Engine rebuilding?...

when an engine has been rebuilt what does that mean? I was doing some research on Alco S-2 Susquehanna #206, that resides in maywood, NJ. She had a massive prime mover failure. However some months before that she was rebuilt. What did that entail? A complete overhaul, like a rebuilt engine, or just some routine maintenance?

The term "rebuilding" as concerns a diesel primemover has been used rather loosely in the railfan press. Every engine does have a prescribed regimen from its manufacturer. As for ALCo there is a full set of Maintenance Instructions (MI's) for the engine as well as Engine Maintenance Schedules for every application, i.e. stationary, marine, railroad, etc. The instruction for locomotives is MI-11273. In it are instructions to be followed daily, weekly, bi-weekly, monthly, semi-annual, annual, bi-annual, four year and eight year. Each of these directs the reader to perform specific MI's except for the eight year which says plainly: "Remove, inspect and recondition engine". I would only consider the eight year maintenance group as a rebuilding.

So, would the 8-year MI basically involve tearing down the engine to its most basic components, inspecting each of those components, and doing whatever is necessary to bring those components back to their original as-built specs/condition?

That is what I always understood a "rebuild" to be.

MEC407 wrote:So, would the 8-year MI basically involve tearing down the engine to its most basic components, inspecting each of those components, and doing whatever is necessary to bring those components back to their original as-built specs/condition?

That is what I always understood a "rebuild" to be.

Yes and the tolerances/criteria are listed in the appropriate MI's.

My two cents:

If the engine is not stripped to the block, with bearings, pistons, rings, piston shafts ad infinitum not replaced or reworked, it's not a rebuild, it's only an overhaul.

That's true whether I'm talking about the straight 6 in my Jeep, a Detroit Diesel 6V53 or 8V71, or an EMD 645 series.

As Mr Carleton notes, rebuilds tend to be life cycle events.