There have been a number
By David A. Kolman,
Contributing Editor
36 Fleet Maintenance | November/December 2017
of important updates
and changes that could
significantly impact
parts selection and service
procedures when
servicing Cummins ISX15
engines – Cummins’
most popular heavy
duty engine, says Steve
Scott, director, technical
support, Industrial
Parts Depot (IPD). These
changes warrant attention,
whether repairing
an engine or performing
a complete overhaul.
IPD (www.ipdparts.com)
manufactures and distributes
a broad range
of replacement parts for
Caterpillar, Cummins,
Detroit Diesel, Volvo and
Waukesha series engines.
There have been five different
changes to the cylinder
liner design, he notes.
“It’s very important that
purchasing and service personnel
are aware of the differences
in engine designs
and installation procedures
when they are servicing ISX
engines – or severe problems
can occur. Potential
problems include excessive
engine parts wear, premature
failures, avoidable
downtime and even catastrophic
engine damage.”
Scott offers five tips that
can help fleets and engine
rebuilders service Cummins
ISX15 engines more accurately
and efficiently, and
in some cases with added
savings of time and costs.
1. CHOOSE
UPDATED
CRITICAL PARTS
Because cylinder kits are
the heart of the Cummins
ISX series engine overhauls,
it is important to use
cylinder kits that reflect
the latest design updates.
“Unfortunately,” observes
IPD’s Scott, not all parts
suppliers are in a position
to keep up with the latest
OE design changes.”
2. USE THE
SPECIAL
PISTON
INSTALLATION
TOOL
Cummins ISX15 cylinder
liners feature a removable
APR (anti-polishing ring) that
overhangs the liner bore.
Its purpose is to remove
carbon deposits from the
upper portion of the piston.
The special piston installation
tool helps prevent
bore polishing – surface
wear that damages the liner
surface – of the liner walls,
a situation that can result
in a significant increase
in oil consumption.
To use the tool, remove the
APR from the liner, insert
the tool and complete
the piston installation,
Scott explains. The tool
prevents the piston rings
from expanding into the
APR groove, thus providing
a smooth transition of the
piston into the cylinder liner.
3. PROTECT OIL
PORTS AND
PASSAGES FROM
PARTICULATES
Replacement of gaskets is
an integral part of every
in-frame or out-of-frame
engine overhaul. When it
comes to servicing ISX series
engines, complete gasket
sets should also contain
a number of small plugs
that are used to protect
the oil ports of the cylinder
head, as well as the cylinder
block from dirt or other
debris, says IPD’s Scott.
The use of these plugs
is important, he notes,
because “most bearing manufacturers
report that the
presence of dirt or foreign
objects in oil passages is
a leading cause of bearing
failure. There is also the
danger of debris entering
the cylinder head ports and
interfering with the camshaft
and upper bushings.”
4. CHOOSE THE
CORRECT STYLE
OF CONNECTING
ROD BEARINGS
Scott points out Cummins
ISX series engines use three
different styles of connecting
rods, making it critical to
match the connecting rod
with the correct bearings
when replacing these parts.
The early engines use nondrilled
rods which do not
have an oil passage running
through the connecting
rod. Later engines use two
types of drilled rods: a sawcut
type and a fractured
type. These terms refer to
the surfaces between the
connecting rod and rod cap.
The saw-cut connecting rod
bearings are composed of
an upper and lower bearing
shell. The shells are marked
according to their proper
locations and feature tabs
that are slightly offset.
“This bearing shell design
does leave room for installation
errors,” he says. “In
fact, it is possible to install
them incorrectly and still
be able to bolt the rod
onto the crankshaft. If this
happens, the rod will not
get the needed oil supply
and the engine will fail.”
The fractured type of rods
also requires upper and
lower bearing shells, but
due to the design, cannot be
installed incorrectly, he says.
5. PRESS-IN TYPE
CAMSHAFT
BUSHINGS
On earlier ISX dual cam
engines, the injector camshafts
are massive compared
to the valve camshaft,
with a journal diameter
of 85 mm (3.346 in.) and
weight of nearly 65lbs, says
Scott of IPD. While it may be
a common practice to drive
the camshaft bushings in for
other engines, installation
instructions specify that the
cam bushings (injector and
valve) need to be pressed
in rather than driven in and
also be pre-lubricated.
“According to several cylinder
head rebuilders, due
to the size and amount of
retention – crush – holding
the injector camshaft
bearings in place, the
bushings cannot be driven
in without distorting or
otherwise damaging them,
which can lead to bushing
failure when the engine is
put into service,” he says.
“Considering the load that
is placed on the injector
camshaft bushings, the
timing for pressurized lube
oil to reach the bushings –
via the large oil port inside
the camshaft – is critical.”
In summary, Scott says, it
is important to review and
understand manufacturer
updates and changes in
order to select the correct
parts for the specific
application, and to follow
current procedures.
How To Avoid Potential Problems
When Servicing Cummins ISX15 Engines
» Service personnel need
to be aware of the number
of cylinder liner design
changes to Cummins
ISX15 engines as to avoid
potential problems when
servicing these engines.
Photo courtesy of IPD
VehicleServicePros.com/20977932
/www.ipdparts.com
/20977932
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