Cast 251 Block

[Super Seis]

DLW designed and purchased 50 CAST 16-251 engine blocks. This was the result of a research project evaluating the suitability of the current fabricated block@ a 3600 hp rating. Supplier is CSR of China.

SS

[Allen Hazen]

Interesting news. The standard version of the 251 seems to have been good for 3600 hp ASSUMING good maintenance and careful fleet monitoring: or so I would assume from the long lives (and repeat orders!) of C-636/M-636 locomotives on iron ore mining railroads. But cast blocks seem to be better at very high horsepower: GE's FDL-16 was successful in 4400 hp locomotives, and I've never heard of anyone trying that with the 251! And even EMD, with a tradition of fabricated blocks going back to the 1930s (I assume that everyone interested in such things has seen Preston Cook's article on the 645 engine in the April 2010 "Railroad and Railfan"?) switched to a cast block for their H-engine.

[Super Seis]

The Australian iron ore roads rated their 16-251's at 3000 hp-and I believe Cartier derated theirs as well. Some of these engines had even been upgraded to the so-called 'heavywall' block.

That said, the 251Plus variant addressed various durability issues with P/A's, cams and other areas.

Suppose that the virtue of a cast block is that the designer can more easily put more metal where the stress concentrations are. In the case of DLW, they have been bumping up their production year after year-and one of the ways to do that is to outsource component manaufacture.

SS

BTW, the same outfit has been able to uprate the EMD 16-710G3 from 4000 to 4500 hp !!