Motor Mounting Screw --- 18 pound-feet 13-25 pound-feet
Thermostat Housing --- 13 pound-feet 10-18 pound-feet
Timing Cover to Engine Block Screws --- 5 pound-feet 4-8 pound-feet
Timing Cover to Engine Block Studs --- 16 pound-feet 13-19 pound-feet
Harmonic Damper Retaining Screw --- 80 pound-feet (lube with Engine Oil) 70-90 pound-feet
Water Pump Mounting --- 13 pound-feet 9-18 pound-feet

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