Pretty certain all 4-stroke diesels currently in production have cast blocks, and that I read that 4-strokes require a cast block. Yet there is a long history of welded block, turbo-ed, 4-strokes. Baldwin built 1000's, ok Baldwin had “problems”, and except for the for some 538/539's every ALCO built. The ALCO 251 was supposedly a good engine with a good number still running. ALCO's had higher operating costs but I have never seen a breakdown as to what was failing and they got the 251 up to 3600 HP which should have stressed the block a bit.
So what gives? Did the 251 have other engine bits fail because of weakness in the block? Have they raised internal pressures that much in new models? Have engineers forgotten how to design strong welded blocks, or their CAD program doesn't cover that? (The “Kids Today!” answer)
The knowledge base here is strong so I'm hoping to hear from people with real world knowledge, Wise-Old-Welders or EMD engineers, etc. We can all speculate but that doesn't provide a real answer.
Thanks for your thoughtful replies.
Don't necessarily know about diesel engines, but the 4 stroke distillate engines were made with welded blocks. Main advantage with cast blocks is a potential reduction in labor costs.
As designed the ALCo 251 is a fabricated (welded) block. Maybe 10 years ago an Indian licensee produced a cast block for the 251.
D.Carleton
FM-ALCo 251 school grad, 2006
Editor Emeritus, This Week at Amtrak
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