GM's 3100, a 3.1-liter V6 engine, was first produced in 1988. It features push rods that operate within the camshaft. Also known as an overhead valve, the push rod opens and closes the intake and exhaust valves in this engine.
The 3.1-liter GM engine had six cylinders with a bore of 89 millimeters and a stroke of 84 millimeters. It had a compression ratio of 8.8-to-one. The cylinders in this engine were positioned at 60-degree angles from one another and fired in a 1-2-3-4-5-6 order.
Certain engines are manufactured with push rods that, through the rockers, put the cam into the block and actuate the valves. This construction is especially beneficial in a "V" engine where there's only one camshaft.
In GM's 3.1-liter V6, the push rod is constructed from either iron or aluminum, depending on the year. The intake push rods are 5.68 inches long, and the exhaust push rods are 6 inches long. They operate from exhaust to intake for cylinders five and two, and from intake to exhaust in cylinders one, three, four and six.
In this engine, the camshaft sprocker bolt requires 18 foot-pounds of torque to tighten properly. The nuts for the rocker arm, which houses the push rod, bolt to 20 foot-pounds of torque and the rocker arm studs bolt to 18 foot-pounds.
