24 Valve Cummins Turbo Diesel
Improvements and design changes that set
it apart from the 12 Valve series
Page 3 - Cylinder Head And Valve Train
Source: Chrysler Master Tech Issue 2 Reference Book -
dated February 1998
CYLINDER HEAD AND VALVE
- A one piece cylinder head (valve) cover (Fig 9) replaces the six individual
covers previously used. The reusable one-piece gasket
(Fig 10) is easier to service, and the gasket is noise-isolated to
reduce engine noise. The gasket and cover are not interchangeable
with the set used on 12 valve engines.
All cylinder head bolts are the same length instead of the 3 different
lengths used earlier. The uniform bolts make service easier and provide
more uniform head clamping.
The cylinder head gasket is a new design and configuration that improves
The exhaust ports (Fig 11) are reshaped to improve combustion efficiency.
The cylinder head now uses two intake and two exhaust valves per cylinder
(Fig 12) - hence the 24 valve designation commonly used. These valves
are smaller than the valves used in 12 valve engines. The new valves
can be identified by the dimple in the center of the valve face (Fig 13).
A new rocker arm design allows removal of fuel injectors without disturbing
valve lash. The crosshead (Fig 14) enables one rocker arm to actuate two
valves at the same time. The crosshead socket acts as a pivot to allow
the crosshead to operate the valves.
- Wider camshaft lobes and tappet faces as well as longer
pushrods reduce valvetrain wear and stress. The fuel lift pump is electric
and the camshaft has no fuel pump lobe.
- A camshaft position sensor, which senses when cylinder
no. 1 is a TDC, is mounted in the the former TDC pin location (Fig 15).
There is also a TDC indication stamped on the outside of the gear housing
A new thermostat is vertically mounted in a housing that is integral to
the 24 valve cylinder head.
||Fuel System - Injectors,
Inj Pump, Pump Drive
Last Update January 2, 1999