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catmastertech
catmastertech, Technician
Category: Heavy Equipment
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Experience:  19 years Cat, 3 years Case
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What is the torque specs for CAT C12 Egine head bolts and rocker

Resolved Question:

What is the torque specs for CAT C12 Egine head bolts and rocker arms and compression brake?
Submitted: 6 years ago.
Category: Heavy Equipment
Expert:  catmastertech replied 6 years ago.

Donnie :

What is your serial number?

Customer:

9NS19741

Donnie :

Ok, give me a minute to find the spec's.

Customer:

Thanks

Donnie :

Cylinder Head

Donnie :

Valve Mechanism

Donnie :

Does that cover what you need?

Donnie :

Use the following adjusting instructions for the electronic unit injector:



     


  1. Loosen the hex thin nut .


     


  1. Turn the rocker arm adjustment screw clockwise. Stop turning the rocker arm adjustment screw when contact is made with the electronic unit injector.


     


  1. Turn the rocker arm adjustment screw in the clockwise direction for additional 180 degrees (1/2 of a turn).


     


  1. Hold the rocker arm adjustment screw in this position.


     


  1. Torque the hex thin nut (2) to 55 ± 10 N·m (41 ± 7 lb ft).

Donnie :



























Quick Reference for Engine Valve Lash Setting
C-10 and C-12 Engines
Inlet Valves Exhaust Valves
Valve Lash Setting
0.38 ± 0.08 mm (0.015 ± 0.003 inch)

0.64 ± 0.08 mm (0.025 ± 0.003 inch)
TC Compression Stroke1-2-41-3-5
TC Exhaust Stroke (1)3-5-62-4-6
Firing Order1-5-3-6-2-4 (2)












( 1 ) 360° from TC compression stroke
( 2 ) The No. 1 cylinder is at the front of the engine.

Donnie :
  • To make an adjustment to the unit injectors on cylinders 1, 2, and 4, remove the timing bolt. Turn the flywheel by 360 degrees in the direction of the engine's rotation. The engine rotates in a counterclockwise manner. This will put the number 1 piston at the top center position on the exhaust stroke.
  • Donnie :

    The above sentence is out of place, below is the corrected line.

    Donnie :

    To make an adjustment to the unit injectors on cylinders 3, 5, and 6 use the following procedure:



       


    1. Put the number 1 piston at the top center position on the compression stroke. Refer to Systems Operation/Testing and Adjusting, "Finding Top Center Position For No. 1 Piston".


       


    1. Turn the unit injector adjusting screw (2) clockwise until contact is made with the unit injector.


       


    1. Turn the unit injector adjusting screw through 180 degrees in a clockwise direction.


       


    1. Hold the adjusting screw in this position and tighten the locknut (3) to a torque of 55 ± 10 N·m (41.0 ± 7.0 lb ft).


       


    1. To make an adjustment to the unit injectors on cylinders 1, 2, and 4, remove the timing bolt. Turn the flywheel by 360 degrees in the direction of the engine's rotation. The engine rotates in a counterclockwise manner. This will put the number 1 piston at the top center position on the exhaust stroke.


       


    1. Repeat 2 through 4.


       


    1. Remove the timing bolt from the flywheel after all of the unit injector adjustments have been made. Reinstall the timing cover

    Customer:

    Donnie I think you got me hooked up! You are the man. Is there a way to print transcripts of this chat session?

    Donnie :

    When you close this session, the page will be easier to print.

    Donnie :

    Switch to Q&A if you need it now.

    Customer:

    ok donnie thanks for the help

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