Caution: When turning the crankshaft, do not use the camshaft sprocket mounting bolt, and do not turn the engine in the opposite direction, i.e. counterclockwise.
1. Top dead center (TDC) is the highest position the piston reaches in the cylinder during its reciprocating motion as the crankshaft rotates. Each piston reaches TDC at the end of the compression stroke and after the end of the exhaust stroke, but TDC is usually related to the piston position on the compression stroke. Piston No.1 is the outermost on the camshaft drive chain side.
2. Setting piston No.1 to the TDC position is an essential part of many operations: such as removing the camshaft drive chain and removing the camshaft itself.
3. Remove the camshaft cover as described in paragraph 4.
4. Using a suitable socket wrench, tighten the pulley/damper mounting bolt to the hub (on some models, you will need to remove the fan shroud and impeller to access it) rotate the crankshaft clockwise until the indicated marks are aligned (see fig 3.4 a, b).
- a) The TDC mark on the crankshaft drive sprocket is aligned with the pointer on the camshaft drive chain cover.
- b) The TDC mark on the front flange of the camshaft is aligned with the lug on the front bearing cover of the camshaft.
Fig. 3.4a The TDC mark on the crankshaft drive sprocket is aligned with the indicator on the camshaft drive chain cover.
Fig. 3.4b The TDC mark on the front flange of the camshaft is aligned with the lug on the front bearing cover of the camshaft.
5. When the marks are aligned as described in step 4, piston No.1 is at TDC before the ignition stroke. If the timing chain is removed, do not rotate the camshaft and crankshaft until the chain is reinstalled.