Description And Operation
The crankshaft drives the overhead camshafts through a chain. The timing chain is located under a cover on the accessory drive belt side of the engine.
The timing system cover is fastened to the engine block, cylinder head and oil pan.
There is sealant applied between the timing cover and the engine to ensure an oil-tight seal.
The crankshaft vibration damper (1) is located on the crankshaft with a key (3). There is an oil seal (2) to seal the oil in the space between the crankshaft vibration damper and the timing system cover.
Fixing the position of the crankshaft vibration damper to the crankshaft, allows a reference mark to be placed on the timing system cover, which indicates when the crankshaft is in the position that corresponds to the 1st and 4th cylinders being at Top Dead Center (TDC).
The crankshaft sprocket is a single component that drives both the cam chain and the oil pump chain. It is located on the crankshaft with a key (3). The smaller of the two sprockets (2) is dedicated to the cam timing and the larger sprocket (1) drives the oil pump and the balance shafts.
This is the layout of the oil pump drive chain routing between the sprockets for the oil pump and the balance shaft on the right side of the engine.
The crankshaft, oil pump and balance shafts must be timed relative to each other. This is accomplished with markings on the sprockets and colored chain links.
The mark on the crankshaft sprocket and the colored chain links must be aligned with the crankshaft in the timing position (1st and 4th cylinders at TDC).
The mark on the right balance shaft sprocket and the colored chain link must also be aligned with the crankshaft at TDC.
The marks on the oil pump, oil pump sprocket and the colored chain link must also be aligned with the crankshaft at TDC.
The major components of the balance shafts (right and left) inside the crankcase are:
- Right balance shaft
- Roller bearings with external races
- Left balance shaft
- Roller bearings with external races
The left balance shaft is driven by a gear fixed to the oil pump shaft (1). The oil pump shaft is driven by the crankshaft through the oil pump drive chain and the oil pump sprocket (2).
The balance shaft can rotate with respect to the bracket that anchors it to the engine block. To align the balance shaft, the hole (2) on the balance shaft must be aligned with the corresponding hole on the anchoring bracket (1), using a dedicated tool.
The crankshaft and camshafts must be timed relative to each other. This is accomplished with markings on the sprockets and colored chain links.
The mark on the crankshaft sprocket (3) and the colored chain links (2) must be aligned with the crankshaft in the timing position (1st and 4th cylinders at TDC).