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Thornycroft 90 And 108 Workshop Manual



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                              MARINE ENGINES

The Thornycroft 90 and 108 engines are both 4 cylinder, 4 stroke naturally
aspirated high speed diesel units, both engines having electrically operated heater
plugs to aid cold starting.

The cast iro n crankcase with ri bbed sidewalls houses a forged steel, fully
counterbalanced crankshaft carried in three or five bearings respectively.

A full press ure wet sump lubric ation system is emplo yed with a full flow
detachable element type oil filter and integrated lubricating oil cooler.

The cooling system is indirect and usually employs an engine mounted heat
exchang er with a belt dr iven ra w wa ter pu mp. This sy stem is known as I FWC
(internal fresh water cooled).

An optional system is EFWC (external fresh water cooled.) This system utilizes the
engine fresh water pump and usually employs skin tanks attached to the hull to serve as heat
exchangers.

The single belt driven alternator and fresh water pump drive include a manual
belt tensioning arrangement for low maintenance completes the comprehensive
engine package.




              90
4 Cylinder naturally aspirated
                                                             108
                                                  4 Cylinder naturally aspirated
Power intermittent at 3500rpm =     36BHP         Power intermittent at 3500rpm =      47BHP
      continuous    at 3000rpm =    30BHP                   continuous at 3000rpm =    38BHP
Maximum torque      at 2500rpm = 531bf ft         Maximum torque      at 2400rpm = 731bf ft
Idle speed                     = 570rpm           Idle speed                     = 570rpm
Minimum full load speed        = 1500rpm          Minimum full load speed        = 1500rpm

ENGINE RATINGS

The type 90 Engine may be set to develop continuous outputs from 13.5 to 30 BHP according to
requirements

The type 108 Engine may be set to develop continuous outputs from 21 to 38 BHP
according to requirements.

For special applications where full power will not be required for periods in
excess of 1 hour in any 12 hours consecutive running the engine can be supplied at an
intermittent rating as shown above.

NOTE: All horsepower ratings quoted are at the engine flywheel. Due allowance must
be made for transmission losses which will depend on the type of gearbox fitted.
For tropical use it is necessary to derate the engine by 2% for each 5%C (10F)
above 30C (85F) air temperature at sea level. In some parts of the wor ld
fur the r de rat ing for h umi dity is n ece ssar y in acco rda nce with

BS 5514/1.
                         INITIAL STARTING OF ENGINE


PAGE

 _.    Engine mounting and dipstick marking. Filling engine with oil.
 2.    Lubricant specification for engine and gearbox. Filling gearbox.
 3.    Coolant/Corrosion inhibitor specification. Filling cooling system.
 4.    Priming the engine oil system.
 5.    Bleeding the fuel system type 90 engines.
 6.    Bleeding the fuel system type 108 engines.
 7.    Initial start. Normal start. Running in.
 8.    Operating guidelines.
 9.    Operating guidelines.

                                MAINTENANCE


       Maintenance schedule.
       Engine oil and filter change
10.    Engine oil and filter change
11.    Fuel filter change. Cleaning Type 90 engines.
12.    fuel lift pump. Gearbox oil Type 108 engines.
13.    change. Cleaning air filter.
14.    Alternator drive belt adjustment
15.    and replacement. Raw water pump
16.    adjustment and replacement.
17.    Checking and setting valve
       clearances. Procedure for
       retorquing cylinder head nuts. Removal/Refitting
18.    fuel injectors.
19     Changing coolant.
20.    Draining raw water system.
21.    External fresh water cooled engines.
22.    Electrical system.
23.    Fault finding.
24.    Fault finding.
25.    Laying up the engine.
26.    Re-commissioning.
27.    Notes.
28.
29.
                                                   CHECKING ENGINE MOUNTING,
THORNYCROFT                                MARKING DIPSTICK, FILLING ENGINE WITH OIL

Page 1
         CHECKING ENGINE MOUNTING

         The maximum installed angle of the engine is 15, engine types 90/2, 108 and 108/2
         (10 for engine type 90). This allows for a further rise of 4 when the craft is
         moving. Check the angle of installation using the centreline of the mounting feet
         bolts as a datum. Measure vertically on the centreline of the underside of the
         front mounting foot bolt to find the angle of installation Fig. 1




         Fig. 1




         Horizontal Line
                 Type 90                                Type 90/2               Type 108
              A 93mm = 10                           A 138mm = 150           A 136mm = 15
                 46mm = 5                               93mm = 10              91mm = 10
                                                         46mm = 5               46mm = 5

         MARKING DIPSTICK, FILLING WITH OIL

         Your engine is despatched from the factory without engine or gearbox oil and with an
         unmarked engine dipstick. After the boat is launched, and is resting at
         its normal trim angle, remove the oil filler cap from the rocker box Fig. 2 and pour 3.9
         litres for type 90, 4.5 litres for type 90/2 or 4.8
         litres for type 108 of specified lubricant through the filler
         hole. Allow 5 minutes for .the oil to drain into the sump,
         withdraw the dipstick and mark it for maximum oil level Fig.
         3 (Use a centre punch for marking as filing a notch can
         cause fatigue and eventual breakage while the engine is
         running). Then mark dipstick using the same method 12.7mm
         (%") below the maximum mark and this will be the minimum
         level.
              LUBRICANT ENGINE AND GEARBOX
                                                                   THORNYCRO
                                                                       FT       `Page 2
                                       ENGINE OIL

RUNNING IN OILS

Do NOT use special running-in lubricating oils for new or rebuilt engines. Use the
lubricating oils specified for normal engine operation.

ENGINE OIL VISCOSITY RECOMMENDATIONS

The use of a multi- graded lubric ating oil h as been fou nd to impro ve oil
consumption and improve engine cranking in cold temperatures while maintaining
lubrication at high operating temperatures. A multi-grade oil conforming to
MIL-L-20104B is. recommended with the viscosity grades shown in Fig. 4. The use of
single grade lubricating oil is not recommended except for synthetic oils used
in arctic conditions.

 Atmospheric Temperature               Viscosity



         Above -10C                     20W50

       -20C to 10C               1OW30 or 1OW40

         Below -10C                    5W30 or 5W40

                                                       Fig. 4.

                                       GEARBOX OIL


Borg Warner            Automatic Transmission Fluid    (T ype A)
Hurth                  Automatic Trnamsission Fluid    (T ype A)
Newage PRM             SAE 20 Engine Oil               Minus 18C to 0C
                       SAE 30 engine Oil               Above 0C


                                FILLING THE GEARBOX

Remove the oil filler plug combined    dipstick from the top of the gearbox. This is
in approximately the same position      on Hurth, Newage PRM and Borg Warner. Using
a plastic bottle or funnel, fill       the gearbox up to the maximum mark on the
dipstick. There is one level mark      on the Hurth dipstick, the others have high
and low marks.
Fig. 5.
THORNYCROFT                                                   COOLING SYSTEM


Page 3

         COOLANT

         Use anti-freeze during all seasons to protect the engine cooling system from
         corrosion as well as freeze damage. Using the following anti-freeze solution %.


                                                    25%                3 3%                5 0%
                                                  Solution          Solution         Solution
          Complete protection                    lOF(-12C)         3F(-16C)      - 4F(-20C)
          Safe protection                         1F(-17C)        -8F(-22C)      -18F(-28C)


         In tropical climates where anti-freeze availability may be limited, corrosion
         inhibitor to protect the engine cooling system.                          use a


         NOTE: Corrosion inhibitor is NOT an anti-freeze. COOLANT QUANTITIES

         Complete system including engine (IFWC) types 90 and 108 engines.

                                                   5.1 Litres


         For external fresh water cooled engines (EFWC) See Page 23. FILLING THE COOLING

         SYSTEM

         Remove the filler cap from the heat exchanger Fig. 6 and fill the system
         with coolant. This will take approximately 5 minutes as the system self
         bleeds. Fill to 5mm below the filler neck level mark. Refit filler cap.




                                                                     M                            Fig. 8
        405i
l
I




    M          Fig. 9
              PRIMING THE ENGINE OIL SYSTEM                        THOMYCWFT
                                                                             Page 4

PRIMING THE ENGINE OIL SYSTEM (TYPE 90/2R ENGINES ONLY)

As only a residual amount of oil is present in the oil pump, filter and oil
galleries of the engine, it is therefore necessary to prime the system before the
engine is run. Connect the engine starter batteries disconnect power to the
fuel solenoid valve on the injection pump Fig. 7 and crank the engine over using
the key starter switch until pressure registers on the oil pressure gauge.
Stop cranking and check the engine and gearbox for oil or water leaks. Replace
power connector.




                                                          Fig. 7




PRIMING THE ENGINE OIL SYSTEM (TYPE 90 AND/108 ENGINES)

As only a residual amount of oil is present in the oil pump filter and oil
galleries of the engine it is therefore necessary to prime the system before the
engine is run. Connect the engine starter batteries, operate the key starter
switch with the stop control out, crank the engine over until pressure registers
on the oil pressure gauge. Stop cranking and check the engine and gearbox for
oil or water leaks.
THORNYCROFT                            BLEEDING THE FUEL SYSTEM TYPE 90 ENGINES




Page 5
      BLEEDING THE FUEL SYSTEM

     Slacken the bleed valve on the injection pump Fig. 8. Operate the lift pump
     Fig. 9 and when the fuel coming from the valve is free of air bubbles, tighten the
     valve.




     Fig. 8

     Slacken the uni ons at the
     injector ends of a ny two high p ressure pipes. Fig. 10. Ensure that the stop
     control is in the run position and the engine speed control is in the fully
     open position. Crank the engine until the fuel coming from both pipes is free from air
     bubbles, then tighten the unions.

     NB. After initial start procedure has been observed start the engine and allow it
     to idle until it is running evenly on all four cylinders.
Fig. 10
           BLEEDING THE FUEL SYSTEM TYPE 108 ENGINES
                                                                       THORN
BLEEDING THE FUEL SYSTEM



 Fig. 11   ~`
                      53
                                                                       YCROF

                                                                                 Fig. 12
                  2        4,6
 Note: After renewing the
 fuel filter element it will only be necessary to bleed the fuel filter as
 described in 1 and 2, provided that the engine has not been cranked while the
 filter is dismantled.

 1    Slacken the blanking plug in the unused outlet connection in the fuel
      filter head Fig. 12. Operate the lift pump Fig. 9 (page 5) until the fuel
      flowing from the plug is free of air bubbles, tighten the plug. NB. Numbers
 2-6 refer to Fig. 11 bleed points.

 2 Slacken the union nut at the injection pump end of the fuel feed pipe.
     Operate the lift pump and when the fuel flowing from the union is free
     from air bubbles, tighten the nut.

 3 Slacken the air bleed screw on the injection pump body. Operate the lift pump
     and, when the fuel flowing from the bleed screw is free from bubbles, tighten the screw.

 4   Slacken the air bleed screw on the injection pump governor housing.
       Operate the lift pump until the fuel flowing from the bleed screw is free
       from air bubbles, leave the bleed screw slack.

 5 Slacken the air bleed screw on the injection pump high pressure banjo bolt.
     Operate the starter motor while operating the throttle control and, when the
     fuel flowing from the high pressure bleed screw is free of air bubbles,
     tighten the bleed screw.

 6 Co ntinue cranking the engine with the starter motor to expel any air
     trapped in th e governor and, when the fuel flowing from the go vernor
     housing bleed screw is free of air bubbles, tighten the screw.

 Slacken the unions at the injector ends of any two high pressure pipes. Fig.
 13.            Ensure that the stop control is in the run position and the engine
 speed control is in the fully open position.             Crank the engine until the fuel
 comibng from both pipes is free from air bubbles, then tighten the unions. NB. After initial
 start procedure has been observed start the engine and allow it to idle until it is
 running evenly on all four cylinders.




                                                                                  Fig. 13
THORNYCROFT                                    INITIAL START, NORMAL START, RUNNING IN

Page 7
         INITIAL START

         With all systems filled, primed and checked the engine may be started. Run it for
         2 to 3 minutes then stop it. Top up engine, gearbox oil and water levels to the
         high mark. The engine and gearbox are now ready for use. Oil pressure should be
         observed within 15 seconds.

         NORMAL STARTING PROCEDURE
         1    Put gearbox selector lever in neutral.

         2    Ensure the stop control is fully disengaged.

         3    Set the engine speed control lever fully open.

         4 Turn the key to 'H' position on starter switch and hold for 30 seconds (this
              preheats the heater plugs). (This is not necessary for a warm engine.
              Also control level only needs to be set half open).

         5    Turn the key to 'H & S' position and the starter motor will crank up the
              engine.
              CAUTION: If the starter fails to crank up the engine within 10 seconds,
              re lea se t he s wit ch k ey a nd w ait for th e starter motor to come to a
              c o m pl et e st o p . T h en tu r n t h e k e y to 'H & S' po s i ti o n a ga i n. D o n o t
              engage the starter motor for more than 30 seconds, then wait 2 minutes
              between unsuccessful attempts.

         6    Move the throttle position to idle as soon as engine starts.

         7    Oil pressure should be observed within 15 seconds.
         8    To stop the engine, pull the stop control.
         RUNNING IN

         The care given to an engine in the first 20 hours of operation will result in
         longer life, better performance and more economical operation. During this
         period follow these recommendations.
         1    Warm up the engine before placing it under load.



         2    Do not operate the engine at idle or full load for more than 5 minutes. 3     Avoid

         constant speed.


         4    Observe oil pressure and temperature gauges. 5

         Check the oil and coolant levels frequently. GENERAL

         PRECAUTIONS

         1    NEVER attempt to start the engine with the gearbox control lever in any
              position other than neutral.

         2    NEVER stop the engine without first engaging neutral.

         3    When changing the control lever from ahead to astern or vice versa pause in
              neutral.
                       OPERATING GUIDELINES
                                                                                 THORNYCROFT

                                                                                             I Page 8

COMPLIANCE WITH THE FOLLOWING RECOMMENDATIONS CAN RESULT IN LONGER LIFE, BETTER PERFORMANCE AND
MORE ECONOMICAL OPERATION OF YOUR ENGINE.

Routinely perform all of the specified maintenance, including the "First Start of
the Day" checks.

Use anti-freeze during all seasons to protect the cooling system from corrosion as well as
freeze damage.

Never operate the engine without a thermostat.


Use quality fuel that is free of water and other contaminants. Monitor the oil

pressure and temperature indicators frequently. AVOID FULL THROTTLE

OPERATION WHEN THE ENGINE IS COLD.

When starting a cold engine, bring the engine up to operating speed slowly to
allow the oil pressure to stabilise as the engine warms up.

If temperatures are below 0C (32F), operate the engine at moderate speeds for 5 minutes before
full loads are applied.

AVOID IDLING THE ENGINE FOR MORE THAN 10 MINUTES

Long periods of idling may be harmful to your engine because combustion chamber temperatures can
drop so low that the fuel may not burn completely. Carbon can then form which may clog the
injector spray holes and also cause valves and piston rings to stick.

AVOID OVERHEATING THE ENGINE

Co ola nt t emp era tur e mu st not ex ceed 99 C (210 F) wi th a 70 kP a ( 10 p si)
expansion tank cap AND A MINIMUM OF 50% mixture of ethylene-glycol and water.

IDLE THE ENGINE A FEW MINUTES BEFORE ROUTINE SHUTDOWN

After full load operation, idle the engine 3 to 5 minutes before shutting it off
to allow th e lu bricating o il and coola nt to car ry h eat away from the
combustion chamber, bearings, shafts, etc.

AVOID LOW COOLANT TEMPERATURE OPERATION
Continual operation at   l ow coo lant temperat ure be low 60C ( 150F) can be

harmful to the engine.             Low coolant temperature can cause incomplete combustion
allowing       carbon and varnish to form that can damage piston rings and injector
nozzles.            A lso, th e unburnt fu el c an enter the crankcase di lut ing the
lubricating oil causing rapid wear to other moving parts.
THORNYCROFT                                         OPERATING GUIDELINES



Page 9

     DO NOT OPERATE THE ENGINE WITH LOW OIL PRESSURE

    When the engine is at normal operating temperature, the minimum oil pressures
     required are:

                 Idle (570 RPM) ........................... 1 bar (15 psi)
                 Full Speed and Load .................... 2.3 bar (35 psi)

     DO NOT OPERATE THE ENGINE WITH FAILED PARTS

     Practically all failures give some warning before the parts fail. Be on the
     alert for changes in performance, sounds and visual tip-offs that indicate
     either service or repair is needed. Some important clues are:

                 Engine misfiring or vibrating severely
                 Sudden loss of power
                 Unusual engine noises
                 Fuel, oil or coolant leaks
                 Sudden change in the engine operating temperature Excessive
                 smoke
                 Loss of oil pressure


           SAFETY PRECAUTIONS

           Saf ety i s bu ilt i nto eve r y en gin e; ho wev er,       l ike any o the r
           mechanical device, it can present serious threat to         life and limb if
           imprudently operated and maintained. Remember                that the best
           safeguards again st accidents are to kee p ever             mindful of the
           potential dangers and to always use good common sense.
                   MAINTENANCE SCHEDULE                                  TH0RNYCROFT
                                                                                           Page 10


DAILY OR EVERY 10 HOURS

Check engine and gearbox oil levels, top up if necessary. Check
coolant level and top up if necessary. Check drive belt
tensions.

AFTER FIRST 25 HOURS

Retorque cylinder head nuts.
Change the engine oil and renew engine oil filter.
Check valve rocker clearances.
Check drive belt tensions
Check oil connections for leaks.
Check water hose connections.
Check all electrical equipment.
Change fuel filter element.
Check and service injectors as necessary.
Check and adjust engine idling speed as necessary (Use a Thornycroft dealer) Check fuel
system for leaks.

                                   ENGINES IN REGULAR USE

EVERY 50 HOURS


Check electrolyte level in batteries.

EVERY 200 HOURS OR YEARLY

Change fuel filter element.
Change engine oil.
Change engine oil filter.
Check drive belts.
Check air cleaner and clean if necessary.
Check for oil or coolant leaks.
Check fuel system for leaks.
Check gearbox oil level.
Check and adjust idling speed as necessary.

EVERY 400 HOURS

In addition to the 200 hour maintenance schedules, change the gearbox oil. Remove heater
plugs and remove carbon from each orifice.

EVERY 800 HOURS

In addition to the 200 hour and 400 hour maintenance schedules Adjust valve
rocker clearances.
Test injectors for spray (Use a Thornycroft dealer)
Check all engine and gearbox connections. Renew oil
filler cap on rocker cover

      ENGINES USED OCCASIONALLY HALVE THE HOURS RECOMMENDED AFTER FIRST 25 HOURS
THORNYCROFT                              ENGINE OIL CHANGE TYPE 90 ENGINES


Page 11

      CHANGE ENGINE OIL

      Run the engine until it reaches normal operating temperature, stop the engine, then
      using the hand pump Fig. 14 drain the oil into a suitable container.




      Fig. 14




      CHANGE ENGINE OIL FILTER

      Slacken the centre fixing bolt '1' Fig. 15 and
      withdraw the filter bowl '2' and filter element
      '3' together. Discard the filter element and
sealing ring '4'.

Replace with new element and sealing ring, ensuring that the ring is
correctly seated i n t he filt er head ' 5' and tig hte n t he centre bolt.

Fill the engine with the specified amount of oil and prime the oil system
as described on Page 4.

Start the engine and check for oil leaks, run the engine for 2 minutes
ensure pressure registers on the gauge. Stop the engine and allow a few
minutes for oil to settle. Check oil level, top up if necessary.

                                           Fig. 15
              ENGINE OIL CHANGE TYPE 108 ENGINES                 THORNYCRO
                                                                     FT           Page 12
CHANGE ENGINE OIL

Run t he engine u ntil it reaches nor mal
operating temperature, stop the engine,
then using the hand pump Fig. 16 drain the
oil into a suitable container.




 Fig. 17




                                                    Unscrew the oil filter cartridge
                                                   Fig. 17. Discard the cartridge and
                                                   its sealing ring.




Lightly smear the sealing ring with clean
engine oil Fig. 18 and screw the filter
cartridge into place using hand pressure
only until the sealing ring abuts with the
filter head face. Then tighten a further
  -   a of   a turn.

Fill the engine with the specified amount                                        as
of oil and prime the oil system described on Page     4.
Start the engine and check for oil leaks, run the engine for 2 minutes ensure
pressure register on the gauge. Stop the engine and allow a few minutes for
Oil to settle, Check oil level and top op if necessary
THORNYCROFT                                         FUEL FILTER CHANGE


Page 13

                RENE W FUE L FILTER ELE MENT

          Turn off the fuel supply tap then support the filter base '1' Fig. 1 9 and unscrew
          the centre bolt '2'. Detach the base and twist the element '3' to separate it from
          the filter head '4'. Remove the three sealing rings '5' from the head and base.
          Discard element and sealing rings. Clean base and head and assemble the filter
          using a new element and sealing rings. Fit the element with its strengthened
          rim uppermost. 'Turn on the fuel supply tap then bleed the air from the system as
          described on Page 5 or 6.
Fig. 19
                  CLEANING FUEL LIFT PUMP                          THORWC"T
                                                                                       Page 14


FUEL LIFT PUMP FILTER

Turn off the fuel supply tap then remove the cap screw '1', Fig. 20. Lift off the cap '2',
gasket '3' and filter gauze '4'. Clean the gauze in a suitable solvent usin g a
sti ff brush. Clean the fuel cham ber '5'. Check that the gasket is serviceable
or renew. Assemble the components. Do not overtighten the cap screw. (Never
clean inside fuel chamber or any other part of the fuel system with a fluffy
cloth.) Turn on the fuel supply tap then bleed the fuel system as described on
Page 5 or 6.
Fig. 20
THORNYCROFT                              GEARBOX OIL CHANGE



Page 1 5

      CHANGING THE GEARBOX OIL

      T he gearbo x o il must be changed when the gearbox has reached operating
      temperature. (After about 1/2 hour driving the craft).

      To help the oil drain easily from the gearbox first remove the oil filler
      dipstick plug from the top of the gearbox. Place a suitable container under the
      gearbox and remove the drain plug from the underside of the gearbox and allow
      the oil to drain completely Fig. 21. The drain plug is in approximately
      the same position on the underside of Hurth, Borg Warner and Newage PRM
      gearboxes.

      Refit the drain plug. Fill the gearbox to the maximum mark on the dipstick.
      Refit the filler plug, start the engine in neutral, and run the engine for 1
      minute to allow the oil to circulate. Stop the engine and check the oil level.
      Top up if necessary to the maximum mark on the dipstick.




                                                                           Fig. 26
Illustration shows PRM 160 gearbox




                                     Fig. 27
                 CLEANING AIR FILTER                                     THORNYC
                                                                           ROFT               Page 16

CLEANING AIR FILTER

Slacken the clip on the breather pipe and pull the pipe off the air cleaner
then, slacken the screw Fig. 22 this allows removal of the outer casing and the air filter gauze.
Submerge the casing and gauze in a bath of clean paraffin or diesel fuel, agitate them
vigorously to remove dirt particles. Shake the filter dry by hand or blow dry with
compressed air, then refit.




Fig. 22




    CAUTION: WHEN USING A COMPRESSED AIR LINE GREAT CARE MUST BE OBSERVED AND
                               GOGGLES MUST BE WORN
THORNYCROFT                            DRIVE BELT ADJUSTMENT AND REPLACEMENT
                                           ALTERNATOR AND RAW WATER PUMP


Page 17

     SAFETY: BEFORE ATTEMPTING THESE OPERATIONS

     DISCONNECT THE STARTER BATTERIES Adjusting

     Alternator Drive Belt


     Type   90  alternator   is   shown in the
     illustration Fig. 23 but procedure for
     adjusting the alternator drive belt is
     the same for type 108 engines.

     Slacken the nuts and bolts 1-4. Move
     alternator away from the engine until the
     deflection of the belt (arrowed) is 19mm
     (0.75 in) when pressed using finger pressure
     only at the longest point between pulleys.
     Excessive tension will cause early wear of
     the   belt,    water   pump   bearing    and
     alternator bearing. While a slack belt
     will slip, causing overheating of the
     engine and insufficient charging of the
     batteries.     Check    deflection     after
     retightening.

     Replacing Alternator Drive Belt

     Slacken the nuts and bolts (Fig. 23) 1-4,
     move alternator in towards engine. Remove
     old belt from pulleys and replace with new
     drive belt. Retighten nuts and bolts.

     Following the instructions above readjust
     the drive belt tension.


                                                                                 Fig. 23

                                                    Adjusting Raw Water Pump Drive Belt

                                                    Slacken the nuts and bolts (Fig. 24) 1
                                                    and 2 an d ret ens ion the b elt as
                                                    described above for the alternator.
                                                    (The deflection of the belt must be
                                                    10-12mm 0.39-0.47in). Check deflection
                                                    after retightening.

                                                    Replacing Raw Water Pump Drive Belt

                                                    Slacken the nuts and bolts (Fig. 24) 1
                                                    and 2. Move pump in towards engine.
                                                    Remove old belt from pulleys and
                                                    replace    with   new    drive   belt.
                                                    Retighten nuts and bolts, following
                                                    the instructions above readjust the
                                                    drive belt tension.




     Fig. 24
       CHECKING AND SETTING VALVE CLEARANCE
                                                                            THORWCWFT
                                                                                         Page 18


SAFETY: BEFORE ATTEMPTING THIS OPERATION DISCONNECT THE STARTER BATTERIES

Setting Valve Clearances Engine Cold


Slacken the rocker cover bolts and remove rocker cover. Discard the gasket. Turn

the crankshaft in the normal direction of rotation and adjust as follows.

Slacken the locknut and adjust with a screw driver until the correct clearance is
obtained. Fig. 25. Insert the feeler blade between the valve stem and rocker arm.
When correct adjustment is obtained the feeler blade is able to be removed with
slight resistance.

Adjust in the following sequence:

                     Set No. 1 tappet with No. 8 valve fully open Set
                     No. 3 tappet with No. 6 valve fully open Set No.
                     5 tappet with No. 4 valve fully open S et No. 2
                     tappet with No. 7 valve fully open Set No. 8
                     tappet with No. 1 valve fully open Set No. 6
                     tappet with No. 3 valve fully open Set No. 4
                     tappet with No. 5 valve fully open Set No. 7
                     tappet with No. 2. valve fully open

                     Rec hec k the clearance wit h the loc knu ts
                      tightened and readjust if necessary.

                                                    Fig. 25
                                                    Valve Clearance - Type 90 engines
                                                    Inlet Valve 0.381mm (0.015in)
                                                    Exhaust Valve 0.381mm (0.015in)

                                                    Valve Clearance - Type 108 engines Up
                                                    to Thornycroft Engine No. 6043 Inlet
                                                    and Exhaust 0.43mm (0.017in)

                                                    Engine No. 6043 onwards
                                                    Inlet and Exhaust 0.35mm (0.014in)




Fit the rocker cover using a new gasket. Tighten the bolts.
Reconnect the battery, start the engine and check the rocker cover for leaks.
    THORNYCROFT                                 PROCEDURE FOR RETORQUING CYLINDER HEAD NUTS



    Page 19
          1   PROCEDURE FOR NEW ENGINES WHICH HAVE RUN FOR 25 HOURS

              A       Run engine and stop when normal operating temperature is reached.

              B Slacken the cylinder head nuts by approximately 1/6" of a turn (one flat
                   of the nut) following the sequence shown using service tool 18G 1457
                   to reach the nuts in the centre row.




Fig. 26




                  C    Tighten the nuts in the sequence shown to 10.4 kgf m (75 lb ft).
I


                                        11        6                    5        12




                                                    00 00 0o
                                                   ? 90 0 9 0 1 0 A
                                                   OQ
                                                        1

                                                                                     13
                                        14 107 3 1 4 89
           Slacken the valve rocker pedestal nuts by 1/6" of a turn (one flat of
           the nut) and retorque to 3.5 kgf m (25 lb ft).                 Adjust valve rocker
           clearances (Page 18).

2   PROCEDURE WHERE PART ENGINES HAVE BEEN FITTED OR WHERE CYLINDER HEADS ARE
    REMOVED OR REPLACED DURING REPAIR OPERATIONS

    A      The cylinder head nuts should not be more than finger tight until the
           rocker shaft assembly has been fitted.

           Tighten the nuts to 10.4 kgf m (75 lb ft) type 108 engines, 9.8 kgf m
    B
           (.71 lb ft) type 90 engines in the sequence shown in procedure                  1.
           Using service tool 18G1457 to reach centre row. Fig. 27.

    C      Tighten the valve rocker pedestal nuts to 3.5 kgf m (25 lb ft).

    D      Adjust the valve rocker clearance as in procedure 1.

When the   engine has run f or Y2 hour carr y out the operat ion descr ibed                in



procedure 1.

Fig. 27
          REMOVAL AND REFITTING FUEL INJECTORS                 THORNY
                                                                CROFT
                                                                                Page 20

REMOVING FUEL INJECTORS

Injector cleaning and spray testing can only be carried out with specialised
equipment, therefore this must be done by a Distributor or Dealer.

Fig. 28. Disconnect the feed pipe '1' and spill rail '2'. Note the sealing
washers '3' on each side of the spill rail banjo union. Remove the injector
securing bolts '4' and withdraw the injector. Fit protective caps to all open
connections.


                                             Fig. 29




Fig. 28

REFITTING FUEL INJECTORS

Remove protective caps. Ensure the washers are fitted to the injectors as
shown in Fig. 29. It is most important to tighten the injector fixings evenly and
to the correct torque of 1.65 kgf m (12 lbf ft), overtightening or uneven
tightening of the injector can distort the nozzle and will usually cause a
misfire to occur when normal running temperature is reached. Reconnect the
injector pipes, do not overtighten the unions.
                                         TO REMOVE HEATER PLUGS AND CLEAN
                                         ORIFICES. Disconnect the battery. Remove
                                         electrical leads '1' Fig.29A and unscrew
                                         each plug '2' from th e cylinder head.
                                         Insert     a    twist   drill   of    4.37mm
                                         (11 /64 in) dia. '3' into t he th rea ded
                                         holes in the head '4'. Turn the drill, by
                                         han d,    to   r emo ve car bon  bui ld- up.
                                         Remove the drill and clean any particles of
                                         carbon from conical seatings in the
                                         cylinder head. Refit the heater plugs
                                         and e lec tri cal l ead s. Re connec t the
battery.



Fig.29A
          TAT                                        CHANGING COOLANT




Page 21

      CHANGING COOLANT

      Remove filler cap from heat exchanger, place a suitable container beneath the drain plug
      Fig. 30. Remove plug and allow to drain.

      Place suitable container beneath drain tap in cylinder block Fig. 31.
                                                                       Remove
      tap and allow to drain.

      Replace both plug and tap then refill with coolant of the correct strength for conditions
to be encountered. See Page. 3.




Fig. 30




i
Fig. 31
             DRAINING RAW WATER SYSTEM




                                                                               Page 22
DRAIN THE RAW WATER SYSTEM

Slacken the six screws Fig.32 on the raw water pump. Remove end covers from
heat exchanger and drain tubes either by removing the tube stack or by blowing out
with compressed air. Remove oil cooler and drain tubes or blow out with
compressed air. Alternatively disconnect raw water pipework before gearbox oil
cooler and pipe from oil cooler into a container of anti-freeze mixture and
flush through system returning anti-freeze mixture from water injection bend
back into container, this ensuring that any water pockets contain anti-freeze.




               CAUTION: WHEN USING A COMPRESSED AIR LINE GREAT
                          CARE MUST BE OBSERVED AND GOGGLES MUST BE
                          WORN.


NOTE: ANTI-FREEZE MIXTURE MUST BE OF CORRECT STRENGTH FOR CONDITIONS TO BE
ENCOUNTERED.




Fig. 32
ROUTINE MAINTENANCE OF RAW WATER SYSTEM IFWC

THESE NOTES DO NOT APPLY TO EXTERNAL FRESH WATER COOLED ENGINES
Examine and clean the sea inlet strainer at regular intervals. Do Not remove the
strainer when the engine is running as foreign matter can be drawn into the system and cause
irreparable damage to the pump. The sea cock must be FULLY OPEN when the engine
is running. If the sea cock is partially closed, air can be drawn in with
consequ ential failure of the raw water pump and engine overheating. Check the
raw water discharge pipe immediately after starting the engine to see if the raw water
pump is functioning.

         The engine MUST NOT run without a flow of raw water through the heat exchanger.

RAW WATER PUMP, the raw water pump is self priming and fitted with a neoprene
impellor. It depends on the raw water for its lubrication. DO NOT run dry.
M ore than 3 0 se con ds runn ing withou t wate r will b urn the impellor and be
contributory to an early failure. When replacing the end cover gasket, it is
essential to use the correct part; variation of the gasket thickness can cause loss of'self
priming ability or seizure.
                                         EXTERNAL FRESH WATER COOLED ENGINES ONLY (EFWC)
THORNYCROFT

Page 2 3

      This consists of a closed circ uit fresh water system with a fre sh water
      circulator, combined header tank and exhaust manifold, dry exhaust outlet and
      water/coolant tanks normally fitted to the skin of the craft. It is therefore
      important when filling this system with anti-freeze solution or corrosion
      inhibitor that the total capacity of the tanks, associated pipework and the
      engine cooling system is taken into consideration. Your boat builder will
      advise you on these figures.

      We have included the box below for you to fill in these figures for your craft.




           Name of Craft                                 External Fresh Water Cooled System
                                                       Capacity     Date      Change Due
                        ELECTRICAL SYSTEM                                    THORNYCROFT
                                                                                                Page 24

Electrical System

An insulated return system      is   employed on the type 90 and 108 engines.

The 12 volt alternator has a built-in voltage regulator which automatically
adjusts the charging rate to provide sufficient electric current to keep the
battery fully charged under normal operating conditions.

The alternator requires no lubrication maintenance.
Do NOT disconnect the battery leads while the engine is running.
Ensure that the correct battery terminal is connected to a good earth on the
starter
A coating of a good grade of petroleum jelly will protect the terminals from
corrosion.

The electrolyte level should be 6 to 9mm (0.25 to 0.38in) above the top of the plates. If the
electrolyte is below the correct level, add the required amount of distilled
water.

Distilled water for battery use should be kept in clean, covered, non-corrodible
vessels. In cold weather, add water only immediately before running the engine, so
that the charging will mix the water and electrolyte and prevent freezing.

If t he b att ery i s al lowed to sta nd at lo w tem per atu res in a p art ial ly
discharged condition there is a possibility that it may freeze, causing damage to the container. Take
care therefore, to keep the battery as fully charged as possible.

The specific gravity of the electrolyte when the battery is fully charged
should be 1,275 at a temperature of 25C (77F). At differing temperatures the specific gravity
of a fully charged battery will change. The specific gravity of any given temperature
can be calculated by subtracting 0.004 from 1,275 for every 6C change above 25C and adding 0.004 to
1,275 for every 6C below 25C.

Keep the battery filler plugs and connections tight and the top of the battery clean. Wiping
the battery with a rag moistened with ammonia will counteract the effect of any
of the solution which may be on the outside of the battery. Wear protective
goggles when carrying out this operation. If ammonia is accidentally splashed in the
eyes, wash out thoroughly at once with clean water and SEEK QUALIFIED MEDICAL ADVICE
IMMEDIATELY.

Using 'Jumper' Cables

To avoid the possibility of extensive damage to your charging system it is
important to observe the following points when using battery 'jumper' cables to start an engine
having a discharged battery. The positive (+) terminals of the batteries must be connected
through one cable (usually red), and the negative (-) terminals connected
through the other cable. If this procedure is not followed, extensive damage may be
done to the charging system.

CAUTION: Since explosive hydrogen gas is always present, sparks or flames
         should not be allowed near the battery. When using 'jumper' cables, the
         cables should always be attached to the booster battery first.
THORNYCROFT                                           FAULT FINDING



Page 25

     FAULT FINDING

     ENGINE WILL NOT START



   Starter does not             ELECTRICAL FAULT
   crank engine                 Battery run down
                             Lead disconnected
                             Faulty starter switch
                             Faulty starter motor


    Starter cranks            ELECTRICAL FAULT
     engine slowly       Battery partly run down
                         Terminal(s) loose
                         Connections dirty Faulty
                         starter motor

                             MECHANICAL FAULT
                             Wrong grade engine oil


     Starter cranks      ELECTRICAL FAULT
     engine normally     Faulty glow plugs
                         Faulty wiring connection

                             MECHANICAL FAULT
                             Injection timing incorrect
                             Poor cylinder compression
                             Blocked air intake

                             FUEL FAULT
     Fuel Not Reaching
     Injection Pump      Insufficient fuel in tank
                         Blocked fuel pipeline
                         Blocked fuel tank vent
                         Restricted fuel filter Air
                         leaks in pipeline

     Fuel Reaching
     Injection Pump      Air in fuel system
                         Faulty injectors


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