Cummins Engine Repair-Adjusting Valves ISB

1. Valve adjustment on a Cummins Engine Repair is the final step. Engine position is very important because the intake and exhaust valves must be in the closed position.

Rotate the engine clockwise [looking from the front] until #6 cylinder rocker arms are both rocking. When you're on the correct stroke the exhaust valve will be moving into the closed position, then once it closes keep rotating the engine until the intake valve JUST starts to open. You are now on #1 Compression Stroke & ready to adjust 1/2 of the engine valves.

Note: The crossheads pictured here on top of the valve stems [#5 & #6 Cyl] are located with the elongated contact surface towards the exhaust manifold. The Rocker arms are held down on aluminum cradles with one retaining bolt and torqued to 27 ft. lbs.

Cummins 24 Valve Turbo Diesel Valve Adjustment Specs.

With the Engine on #1 Compression Stroke.

*Adjust #1 #2 #4 Intake Valves to .010 inch.

*Adjust #1 #3 #5 Exhaust Valves to .020 inch.

*Rotate Engine One Full Turn. #1 Cylinder Valves will rock like #6 did previously positioning the engine on #6 Compression Stroke.

*Adjust #3 #5 #6 Intake Valves.

*Adjust #2 #4 #6 Exhaust Valves.

It's not hard to adjust valves on a Cummins 24 Valve Turbo Diesel once you get the hang of it. All you have to know is how to position the engine correctly, the valve settings and some basic tools. That's it for now on Cummins Engine Repair.




Recommended: Diesel Engine Repair Manuals

Cummins Engine Repair - Installing Injectors

Cummins Engine Repair
Replace o-ring on the injector body and copper sealing washer on injector tip. Position into head with orifice pointing towards fuel connector tube opening. [click photo to enlarge]





The injector hold down installs only one way to index the injector position aligning it with the fuel connector tube. The hold down retaining bolts are torqued to 89 in. lbs.






Install fuel connector tubes [with new o-ring] into the head bore. The tube has a tapered tip that aligns with injector body. Torquing the fuel line retaining nut forces contact and a proper seal between the injector body and connector tube.





The injector lines are what retains contact between the fuel injector and connector tube. Torque the fuel line nuts to 28 ft. lbs. using a crowfoot wrench.
That's it for this post with more to come on Cummins Engine Repair.





Recommended: Diesel Engine Repair Manuals

Cummins Engine Repair - Torquing Cylinder Head Bolts

Cummins Engine Repair - Torquing Head Bolts on a Cummins 24 valve turbo diesel. The torque pattern is circular starting from the middle and working both ways to each end of the cylinder head.

Torque Specs Are As Follows:

• 59 ft. lbs.
• 77 ft. lbs.
• Check again at 77 ft. lbs.
• Finally advance each head bolt an additional 90 degrees
• Since each flat side of the "hexagonal" bolt head is 60 degrees [60 X 6 sides=360 degrees]
• One flat and 1/2 = 90 degrees.
  

This is the most important step when replacing any engine cylinder head gasket. If the proper torque specs are not followed bolt stretch [over torqued] or coolant leaks [under torqued] will occur and you'll have to start all over again with your Cummins Engine Repair.

Recommended: Diesel Engine Repair Manuals

Cummins Engine Repair - ISB Model

Cummins Engine Repair on a 2002 Thomas Freightliner School Bus. The head gasket was leaking coolant from the right front corner. The first step is to unhook the battery and drain the coolant.
The Turbocharger [pictured] can be removed as a complete assembly attached to the exhaust manifold. The fuel lines are removed from the opposite side.


The Cummins 24 valve turbo diesel has 2 intake valves and 2 exhaust valves for each cylinder. The parts displayed here have been cleaned and inspected for pitting, hard surface wear and corrosion [head bolts]. Head bolts are measured for length, with a special guage provided by Cummins [usually comes with the head gasket kit].


The cylinder head itself weighs approxiamately 80 lbs. [3 Mechanics removed the head off the block manually and it's a clumsy operation!]
Here I'm using the hydraulic hoist to install the head, the only problem we encountered was the reach was not long enough on the hoist boom so I removed the front wheel to enable rolling the hoist into the engine compartment further. [An overhead hoist would be perfect for this job!]

Cummins Engine Repair involves cleaning and inspecting, especially when it comes to the block surface. Look for any cylinder scoring and cracks then run a straight edge on the block surface where only a few thousands of an inch wear is allowed. Use a .003 in. feeler guage to check the block wear.




Removing the injectors is easy once the fuel connector tubes inside the head are removed [Below]. The injectors have hold downs on top that have 2 fasteners, when removed the injector has a threaded hole on top that can be used to pull the injector out which is held in by an o-ring.
NOTE: Remove injectors before removing cylinder head, the injector tips protrude past the head surface.


The fuel connectors in the Cummins 24 valve turbo diesel have an o-ring seal and connect the fuel between the fuel injector lines and the injectors. They are tapered and have a machine fit into the injector body. The injector hold downs only install one way and index the injector in the head bore so the connector tube aligns with the injector.



I hope this basic overview has helped you get more aquainted with Cummins Engine Repair

More To Come!

Recommended: Diesel Engine Repair Manuals