Chevrolet 12537202 Chain Assembly, Timing

A chain tensioner should be removed first and also the camshaft gear. The method for replacing a timing chain on a Chevrolet V8 engine, such as the 305 or 350, is to remove the front cover of the crank case housing. Turn the motor until the timing marks on both sprockets are close together and in line between the centerlines of the shafts. The three bolts holding this sprocket to the camshaft can be removed because it is just pressed on lightly and also aligned with a dowel pin. Along with that, remove them from each other. Consequently, removing this sprocket will loosen up the entire camshaft assembly including its timing chain. It is necessary to use a gear puller to take out a crankshaft sprocket then. However, do not touch any part of your engine as you install new crank sprocket on shaft and put chain over camshaft sprocket too. As a result, putting these marks right between shaft centers and inserting dowel hole in cam sprocket, ensure alignment of timing marks at end of camshaft sprocket while re-fitting it by using those three aforementioned bolts for fastening purposes. Thereafter, fit it onto camshaft with chain intact by using those three screws/bolts for tightening purposes only (APOLLO 2007). After installing the sprockets, turn through two full revolutions to ensure correct alignment between timing marks on sprockets located centrally between shaft centers (APOLLO 2007). In addition to that, Oldsmobile engines have their own versions like 307; 350; 403 where you should start off by removing rear timing case cover before detaching can shaft gear itself from there on out (APOLLO 2007). Remember that this gear has its fuel pump operating clog stuck at its face which will help locate it into that camshaft using this dowel sleeve too (APOLLO 2007). Then, take out the oil slinger as well as the timing chain and the camshaft sprocket (APOLLO 2007). In case of need replacing crank shaft sprocket, it should be carefully pulled out from the shaft; first, however, it is essential to remove crankshaft key by means of a puller. Nevertheless, when removing it make sure that one does not overlap the end part of key during its removal since this keyway is machined partially into the crank gear (APOLLO 2007). Reinstalling the crankshaft sprocket requires aligning its keyway in relation to gears on engine shafts or flywheel and starter teeth. Turn the timing mark on the crankshaft gear so that it points at center of camshaft (APOLLO 2007). Put timing gear over camshaft gear and start camshaft gear onto its shaft with timing marks as close to each other as possible and aligned between centers of both shafts respectively (APOLLO 2007). Align new priced camshaft with outer end key way so you can even install fuel pump eccentric with flat edge facing towards rear part also put in oil flinger which will be finally driven until it bottoms (APOLLO 2007). On Oldsmobile Diesel Engines 263, replacing a chain and gears makes it necessary to retime engine injection pump. The valve covers must be removed off with front timing chain cover before that rockers' arm pivot bolts can be equally loosened for lash purposes except if such related activities are being performed on them. Remove bolt washer for cam sprocket and oil slinger from crankshaft. Timing chain should be removed together with sprockets for both cams along with cranks ones too. When removing this tight-fitting crank sprocket from its position on a crankshaft, you will need to use a suitable puller (APOLLO 2007). Next, position the crankshaft sprocket such that the keyway is lined up straight and rotate it through this timing mark of gear on crankshaft until it points at center for camshaft (APOLLO 2007). Position one timing gear over other so that in between shafts they have marks as close as possible (APOLLO 2007). The camshaft should be rotated to enable proper alignment with the new gear (APOLLO 2007). Place eccentric on top of fuel pump facing rear after which hammer key in until completely bottomed out; later push oil slinger into place. Therefore, the remaining steps of installation are carried out other way around and then, do not forget to deplete valve lifters while checking for injection timing once everything gets set accordingly (APOLLO 2007).

When replacing the timing chain and gears on Oldsmobile 263 Diesel Engines, follow these steps:Remove the front timing chain cover and valve covers.Evenly loosen all rocker arm pivot bolts to create lash between the rocker arms and valves.Remove the crankshaft oil slinger and the camshaft sprocket bolt washer.Remove the timing chain, camshaft, and crankshaft sprockets.If the crankshaft sprocket is tightly fitted on the crankshaft, use an appropriate puller to remove it.To install, reposition the crankshaft sprocket, ensuring the keyway is perfectly aligned.Rotate the crankshaft gear's timing mark to face the center of the camshaft.Mount the timing gear over the camshaft gear and ensure the timing marks align closely between the shaft centers.Rotate the camshaft to align it with the new gear.Install the fuel pump eccentric with the flat side towards the rear.Drive the key in until it bottoms and reinstall the oil slinger.Complete the remaining installation steps in reverse order.Bleed down the valve lifters and check injection timing after completing the process.

Turn the engine until the marks on the camshaft and crankshaft sprockets are in alignment, ensuring not to remove either sprocket or the chain until this is accomplished.

Remove both the camshaft sprocket and chain, and work the crankshaft sprocket off the crankshaft.

Install the timing chain over the camshaft sprocket, allowing slack in the chain to hang down over the crankshaft sprocket.

Clean the timing chain, sprockets, and crankshaft oil slinger thoroughly in the proper solvent.

Remove the timing chain cover and temporarily install the harmonic balancer bolt and washer on the crankshaft.

If the engine has been removed from the car, disregard the following steps which do not apply.

Remove the three camshaft sprocket retaining bolts and lift the camshaft sprocket and timing chain off the engine, using a soft-faced hammer if necessary.

After ensuring the timing marks on both sprockets are properly aligned, check that a line drawn through the center of both sprockets passes through each mark.