Chevrolet 12507945 Bearing, Camshaft #1

You can Select Your Vehicle to check if 12507945 fits your vehicle.

Utilize a specific set of tools for bearing removal and installation, ensuring the correct order of removal and installation for each bearing.

This procedure is applicable to 2.0/2.2 liter four-cylinder overhead valve engines and all V6 engines, but it requires the engine to be removed from the vehicle and mounted on a stand due to space constraints for camshaft removal. To check camshaft lobe lift with the cylinder head installed, start by removing the rocker arm cover(s) and positioning the number one piston at top dead center (TDC) on the compression stroke. Loosen the rocker arm nuts and pivot the rocker arms aside, then mount a dial indicator on the engine and place the plunger on top of the first rocker arm directly above the pushrod. Zero the dial indicator and slowly turn the crankshaft clockwise until the indicator needle stops and reverses direction, indicating maximum cam lobe lift. Record this measurement and repeat the process for all valves, ensuring each piston is at TDC on the compression stroke. If the camshaft lobe lift is less than specified, it indicates wear, necessitating camshaft replacement. If the cylinder head(s) have been removed, an alternate method involves measuring the lobe at its highest point and the base circle perpendicular to the lobe using a micrometer. Subtracting the base circle measurement from the lobe height gives the lobe lift. For camshaft removal, follow the steps which include removing the timing chain and sprockets, lifters, pushrods, and the oil pump drive. Use long bolts as handles for camshaft removal, taking care to support the camshaft near the block to prevent damage to the bearings. Inspect the camshaft for wear, bearing journal condition, lobes, and oil pump drive and gears. If components are in good condition and lobe lift measurements are within specifications, reuse is possible. However, inspect the block's bearings for wear and damage and measure the bearing journals' inside diameter to determine bearing oil clearance. Excessive clearance warrants new bearings, but camshaft bearing replacement requires specialized tools and expertise, so it's recommended to consult an automotive machine shop for this task.