GM 12-567 diesel block for locomotives

[Diamondback]

Y'all, as part of my passenger-train project I'm trying to design "working" (well, pistons moving, they're powered rather than powering) prime-movers for the locomotives. First up, GM 12- and 16-567 blocks (first number in a GM engine is cylinders, second is cubic-inches per cylinder displacement).

And now we meet the problem:

Green pieces will mate the cylinders to the rest of the block, white is the electric motor (creatively disguised as an attached generator). I've lifted an entire bank of cylinders off the rest of the submodel in order to show its interior; if you're interested in giving it a whack in LDraw PM me and I'll email you the .LDR file.

Problem is, building up a frame to hold both banks of cylinders on this V-12 together, without getting any wider than it already is, and preferably with no length-gain while still allowing room for the crankshaft. (If someone can find a way to shorten the crank and still keep it all concentric, that'd help a lot too.

Ideas, anyone?

[Freddie]

Have you tried using a pair of these: Technic Engine Block 1 x 5 x 3 That'll give the engine block a sturdy frame to rest on. It doesn't need to sit right up next to the cylinder banks either, so a set of axles can be used to suspend the block, allowing you to keep the crankshaft at its current length.

If you use LEGO's standard approach to crankshafts, and not the more realistic and complex you've used here, it'll also shorten it with three studs. It will also make it possible to mount the block directly to the frame.

[Diamondback]

If you use LEGO's standard approach to crankshafts, and not the more realistic and complex you've used here, it'll also shorten it with three studs. It will also make it possible to mount the block directly to the frame.

Thanks, I'll have to look at that part--I was trying to keep it as narrow as possible to allow a 'walkway' on either side. (Historically, E- and F-units were a tight squeeze trying to get around the prime-mover--E's were double the fun 'cause you had to dodge two V-12s instead of a single V-16--and the 567 made passage near-impossible when retrofitted into Fairbanks-Morse locomotives.)

Basically, you're suggesting I turn this into a four-extra-cylinders version of 10077 from 2003 where one one piston hits Top Dead Center all the others are also at either TDC or Bottom Dead Center, right? Sounds possible, since a diesel's only a 2-stroke motor...

In some ways, I'm thinking a working FM 38D8-1/8 would be easier than a V--top and bottom pistons around a common combustion-chamber, but the downside is it'd be a lot more difficult to show the pistons without sacrificing realism with a transparent set of upper blocks... On the upside, it looks like I can also convincingly fake ALCo blocks with a "generic V".

Muchas gracias!

[Freddie]

Basically, you're suggesting I turn this into a four-extra-cylinders version of 10077 from 2003 where one one piston hits Top Dead Center all the others are also at either TDC or Bottom Dead Center, right? Sounds possible, since a diesel's only a 2-stroke motor...

Exactly! But my thought of reason was that most people simply wouldn't notice the difference. I honestly have no idea what the firing order are on these engines, but what little I know of these (as they are/were used in the NOHAB MX/MY and MZ locomotives plus the single G12 that runs up here in the north) getting a correct "firing order" is impossible within the constraints of the current selection of LEGO parts.

Nevertheless, good luck with your project!

[Lasse D]

If you want to shorten it further, get the right firing order and added realism, You could try to make the valves and camshafts move instead of the cylinders.

Have a crankshaft poke some pins through the cylinder head and it should be possible to get a really nice result. This is the approach I'm beginning to take with my engines because it saves space and and looks quite different from the conventional LEGO Technic engine.

It might take a lot of work to get it right, but it should be possible.

[Thee Pirate]

That's interesting.. When you're done you should film it and put it on Youtube.

[Diamondback]

Another complication: unless LEGO is willing to mold, pull and package a custom part-mix not found in any of Digital Designer's products, this is confined to an LDraw project. (Between certain colors some parts aren't made in, and no-longer-made parts like the old M:Tron magnet holders and the illustrated 4.5V Technic motor...)