Sunday, January 13, 2008

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

1 comment :

Anonymous said...

Hi John,

Glad to see your blog and get the professional idea.

We are dealing with Cummins 5.9 24valve cylinder right now.

Some machine shop tell us there are two different heads for 24 valve Cummins 5.9.(ISB & ISD)

Can we us ISB head on a 12valves
5.9 block to increase the power?