A57 Thirty Cylinder

[Subdeacon Joe]

Here we have a unique view of an A57 Multibank engine without most of its ancillary components attached.

The A57 is a monster of an engine, and infamously complex. It was created in the early years of the Second World War to alleviate some of the engine supply issues for Shermans and M3s.

The A57 was rapidly developed as the situation was desperate. This haste was possible because it used common parts already in production.

It is comprised of five (yes, five) Chrysler straight six engines, each displacing 4.1 litres (250 cu in). A gear was fitted to the end of each straight sixes' crankshaft, all of which meshed with a central output shaft to the transmission.

All in the A57 had 30 cylinders, displaced 20.5 litres (1,250 cu in) and produced around 400 hp. 

Its five-engine nature meant it needed five distributors, five sets of inlet and exhaust manifolds, 30 spark plugs and five carburettors. Despite the complexity, it did give its host tank added redundancy, as it could still run even with two of the five engines down.

It was fitted in the Sherman M4A4. M4A4s are easy to spot as their hulls had to be lengthened to fit the engine - simply look for larger gaps between the bogie roadwheels.

 

[Abilene Slim SASS 81783]

Used in the Sherman “Firefly”

 

https://en.m.wikipedia.org/wiki/Sherman_Firefly