Re: (erielack) ALCOS

[paultup_@_comcast.net]

Ed Montgomery asked: 


>Alco engines always seemed to accelerate with a blast of dark exhaust 
>coming out the stack. I remember hearing this was caused by the 
>turbocharger lagging. Could this have been corrected or was it part of the 
>engine design? 


I've always wondered that myself. Alcos and GEs tend to have the black exhaust spurts common to turbo lag - and coincidentally, both use 4-cycle prime movers. 


Notably, earlier Alcos (539 series prime movers) don't really show large black clouds like this (think RS1 and S2/S4), which also puzzles me. 




> Was it common to all ALCO engines? 


It seems to happen most on 244 and 251 engines, notably the latter. I'm assuming EMD's turbo design had better free-flow in the turbo, which results in less exhaust. This really would be a turbocharger issue rather than a prime mover problem, IMHO. If Alco used a larger turbo with heavier blades, the inertia at the start would be greater, allowing the initial exhaust burst to fly past the turbine blade before they were up to speed. 




> I heard stories of fires breaking out around the exhaust stack of the PA's. Was this common 
> to the RS and S units as well? 


I've never heard of those, but it could be because of the PA's carbody design and oil accumulation at the stack. 


- - Paul 





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