model engines?

Pocher makes a 1/8 Volvo  truck engine that could masquerade as something larger in a smaller scale.  Any big truck or construction equipment kit would have a big diesel engine that might work.  THese engines are mostly big blocks and tubes, so scratchbuilding could be a possibility.  There are a couple of books called "Engines Afloat" that has good histories and reference pictures. 
Hope this helps,
Andrew

Harbor Models has a large EMD 20 cylinder Diesel in cast polymer at the bottom of the page.

Thanks CG Bob I hadn't seen this before. The web page didn't list any scale so I wrote to them and asked what scale it was here is their reply.

"Can you tell me what scale the emd model engine is?
>Thanks,
>Tug
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> 
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The actual motors all look very similar regardless of their power and
actual size.  Therefore, the scale is not important compared to how it
will fit in the model."

 

This turned out to be inaccurate information. Researching this further I ended up at the Kirby Corporate web site and I talked to an applications engineer there who was kind enough to send me a overall dimensions layout of a 20 cylinder EMD Marine engine. It turns out that the size of the engine is  255.673 inches which is 1/32 scale. Seeing that the Mr. Darby is also that scale it seems to fit as to why they carry it. Still it will be useful in a boat that size. Now if someone made one for others scales how nice that would be.

Tug