Facebook Page
SP 5623

The 5623 is powered by an EMD, 16 cylinder, 2 cycle, 1750 horsepower diesel engine. Being a 2 cycle engine means that each cylinder fires every time it comes to the top of its stroke. So, in one revolution, the engine fires 16 times which is why EMD's sound so smooth. If one considers the cab end of a Geep to be the front end, the engine is mounted in the locomotive backwards. The rear of the engine is the end attached to the main generator and that, as we know, is next to the cab. Why, you ask?  The high voltage connections are much shorter this way. With very few exceptions (really old Alcos come to mind), all diesel electric locomotives are built this way.

There are times when it is necessary to turn the engine over by hand. Setting the valves and injector timing requires precise positioning of the crankshaft for each cylinder. Inspecting the pistons and liners for wear and checking the piston rings also necessitates turning the engine manually. The bar shaped affair in this photo is called an "engine jack" or "baring tool" and has ears that engage with holes in the flywheel. Pushing the handle down causes the crankshaft to turn 4 degrees and pulling it up, another 4. So, it takes 90 strokes of the jack to turn the shaft over one revolution. This can get to be work.

Each bank of cylinders has 1 camshaft, driving 24 cam followers. There is one follower in the center of the cylinder for the injector and, on either side of that, 1 follower activating 2 exhaust valves each. The connecting link between the injector rack and the lay shaft rack can be seen along with the adjustment nuts on the link. The nuts are for adjusting the injector rack position which controls the amount of fuel delivered to each cylinder each time the cam follower drives the injector plunger down.

This is the view inside the left hand airbox with the number 9 hand hold cover removed. You can see the intake air ports in the side of the cylinder liner. By cranking the engine by hand to the proper position, the piston rings can be made visible for inspection through the ports. The large horizontal pipe in the photo is the water manifold that carries cooling water from the pump. Each cylinder has a jumper pipe that connects from the manifold to the liner. Cooling water flows from the manifold, through the liner, up through the head and then out through a jumper into the block.

This is what the blower mount looks like. The photo was taken on the Alameda Belt Line #44 at the time I was changing out a blower. When the seal on the input shaft gets old, oil from the gear train housing gets sucked into the blower and burned in the cylinders, one of the causes of a condition known as "puking". The drive gears for the blower and camshaft gear are visible in the photo. The blower bottom housing leads to the "air box" which is pressurized by the blower and from which fresh air enters the cylinders when the piston reaches the bottom of its stroke.

The rear of a roots blower is about all one can see as most of it is hidden behind a body panel. The silver colored box above the blower is one of the 2 dry element air cleaners found on the intake of each blower. The tube exiting the rear cover drains excess oil from the gear train inside the blower. The other photo is of the ABL #44 during the blower replacement and shows clearly the blower mounting.

This motor drives an oil pump which is used to pre-lubricate the engine. Since the 5623 sits for extended periods, I installed the arrangement to fill the oil galleries in the engine and insure that it was fully lubricated on startup. The pump sucks oil through a pickup tube in the number 9 cylinder crank case inspection cover and pumps it through a check valve into the oil pump outlet elbow. The pump is controlled by a pressure valve which turns it off when engine oil pressure reaches 4 pounds.

These views of the right side of the block (locomotive left) show the 2 spin on fuel filters and the right hand side water pump. The rod just above the center of the left hand photo is the connection between the engine governor and the right bank of injectors. The suction elbow between the ice cream freezer and the intake side of the lube oil pressure pump is also visible.

There are 4 mufflers (called "stacks") on the engine, each handling the exhaust from 4 cylinders. The stacks are joined in pairs with each pair exhausting through the carbody roof. The front and rear stack pairs are mounted pointing opposite from each other. Each stack has a cleanout port to allow the removal of accumulated carbon trapped by cyclonic baffles inside the housing.

This is the "ice cream freezer", so called because of its shape. It is actually 2 separate oil filters in one housing. The square cover toward the rear is in the suction side of the system and the 2 round covers are in the pressure side. There are no "elements" inside the housing, just a screen strainer under each round cover. The primary function of these filters is to catch nuts or bolts or errant engine parts and prevent them from destroying the teeth in the engine oil pressure pumps. Just below the water pump and to its right is the engine lube oil pressure pump. This is actually 2 pumps in one housing. One part supplies the engine lube oil and the other the piston cooling oil through what are called "Pee Pipes".

In the upper part of the left photo, is the left bank water pump. Below that, in the center of the block, is the lube oil suction pump. At the top of the front of the block, is the engine governor. It is connected via rods to the injector racks on each bank. The vertical handle is also connected to these racks and is used to assist in engine starting. An electrical connection is on the other side of the governor top.

Return To Details Page