American purchase programs, alternatives and reality, 1937-43

[marathag]

Chrysler flathead six, times five, should be reliable if the gear train is.

It seems to have been a reliable lump of iron, and was a 'power egg' of sorts

since there was no way to really work on it inside the tank, had to be lifted out for any work

 

[ThomasP]

I have come across a couple of different sources that said the A-57 was the most reliable of the 4 major types fitted to the Lee/Grant and Sherman - at least until reliability issues with the Ford GAA were worked out - but it also required a bit more routine maintenance.

 

[Frog]

The Chrysler powered M4A4 was favored by the British for the Firefly conversion because of it longer engine compartment that helped to counterbalance the gun barrel weight.

 

[EwenS]

The Chrysler powered M4A4 was favored by the British for the Firefly conversion because of it longer engine compartment that helped to counterbalance the gun barrel weight.

No.

The earliest conversion were from the M4A4 because it was the version with the greatest population in Britain in late 1943 when work began. Shermans for Firefly conversion had to have certain features (wide mantle, petrol engine, hydraulic turret traverse and M34A1 gun mounting) before conversion could even be considered. When they ran short of suitable M4A4 attention turned to M4 Sherman I hulls with those features.

This is the tank census for Britain in June 1944

21st Army Group Tank Strengths - June 1944

By mid-1944, conversions were being carried out in numbers on the short M4 Sherman I chassis, both from vehicles with fully welded hulls and those with composite or hybrid hulls (cast front section & welded rear section). These were turning up in Normandy by mid-July 1944. By the beginning of 1945 Sherman IC outnumbered Sherman VC about 2 to 1 in 21st Army Group.

There were differences in internal layout between the two versions regarding the ammunition bins.

The M4A4 Sherman V tanks were also in demand in 1943/44 for conversion to Crab Flail Tanks due to the greater power of the Chrysler Multibank engine v the other engine options.

 

[marathag]

The M4A4 Sherman V tanks were also in demand in 1943/44 for conversion to Crab Flail Tanks due to the greater power of the Chrysler Multibank engine v the other engine options.

On paper, the GAA had 500HP and 1040 ft-lbs of torque, vs 425HP and 1060 ft-lbs of torque.
The difference was, the Multibank torque peak was at 1400 rpm, compared to the Ford that came in at the far higher 2200rpm

So the Chrysler had more usable power at lower rpms.
that 4000 pound of extra cast iron block at the rear helped balance out that Crab as well