... -T Crankshaft (Forged Steel) ,1. Isuzu 4JB1 Crankshaft (Shanghai Forging) , 2. Isuzu 4JB1 Crankshaft (Alloy steel), 3. Isuzu 4JB1 Crankshaft (Casting Steel), 4 ... . Isuzu 4JB1 Crankshaft (Strong Steel), 5. Isuzu 4JA1 Crankshaft (Chongqing Forging), 6. Isuzu 4JA1 Crankshaft (Shanghai Forging), 7. Isuzu 4JA1 Crankshaft (Casting ...