Cylinder Block; Cylinder Head; Crankshaft - Jeep cherokee 2000 Service Manual

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DESCRIPTION AND OPERATION (Continued)

CYLINDER BLOCK

DESCRIPTION
The cylinder block is a cast iron inline six cylinder
design. The cylinder block is drilled forming galleries
for both oil and coolant (Fig. 3).
Fig. 3 4.0L Cylinder Block with Main Bearing Caps
and Cap Brace
1 – BLOCK
2 – MAIN BEARING CAP BRACE

CYLINDER HEAD

DESCRIPTION
The cylinder head is made of cast iron containing
twelve valves made of chrome plated heat resistant
steel, valve stem seals, springs, retainers and keep-
ers. The cylinder head and valve seats can be resur-
faced for service purposes.
The valve guides are integral to the cylinder head,
They are not replaceable. However, they are service-
able.
The cylinder head uses dual quench-type design
combustion chambers which cause turbulence in the
cylinders allowing faster burning of the air/fuel mix-
ture, resulting in better fuel economy (Fig. 4).
Fig. 4 Cylinder Head 4.0L Engine
1 – CYLINDER HEAD BOLTS
2 – CYLINDER HEAD GASKET
3 – CYLINDER HEAD

CRANKSHAFT

DESCRIPTION
The crankshaft is constructed of nodular cast iron.
The crankshaft is a crosshaped four throw design
with eight counterweights for balancing purposes.
The crankshaft is supported by seven select main
bearings with the number three serving as the thrust
washer location. The main journals of the crankshaft
are cross drilled to improve rod bearing lubrication.
The select fit main bearing markings are located on
the crankshaft counter weights. The crankshaft rear
oil seal is a two piece design. The front oil seal is a
one piece design retained in the timing chain cover
(Fig. 5).
Fig. 5 Crankshaft with Select Fit Marking Location
1 – 1/4" LETTERS
2 – (ROD)
3 – (MAIN)
4.0L ENGINE 9 - 65