IHC diesel

Is there any of the older diesel mechanics out there that are familiar with the older model IHC diesel tractors ?? WD9, 600, 650 etc, started on gas and then switched to diesel. Please provide the theory under which they operated... when you switched over to diesel, what happened to the sparkplugs, gas valves etc... heads were prone to cracking as well..
I appreciate any input

This is well-covered territory. Search the archives. Include the MD, Super MD, 400D, 450D. Same design, smaller engine.

Chris B.

Yes, heads were prone to cracking if they were not operated per instructions...I have heard it was the shutdown procedure that was most important but then again I have had others tell me different. I have one of these in my small collection and have done a little research on operation. Mine needs service and I have put it off a little too long now. There is a lever you operate to switch it to diesel and, if memory serves me, this closes off the plugs and changes it around so it will combust diesel under pressure. That is the best I can tell you and I would definitely recommend that you do a search for more and better info. These engines are very interesting. If you stand on the right side of the tractor you are looking at a gasoline engine setup. Move to the left side and it looks like a diesel. Do the recommended search.

Hello Always: The early history as I heard it was that in the 1930's great depression era, Waukesha designed an engine that could be hand started on gas due to low (6:1) compression which resulted in no need for a battery or any electrical system since a mag was standard back then. With this easy and cheaper starting system, money could be used to build a stronger engine internals for higher compression diesel which was cheaper power. Waukesha got this gas start then switch to diesel by designing the head with a 3ed valve and extra chamber. When the 3ed valve was open to this chamber, compression was low and exposed a sparkplug. Extra mechanical methods used opened a gas carb for starting but shut off when switched to diesel. When 3ed valve closed this extra chamber, compression went to 15:1 and higher for diesel mode. Important to remember this was the 1930's depression and wide use of internal combustion engines was still new to many. In fact there was even some Model T Fords still in use on the highways and many farms did not have electric or a telephone.(hard to believe?) So Waukesha had a good design for industrial use for that period of time. IHC used it then for tractors. Hope the reason behind this design back in the 1930s helps fill in any other info you find. ag

While a good many people here know and understand them, Mr. Jim Nicholson does about the best job of putting the theory to words.

Here’s what the IT shop manual has to say about M Diesels—yours will be almost the same:


“International Diesel engines are started on ordinary gasoline after first closing the Diesel engine throttle and pulling the compression release lever. Pulling the compression release lever accomplishes four things: A starting valve in each engine cylinder is opened, thereby enlarging the combustion chamber and reducing the compression ratio to approximately 6.4 to 1. It closes two butterfly valves in the Diesel air intake manifold, and allows air to pass through the starting carburetor. The magneto or battery ignition electrical circuit is completed by opening of the grounding switch which is located in the forward portion of the intake manifold. It releases the float in the carburetor, allowing the carburetor inlet needle to be actuated by the float.

After the engine runs on gasoline approximately one minute, the engine is switched over to full Diesel operation by releasing the compression release mechanism and at the same time opening the Diesel engine throttle. Releasing the compression release mechanism opens the manifold butterfly valves, closes the cylinder head starting valves, locks the carburetor needle valve on its seat and closes the magneto or battery ignition grounding switch.

Very good explanations of how this engine design works and IH history indicates also that the head engineer insisted on having an engine that could be started with a crank. Had a customer many years ago that claimed he did start his MD with the crank, I would not relish doing that myself. Shut it off on diesel cycle after allowing it to cool down. If you run it on gas before shut down it will heat up the starting valves,and you want them to cool down in diesel mode so they cool on their seats as they warp very easily if left open.

Hi Pete23: I was told Waukesha wanted hand crank for OIGINAL design consideration for THEIR work which most likely did not consider that IHC would later on want to adapt this design idea to tractors. Waukesha original design was for various industrial engines. There were other multi fuel engines around in those early days too. Gas start then after warmed up switch to distellate. My comments about hand crank were not about later designs being used by IHC. The basic idea of hand crank was for Waukesha and may have been a smaller cubed unit and for certain many years before IHC building the first MD. Quite likely IHC was the one wanting electric starters designed for MD because of more cubes. There were many changes going on in industry after WW-1. Probably so many ideas being used that it may be best to NOT try and add and background to any topic about early designs being tried. ag

I have seen (and at the moment I can't for the life of me tell you where except in a book!) and old advertisement that showed a forearm on a handcrank with the title "International Diesels start by hand" so I would think that even if they didn't intend it that way IH certainly took advantage of the possibility of starting MD's by hand. Sam