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Mike Canter · 01-30-2011, 09:01 AM

You might find this video interesting. It is a V-12 Deltic Locomotive engine. It is a two cycle opposed piston engine. If you count them you will get 24 pistons and three crankshafts. It is a very common engine in European trains. Our WWII diesel subs used 8, 10 and 12 cylinder 2 cycle opposed piston Locomotive engines. These motors only ran at 720-750 rpm max. Some other subs used diesel motors that run from 250 to 500 RPM.

YouTube - Deltic engine

powderman · 01-30-2011, 09:16 AM

I worked in a locomotive shop where we did repairs. I can't imagine why they left it outside without running. Those things have 13" pistons, and take a couple of drums of coolant (thats why we let them run all the time, as instead of coolant we used water). In the first part of that video they had the rack pulled, so it was turning over without compression, but I'll bet those batteries were warm.

Mike Canter · 01-30-2011, 09:21 AM

Wow Powderman, that had to be fun. So when they pull the rack does that lift the valve so no compression. Do they do that to pre-oil them plus to blow out any water in the cylinders?

powderman · 01-30-2011, 09:38 AM

Probably all of the above, but I never asked. I imagine for the most part they had to cut the compression just to turn it over. They had huge battery banks on both sides to crank the thing. At idle, you could just about count each cylinder as it fired. When I first started as an apprentice (Youngstown Sheet & Tube Locomotive Shop), they were in the middle of a rebuild. Wet sleeves, and pistons that are hard to imagine. Those were the good old days.

Mike Canter · 01-30-2011, 10:22 AM

When I was in the Navy I took a ride in a diesel sub. It was amazing back in the engine room. They had Fairbanks Morse 10 cylinder locomotive engines and yes you could feel and hear each cylinder firing at 700 RPM.

distaff · 01-31-2011, 10:16 AM

How much would the block on one of those locomotive diesels expand between dead cold and full operating temperature?

Mike Canter · 01-31-2011, 10:31 AM

Paul that is a lot of cast iron and I would say a lot. Even a small motor exoands a lot . To give you an idea if we set the valve lash at .012 on our race engines cold it measures .025 hot. The supercharger belts from the crankshaft to the blower on top of the motor are loose on a cold motor and real tight on a hot motor. All this is on a regular V8 car motor. This is one reason that a majority of truck drivers start their motors and sit at high idle for at least five minutes before they move.

Hey Paul, stop sending all that cold Canadian air and snow down into the lower 48. We give up and cry uncle (lol)

Dadeaux · 01-31-2011, 10:55 AM

As a young man working the rice fields of Arkansas we had diesel tractors that you would "pull the rack" on to start, it was hopeless without that.

distaff · 01-31-2011, 11:05 AM

Mike,

We don't create it, but we sure do need to get rid of it, sending it north isn't an option, so sorry.

We had 8" this weekend, -17 F this morning here in Calgary. Should be close to 40 F by the weekend.

We can't run south this year, had puppies on Dec. 26 and I'm busy trying to get some deals done, so we have to hunker down.

I am curious (on any engine but especially these big beasts) if the cylinders remain true when they expand or if they deform. I can't imagine that the expansion forces are perfectly consistent and symmetrical. I wonder if the piston rings compensate for shape as well as dimension changes.

RustyJC · 01-31-2011, 11:19 AM

Quote:

Originally Posted by distaff

How much would the block on one of those locomotive diesels expand between dead cold and full operating temperature?

The coefficient of thermal expansion of gray cast iron is 0.000006 inch per inch of length per degree Fahrenheit. Therefore, if the block were 15 feet (180 inches) long and the temperature changed from 35 degrees F to 160 degrees F (delta T of 125 degrees F), the growth in length would be 0.000006 x 180 inches x 125 degrees = 0.135 inch or slightly more than 1/8 inch (0.125 inch).

Rusty

distaff · 01-31-2011, 11:27 AM

Rusty,

Thanks, very interesting and less than I thought.

Mike Canter · 01-31-2011, 12:36 PM

Paul, those diesel and the ones in the MHs use what is called a wet sleeve. The sleeve is a lot better quality metal than the cast iron blocks and since it is surrounded by water instead of cast iron it maintains its shape better throughout the temperature range. The other thing that is great about wet sleeves is that you can change one or all cylinders while the block remains in the vehicle or locomotive or submarine or ship. This is what is meant by an in frame overhaul. The submarine I went out in had a couple of engines that had bad cylinders in them. They would shut off the fuel to those cylinders and if they had to they disconnected the connecting rod so the piston didn't move. When they got back into port they would pull that wet sleeve and put a new sleeve, piston and rod in it and a way they would go again. You can do that on our MH diesel engines but you have to pull the whole head off. Some diesels have invidual heads for each cylinder that would make that easier.