Buick 24505393 Sprocket, Camshaft

To remove the timing chain cover, slide the shim off the nose of the crankshaft, ensuring the shim's notch fits over the key in the crankshaft. Replace the timing chain if the total free play between the sprockets exceeds one inch to avoid erratic engine performance, loss of power, and reduced fuel mileage. Temporarily install the vibration damper bolt and turn the crankshaft clockwise to align the timing marks on the crankshaft and camshaft sprockets directly opposite each other, with the camshaft sprocket marked by a dimple and the crankshaft sprocket by a raised dot. Remove the timing chain damper, detaching the spring on earlier models if necessary, and then remove the camshaft sprocket bolts, taking care not to turn the camshaft. Pull the camshaft sprocket and crankshaft sprocket forward alternately to remove them along with the timing chain as an assembly, followed by the camshaft gear. Clean the timing chain components with solvent and dry them with compressed air while wearing eye protection, then inspect for wear and damage, looking for deformed, chipped, pitted, polished, or discolored teeth. If the crankshaft has been disturbed, temporarily install the sprocket and turn the crankshaft until the mark on the crankshaft sprocket is at the top; if the camshaft was disturbed, do the same for the camshaft until its timing mark is at the bottom. Assemble the timing chain on the sprockets and slide the sprocket and chain assembly onto the shafts with the timing marks aligned, ensuring the balance shaft gears are also aligned before installing the camshaft timing chain sprocket. Install and tighten the camshaft sprocket bolt(s) to the specified torque, attach the timing chain damper assembly to the block, and install the spring. For 1994 and earlier models, install the camshaft thrust button and spring, securing it with grease. Lubricate the chain and sprocket with clean engine oil and install the timing chain cover, remembering to lubricate the oil pump cavity beforehand.

Remove the camshaft sprocket bolts using the sprocket holding tool to hold the sprockets while loosening the bolts.

Remove the crankshaft pulley and the timing chain cover.

Check the timing marks and adjust as needed, then install the chain housing-to-block stud and reload the timing chain tensioner assembly.

After removing the crankshaft pulley, detach the timing gear cover by removing the bolts and cleaning the sealing surfaces with a scraper and degreaser.

The crank sprocket should be pressed on for the last 8 mm of its travel, and timing marks must be aligned after installation.

The timing chain should be replaced if the engine has high mileage, shows visible damage, or if the free play between the sprockets exceeds one inch. Failure to replace it may lead to erratic engine performance, loss of power, decreased fuel mileage, and the risk of the chain "jumping" timing or breaking, which can cause severe engine damage.