Cylinder Head - Mercedes-Benz OM 651 Service Manual

General
The cylinder head is made of high-strength aluminum.
It is equipped with two camshafts and four valves per
cylinder. The cylinder head cover is made of plastic
with integrated ventilation. The cylinder head is char-
acterized by the following new features:
• Maximum ignition pressure of 200 bar (previously
160 bar)
• Tangential and spiral intake ports
• Bore for piezo injector of 19 mm diameter
The upper duct of the two-piece water jacket supplies
the cylinder head with coolant. The advantages of the
two-piece water jacket include:
• Greater structural rigidity
• Better heat dissipation
• Improved thermal management
Cross-section of cylinder head
1 Ventilation
2 Main bearing bridge
3 Cylinder head cover
– This printout will not be recorded by the update service. Status: 09 / 2008 –
The improved thermal management system is particu-
larly beneficial in those areas which are exposed to
very high temperatures. The high ignition pressure of
200 bar is only made possible by targeted cooling of
the individual components. The increased pressure
potential and optimized injection quantity are respon-
sible for the high engine torque of 500 Nm and the
engine output of 150 kW.
4 Glow plug
5 Exhaust valve
6 Piezo injector
Introduction of New Generation of 4-Cylinder Inline Engines, OM 651

Cylinder head

7 Intake valve
8 Valve spring
9 Valve clearance compensation
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