Origins of the GE FDL engine

[MEC407]

Yes, it's been denied several times on the previous page of this thread. I know it's a lot to digest, but it's worth taking the time to read if you're genuinely interested in the topic of GE engines.

If you don't have time, here's the Cliff Notes version (copied from the previous page):

The GE FDL is not similar in any way to any Alco...there are basic differences
in the cylinder/piston/rod. The blocks are (were) both cast but of course are
also completely different.

[Allen Hazen]

Amtk822401--
A relationship between the Alco and GE engines is an obvious hypothesis, given their resemblance in being turbocharged 4-cycle engines with the same cylinder dimensions (9inch bore, 10.5 inch stroke). My guess is that one thing that might have influenced GE in its choice of the FDL engine (around the time of the breakdown of the Alco-GE consortium in the locomotive business, GE surveyed a large number of diesel engine types, American and other, before deciding that the FDL was the best available for locomotive purposes and making arrangements to acquire the design) is that their experience with Alco indicated that this was a good size of engine to use, and that this consideration was a plus for the FDL design.

But, as MEC407 points out, the resemblance breaks down when you look at details. (Or just look at the engines: they are visually very different!) For example: one of the things GE's engineers liked abut the ancestral FDL was its large bearing surfaces, which suggested that it had good growth potential for later, higher-power, development… and the FDL's configuration of driving rods, with the bearing surfaces between the pistons and crankshaft, is about as different from that of the Alco engines as it could be. (Note that one of the differences between the 244 and 251 designs is that the piston rod big ends and crankshaft bearing surface are different: this was an area that Alco thought needed revision in the 244 design. And the solution they adopted in the 251 is very different from that used in GE's engine.)

There is also a historical problem with the hypothesis. The FDL derives from a Cooper-Bessemer design dating from the WW II period, so it is just about as old as the Alco 241/244, so can't be a descendant of an Alco engine.