The main bearing cap of an engine is used to keep the crankshaft of the engine in place. The crankshaft is used to rotate the pistons of your engine. The process by which the crankshaft rotates the pistons is important because the pistons fire fuel into the engine and open up the exhaust and intake valves. The main bearing cap requires that torque be applied to the bolts on it in order to secure the crankshaft under it.
The 7/16-inch outer main bearing cap bolts for a small block Chevrolet engine require 65 foot-pounds of torque, while the 7/16-inch inner bolts require 70 foot-pounds of torque. The 3/8-inch outer main bearing cap bolts need 40 foot-pounds of torque. The main cap bolts for a big block Chevrolet engine with two bolts are tightened with 95 foot-pounds of torque, while the main cap bolts for a big block Chevrolet with four bolts are tightened with 100 foot-pounds of torque.
The main bearing cap bolts for a HEMI 426 engine require 100 foot-pounds of torque and the main cap tie bolts require 45 foot-pounds of torque. The big block Chrysler engines including the 383, 400, and 440 B and RB engines as well as the small block Chrysler engines including the 273, 318, 340, and 360 A engine use 85 foot-pounds of torque on the main bearing cap bolts.
The inner main cap bolts for the 260, 289, and 302 engines use 60 to 70 foot-pounds of torque on inner main cap bolts and 35 to 40 foot-pounds of torque on the outer main cap bolts. The main cap bolts for the 351 Windsor, 351 Cleveland, and 351 Michigan engines require 95 to 105 foot-pounds of torque. The main cap bolts for the Ford engines with a displacement between 429 and 460 as well as the 360, 390, 406, 427, and 428 FE also use 95 to 105 foot-pounds of torque.
The main bearing cap bolts 1 to 4 on the 301 engine require to foot-pounds of torque if they measure 7/16 inches or 100 foot-pounds of they measure 1/2 inches. Every other Pontiac engine requires 100 foot-pounds of torque for the main bearing cap bolts 1 to 4. The rear main bearing cap bolts for the 301 engine require 100 foot-pounds of torque, while the rear main bearing cap bolts for all other Pontiac engines require 120 foot-pounds of torque.
