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I was reading an article about EMD engines and this question resurfaced, something I have wondered about before.

These EMD engines were built with exhaust passages integral to the crankcase, which pass through a water manifold also integral to the crankcase. What is the logic of this? The cooling system gets an extra heat load, and some exhaust heat energy is removed which might otherwise have driven the turbocharger. Of course, turbochargers were a later addition to the 567 engines.

One theory: the 45° "vee" design of the engine cramps the space for the exhaust risers out of the cylinders in the narrow space at the top of the "vee", so they end up sharing space with the water manifold. The engine layout requires that cylinder water jacket and exhaust both discharge from the top of the cylinder assemblies. The fabricated crankcase has a unitized configuration which fully encases the cylinder assemblies and reduces the external connections for air, exhaust and water manifolds.

Another thought: did the early engine designers deliberately intend to cool the exhaust to reduce the risk of fire danger from possible exhaust sparks?

I'm also wondering about the evolution of 567 engines versions A - B - C. As I recall, the A version relied on large O-rings around the cylinder assembly to seal water inlet and outlet passages from the crankcase block to the cylinder. From a mechanical design standpoint it appears to be a tidy arrangement because the cylinder assemblies slide into the block without any external manifolds to connect. In reality, the O-ring surfaces became corroded over time and it became difficult to remove and replace cylinder assemblies into the block because the O-ring sealing surfaces became rough and would damage the O-rings. So the B and C versions of 567 engine were modified to have separate "jumper" and "elbow" connections for the water inlet and outlet to each cylinder assembly. The inlet jumpers were accessed from inside the airbox; the outlet elbows were accessed from the top deck. One of the quirks of EMD engine design was that leaking water connections to a cylinder assembly did not go external; they could go into the airbox plenum or crankcase oil.

The 567A engines were considered less desirable candidates for major rebuilds compared to a 567C. The 645E engines by comparison were considerably refined for easier maintenance and better longevity, as well as increased power per cylinder.

Overall the EMD engines were an extremely successful design. I'm interested to know more about the engine design characteristics and how they evolved.

Omaha Shops-inside

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Last edited by Ace
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Ace - A couple of things to consider.

  1. Your typical V8 engine has the two cylinder banks at 90 degrees. Your typical V6 engine has the cylinder banks at 60 degrees. The EMD567/645/710 engines all have a 45 degree angle between the cylinder banks. This narrow angle limits the space between the cylinder banks. You probably couldn't fit a 90 degree engine of similar displacement in the locomotive. Check out this link on the physics behind the angle between cylinder banks. Hopefully Rich won't mind me posting a link to car and driver magazine. http://www.caranddriver.com/fe...-bank-angles-feature
  2. The exhaust passages in your car/truck engine cylinder head are water cooled. The cooling system deals with the heat load just fine. If you think about it, the cylinders in your engine block have much more surface area than the exhaust passages and probably contribute much more heat to the cooling system. A lot of new car/truck engines actually come with the exhaust manifolds cast as part of the cylinder heads. These are essentially water cooled to an extent.
Ace,

Not sure if you have come across this, but there is an excellent design and development summary of the EMD 567 written by Eugene Kettering and presented to the American Society of Mechanical Engineers in 1951.  It is available for download at:

http://utahrails.net/pdf/EMD_5...Development_1951.pdf

When you read this, you really understand how the EMD designs were continuously improved based on testing and experience from their railroad customers.  It is a pretty interesting read.

 

Scott Griggs

Louisville, KY

Last edited by Rich Melvin
Thanks very much Scott, that is a very interesting read with a direct and authoritative discussion of the development process through the 201-201A-567-567A-567B-567C engine models. At the time of writing, the 567C was the latest development but not yet in regular production.

Near the end of the document is a frank admission of the trial and error process:
"In closing it must always be kept in mind that the 567 engine was neither designed or developed by any super intelligent or analytical mind. The engine has dictated every improvement that has been made. We, at Electromotive, have only done our best to interpret what the engine was trying to tell us."

As for my original question - I guess it just boils down to how the engine needed to be packaged for a rail application. The 567 engine (and its later derivatives, the 645 and 710 models) was a unique development of a 2-stroke diesel engine with overhead camshafts, unit injectors and a fabricated block with integral airbox and water manifolds. The block largely encased the cylinder heads to help keep the overhead camshafts under the valve covers.

I can't help but think that the exhaust passages through the water manifold probably compromised turbocharger performance to some extent, especially when the 645 and 710 engines were pushed to higher horsepower ratings in later years. A moot point I suppose, since the 710 engine has been superseded by newer 4-stroke designs.

EMD-645-cross-section-

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Last edited by Rich Melvin

One item to remember about the early Winton Engines, as well as the early 567 engines from EMC, they were ALWAYS mounted in an enclosed carbody such as a "Doodle Bug", "shovel nose", or "E Type" unit. Thus, it was pretty desirable to keep the temperatures of the top deck reasonably cool so as NOT to bake the lube oil flowing through and out of the overhead camshafts and associated valve train "jewelry". The exhaust manifolds were hot enough as it was, so there wasn't any reason to add to that terrific heat by NOT water cooling the top deck area.

Hot Water posted:

One item to remember about the early Winton Engines, as well as the early 567 engines from EMC, they were ALWAYS mounted in an enclosed carbody such as a "Doodle Bug", "shovel nose", or "E Type" unit. Thus, it was pretty desirable to keep the temperatures of the top deck reasonably cool so as NOT to bake the lube oil flowing through and out of the overhead camshafts and associated valve train "jewelry". The exhaust manifolds were hot enough as it was, so there wasn't any reason to add to that terrific heat by NOT water cooling the top deck area.

Very interesting. That reminds me of seeing gummy old wads of cooked lube oil in some of the nooks and crannies of the cylinder heads and top deck in 645 engines. Lots of hot oil smell when you open them big valve covers, especially when checking things out on an idling engine. Oil pouring out of lash adjusters with sloppy clearances. Shop people would change out power assemblies and not think to change out the lash adjusters too.

I never saw inside a Winton engine and the ranks of 567 engines were thinning rapidly during my time.

EMD-TopDeck

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