Timing the Cam to the Crank
There are several ways to time the cam to the crank. Be sure to check the manual before you install the timing chain or belt.
If the old parts are available, carefully compare the new gears or sprockets with the old ones. Check the keyway and timing marks just in case there might have been an error made in manufacturing. Sprockets are sometimes stamped backward. Its much better to find the problem during assembly, rather than waiting until problems show up after reassembly and reinstallation.
Maintaining Valve Timing
During a valve job, it is essential to keep the timing chain or belt in place to maintain correct valve timing. Position the number one cylinder at TDC. Some overhead cam engines use a single long chain for a cam drive. The chain can be wedged against its guides with a tapered block of wood.
the chain tensioner on some ohc engines must be wedged to keep the chain in position during cylinder head removal. courtesy of nissan motors.
Some engines have a lower and upper chain. These engines do not require special attention to wedging the chain. Be sure to look for hidden head bolts and check the repair manual before removing the OHC head.
Install a retaining clip on the tensioner to hold plunger IN during installation.
marking timing chain
Position the crankshaft using the special tool. Then remove the tool.
Crankshaft special tool positioning
Install the crankshaft sprocket with flange facing forward.
Crankshaft sprocket timing mark
Position the left timing chain on the camshaft sprocket. The timing mark on the camshaft sprocket must be aligned between the 2 copper (or marked) chain links.
Left camshaft sprocket timing mark
Position lower end of right (outer) timing chain on the crankshaft sprocket. Align the copper (or marked) chain link with the timing mark on the outer flange of the crankshaft pulley.
Right camshaft sprocket timing mark
Align the chalk mark on the balance shaft with the camshaft timing mark.
Balance shaft bearing caps
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