Bendix Commercial Vehicle Systems TU-FLO 600 User Manual
®
Bendix® TU-FLO® 600 Air Compressor
SD-01-336
TU-FLO® 600 AIR COMPRESSOR VERTICAL MOUNT TU-FLO® 600 AIR COMPRESSOR FLANGE MOUNT
GENERAL
The function of the air compressor is to build up and maintain
the air pressure required to operate air powered devices in
air brake or air auxiliary systems.
DESCRIPTION
The Tu-Flo® 600 compressor is a two cylinder reciprocating
single stage compressor with a rated displacement of 14.5
cfm at 1250 rpm.
The Tu-Flo® 600 compressor is constructed with a crankcase,
block, and head assembly. The crankcase assemblies, in
particular , are essentially the same as corresponding Tu-Flo
500 compressors. The block assembly includes the air inlet
cavity , automatic inlet valves and unloader valves. V ertical
mounting pads for governor mounting are included at each
end of the block. The head assembly includes the discharge
valves with discharge ports either on the side or top of the
block.
All Tu-Flo® 600 compressors are liquid cooled, both head
and block, by coolant from the engine cooling system.
Various mounting and drive configurations are used as
required by different vehicle and engine designs. See Fig. 1.
All Tu-Flo® 600 compressors receive oil under pressure from
the engine lubricating system for the lubrication of the
internal parts. Fig. 2 shows a cross section of a typical
Tu-Flo® 600 compressor and the oil flow therein.
Oil is forced through the oil passage in the crankshaft to
each connecting rod journal. Oil is forced out at the journals
and is thrown by centrifugal force against the cylinder walls
and crankshaft main bearings, providing lubrication.
The wrist pins and wrist pin bushings are lubricated in two
®
ways depending on the type connecting rod used. Some
older compressors, and one current design use forged steel
rifle drilled rods, through which oil is forced to the wrist pin
bushings. Standard current design consists of a diecast
aluminum or forged steel rod with an “oil catch-funnel” at
the top of the rod and a short hole connecting to the wrist
pin bushing. See Fig. 3.
1
FIGURE 2 - TU-FLO® 600 AIR COMPRESSOR SECTIONAL
VIEW
FIGURE 1 - FLANGE CONFIGURATIONS
OLD DESIGN
WRIST
PIN
BUSHING
WRIST
PIN
OIL PASSAGE
FIGURE 3 - TU-FLO® 600 AIR COMPRESSOR PIST ON/PIN
DESIGN
CONNECTING
WRIST
PIN
BUSHING
PISTON WRIST
PIN LOCK WIRE
CAST IRON
PISTON
STEEL
ROD
NEW DESIGN
“CATCH FUNNEL”
TEFLON
PLUG
DIE
CAST
PISTON
DIE CAST
CONNECTING
ROD
NAME PLA TE
A name plate is attached to the crankcase of all
compressors. It shows the piece number, type and serial
number (Fig. 4). A name plate with a black background
denotes a new compressor, whereas a name plate with a
red background designates that the compressor is a factory
reconditioned unit. All compressors are identified by the piece
number which is the number to be used when reference is
made to a particular compressor . The type and serial number
is supplementary information.
2
DISCHARGE
VALVE
TO RESERVOIR
INLET VALVE
UNLOADER
PLUNGER
FIGURE 4
OPERATION
GENERAL
All compressors run continuously while the engine is
running, but actual compression of air is controlled by a
governor which stops or starts the compression of air by
loading or unloading the compressor in conjunction with its
unloading mechanism. This is done when the air pressure
in the system reaches the desired maximum or minimum
pressures.
TO RESERVOIR
INLET VALVE
DISCHARGE
VALVE
PISTON
UNLOADER
PLUNGER
INTAKE
STRAINER
PISTON
TO GOVERNOR
STROKE
FIGURE 6
INTAKE
STRAINER
COMPRESSION
NON-COMPRESSION (UNLOADED)
When the air pressure in the reservoir reaches the high
pressure setting of the governor, the governor opens,
allowing air to pass from the reservoir through the governor
and into the cavity beneath the unloader pistons. This lifts
the unloader pistons and plungers. The plungers move up
and hold the inlet valves off their seats (Fig. 7).
TO GOVERNOR
STROKE
INTAKE
FIGURE 5
INT AKE AND COMPRESSION (LOADED)
During the down stroke of the piston, a slight vacuum created
above the piston causes the inlet valve to move off its seat.
Atmospheric air is drawn in through the compressor intake,
by the open inlet valve, and on top of the piston (Fig. 5). As
the piston starts its upward stroke, the air that was drawn in
on the down stroke is being compressed. Now, air pressure
on top of the inlet valve plus the force of its spring, returns
the inlet valve to its seat. The piston continues the upward
stroke and compresses the air sufficiently to overcome the
discharge valve spring and unseat the discharge valve. The
compressed air then flows past the open discharge valve,
into the discharge line and on to the reservoirs (Fig. 6).
As the piston reaches the top of its stroke and starts down,
the discharge valve spring returns the discharge valve to its
seat. This prevents the compressed air in the discharge
line from returning to the cylinder bore as the intake and
compression cycle is repeated.
TO RESERVOIR
DISCHARGE
VALVE
PISTON
STROKE
FIGURE 7
INLET VALVE
UNLOADER
PLUNGER
INTAKE
STRAINER
TO GOVERNOR
UNLOADING
With the inlet valves held off their seats by the unloader
pistons and plungers, air is merely pumped back and forth
between the two cylinders. When air is used from the
reservoir and the pressure drops to low pressure setting of
the governor, the governor closes and in doing so exhaust s
the air from beneath the unloader pistons. The unloader
saddle spring forces the saddle, pistons and plungers down
and the inlet valves return to their seats. Compression is
then resumed.
3
Discharge
Line
Optional “Ping” T ank
Air Dryer
The Air Brake Charging System supplies the
compressed air for the braking system as well as other air
accessories for the vehicle. The system usually consists
of an air compressor, governor, discharge line, air dryer ,
and service reservoir.
Compressor
Governor
(Governor plus Synchro valve
for the Bendix
FIGURE 8A - SYSTEM DRAWING
®
DuraFlo™ 596
Compressor)
COMPRESSOR & THE AIR BRAKE SYSTEM
GENERAL
The compressor is part of the total air brake system, more
specifically, the charging portion of the air brake system. As
a component in the overall system its condition, duty cycle,
proper installation and operation will directly affect other
components in the system.
Powered by the vehicle engine, the air compressor builds
the air pressure for the air brake system. The air compressor
is typically cooled by the engine coolant system, lubricated
by the engine oil supply and has its inlet connected to the
engine induction system.
As the atmospheric air is compressed, all the water vapor
originally in the air is carried along into the air system, as
well as a small amount of the lubricating oil as vapor. If an
air dryer is not used to remove these contaminants prior to
entering the air system, the majority , but not all, will condense
in the reservoirs. The quantity of contaminants that reach
the air system depends on several factors including
installation, maintenance and contaminant handling devices
in the system. These contaminants must either be eliminated
prior to entering the air system or after they enter .
DUTY CYCLE
The duty cycle is the ratio of time the compressor spends
building air to the total engine running time. Air compressors
are designed to build air (run "loaded") up to 25% of the
time. Higher duty cycles cause conditions that affect air
brake charging system performance which may require
additional maintenance. Factors that add to the duty cycle
are: air suspension, additional air accessories, use of an
undersized compressor, frequent stops, excessive leakage
Optional Bendix® PuraGuard® QC
™
Oil Coalescing Filter
Service Reservoir
(Supply Reservoir)
Reservoir Drain
from fittings, connections, lines, chambers or valves, etc.
Refer to T able A in the Troubleshooting section for a guide to
various duty cycles and the consideration that must be given
to maintenance of other components.
COMPRESSOR INST ALLATION
While the original compressor installation is usually
completed by the vehicle manufacturer, conditions of
operation and maintenance may require additional
consideration. The following presents base guidelines.
DISCHARGE LINE
The discharge line allows the air, water-vapor and oil-vapor
mixture to cool between the compressor and air dryer or
reservoir. The typical size of a vehicle's discharge line, (see
column 2 of T able A in the Troubleshooting section) assumes
a compressor with a normal (less than 25%) duty cycle,
operating in a temperate climate. See Bendix and/or other
air dryer manufacturer guidelines as needed.
The discharge line must maintain a constant slope down
from the compressor to the air dryer inlet fitting or reservoir
to avoid low points where ice may form and block the flow . If,
instead, ice blockages occur at the air dryer or reservoir
inlet, insulation may be added here, or if the inlet fitting is a
typical 90 degree fitting, it may be changed to a straight or
45 degree fitting. Shorter discharge line lengths or insulation
may be required in cold climates.
While not all compressors and charging systems are
equipped with a discharge line safety valve this component
is recommended. The discharge line safety valve is installed
in the cylinder head or close to the compressor discharge
port and protects against over pressurizing the compressor
in the event of a discharge line freezeup.
4
THREAD
HOLE
FIGURE 8B - DISCHARGE LINE SAFETY VALVE
DISCHARGE LINE TEMPERA TURE
When the temperature of the compressed air that enters
the air dryer is within the normal range, the air dryer can
remove most of the charging system oil. If the temperature
of the compressed air is above the normal range, oil as oilvapor is able to pass through the air dryer and into the air
system. Larger diameter discharge lines and/or longer
discharge line lengths can help reduce the temperature.
The air dryer contains a filter that collects oil droplets, and a
desiccant bed that removes almost all of the remaining water
vapor. The compressed air is then passed to the air brake
service (supply) reservoir. The oil droplets and the water
collected are automatically purged when the governor
reaches its "cut-out" setting.
For vehicles with accessories that are sensitive to small
amounts of oil, we recommend installation of a Bendix
PuraGuard® QC™ oil coalescing filter, designed to minimize
the amount of oil present.
FIGURE 9 - SPONGE TYPE STRAINER
DRY ELEMENT - PLEATED PAPER AIR STRAINER
(FIG . 10)
Remove the spring clips from either side of mounting baffle
and remove the cover. Replace the pleated p aper filter and
remount the cleaned cover making sure the filter is in
position. Be sure to replace the air strainer gasket if the
entire air strainer is removed from the compressor intake.
NOTE: Some compressors are fitted with compressor intake
adapters (Fig. 1 1) which allow the compressor intake to be
connected to the engine air cleaner.
In this case, the compressor receives a supply of clean air
from the engine air cleaner. When the engine air filter is
changed, the compressor intake adapter should be checked.
If it is loose, remove the intake adapter , clean the strainer
plate, if applicable, and replace the intake adapter gasket,
and reinstall the adapter securely . Check line connections
®
both at the compressor intake adapter and at the engine air
cleaner. Inspect the connecting line for ruptures and replace
it if necessary .
AIR CLEANER MAINTENANCE
POL YURETHANE SPONGE STRAINER (FIG . 9)
Remove and wash all of the parts. The strainer element
should be cleaned or replaced. If the element is cleaned, it
should be washed in a commercial solvent or a detergent
and water solution. The element should be saturated in clean
engine oil then squeezed dry before replacing it in the strainer.
Be sure to replace the air strainer gasket if the entire air
strainer is removed from the compressor intake.
FIGURE 10 - DRY ELEMENT STRAINER
5
Always use a new mounting gasket and be sure oil hole in
gasket and compressor is properly aligned with oil supply
line.
Inspect pulley or gear and associated parts for wear or
damage. They must be a neat fit on compressor crankshaft.
Replace pulley or gear if worn or damaged.
FIGURE 11 - INLET ADAPTER
AIR LEAKAGE TESTS
Leakage past the discharge valves can be detected by
removing the discharge line, applying shop air back through
the discharge port and listening for escaping air. Also, the
discharge valves and the unloader pistons can be checked
for leakage by building up the air system until the governor
cuts out, then stopping the engine. With the engine stopped,
carefully listen for escaping air at the intake. To pin-point
leakage if noted, squirt oil around the unloader pistons. If
there is no noticeable leakage at the unloader pistons, the
discharge valves may be leaking.
If the compressor does not function as described above, or
leakage is excessive, it is recommended that it be returned
to the nearest Bendix authorized distributor for a factory
rebuilt compressor under the repair exchange plan. If this is
not possible, the compressor can be repaired with genuine
Bendix parts in which case the following information should
prove helpful.
REMOVING AND INSTALLING
REMOVING
These instructions are general and in some cases additional
precautions must be taken.
Drain air brake system.
Drain engine cooling system, compressor cylinder head and
block.
Disconnect all air lines, water and oil lines to and from
compressor.
Remove compressor mounting bolts and compressor from
engine.
Use a gear-puller to remove the gear or pulley from
compressor crankshaft.
INST ALLATION
Clean oil supply line. Before connecting this line to the
compressor run the engine briefly to be sure oil is flowing
freely through the supply line.
Clean the oil return line or return passages through the
brackets; these passages must be unrestricted so oil can
return to the engine.
Prelubricate compressor cylinder walls, piston rings, and
bearings with clean engine oil before assembling compressor.
Install pulley or gear on compressor crankshaft making sure
it properly contacts the shaft and does not ride the key.
Tighten crankshaft nut to 65-70 f t. lbs. and install cotter pin.
Be sure the air cleaner is clean and properly installed. If the
compressor intake is connected to either the engine air
cleaner or supercharger, these connections must be tight
with no leakage.
Clean or replace any damaged or dirty air or water lines
which may be corroded, before connecting them to the
compressor. Use a new discharge fitting gasket.
Align compressor drive and adjust proper belt tension.
Tighten mounting bolts securely and evenly .
After installation run compressor and check for air, oil, or
water leaks at compressor connections. Also, check for
noisy operation.
DISASSEMBLY
GENERAL
Clean compressor exterior of road dirt and grease using a
good cleaning solvent. Before compressor is completely
disassembled the following items should be marked to show
their relationship when the compressor is assembled:
The cylinder block in relation to crankcase, end covers’
relation to crankcase, position of crankshaft in relation to
crankcase, the cylinder head’s relation to the block.
A convenient method to indicate the above relationships is
to use a metal scribe to mark the parts with numbers or
lines. Do not use a marking method that can be wiped off
or obliterated during rebuilding, such as chalk. Remove all
compressor attachments such as governors, air strainers
or inlet fittings, discharge fittings and pipe plugs.
CYLINDER HEAD
Remove the cylinder head cap screws and tap the head
with a soft mallet to break the gasket seal. Remove the inlet
valve springs from the head and inlet valves from their guides
in the block. Remove inlet valve guides from around the
inlet valve seats on the block taking care not to damage
seats. Scrape off any gasket material from the cylinder
head and block. Unscrew the discharge cap nuts from the
head and remove the discharge valves and springs. Inspect
the discharge valve seats for nicks, cracks, and excessive
wear and remove and replace if necessary .
6
The discharge valve cap nuts should be inspected for wear
and replaced if excessive peening has occurred. To
determine if excessive peening has occurred, measure the
discharge valve travel. Discharge valve travel must not
exceed .046 inches (1.168 mm).
If the pistons are removed from the rod, inspect the bronze
wrist pin bushing. Press out and replace the bushing if it is
excessively worn. (See inspection of parts.) Discard the
piston rings and the connecting rod journal bearings. Discard
the wrist pin bushings if they were removed (Fig. 13).
CRANKCASE BASE PLA TE OR ADAPTER
Remove the cap screws securing the base plate or base
adapter. T ap with soft mallet to break the gasket seal. Scrape
off any gasket material from crankcase and plate or adapter .
CONNECTION ROD ASSEMBLIES
NOTE: Before removing the connecting rods, mark each
connecting rod and its cap. Each connecting rod is
matched to its own cap for proper bearing fit, and
these parts must not be interchanged.
Straighten the prongs of the connecting rod bolt lock strap
and remove the bolts and bearing caps. Push the piston
with the connecting rods attached out the top of the cylinder
block. Replace the bearing caps on their respective
connecting rods. Remove the piston rings from the pistons.
If the pistons are to be removed from the connecting rods,
remove the wrist pin lock wires and press the wrist pins
from the pistons and connecting rods. If the wrist pins have
teflon plugs, remove plugs, then press out the wrist pins.
CRANKCASE (FIG . 14)
Remove end cover with oil seal, remove end cover gasket.
Replace oil seal after cleaning end cover .
Remove cap screws that hold opposite end cover to
crankcase; remove end cover and its gasket. Some
compressors have crankcases that have a shoulder for
positioning the crankshaft. In these cases, the crankshaft
must be removed through one particular end.
Press the crankshaft and ball bearings from the crankcase
then press ball bearings from crankshaft. Many compressors
will have sleeve type bearings in the crankcase or in the
end cover. If the clearance between crankshaf t journal and
bearing exceeds .0065 in. (.165 mm) the sleeve bearing
should be replaced with appropriate undersize.
BLOCK (FIG . 15)
If compressor is fitted with an air strainer, inlet elbow or
governor, remove same.
Remove cap screws securing cylinder block to crankcase;
separate crankcase and cylinder block and scrape off gasket.
Remove unloader spring, spring saddle and spring seat from
cylinder block (Fig. 15).
Remove unloader guides and plungers and with the use of
shop air blow unloader pistons out of cylinder block unloader
piston bores.
Remove inlet valve guides; inlet valve seats can be removed,
but only if they are worn or damaged and are being
replaced. Unloader bore bushings should be inspected but
not removed unless they are damaged.
PREVENTATIVE MAINTENANCE
Regularly scheduled maintenance is the single most
important factor in maintaining the air brake charging system.
Refer to T able A in the Troubleshooting section for a guide to
various considerations that must be given to the maintenance
of the compressor and other related charging system
components.
CLEANING AND INSPECTION OF PARTS
CLEANING
All parts should be cleaned thoroughly in mineral spirits
before inspection.
FIGURE 12 - TU-FLO® 600 AIR COMPRESSOR CYLINDER
HEAD
7
FIGURE 13 - TU-FLO® 600 AIR COMPRESSOR CYLINDER BLOCK ASSEMBLY
FIGURE 14 - TU-FLO® 600 AIR COMPRESSOR CRANK CASE ASSEMBL Y
8
CYLINDER HEAD ASSEMBL Y
Remove all carbon deposits from discharge cavities and all
rust and scale from cooling cavities of cylinder head body .
Scrape all foreign matter from body surfaces and use air
pressure to blow dirt particles from all cavities.
Discharge valves can be dressed by lapping them on a
piece of fine crocus cloth on a flat surface, provided they
are not excessively worn.
CYLINDER BLOCK
Clean carbon and dirt from inlet and unloader passages.
Use air pressure to blow carbon and dirt deposits from
unloader passages.
Inlet valves, as in the case of discharge valves, not worn
excessively can be cleaned by lapping them on a piece of
fine crocus cloth on a flat surface.
LUBRICATION
Check the exterior of the compressor for the presence of oil
seepage and refer to the TROUBLESHOOTING section for
appropriate tests and corrective action.
OIL P ASSING
FIGURE 15 - TU-FLO® 600 AIR COMPRESSOR BLOCK ASSY
INSPECTION OF PARTS
CYLINDER HEAD BODY
All reciprocating compressors currently manufactured will
pass a minimal amount of oil. Air dryers will remove the
majority of oil prior to entrance into the air brake system.
For particularly oil sensitive systems the Bendix® PuraGuard
QC™ oil coalescing filter can be used in conjunction with a
Bendix air dryer.
If compressor oil passing is suspected, refer to the
TROUBLESHOOTING section and TABLE A for the
symptoms and corrective action to be taken. In addition,
Bendix has developed the "Bendix Air System Inspection
Cup" or BASIC test to help substantiate suspected excessive
oil passing. The steps to be followed when using the BASIC
test are presented in APPENDIX A at the end of the
TROUBLESHOOTING section.
OIL P ASSAGE
Clean thoroughly all oil passages through crankshaft,
connecting rods, crankcase, end covers and base plate. If
necessary , inspect p assages with a wire and blow foreign
matter out with air pressure.
Inspect cylinder head body for cracks or damage.
WATER-COOLED TYPE
®
Use air pressure to test water jackets of cylinder head and
block for leakage. Replace unit if leakage is found.
DISCHARGE V AL VES AND SEA TS
If discharge valves are worn and grooved where they contact
the seats, they should be replaced. If the discharge valve
seats are worn excessively so that there is no longer enough
metal left to reclaim them by lapping, the seats should be
replaced.
DISCHARGE VA LVE SPRING AND CAP NUTS
Replace all used discharge valve springs and cap nuts if
cap nuts cannot be reclaimed.
CRANKCASE AND END COVERS
Check for cracks or broken lugs in crankcase and end
covers. Also, check oil passages to make sure they are
open and clean.
If an oil seal ring is used in the end cover, check fit of ring in
ring groove. There should be .008 in. (.203 mm) to .015 in.
(.381 mm) clearance at the gap when placed in the end bore
of the crankshaft. If the oil ring is worn thin or is damaged, it
should be replaced. Inspect oil ring groove in end cover; if
groove is worn excessively , replace end cover or machine
groove for next oversize oil seal ring. If the crankshaft main
bearings are installed in the end cover, check for excessive
wear and flat spots; replace if necessary .
9
CYLINDER BLOCK
Check for cracks or broken lugs on cylinder block. Also
check unloader bore bushings to be sure they are not worn,
rusted or damaged. If these bushings are to be replaced,
they can be removed by running a 1/8 in. pipe thread tap
inside the bushing, then inserting a 1/8 in. pipe threaded
rod and pulling the bushing straight up and out. Do not use
an easy-out for removing these bushings.
INLET V AL VES AND SEA TS
If inlet valves are grooved or worn where they contact the
seat, they should be replaced. If the inlet valve seats are
worn or damaged so they cannot be reclaimed by facing,
they should be replaced.
CYLINDER BORES
5 Ring Wrist Ring *Piston Pin
Size Piston Pin Set Maint. Kit
Standard 292529 292530 282525 289891
.010”
Oversize 292547 292530 282526 289892
.020”
Oversize 292548 292530 282527 289893
.030”
Oversize 292549 292530 282528 289894
* Includes 1 piston, 1 wrist pin, and 2 pin buttons.
FIGURE 17
Cylinder bores which are scored or out of round by more
than .002 in. (.051 mm) or tapered more than .003 in. (.076
mm) should be rebored or honed oversize. Oversize pistons
are available in .010 in., .020 in., and .030 in. oversizes (Fig.
16).
Cylinder bores must be smooth, straight, and round.
Clearance between cast iron pistons and cylinder bores
should be between .002 in. (.051 mm) minimum and .004
in. (.102 mm) maximum (Fig. 16).
If the compressor has five ring pistons which are to be reused,
they should be checked for scores, cracks or enlarged ring
grooves; replace pistons if any of these conditions are found.
Measure each piston with a micrometer in relation to the
cylinder bore diameter to be sure the clearance is between
.002 in. (.051 mm) minimum and .004 in. (.102 mm)
maximum.
Check fit of wrist pins in pistons. Wrist pin clearance should
be from .0000 in. to .0006 in. (.015 mm). Check fit of wrist
pin in connecting rod bushing. This clearance should not
exceed .0007 in. (.018 mm). Replace wrist pin bushings if
excessive clearance is found. Wrist pin bushings should be
reamed after being pressed into connecting rods. Replace
used wrist pin lock wires. Compressors manufactured after
December, 1977, will have Teflon plugs in each end of the
wrist pins instead of the lockwire. The Teflon plugs (piece
number 292392) may be used instead of the lockwires on
all compressors (see Fig. 3).
PISTON RINGS
Check fit of piston rings in piston ring grooves. Check ring
gap with rings installed in cylinder bores. Refer to Fig. 18 for
correct gap and groove clearance.
FIGURE 16 - CHECKING CYLINDER BORE
PISTONS
Any of three different piston designs may be found in Tu-Flo
600 compressors as follows: three ring cast iron, three ring
aluminum or five ring cast iron. If either of the three ring
designs are found, it is recommended that the unit be updated
to the current five ring design. Piece numbers of five ring
piston, wrist pin maintenance kits and piston ring sets are
shown in Fig. 17.
10
All rings must be located in their proper ring grooves as
shown. The rings can be identified by the width and should
be installed with the bevel or the pip mark (if any) toward the
top of the piston as shown.
®
®
500 & 600 AIR COMPRESSOR
TU-FLO
CORRECT GROOVE
CLEARANCE
WIDE RING
NARROW
RING
.0035”
.0015”
.002”
.004”
NARROW
WIDE
INCHES
MM
.038.0015
.051.002
REPAIRS
DISCHARGE V AL VES AND SEA TS
If discharge valve seats merely show signs of slight wear,
they can be dressed by using a lapping stone, grinding
compound and grinding tool. Install new valve springs and
re-dressed or new discharge valves.
CORRECT GAP
CLEARANCE WITH
RING IN CYLINDER
.0035
.015
FIGURE 18 - PISTON RING POSITIONS GAPS & GROOVE
CLEARANCE
NARROW
WIDE
.089.0035
.102.004
.381.015
CRANKSHAFT
Check crankshaft screw threads, keyways, tapered ends
and all machined and ground surfaces for wear, scores, or
damage. Crankshaft journals which are out of round more
than .001 in. (.025 mm) must be reground. Bearing inserts
are available in .010 in. (.254 mm), .020 in. (.508 mm), and
.030 in. (.762 mm) undersizes for reground crankshafts.
Main bearing journals must be maintained so bearings are
snug fit. The oil seal ring groove or grooves in crankshafts
fitted with oil seal rings must not be worn. The ring groove
walls must have a good finish and they must be square.
Check to be sure the oil passages are open and clean
through the crankshaft.
CONNECTING ROD BEARINGS
Check connecting rod bearings on crankshaft journals for
proper fit. Used bearing inserts should be replaced.
Connecting rod caps are not interchangeable. The locking
slots of the connecting rod and cap should be positioned
adjacent to each other.
Clearance between the connecting rod journal and the
connecting rod bearing must not be less than .0003 in. (.008
mm) or more than .0021 in. (.053 mm) after rebuilding.
MAIN BEARINGS
Check for wear or flat spots; if found, bearings should be
replaced. If type with sleeve bearing, this bearing should
be checked for scores and wear and replaced if necessary .
UNLOADER MECHANISM
Used unloader mechanism should be replaced by unloader
kits (piece number 279615).
To test for leakage past the discharge valves, apply about
100 pounds of air pressure through the cylinder head
discharge port and apply soap suds at the discharge valves
and seats. Leakage which will permit the formation of bubbles
is permissible.
If excessive leakage is found, leave the air pressure applied,
and with the use of a fibre or hardwood dowel and hammer,
tap the discharge valves off their seats several times. This
will help the valves to seat and should reduce any leakage.
With the air pressure still applied at the discharge port of
the cylinder head, check for leakage at the discharge valve
cap nuts. No leakage is permissible.
INLET V AL VES AND SEA TS
If inlet valve seats show sign of slight nicks or scratches,
they can be redressed with a fine piece of emery cloth or
by lapping with a lapping stone, grinding compound and
grinding tool. If the seats are excessively damaged to the
extent that they cannot be reclaimed, they should be
replaced. The dimension from the top of the cylinder block
to the inlet valve seat should not exceed .1 13 in. (2.870 mm)
not be less than .101 in. (2.565 mm).
Slightly worn or scratched inlet valves can be reclaimed by
lapping them on a piece of fine crocus cloth on a flat surface,
but it is suggested that new inlet valves be installed.
ASSEMBLY
INST ALLING CYLINDER BLOCK
Position cylinder block gasket and block on crankcase
according to markings made prior to disassembly. Using
cap screws with lockwashers, secure cylinder block to
crankcase at 220 to 250 inch pounds.
INST ALLING CRANKSHAFT
If the crankshaft is fitted with oil seal rings, install rings.
Position ball bearings and crankshaft in crankcase making
sure the drive end of the crankshaft is positioned as marked
before disassembly .
If one end of the crankcase is counterbored for holding a
bearing, be sure the crankshaft is installed through the
correct end of the crankcase.
The new unloader pistons should be a loose sliding fit in the
unloader piston bores of the cylinder block.
Carefully press crankshaft and bearings into crankcase
using arbor press.
11
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