Detroit Diesel 353, 453, 6V53, 8V53 Engine Tune Up

June 28, 2022

Detroit Diesel 53 Series Engine Tune Up Procedures

There is no scheduled interval for performing an engine tune-up. As long as the engine performance is satisfactory, no tune-up should be needed. Minor adjustments in the valve and injector operating mechanism governor, etc should only be required periodically to compensate for normal wear and tear on parts. 

The type of governor used depends upon the engine application. Since each governor has different characteristics the tune-up procedures vary accordingly. The following types of governors are used.

 

  1. Limiting Speed Mechanical 
  2. Variable Speed Mechanical

 

The mechanical governors are identified by a name plate attached to the governor housing. The letters DlWl -L.S. stamped on the name plate denote a double weight limiting speed governor. A single-weight variable speed governor name plate is tamped S.W. -V.S.

 

Normally, when performing a tune-up on an engine in service, it is not only necessary to check the various adjustments for a possible change in the settings. However, if a cylinder head, governor or injectors have been replaced or overhauled, then certain tune-up adjustments are required. Accurate tune-up adjustments are required. Accurate tune-up adjustments are very important if maximum performance and economy are to be obtained. 

 

NOTICE: If a supplementary governing device, such as load limit device is used it must be disconnected prior to tune-up. After the governor and injector rack adjustments are completed, the supplementary governing device must be reconnected and adjusted. 

 

To tune-up an engine completely, perform all of the adjustments in the applicable tune up sequence given below. 

 

CAUTION: To prevent the possibility of personal injury , use turbocharger inlet shield J26554-A anytime the turbocharger inlet is exposed.

 

Use new valve rocker cover gaskets after the tune-up is completed. 

 

Tune-Up Sequence For Mechanical Governor

 

Before starting an engine after an engine speed control adjustment or after removal of the engine governor cover, the service technician must determine that the injector racks move to the no fuel position when the governor stop lever is placed in the stop position. Engine overspeed will result if the injector racks cannot be positioned at the no fuel with the governor stop lever. 

CAUTION: An overspeeding engine can result in engine damage which could result in personal injury. 

 

  1. Adjust the exhaust valve clearance, cold. 
  2. Time the fuel injectors.
  3. Adjust the governor gap.
  4. Position the injector rack control levers. 
  5. Adjust the maximum no-load speed. 
  6. Adjust the idle speed. 
  7. Adjust the buffer screw.
  8. Adjust the throttle booster sprint (variable speed governor only).
  9. Adjust the supplementary governing device, if used.

 

Exhaust Valve Clearance Adjustment Detroit Diesel Series 53 Engines

The correct exhaust valve clearance at normal engine operating temperature is important for smooth, efficient operations of the engine. 

 

Insufficient valve clearance can result in loss of compression, misfiring cylinders and, eventually, burned valve seats and valve seat inserts. Excessive valve clearance will result in noisy operation, increased valve face wear and valve lock damage. 

 

Whenever the cylinder head is overhauled, the exhaust valves are reconditioned or replaced, or the valve operating mechanism is replaced or distributed in any way, the valve clearance must be adjusted to the cold setting to allow for normal expansion of the engine parts during the engine warm-up period. This will ensure a valve setting that is close enough to the specified clearance to prevent damage to the valves when the engine is started. 

 

All of the exhaust valves may be adjusted in firing order sequence during one full rotation of the crankshaft. Refer to the General specifications section at the front of your service manual for the engine firing order.

 

Engines With Four-Valve Cylinder Heads

Valve Clearance Adjustment (Cold Engine)

 

  1. Remove the loose dirt from the valve rocker cover(s) and remove the cover(s). Discard the gasket(s).
  2. Place the governor speed control lever in the idle speed position. If a stop lever is provided, secure it in the stop position.
  3. Rotate the crankshaft manually  or with the starting motor, until the injector follower is fully depressed on the particular cylinder to be adjusted. 

 

    • NOTICE: The hex head of the crankshaft bolt may be used to bar, or turn, the crankshaft. However, the barring operation should always be performed in a clockwise direction. It is very important to make certain that the bolt has not been loosened during the barring operation. Otherwise serious engine damage may result if the vibration damper or pulley is not securely fastened to the crankshaft. 
    • NOTICE: Barring a left-hand rotating marine engine equipped with a Jabsco raw water pump may result in damage to the rubber impeller if the impeller vanes are forced to rotate against their normal direction of deflection. To avoid damage, detach the cover and remove the impeller before barring the engine. Mark the front of the impeller for easy reinstallation.  

 

  • CAUTION: To reduce risk of personal injury when barring over or “bumping” the starter , personnel  should keep their hands and clothing away from the engine as there is a remote possibility the engine could start. 

 

  1. Loosen the exhaust valve rocker arm push rod locknut. 
  2. Place a 0.026” feeler gage (J 9708-01) between the end of one exhaust valve stem and the rocker arm bridge. Adjust the push rod to obtain a smooth pull on the feeler gage. 
  3. Remove the feeler gage. Hold the push rod with a 5/16” wrench and tighten the locknut with a ½” wrench. 
  4. Recheck the clearance. At this time, if the adjustment is correct , the 0.025” feeler gage will pass freely between the end of one valve stem and the rocker arm bridge but the 0.027” feeler gage will not pass through. Readjust the push rod, if necessary.
  5. Adjust and check the remaining exhaust valves in the same manner as above. 

 

Valve Clearance Adjustment (Hot Engine)

 

It is not necessary to make a final hot engine exhaust valve clearance adjustment after a cold engine adjustment has been performed. However, if a hot engine adjustment is desired, use the following procedures. 

 

Maintaining normal engine operating temperature is particularly important when making the final exhaust valve clearance adjustment. If the engine is allowed to cool  before setting any of the valves, the clearance, when running at full load, may become insufficient.

 

NOTICE: Since the adjustments are normally made while the engine is stopped, it may be necessary to run the engine between adjustments to maintain normal operating temperature. 

 

  1. With the engine at normal operating temperatures, set and exhaust valve clearance with feeler gage J9708-01.  At this time, if the valve clearance is correct, the 0.023” gage will pass freely between the end of one valve stem and the rocker arm bridge, but the 0.025” feeler gage will not pass through. Readjust the push rod, if necessary.
  2. After the exhaust valve clearance has been adjusted, check the fuel injector timing.

 

Check Exhaust Valve Clearance Adjustment

 

  1. With the engine 100 degrees fahrenheit (38 degrees celsius) or less, check the valve clearance. 
  2. If a 0.026” feeler valve (c.006”) will pass between the valve stem and the rocker arm bridge, the valve clearance is satisfactory. If necessary, adjust the push rod.

 

Fuel Injector Timing For Detroit Diesel Series 53 Engines

 

To time an injector properly, the injector follower must be adjusted to a definitie height in relation to the injector body. 

 

All of the injectors can be timed in firing order sequence during one full revolution of the crankshaft. 

 

Refer to the General Specifications section of your service manual to see the engine firing order.

 

Time Fuel Injector

 

After the exhaust valve clearance has been adjusted, time the fuel injectors as follows. 

 

  1. Place the governor speed control lever in the idle speed position. If a stop lever is provided,secure it in the stop position.
  2. Rotate the crankshaft manually or with the starting motor , until the exhaust valves are fully depressed on the particular cylinder to be timed. 

 

    • NOTICE: The hex head of the crankshaft bolt may be used to bar, or turn, the crankshaft. However, the barring operation should always be performed in a clockwise direction. It is very important to make certain that the bolt has not been loosened during the barring operation. Otherwise serious engine damage may result if the vibration damper or pulley is not securely fastened to the crankshaft. 
    • NOTICE: Barring a left-hand rotating marine engine equipped with a Jabsco raw water pump may result in damage to the rubber impeller if the impeller vanes are forced to rotate against their normal direction of deflection. To avoid damage, detach the cover and remove the impeller before barring the engine. Mark the front of the impeller for easy reinstallation.  

 

  • CAUTION: To reduce risk of personal injury when barring over or “bumping” the starter , personnel  should keep their hands and clothing away from the engine as there is a remote possibility the engine could start. 

 

  1. Place the small end of the injector timing gage in the hole provided in the top of the injector body with the flat of the gage toward the injector follower.  Refer to the engine option label for the correct timing dimension. 
  2. Loosen the injector rocker arm push rod lock nut.
  3. Turn the push rod and adjust the injector rocker arm until the extended part of the gage will just pass over the top of the injector follower. 
  4. Hold the push rod and tighten the lock nut. Check the adjustment and, if necessary, readjust the push rod. 
  5. Time the remaining injectors in the same manner as outlined above. 
  6. If no further engine tune-up is required, install the valve rocker cover, using a new gasket. 

 

Variable Speed Mechanical Governor (Open Linkage) And Injector Rack Control Adjustment

 

Inline Engines

 

After adjusting the exhaust valves and timing the fuel injectors adjust the governor and the injector rack control levers. 

 

Before proceeding with the governor and injector rack adjustments disconnect any supplementary governing device. On turbocharged engines, the fuel (air box) modulator level and roller assembly must be positioned free from cam contact. After the adjustments are completed reconnect and adjust the supplementary governing devices. 

 

Preliminary Governor Adjustments

 

  1. Clean the governor linkage and lubricate the ball joints and bearing surfaces with clean oil.
  2. Back out the buffer screw until it projects 9/16” from the boss on the control housing.
  3. Back out the booster spring eyebolt until it is flush with the outer locknut. 

 

Adjust Variable Speed Spring Tension

 

  1. Adjust the variable speed spring eyebolt until ⅛” of the threads project from the outer locknut. This setting of the eyebolt will produce approximately 7% drop in engine speed from no load to full load.
  2. Tighten both locknuts to retain the adjustment. 

 

Position Injector Rack Levers

 

 The position of the injector control racks must be correctly set in relation to the governor. Their position determines the amount of fuel injected into each cylinder and ensures equal distribution of the load. Adjust the rear injector rack control lever first to establish a guide for adjusting the remaining levers. 

 

  1. Clean and remove the valve rocker cover. Discard the gasket.
  2. Disconnect the fuel rod  at the stopper level.
  3. Loosen all of the injector rack control lever adjusting screws. Be sure all of the injector rack control levers are free on the injector control tube.
  4. Move the speed control lever to the maximum speed position.
  5. Move the rear injector control rack into the full-fuel position and note that the clearance between the fuel rod and the cylinder head bolt. The clearance should be 1/32” or more. If necessary, readjust the injector rack adjusting screws until a clearance of at least 1/32” to 1/16” exists. Tighten the adjustment screws or screw and locknut. 
  6. Loosen the nut which locks the ball joint on the fuel rod. Hold the fuel rod in the full-fuel position and adjust the ball joint until it is aligned and will slide on the ball stud on the stop lever. Position the shutdown cable clip and tighten the fuel rod locknut to retain the adjustment.
  7. Check the adjustment by pushing the fuel rod toward the engine and make sure the injector control rack is in the full-fuel position. If necessary, readjust the fuel rod. On units having the governor on the opposite side of the control rack, be sure the control rack lever will not contact the rocker cover. 
  8. Manually, hold the rear injector rack in the full-fuel position, with the lever on the injector control tube. Turn the adjusting screw of the adjacent injector rack control lever until the injector rack moves into the full-fuel position.

 

On the Two Screw Assembly, turn the outer adjusting screw down until it bottoms out lightly on the injector control tube. Then, alternately tighten both the inner and outer adjusting screws. On the One Screw and Locknut Assembly, turn the adjusting screw until a slight roll-up on the injector rack clevis is observed or an increase in effort to turn the screwdriver is noted, then securely lock the adjusting screw locknut.

 

NOTICE: Overtightening of the injector rack control lever adjusting screws during installation or adjustment can result in damage to the injector control tube. The recommended torque of the adjusting screws is 24-36 Lb-in (3-4 N*m).

 

9) Recheck the rear injector rack to be sure that it has remained snug on the ball end of the rack control lever while adjusting the adjacent injector rack. If the rack of the rear injector has become loose, back off the adjusting screw slightly on the adjacent injector rack control lever. When the settings are correct, the racks of all injectors must be snug on the ball end of their respective control levers.

 

10) Position the remaining injector rack control levers as outlined in steps 8 and 9.

 

CAUTION: Before starting an engine after an engine speed control adjustment or after removal of the engine governor cover and lever assembly, the service technician must determine that the injector racks move to the no-fuel position when the governor stop lever is placed in the stop position. Engine overspeed will result if the injector racks cannot be positioned at no fuel with governor stop lever. An overspeeding engine can result in engine damage which could cause personal injury. 

 

Adjust Maximum No-Load Speed

 

  1. With the engine running, move the speed control lever to the maximum speed position. Use an accurate tachometer to determine the no-load speed of the engine. Do not overspeed the engine. 
  2.  Loosen the locknut and adjust the maximum speed adjusting screw until the required no load speed is obtained. 
  3. Hold the adjusting screw and tighten the lock nut.

 

Adjust Engine Idle Speed

 

  1. Make sure the stop lever is in the run position and place the speed control lever in the idle position. 
  2. With the engine running at normal operating temperature, loosen the locknut and turn the idle speed adjusting screw until the engine idles at the recommended speed. THe recommended idle speed is 500 rpm. However, the idle speed may vary with typical engine applications. 
  3. Hold the idle speed adjusting screw and tighten the locknut. 

 

Adjust Buffer Screw

 

  1. With the engine running at idle speed, turn the buffer screw in so that it contacts the stop lever as lightly as possible and still eliminates engine roll. Do not raise the engine idle speed more than 20 rpm with the buffer screw.
  2. Check the maximum no-load speed to make sure it has not increased over 25 rpm by the buffer screw setting.

 

Adjust Governor Booster Spring

 

The governor booster spring is used on some engines to reduce the force necessary to move the speed control lever from the idle position to the maximum speed position. Adjust the booster spring as follows:

 

  1. Move the speed control lever to the idle speed position.
  2. Reduce the tension on the boost spring, if not previously reduced, to the minimum by backing off the outer locknut until the end of the booster spring eyebolt is flush with the end of the nut.
  3. Adjust the eyebolt in the slot in the bracket so an imaginary line through the booster spring will align with an imaginary center line through the speed control shaft. Secure the locknuts on the eyebolt to retain the adjustment.
  4. Move the speed control lever to the maximum speed position and note the force required. To reduce the force, back off the inner locknut and tighten the outer locknut to increase the tension on the booster spring. Before tightening the locknuts, reposition  the booster storing as in Step 3. 

 

The setting is correct when the speed control lever can be moved from the idle speed position to the maximum speed position with a constant force, while the engine is running and when released it will return to the idle speed position.

 

Adjust Engine Speed Droop

 

The adjustment of the spring tension as outlined under Adjust Variable Speed Spring Tension will result in approximately 7% droop from the maximum no load speed to full-load speed. This is the optimum droop setting for most applications. However, the droop may be changed as necessary, for a particular engine application. 

 

  1. Lower the speed droop by increasing the spring tension.
  2. Raise the speed droop by decreasing the spring tension.

A change in the variable speed spring tension will change the engine idle speed and maximum no-load speed which must be readjusted.  

 

Variable Speed Mechanical Governor (Enclosed Linkage) And Injector Rack Control Adjustment

Inline Engines

After adjusting the exhaust valves and timing the fuel injectors, adjust the governor and position the injector rack control levers.

 

Before proceeding with the governor and injector rack adjustments, disconnect any supplementary governing device. On turbocharged engines, the fuel (air box) modulator lever and roller assembly must be positioned free from cam contact.

Adjusting Governor Gap

 

With the engine stopped at operating temperature, adjust the governor gap as follows. 

 

  1. Disconnect any linkage attached to the governor levers. 
  2. Back out the buffer screw until it extends approximately ⅝” from the locknut.
  3. Clean and remove the governor cover and valve rocker cover. Discard the gaskets.
  4. Place the speed control lever in the maximum speed position.
  5. Insert a 0.006” feeler gage between the spring plunger and the plunger guide. If required, loosen the locknut and turn the gap adjusting screw in or out until a slight drag is noted in the feeler gage.
  6. Hold the adjusting screw and tighten the locknut. Check the gap and readjust, if necessary. 
  7. Use a new gasket and reinstall the governor cover as follows:
  1. Place the cover on the governor housing, with the pin in the throttle shaft assembly by entering the slot in the differential lever. 
  2. Install the four cover screws and lock washers finger tight. 
  3. Pull the cover assembly in a direction away from the engine, to take up the slack, and tighten the cover screws. This step is required since no dowels are used to locate the cover on the housing.

 

Position Injector Rack Control Levers

 

The position of the injector control rack levers must be correctly set in relation to the governor. Their position determines the amount of fuel injected into each cylinder and ensures equal distribution of the load. 

 

Properly positioned injector control rack leveers with the engine at full load will result in the following:

 

  1. Speed control lever at the maximum speed position.
  2. Stop lever in the run position. 
  3. Injector fuel control racks in the full-fuel position.

 

Adjust the rear injector rack control lever first to establish a guide for adjusting the remaining levers. 

 

  1. Loosen all of the inner and outer injector rack control lever adjusting screws or the adjusting screws and locknuts. Be sure all of the levers are free on the injector control tube. 
  2. Move the speed control lever to the maximum speed position. 
  3. Move the stop lever to the run position and hold it in that position with light finger pressure.

Two Screw Assembly

  1. Turn the inner adjusting screw of the rear injector rack control lever down until a slight movement of the control tube is observed or a step-up in effort to turn the screwdriver is noted. This will place the rear injector rack in the full -fuel position. 
  2. Turn the outer adjusting screw down until it bottoms lightly on the injector control tube.
  3. Then alternatively tighten both the inner and outer adjusting screws. 

 

One Screw And Locknut Assembly

 

  1. Tighten the adjusting screw of the rear injector rack control lever until the injector rack clevis is observed to roll up or an increase in effort to turn the screwdriver is noted. 
  2. Tighten the screw approximately ⅛ of a turn more and lock securely with the adjusting screw locknut. This will place the rear injector rack in the full fuel position.

 

         This should result in placing the governor linkage and the control tube in the respective positions that they will attain while the engine is running at full load. 

 

NOTICE: Overtightening of the injector rack control lever adjusting screws during installation or adjustments can result in damage to the injector control tube. The recommended torque of the adjusting screws is 24-36 lb-in (3-4N*m).

 

4) To be sure of proper rack adjustment, hold the stop lever in the run position and press down on the injector rack with a screwdriver or finger tip and note “rotating” movement of the injector control rack. Hold the stop lever in the run position and using a screwdriver, press downward on the injector control rack. The rack should tilt downward and , when the pressure of the screwdriver is released the control rack should “spring” back upwards. 

 

If the rack does not return to its original position it is too loose. To correct this condition with the Two Screw Assembly, back off the outer adjusting screw slightly and tighten the inner adjusting screw. To correct this condition with the One Screw and Locknut Assembly, loosen the locknut and turn the adjusting screw clockwise a slight amount and retighten the locknut.

 

The setting is too tight if, when moving the stop lever from the stop to the run position, the injector rack becomes tight before the stop lever reaches the end of its travel. This will result in a step-up in effort required to move the stop lever to the run position and a deflection in the fuel rod (ruel rod deflection can be seen at the bend).

 

If the rack is found to be too tight with the Two Screw Assembly, back off the inner adjusting screw slightly and tighten the outer adjusting screw. To correct this condition with the One Screw And Locknut Assembly, loosen the locknut and turn the adjusting screw counterclockwise a slight amount and retighten the locknut. 

 

5) Manually hold the rear injector control rack in the full-fuel position with lever on the injector control tube and proceed as follows. 

 

Two Screw Assembly

 

  1. Turn down the inner adjusting screw on the injector rack control lever of the adjacent injector until the injector rack has moved into the full-fuel position and the inner adjusting screw is bottomed on the injector control tube. 
  2. Turn the outer adjusting screw down until it bottoms lightly on the injector control tube. 
  3. Then alternately tighten both the inner and outer adjusting screws. 

 

One Screw And Locknut Assembly

 

  1. Tighten the adjusting screw of the adjacent injector rack control lever until the injector rack clevis is observed to roll up or an increase in effort to turn the screwdriver is noted.
  2. Securely lock the adjusting screw locknut

 

NOTICE: Overtightening the injector rack control tube lever adjusting screws during installation or adjustment can result in damage to the injector control tube. The recommended torque of the adjusting screws is 24-36 lb-in (3-4N*m)

 

6) Recheck the rear injector rack to be sure that it has remained snug on the ball end of the rack control lever while adjusting the adjacent injector rack. If the rack of the rear injector has become loose with the Two Screw Assembly back off the inner adjusting screw slightly on the adjacent injector rack control lever and tighten the outer adjusting screw. With the One Screw and Locknut Assembly, turn the adjusting screw counterclockwise slightly until the rear injector rack returns to its full-fuel position and secure the adjusting screw locknut. 

 

When the settings are correct, the racks of both injectors must be snug on the ball end of their respective control levers.

 

7) Position the remaining injector rack control levers as outlined in Steps 4,5,and 6.

 

8) When all of the injector rack control levers are adjusted, recheck their settings. With the control tube lever in the full-fuel position, check each control rack as in Step 4. All of the control racks must have the same “spring” condition with the control tube lever in the full-fuel position.

 

9) Insert the clevis pin in the fuel rod and the injector control tube levers.

 

CAUTION: Before starting an engine after an engine speed control adjustment or after removal of the engine governor cover and lever assembly, the service technician must determine that the injector racks move to the no-fuel position when the governor stop lever is placed in the stop position. Engine overspeed will result if the injector racks cannot be positioned at no fuel with governor stop lever. An overspeeding engine can result in engine damage which could cause personal injury. 

 

10) Use a new gasket and reinstall the valve rocker cover.

 

Adjusting Maximum No-Load Speed

 

All governors are properly adjusted before leaving the factory. However if a governor has been reconditioned or replaced , and to ensure the engine speed will not exceed the recommended no-load speed as given on the option plate, the maximum no-load speed may be set as follows:

 

  1. Disconnect the booster spring and the stop lever retracting spring.
  2. Remove the two attaching bolts and withdraw the variable speed spring housing and the variable speed spring retainer located inside of the housing. 

 

Full Load Speed RPM STOPS Shims
Solid Ring Split Ring
2575-2800 0 0 As Required
2101-2575 1 0 As Required
1701-2100 1 1 As Required
1200-1700 1 2 As Required

 

Table 1

 

  1. Refer to Table 1 and determine the stops or shims required for the desired full-load speed. Do not use any more than four thick and one thin shim. A split stop can only be used witha stolid stop. 
  2. Install the variable speed spring retainer and housing and tighten the two bolts.
  3. Connect the booster spring and stop lever spring. Start the engine and recheck the maximum no load speed. 
  4. If required, add shims to obtain the necessary operating speed. For each 0.001” in shims added, the operating speed will increase approximately 2 rpm. 

 

                If the maximum no-load speed is raised or lowered more than 50 rpm by installation or removal of shims recheck the governor gap. If readjustment of the governor gap is required, the position of the injetor racks must be rechecked. Governor stops are used to limit the compression of the governor spring which determines the maximum speed of the engine.

 

Adjust Idle Speed

 

With the maximum no-load speed properly set, adjust the idle speed as follows: 

 

  1. Place the stop lever in the run position and the speed control lever in the idle position.
  2. With the engine running at normal operating temperature back out the buffer screw to avoid contact with the differential lever.
  3. Loosen the locknut and turn the idle speed adjusting screw until the engine is operating at approximately 15 rpm below the recommended idle speed. The recommended idle speed is 550rpm but may vary with special engine applications.
  4. Hold the idle speed adjusting screw and tighten the locknut. 

 

Adjust Buffer Screw

 

  1. With the engine running at normal operating temperature, turn the buffer screw so that it contacts the differential lever as lightly as possible and still eliminates engine roll. Do not increase the engine idle speed more than 15rpm with the buffer screw.

 

  1. Hold the buffer screw and tighten the locknut.

 

Adjust Booster Spring

 

With the engine idle speed set, adjust the booster spring as follows: 

 

  1. Move the speed control lever to the idle position.
  2. Loosen the booster spring retaining nut on the speed control lever. Loosen the locknuts on the eyebolt at the opposite end of the spring. 
  3. Move the spring retaining bolt in the slot of the speed control lever until the center of the bolt is on or slightly over center (toward the idle speed position) of an imaginary line through the bolt, lever shaft and eyebolt. Hold the bold and tighten the locknut. 
  4. Start the engine and move the speed control lever to the maximum speed position and release it. The lever should return to the idle speed position. If it does not, reduce the booster spring tension. If it does, continue to increase the spring tension until the point is reached where it will not return to idle. Then reduce the spring tension until the lever does return to idle and tighten the locknuts on the eyebolt. This setting will result in the minimum force required to operate the speed control lever. 
  5. Connect the linkage to the governor levers. 

 

If the engine is equipped with a supplementary governing device, adjust it at this time.

 

Variable Speed Mechanical Governor Injector Rack Control Adjustment

 

6V-53 Engines

 

The variable speed mechanical governor assembly is mounted at the rear of the 6V engine, between the flywheel housing and the blower. The Governor is driven by the right-hand blower rotor drive gear.

 

After adjusting the exhaust valves and timing the fuel injectors, adjust the governor and injector rack control levers. 

 

NOTICE: Before proceeding with the governor and injector rack adjustments, disconnect any supplementary governing device. After the adjustments are completed, reconnect and adjust the supplementary governing device.

 

Adjust Governor Gap

 

With the engine stopped and at normal operating temperature, adjust the governor gap as follows. 

 

  1. Disconnect any linkage attached to the governor levers. 
  2. Back out the buffer screw until it extends approximately ⅝” from the lock nut.
  3. Clean and remove the governor cover and the valve rocker covers. Discard the gaskets.
  4. Place the speed control lever in the maximum speed position. 
  5. Insert a 0.006” feeler gage between the spring plunger and the plunger guide. If required loosen the lock nut and turn the adjusting screw in or out until a slight drag is noted on the feeler gage.
  6. Hold the adjusting screw and tighten the lock nut. Check the gap and readjust if necessary. 
  7. Use a new gasket and install the governor cover. 

 

Position Injector Rack Control Levers

 

The position of the injector control racks must be correctly set in relation to the governor. Their position determines the amount of fuel injected into each cylinder and ensures equal distribution of the load. 

 

Current engines use spring-loaded injector control tube assemblies which have a yield spring at each injector rack control lever and only one screw and lock nut to keep each injector rack properly positioned. Adjust the single screw and lock nut on each injector rack control lever the same as for the two screw rack control lever. 

 

Properly positioned injector rack control levers with the engine at full load will result in the following: 

 

  1. Speed control lever at the maximum speed position. 
  2. Stop lever in the RUN position.
  3. Injector fuel control racks in the full-fuel position.

 

The letters R or L indicate the injector location in the right or left cylinder bank as viewed from the rear of the engine. Cylinders are numbered starting at the front of the engine on each cylinder bank. Adjust the No 3L injector rack control lever first to establish a guide for adjusting the remaining levers. 

  1. Remove the clevis pin from the fuel rod and the right cylinder bank injector control tube lever. 
  2. Loosen all of the inner and outer injector rack control lever adjusting screws on both injector control tubes. Be sure all of the injector rack control levers are free on the injector control tubes. 
  3. Move the speed control lever to maximum speed position.
  4. Move the stop lever to the run position and hold it in that position with light finger pressure. Turn the inner adjusting screw of the No 3L injector rack control lever down until a slight movement of the control tube is observed, or a step up in effort to turn the screw driver is noted. This will place the No 3L injector rack in the full-fuel position. Turn the outer adjusting screw down until it bottoms lightly on the injector control tube. Then alternately tighten both the inner and outer adjusting screws. 

 

NOTICE: Overtightening of the injector rack control lever adjusting screws during installation or adjustments can result in damage to the injector control tube. The recommended torque of the adjusting screws is 24-36Lbs (3-4N*m)

 

The above steps should result in placing the governor linkage and control tube in the respective position that they will attain while the engine is running at full load. 

 

  1. To be sure of proper rack adjustment, hold the stop lever in the run position and press down on the injector rack with a screwdriver or finger tip and note the “rotating” movement of the injector control rack.

 

Hold the stop lever in the run position and, using a screwdriver, press downward on the injector control rack. The rack should tilt downward and when the pressure of the screwdriver is released, the control rack should “spring” back upward. 

 

If the rack does not return to its original position, it is too loose. To correct this condition back off the outer adjusting screw slightly and tighten the inner adjusting screw. The setting is too tight if, when moving the stop lever from the stop to the run position, the injector rack becomes tight before the governor stop lever reaches the end of its travel. This will result in a step-up in effort required to move the stop lever to the run position and a deflection in the fuel rod (fuel rod deflection can be seen at the bend). If the rack is found to be too tight, back off the inner adjusting screw slightly and tighten the outer adjusting screws. 

 

  1. Remove the clevis pin from the fuel rod and the left bank injector control tube lever. 
  2. Insert the clevis pin the fuel rod and right cylinder bank injector control tube lever and position the No 3R injector rack control lever as previously outlined in Step 4 for the No. 3L control lever. 
  3. Insert the clevis pin in the fuel rod and the left bank control tube lever. Repeat the check on the 3L and 3R injector rack control levers as outlined in Step 7. Check for and eliminate any deflection which may occur at the bend in the fuel rod where it enters the cylinder head.
  4. To adjust the remaining injector rack control levers, remove the clevis pin from the fuel rods and the injector control tube levers, hold the injector control racks in the full-fuel position by means of the lever on the end of the control tube and proceed as follows: 

 

  1. Turn down the inner adjusting screw of the injector rack control lever until the screw bottoms (injector control rack in the full-fuel position).
  2. Turn down the outer adjusting screw of the injector rack control lever until it bottoms on the injector control tube.
  3. While still holding the control tube lever in the full-fuel position, adjust the inner and outer adjusting screws to obtain the same condition as outlined in Step 5. Tighten the screws.

 

Notice: Once the No. 3L and No. 3R injector rack control levers are adjusted, do not try to alter their settings. All adjustments are made on the remaining control racks.

 

10) When all of the injector rack control levers are adjusted, recheck their settings. With the control tube lever in the full-fuel position, check each control rack as in Step 5. All of the control racks must have the same “spring” condition with the control tube lever in the full-fuel position.

 

11) Insert the clevis pin in the fuel rods and the injector control tube levers. 

12) Use new gaskets and install the valve rocker covers.

 

Adjust Maximum No-Load Speed

 

All governors are properly adjusted before leaving the factory. However, if the governor has been reconditioned or replaced, and to ensure the engine speed will not exceed the recommended no load speed as given on the engine option plate, the maximum no load speed may be set as follows. 

Start the engine and after it reaches normal operating temperature, determine the maximum no load speed as given on the engine option plate, the maximum no load speed may be set as follows. 

 

Start the engine and after it reaches normal operating temperature, determine the maximum no-load speed  as given on the engine option plate, the maximum no load speed may be set as follows: 

 

Start the engine and after it reaches normal operating temperature, determine the maximum no load speed of the engine with an accurate tachometer. Then stop the engine and make the following adjustments if required: 

 

  1. Disconnect the booster spring and the stop lever retracting spring.
  2. Remove the variable speed spring housing and the spring retainer, located inside of the housing from the governor housing. 
  3. Refer to the table below to determine the stops or shims required for the desired full load speed. A split stop can only be sued with a solid stop. 

 

Table 2

Full Load Speed Stops Shims *
Solid Split
1200-2100 1 1 As Required
2100-2500 1 0 As Required
2500-2800 0 0 As Required

 

*Maximum amount of shims .325”

 

  1. Install the variable speed spring retainer and housing and tighten the bolts. 
  2. Connect the booster spring and the stop lever spring. Start the engine and recheck the maximum no-load speed. 
  3. If required add shims to attain the necessary operating speed. For each 0.001” in shims added, the operating speed will increase approximately 2 rpm.

 

If the maximum no-load speed is raised or lowered more than 50 rpm by the installation or removal of shims recheck the governor gap. If the readjustment of the governor gap is required, the position of the injector racks must be rechecked. 

 

Governor stops are used to limit the compression of the governor spring, which determines the maximum speed of the engine.

 

Adjust Idle Speed

 

With the maximum no-load speed properly adjusted, adjust the idle speed as follows:

 

  1. Place the stop lever in the run position and the speed control lever in the idle position. 
  2. With the engine running at normal operating temperature, back out the buffer screw to avoid contact with the differential lever.
  3. Loosen the lock nut and turn the idle speed adjusting screw until the engine is operating at approximately 15 rpm below the recommended idle speed. The recommended idle speed is 550 rpm, but may vary with special engine applications.
  4. Hold the idle speed adjusting screw and tighten the lock nut. 

 

Adjust Buffer Screw

 

With the engine idle speed properly set, adjust the buffer screw as follows.

 

  1. With the engine running at normal operating temperature, turn the buffer screw in so that it contacts the differential lever as lightly as possible and still eliminates engine roll. Do not raise the engine idle speed more than 15 rpm with the buffer screw.
  2. Hold the buffer screw and tighten the lock nut. 

 

Adjust Booster Spring

 

With the idle speed set, adjust the booster spring as follows:

 

  1. Move the speed control lever to the idle speed position.
  2. Loosen the booster spring retaining nut on the speed control lever. Loosen the lock nuts on the eye bolt at the opposite end of the booster spring.
  3. Move the spring retaining bolt in the slot of the speed control lever until the center of the bolt is on or slightly over center (toward the idle speed position) of an imaginary line through the center of the bolt, lever shaft, and eye bolt. Hold the bolt and tighten the lock nut. 
  4. Start the engine and move the speed control lever to the maximum speed position and release it. The speed control lever should return to the idle position. If it does not, reduce the tension on the booster spring. If the lever does not return to the idle position, continue to increase the spring tension until the point is reached that it will not return to idle. Then reduce the tension until it does return to idle and tighten the lock nut on the eye bolt. This setting will result in the minimum force required to operate the speed control lever. 
  5. Connect the linkage to the governor levers.

 

8V53 Engines

 

The variable speed mechanical governor assembly is mounted at the front end of the 8V engine. After adjusting the exhaust valves and timing the fuel injectors, adjust the governor and the injector rack control levers. 

 

Before proceeding with the governor and the injector rack adjustments, disconnect any supplementary governing device. After the adjustments are completed, reconnect and adjust the supplementary governing device. 

 

Adjust Governor Gap

 

With the engine stopped and at normal operating temperature, adjust the governor gap as follows: 

 

  1. Disconnect any linkage attached to the governor levers. 
  2. Back out the buffer screw until it extends approximately ⅝” from the lock nut.
  3. Clean and remove the governor cover and the valve rocker covers. Discard the gaskets. 
  4. Place the speed control lever in the maximum speed position.
  5. Insert a 0.006” feeler gage between the spring plunger, and the plunger guide. If required, loosen the lock nut and turn the adjusting screw in or out until a slight drag is noted on the feeler gage. 
  6. 6) Hold the adjusting screw and tighten the lock nut. Check the gap and readjust if necessary. 
  7. Use a new gasket and install the governor cover.

 

Position Injector Rack Control Levers

 

The position of the injector control racks must be correctly set in relation to the governor. Their position determines the amount of fuel injected into each cylinder and ensures equal distribution of the load.

 

Properly positioned injector rack control levers with the engine at full load will result in the following. 

 

  1. Speed control lever at the maximum speed position.
  2. Stop lever in the RUN position. 
  3. Injector fuel control racks in the full-fuel position.

 

The letters R or L indicate the injector location in the right or left cylinder bank as viewed from the rear of the engine. Cylinders are numbered starting at the front of the engine on each cylinder bank. Adjust the No. 1L injector rack control lever first to establish a guide for adjusting the remaining levers. 

 

  1. Remove the clevis pin from the fuel rod and the right cylinder bank injector control tube. 
  2. Loosen all of the inner and outer injector rack control lever adjusting screws on both injector control tubes. Be sure all of the injector rack control levers are free on the injector control tubes.
  3. Move the speed control lever to the maximum speed position.
  4. Move the stop lever to the run position and hold it in that position with light finger pressure. Turn the inner adjusting screw of the No 1L injector rack control lever down until a slight movement of the control tube is observed, or a step up in effort to turn the screwdriver is noted. This will place the No 1L injector rack in the full-fuel position. Turn the outer adjusting screw down until it bottoms lightly on the injector control tube. Then alternately tighten both the inner and outer adjusting screws. 

 

NOTICE: Overtightening of the injector rack control lever adjusting screws during the installation or adjustments can result in damage to the injector control tube. The recommended torque of the adjusting screws is 24-36 lb-in (3-4N*m). 

 

The above steps should result in placing the governor linkage and control tube in the respective position that they will attain while the engine is running at full load. 

 

  1. To be sure of proper adjustment, hold the stop lever in run position and press down on the injector rack with a screwdriver or finger tip and now that the “rotating” movement of the injector control rack. Hold the stop lever in the run position and, using a screwdriver, press downward on the injector control rack. The rack should tilt downward and when the pressure of the screwdriver is released, control should “spring” back upward.

 

If the rack does not return to its original position, it is too loose. To correct this condition, back off the outer adjusting screw slightly and tighten the inner adjusting screw. The setting is too tight if, when moving the stop lever from the stop to the run position, the injector rack becomes tight before the governor stop lever reaches the end of its travel. This will result in a step-up in effort required to move the stop level to the run position and a deflection in the fuel rod (fuel rod deflection can be seen at the bend) If the rack is found to be too tight, back off the inner adjusting screw slightly and tighten the outer adjusting screws.

 

  1. Remove the clevis pin from the fuel rod and the left bank injector control tube lever. 
  2. Insert the clevis pin in the fuel rod and the right cylinder injector control tube lever and position the No. 1 R injector rack control lever as previously outlined in Step 4 for the No 1L control level.
  3. Insert the clevis pin in the fuel rod and the left bank injector control tube lever. Repeat the check on the 1L and 1R injector rack control levers as outlined in Step 5. Check for and eliminate any deflection which may occur at the bend in the fuel rod where it enters the cylinder head.
  4. Manually hold the No. 1L injector rack in the full-fuel position, with the lever on the injector control tube, and turn the inner adjusting screw of the No. 2L injector rack control lever down until the No. 2L injector rack moves into the full-fuel position. Turn the outer adjusting screw down until it bottoms lightly on the injector control tube. Then alternatively tighten both the inner and outer adjusting screws. 
  5. Recheck the No. 1L injector rack to be sure that it has remained snug on the ball end of the rack control lever while positioning the No. 2L injector rack. If the rack of the No 1L injector has become loose, back off the inner adjusting screw slightly on the No. 2L injector rack control lever and tighten the outer adjusting screw. When the settings are correct, the rack of each injector must be snug on the ball end of its respective control lever. 
  6. Position the No. 3L and No. 4L injector rack control levers as outlined in Steps 9 & 10.
  7. Position the No 2R 3R and 4R injector rack control levers as outlined for the left cylinder bank in Steps 9 through 11.
  8. Use new gaskets and install the valve rocker covers.

 

Adjust Maximum No-Load Speed

 

All governors are properly adjusted before leaving the factory. However, if the governor has been reconditioned or replaced, and to ensure the engine speed will not exceed recommended no-load speed as given on the engine option plate, the maximum no-load speed may be set as follows:

 

NOTICE: The maximum no-load speed must not exceed 150 rpm above the full-load speed.

 

Start the engine and after it reaches normal operating temperature, determine the maximum no-load speed of the engine with an accurate tachometer. Then stop the engine an make the following adjustments if required:

 

  1. Disconnect the booster spring and the stop lever retracting spring.
  2. Remove the variable spring housing and the spring retainer, located inside the housing, from the governor housing.
  3. Refer to Table 2 and determine the stops and shims required for the desired full-load speed. A split stop can only be used with a solid stop.
  4. Install the variable speed spring retainer and housing and tighten the two bolts.
  5. Connect the booster spring and stop lever spring. Start the engine and recheck the maximum no-load speed. 
  6. If required add shims to obtain the necessary operating speed. For each 0.001” in shims added, the operating speed will increase 2rpm. 

 

If the maximum no-load speed is raised or lowered more than 50 rpm by the installation or removal of shims, recheck the governor gap. If readjustments of the governor gap is required, the position of the injector racks must be rechecked.

 

Governor stops are used to limit the compression of the governor spring which determines the maximum speed of the engine.

 

Adjust Idle Speed

 

With the maximum no-load speed properly set, adjust the idle speed as follows: 

 

  1. Place the stop lever in the run position and the speed control lever in the idle position.
  2. With the engine running at normal operating temperature, back out the buffer screw to avoid contact with the differential lever.
  3. Loosen the lock nut and turn the idle speed adjusting screw in or out until the engine idles at 600 rpm.
  4. Hold the idle speed adjusting screw and tighten the lock nut.

 

Adjust Buffer Screw

 

With the engine idle speed properly set adjust the buffer screw as follows:

 

  1. With the engine running at normal operating temperature, turn the buffer screw in so that it contacts the differential lever as lightly as possible and still eliminates engine roll. Do not raise the engine idle speed more than 15 rpm with the buffer screw. 
  2. Hold the buffer screw and tighten the lock nut.

 

Adjust Booster Spring

 

With the engine idle speed set, adjust the booster spring as follows:

 

  1. Move the speed control lever to the idle position.
  2. Loosen the booster spring retaining nut on the speed control lever. Loosen the lock nuts on the eye bolt at the other end of the spring.
  3. Move the spring retaining bolt in the slot of the speed control lever until the center of the bolt is on or slightly over the center (toward the idle speed position) of an imaginary line through the center of the bolt, lever shaft and eye bolt. Hold the bolt and tighten the lock nut.
  4. Start the engine and move the speed control lever to the maximum speed position and release it. The speed control lever should return to the idle position. If it does not , reduce the tension on the booster spring. If the lever does return to the idle position, continue to increase the spring tension until the point is reached that it will not return to idle. Then reduce the tension until it does return to idle and tighten the lock nut on the eye bolt. This setting will result in the minimum force required to operate the speed control lever. 
  5. Connect the linkage to the governor levers.

 

 

No patent liability is assumed with respect to the use of information contained in this blog post. While every precaution has been taken in preparation of this blog post, the author assumes no responsibility for errors and omissions. Neither is any liability assumed for damages resulting from the use of the information contained in this blog post. 

 

All instructions, diagrams, videos have been checked for accuracy and ease of application; however success and safety in working with tools depend to a great extent upon individual accuracy, skill, and caution.  For this reason, the authors are not able to guarantee the result of any procedure contained in this blog post. Nor can they assume responsibility for any damages to property or injury to persons occasioned from the procedures. Persons engaging in the procedures do so entirely at their own risk.

 

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