New Holland 40 Series Repair Manual page 19

PART1
ENGINE SYSTEMS
Chapter 1
DIESEL ENGINES
Section
A
DESCRIPTION AND OPERATION
Page
1
B
FAULT FINDING
4
C
D
E
DISASSEMBLY AND OVERHAUL
COMPRESSION TEST
SPECIFICATIONS
8
37
38
48 F SPECIAL TOOLS
A.
DIESEL ENGINE - DESCRIPTION AND OPERATION
MODEL
5640 6640
No of Cylinders 4 4
BORE (ins.) 4.4 4.4
(mm) 111.8 111.8
STROKE (ins.) 4.4
5.0
(mm). 111.8 127.0
DISPLACEMENT (cu. in.) 268 304
(cu. cm.) 4393 4983
(T)
=
Turbocharger
This chapter describes the overhaul and re-
pair of the new series, direct injection diesel
engines.
These engines are available in 4 or 6 cylinder
naturally aspirated forms, with the 4 cylinder
also being available in turbocharged form.
As these engines are of similar design and
service procedures are common throughout
the range. The 4 cylinder engines have a de-
sign difference in that they are fitted with a dy-
namic balancer assembly.
All engines feature cross flow cylinder heads,
with the inlet and exhaust manifolds on oppo-
site sides of the cylinder head. The fuel and
air combustion process, takes place in the
specially designed bowl in the crown of the
pistons.
CYLINDER HEAD ASSEMBLY
The cylinder head incorporates valves and
springs with the valve rocker arm shaft as-
sembly bolted to the cylinder block through
the cylinder head. Cylinder head retaining
bolts are evenly spaced with a six point pat-
tern around each cylinder, this ensures an
even clamping load across the cylinder head
area.
The intake and exhaust manifolds are bolted
to the head. The intake manifold is mounted
1
7740 (T) 7840 8240 8340
4
6 6 6
4.4 4.4 4.4 4.4
111.8 111.8 111.8 111.8
5.0
4.4
5.0 5.0
127.0 111.8 127.0 127.0
304 401 456 456
4983
6570
7472 7472
on the right hand side of the engine
with
the
diesel injectors mounted outside the rocker
cover. The exhaust manifold is mounted on
the left hand side of the engine, water outlet
connections and thermostat being attached
to the front of the cylinder block directly be-
hind the radiator.
Valve guides are integral in the cylinder head
and valves with oversize stems are available
in service. Special replaceable cast alloy
valve seats are pressed into each valve port
during manufacture, with oversize valve
seats also available in service.
All valves are fitted with positive valve rota-
tors, with both Intake and exhaust valves us-
ing umbrella type oil seals. Valve lash is main-
tained by adjustment of the self locking ad-
justing screw, mounted in each of the rocker
arms.
CAMSHAFT ASSEMBLY
The camshaft runs in replaceable bearings,
with 3 fitted in the 4 cylinder and 5 fitted in the
6 cylinder. The camshaft drive gear is in mesh
with, and driven by the camshaft idler gear
and crankshaft timing gear.
Camshaft end thrust is controlled by a thrust
plate bolted to the block and located between
the camshaft gear and the front camshaft
journal.
A helical gear is mounted on the rear of the
camshaft and drives the engine oil lubrication
pump mounted forward of the flywheel.