The Best Diesel Engine-DT 466 International School bus

The Best Diesel Engine? By far the DT 466 by International. For the Medium Duty fleet operator this engine is the most reliable of all. Pictured is the DT 466 E [electronic version]. Each injector is controlled electronically by the engine ECM and injection is actuated by high pressure oil. These injectors are HEUI [hydraulic electronic unit injector] that are reliable but typically have to be resealed if there's a fuel in the oil problem...for example.














Here I'm setting valves which is .025 for both the exhaust and intake. One of the differences with the electronic engine and the older non-electronic models is the newer engines have the intake manifold built into the valve cover so it weighs much more, making it difficult to remove. There is the Engine Control Module as well fastened to the valve cover on the driver side.

Below is an electronic unit injector that can be tested while running with a laptop for proper injection cycles.















On the International School Bus the dog house inside the cab also has to be removed to gain access to the rear cylinders. This aside the reliability of the DT 466 E and older DT 466 in my opinion is the most reliable model for a medium duty fleet operation. One characteristic with the electronic version is a very rough start up in cold weather because of the engine oil pressure feeding the high pressure system. It takes a bit of high idling to get smooth fuel injection happening.

If you can find a mechanical DT466 then you have reached diesel heaven! With no HEUI and a Bosch fuel injection system you will have very dependable power unit. I can remember in-framing these engines for $1200.00 they are very basic and easy to work on. But technology has taken over and fuel emissions are here to stay.

Diesel Engine Oil - Switching to CJ-4 For 2007

To meet 2007 EPA standards low emission engines must use CJ-4 engine oil formulated especially for diesel engines using exhaust aftertreatment systems. New EPA standards are a 50% reduction in oxides of Nitrogen and 90% reduction in particulate matter. CJ-4 is a low ash diesel engine oil that can be used in older engines but comes at a higher price. The warranty becomes invalid if regular CL-4 oil is used in '07 diesel engines but the 10 to 30% increase in price is significant when it comes to a fleet operation.

You could stock both oils but there is a risk of operators who normally add oil to there assigned unit could inadvertently grab the wrong oil and mix the two. Mind you one litre of the wrong oil would not be detrimental to the life of the 2007 diesel engines but over time it would make a difference. The possibility of an engine oil test after a failure could happen.


Our fleet operation only stocks the CJ-4 so there is no confusion and zero risk to jeopardizing the integrity of the DPF [Diesel Particulate Filter]. The DPF has a regenerating cycle when a difference in input and output exhaust gases in the DPF [muffler] are picked up by the engine ECM [electronic control module]. The DPF literally cooks out the carbon build up and it gets kicked out the exhaust pipe which creates extremely high temperatures.


EPA standards are here to stay, with vehicle emission standards being on top of the heap when it comes to environmental concerns. Our School Bus Fleet will be receiving a Hybrid International School Bus next September. This will be an interesting technology to experience and another brand new learning curve to grasp.

Deutz Engine Assembly - Animated Version

Deutz Engines are a quality engine and here is an amazing animated video showing the assembly of an automotive 4 cylinder model. I believe this one is a 2.0 Litre displacement. You'll notice the double overhead cam construction which is run off a timing chain run off the crankshaft. This looks easy with fancy graphics but don't be fooled!


I would love to have this type of software when assembling an engine especially a Deutz Engine Assembly.

Thomas Buses-HDX Rear Emergency Window Modification

Thomas Bus HDX Pushers have a rear emergency exit window that has 2 ground switches. One for the alarm, warning the driver that the window is open and the other is an interlock that does not allow the bus to start when the window is latched.

The problem we were having was water seeping through the seal causing a circuit to ground tripping the alarm even when the window was fully closed. The quick fix was to grab an air line and dry off around the switch and grounds. Pictured here is the alarm ground switch[click on pic to enlarge]

This is the window locking latch that must be unlatched for the bus to start. The rivet on the outside is going to ground while the handle contacts a strip riveted on the inside of the frame.






We installed 2 intermittent switches in a currently available Thomas Part that encases the 2 switches and does the same job as the factory install.






The window must be removed to rewire the new installation. The 2 original ground switch wires are attached to the new switches in the casing and grounded at the case.






Once installed the [starting interlock] bolt style latch locks the window and the other switch is depressed [just above] to shut off the window alarm.
The latch catches on a "C" shaped flat bar that was fabricated to lock the window.




The latch bolt is in the open [run] position and the bus will start, this is a safety factor that newer Thomas Buses come with from the factory.

I will be updating this post soon with part numbers.