"Detroit Diesel" 2-stroke cycle engine naming scheme:

• Number of cylinders -- 1, 2, 3, 4, 6, 8, 12, 16, 20, 24
• "v" if it is a V-configuration engine, "-" if it is an inline.
• Size of each cylinder, cubic inches -- 53, 71, 92, ... up to about 1,000 (per cylinder!)
• t == turbo
• a == aftercooler (between the supercharger and the air plenum)
• i == intercooler (between turbo and supercharger)
• There's sometimes an "l" (ell) between the number of cylinders and the inline/v configuration letter, e.g., "6L-71TA". I don't know what that is.
• There's also a "b", I don't know what that is
• There's also a "c", I don't know what that is
• There's also an "e", I forget what that is
• There's also an "m", which may stand for "mechanical governor", compared to DDEC (see below) or "marine".
• There's also a "v", separate from the engine configuration, I don't know what that is
• "tt" is reportedly constant-speed
• "tta" is reportedly constant-speed emissions-reduced

Engines over 6 cylinder are V configuration only.

Engines under 6 cylinder are inline only.

"-series" engine means number of cubic inches, for example 53-series is all engines with 53 cubic inches per cylinder.

There are many details, for example a "T" (turbo) engine has a different compression ratio than a non-T engine. They can be converted, but if you have a bad engine with a good turbo, you don't just bolt the turbo on to any ol' engine.

There are "low block", "high block" and "high compression" engines, each newer, and higher horsepower; high-compression engines are also cleaner and more fuel efficient (though nowhere near a modern diesel). Parts interchangeability varies.

Engines can be configured to run either "left-hand" (counter-clockwise when viewed from the fan end of the engine, clockwise viewed from the flywheel end of the engine) or "right-hand" (clockwise viewed from the fan end, counter-clockwise viewed from the flywheel). V-drive buses typically use left-hand rotation, T-drive buses right-hand.

Inline engines can be configured with the supercharger, fuel pump, water pump, and governor on either side of the engine, and with the exhaust manifold on either side of the engine. When viewed from the flywheel, blower left/exhaust right is "A"; blower left, exhaust left is "B"; blower right, exhaust left is "C"; and blower right, exhaust right is "D".

Heads may have 2 valves per cylinder or 4 valves per cylinder.

Fuel control is "mechanical" ("M" or "MUI") or Detroit Diesel Electronic Control ("DDEC"). DDEC engines are a more complicated to set up but can give higher efficiency, lower emissions, a wider power band, higher peak power, or if not tuned for higher power can give better service life.

Mechanical governor types include "constant-speed"; "variable speed", used in e.g., bus and truck service; "fuel-modulating", which injects less fuel per stroke at lower engine speeds, thus reducing changes of engine damage; and "hydraulic", used in fixed-speed applications where more accurate speed control is desired.

There are at least 4 series of DDEC: DDEC-I, DDEC-II, DDEC-III, and DDEC-IV.

Injectors have a size, which is the maximum millilitres of fuel (mm³) per injection. Injector types include low-valve, high-valve, needle valve ("N"), offset body uesd with 4-valve heads ("S"), early emissions ("C" or "California"), later emissions ("B").

• Toroflow and Detroit Diesel -71 series

Detroit Diesel 6v53t

1-71 #545 of only 900 made; marine version.

The 1-71 was the smallest Detroit Diesel made. There was a 2-53 but no 1-53.

4-71

8v71

8v71t

12v71

From wwwxpertdiesel.com/photos.htm as of 2004/10. (Click for larger.)

12v149

DD 12v1163tb83

Is that 19 litres (1163 cubic inches) per cylinder? It seems that in very large sizes the naming scheme is different.

From http://home.amnet.net.au/~kdove/MTU.htm, more 12v1163tb83 pictures:      

According to http://www.mtu-online.com/en/prod-services/proddies/proddiesnorm/proddies1163 as of 2006/11, the bore/stroke of an 1163-series engine is 230mm/280mm, which gives 11630 cc's or 11.63 litres per cylinder.

DD 16v4000m70, 20v8000

CD 24x71 (Unofficial Designation)

Detroit/Cleveland "radial" engine:

Detroit_Diesel_X-Series_Submarine_Engine.doc

It appears to be an X configuration (four banks). Cleveland Diesel was originally Winton, which was bought by GM. The article http://www.rypn.org/RyPN/articles/viewarticles.asp?filename=061130231209.txt says, among other things:

Detroit Diesel 6-71 "quads" assembled by EMD, all on contracts handled by Cleveland Diesel

If that is the same engine, that suggests it is a 24x71.