The M4 Sherman Tank Epic Information Thread.. (work in progress)

[Jeeps_Guns_Tanks]

 I've updated the Engine Section, heavily updating the information on the Ford GAA and Chrysler A57. 

 

The motors: Why so many, and why the weird ones?

     The Sherman had four different motors that made it into production tanks. The R975 radial, The GM 6046 ‘twin’ diesel, the A57 multibank, and the Ford GAA V8.  There was also a Caterpillar motor they were playing with I’ll cover at some point.

     There are several reasons the US went with the radial aircraft engine instead of a dedicated power plant, and this was mostly due to lack if money to develop tanks and there drive trains between wars. When the US got serious about tank motors, there was a limited number of choices and the R975 was the best one. Then they turned to the US auto industry for other motor ideas, but only after war was clearly looming.

     GM came up with their twin bus motor, the 6046 and it was well liked right from the beginning. Then Chrysler came out with the nutty but fantastic A57. The US Army didn’t like either, and didn’t want to even use them for training. If the British hadn’t been willing take the A57 versions, the Army would have regulated them to training use only. It wouldn’t be until Ford figured out the bugs in the GAA v8 that the army would make the switch from the R975.

Post war many A4 tanks would have R975s put in them, or in much rarer cases, the 6046.  Parts for the A57 became rare post war, and people who knew how to keep them working were probably rarer. I’m pretty sure almost all A4s used post the 50s were converted to one or the other of these motors. Conversions to the Ford GAA were not done as far as I can tell, I think because the US Army was stingy with this model and spares for it , so they could kept for their use.  

 

R975 without the fan and other accessories. Courtesy of the Sherman Minutia site. http://the.shadock.free.fr/sherman_minutia/engines/Continental_R975C1_3.JPG

The Continental R975 C1/C4:

Type: 9 cylinder, 4 cycle, radial

Cooling system: Air Ignition: Magneto

Displacement: 973 ci Bore and stroke: 5x5.5 inches Compression Ratio: 5.7:1

Net Horsepower:C1/C4 350/400 hp Gross Horsepower: C1/C4 400/460 hp

Net Torque: C1/C4 800/ft-lb/940/ft-lb Gross Torque: C1/C4 890ft-lb/1025ft-lb

Weight: 1212lbs dry Fuel: 80 Octane gasoline Engine Oil Capacity: 36 quarts

      This motor was a license built version of the Wright R-975 built by Continental for tank use. It had been around nearly ten years and used in civil aviation before the army started putting it in tanks, starting with the M2 medium in 1939 and would go on to produce more R-975s than Wright ever would, 53,000 motors. The military version put out more horsepower than the civil version as well.  This was a solid and reliable tank motor, but not ideal. It was a little underpowered, and had to be revved up a lot to get the tank moving. The Army considered this a superior choice over the 6046 diesel and A57 motors.  This motor would be swapped into M4A4 hulls by the French post war.

 

GM 6046 diesel, note the 6-71 roots type super charger. Image courtesy of Sherman minutia site. http://the.shadock.free.fr/sherman_minutia/engines/General_Motors_6046_4.JPG

The General Motors 6046:

Type: 12 cylinder, 2cycle, twin in-line diesel

Cooling system: Liquid Ignition: compression

Displacement: 850 ci Bore and stroke: 4.25x5 inches Compression Ratio: 16:1

Net Horsepower: 375 Gross Horsepower: 410

Net Torque: 1000ft-lbs Gross Torque: 885-lb

Weight: 5110 lbs. dry Fuel: 40 cetane diesel oil Engine Oil Capacity: 28 quarts

      First used in the M3A3 and M3A5 and then in the M4A2. This motor tied two GM super charged truck diesels together on a common crank case. The motors could be run independently, so if one was damaged the other could be used to get the tank back to a repair depot, or to keep fighting. The engine weighed more than the R975, but had better torque characteristics, and the tanks with this motor handled low speed operation better because of the superior torque. 

      This version was ruled out for use by the Army because they didn’t want to complicate the tank supply chain by adding another fuel to it. This motor was well liked by its users, and the only version of the Sherman the Soviet Union would take via lend lease were the ones powered by this motor.  The Army testing of this motor found it was as reliable as or more so than the R975.

 

(image courtesy of the Sherman Minutia site.)

The Chrysler A57 multibank:

Type: 30 cylinder, 4 cycle, multibank

Cooling system: Liquid Ignition: Battery

Displacement: 1253 ci Bore and stroke: 4.37x4.5 inches Compression Ratio: 6.2:1

Net Horsepower: 370 Gross Horsepower: 425

Net Torque: 1020ft-lbs Gross Torque: 1060ft-lbs

Weight: 5400 lbs. dry Fuel: 80 octane gasoline Engine Oil Capacity: 32 quarts

     This motor was a bit of an orphan in US Service. It powered the M3A4 and M4A4. The Army used the motor for training, and tried to pawn a few off on the Marines. That lasted about two months at the Marine Tank School. The ever growing need for tanks by the British ultimately solved what to do with the tanks that ended up with this motor. They would end up taking over 8000 of them. Chrysler sent tech reps to England with these tanks and showed the maintenance crews how to keep them running.  This worked well and the engines served their purpose with little trouble. Often powering the best pure AT version of the Sherman, the Sherman VC firefly.  This motor saw a lot of use, during the war, and after with many countries being given Firefly Shermans to help out their recovery military. Some even ended up in South America, but I’m not sure what versions. This is my favorite Sherman motor, because it so absurdly complicated, it’s almost German, but it actually worked, so not German at all.

     This motor was fairly robust, and would continue to run and allow the tank to move with three of the five, cylinder banks not working. This would make the tank severely underpowered, but would be useful to get it back to the repair yard, or onto a dragon wagon. I’m sure it was much more common to have one of the five not operating right, and that level of power loss would be an annoyance, but wouldn’t keep the tank from fighting if it was really needed.

     During the war Chrysler really went to bat to keep these motors working well. Since it was based off a motor already long in production, spare parts were readily available. I’m not sure how long support for the motor lasted after the war. I doubt it was very long, and American car parts were probably not easy to acquire to keep these motors running. Because of this, the M4A4, more than any other model seems to have its engine replaced.  I’ve read about the twin diesel and the R975 being swapped in.  There are a few M4A4s around in Europe with running A57 motors, both fireflies if I recall right.  You have to love anyone willing to keep one of these motors running.

 

(image courtesy of the Sherman Minutia site.)

The Ford GAA:

Type: 8 cylinders, 4 cycle, 60 degree V8

Cooling system: Liquid Ignition: Magneto

Displacement: 1100 ci Bore and stroke: 5.4 x 6 inches Compression Ratio: 7.5:1

Net Horsepower: 450 Gross Horsepower: 500

Net Torque: 950ft-lbs Gross Torque: 1040ft-lbs

Weight: 1560 lbs. dry Fuel: 80 octane gasoline Engine Oil Capacity: 32 quarts

     The Ford GAA only made it into one Lee as a test bed, in one tank. But it powered a lot of Shermans, both large and small hatch. It would go on to be the motor of choice for the US Army for the rest of the war, and in the next tank, the M26. Just look at the numbers above and compare them to the rest of the motors. The GAA is really a much better motor for a tank in the Shermans weight range. This tank was not lend leased to the other allies in large numbers if at all. The USSR may have gotten one to evaluate, the UK too, but the Army wanted to switch over to this and stop using R975 powered tanks. After the war, the only Shermans they kept were M4A3 76 w tanks, and over time they converted as many of these to HVSS suspension as possible. They went as far as swapping T23 turrets from M4A1 76 W tanks onto M4A3 75 hulls. The army would produce several other gas powered tank engines, but none would really shine like this one did in the Sherman.

     The motor started life as a V12 Ford had designed to compete with the Rolls Royce Merlin, after a deal to produce the RR engine fell through. Ford was incensed that a deal could not be worked out and decided build his own V12 aircraft motor. When he tried to sell it to the Army he was turned down, but later when the army needed tank motors he used the V12 as a basis for the V8, by removing 4 cylinders. As a tank motor, it was under very low stress putting out only 500 horsepower.

     This motor does not get much credit for how advanced it was. The much talked about, and unreliable as hell,  German Maybach HL 230 P30, the motor used to power the Tigers, and Panther tanks, was not nearly as advanced, or as reliable as this amazing V8. This V8 is apparently the largest gas powered V8 ever produced. It has some very advanced features, even for a modern V8, like a one piece cast aluminum block with dual overhead cams and four valves per cylinder a true, dual overhead cam motor or DOHC. It had a very innovative 8 way power drive system for its accessories, like the alternators, fuel and water pumps, and two magnetos. The motor used no belts or chains.

     This motor saw post war use in various civilian uses, from logging equipment, to use a stationary pump motor. The most interesting post war use is in pro tractor pulling and hotrod use. These installations in most cases just update the intake and exhaust using modern carbs, but in one crazy case down in Brazil they have updated a GAA with coil on spark plug and crank sensor ignition, computerized ignition and fuel injection and twin turbos, and just 8 pounds of boost it makes 1500 hp, with a higher boost number the engine is capable of 3000 HP. That's much more than a modern tank motor, but not nearly as practical. 

 

For more info on these modifications and some pics, check out this link.   

[Belesarius]

Shermans can levitate. 

 

 

Inflatable decoy

[Belesarius]

Sherman Flail on display in the snow at CFB Borden.  I've climbed over that one when I was a kid.

 

[LoooSeR]

M4 in Italy.

 

http://477768.livejournal.com/3324286.html

[Jeeps_Guns_Tanks]

They are going to need another tank to get them out, or an ARV. 

[LoooSeR]

Krauts in trophy M4

[EnsignExpendable]

Haha I love that even though it's just bumming around the proving grounds it still gets a license plate.

[Jeeps_Guns_Tanks]

It's an early production M4A1 with DV ports. It was probably captured in North Africa?

 

Poor tank in Nazi servitude. 

[Jeeps_Guns_Tanks]

So I went and did this. 

 

http://www.theshermantank.com/

 

I felt bad taking Walt's time with bugging him to update things.  My wife out of the blue offered to buy the page. 

 

I'm still going to use this thread as a feedback place and all new sections will be posted here first for discussion. 

[Walter_Sobchak]

So I went and did this. 

 

http://www.theshermantank.com/

 

I felt bad taking Walt's time with bugging him to update things.  My wife out of the blue offered to buy the page. 

 

I'm still going to use this thread as a feedback place and all new sections will be posted here first for discussion. 

Cool!  

[Belesarius]

Just used your website to smack a wehraboo on FB.

[Jeeps_Guns_Tanks]

Just used your website to smack a wehraboo on FB.

 

Nice.

I just sent a link to it to Stur303 on the WOT forums cause he PMed me for info to help crush a boo. 

[Jeeps_Guns_Tanks]

New Section:

 

Sunken Shermans: Shermans that the Nazis sent to the bottom of the sea

Several cargo ships loaded with Sherman tanks were sunk during the war. A couple of these wrecks have been discovered. The first we’re going to talk about is the SS Empire Heritage, originally named Tafelberg. She was a steam tanker built in 1930. She was 508 feet long and just under 14,000 gross tons. She was built by Armstrong W.G. & Whitworth Co. Ltd. Her captain’s name was James Campbell Jamieson, and she had a 76 man crew and she had 160 people on board. She was reroute from New Your to Liverpool with 16,000 tons of fuel oil and 1900 tons of cargo, including Sherman tanks.

On September 8^th 1944 just 15 miles north of Donegal Northern Ireland, she was torpedoed by Nazi Submarine U-482 with the loss of 113 lives. From what I can tell, the wreck was discovered in 2014 and is 220 feet below the sea, just within reach of very technical divers. They took some very interesting pictures.

M4A1 76w tanks that went down with the SS Empire HeritageMore shots of the M4A1 76W tanks

 

 

The next wreck were going to talk about is the SS Thomas Donaldson. She was a 7200 ton Liberty Ship built in 1944 by Bethlehem Fairfield Shipbuilding Corp. Ltd. in Fairfield California, under the command of Robert Headden. She left Loch Ewe, Scotland, as part of Artic Convoy JW-65, on March 11, 1945. The convoy she was a part of had 26 ships and the SS Thomas Donaldson was the only one that didn’t make it to the Russian Port in the Kola Inlet. Late on the afternoon of the 20^th, the Nazi U-boat U-968 attacked the convoy. They were just twenty miles south of their destination when the Nazis struck.

The Ship was hit by a single torpedo that took out the ships engine. It also killed three of her crew. The Captain ordered the ship abandoned due to her dangerous cargo, but a small crew including the Captain stayed aboard and tried to save the ship. She was taken under tow, and almost made it in, but sunk short of the port. Only one more crewman died of his injuries and the whole repair crew made it off.

In July of 2014 a Sherman was recovered from the wreck, and they say there are two more down there that can be recovered as well.

An M4A2 76 W tank recovered from the wreck of SS Thomas Donaldson, sunk on March 20, 1944.

[LoooSeR]

Soviet Sherman (looks like)

[Jeeps_Guns_Tanks]

Then it should be an M4A2 76 W with steel tracks. Pretty much like the ones fished out of the ocean in the pics above. 

[EnsignExpendable]

Huh, a track that alternates links with grousers and without? I don't think I've ever seen one of those.

[Jeeps_Guns_Tanks]

Huh, a track that alternates links with grousers and without? I don't think I've ever seen one of those.

 

Yeah, that's really weird, I've never seen or heard of that before on Shermans. 

[Meplat]

Huh, a track that alternates links with grousers and without? I don't think I've ever seen one of those.

 

 

Yeah, that's really weird, I've never seen or heard of that before on Shermans. 

 

Likely a case of "use what you have". Akin to wheeled vehicles being shipped with a mix of combat and highway tread.

[LoooSeR]

'Jumbo'?

[LoooSeR]

[BattlefieldVegas]

Hi folks,

 

I own a M4A3 Sherman and I am looking for information on the Israeli diesel conversions. I'm actually going with a Detroit 8V92T with an Allison transmission but I'm looking for pictures of the engine compartment. 

 

My Sherman is in the middle of a complete restoration and we are not going with a stock restoration. I am going to modernize it with air conditioning, viewing monitors, modern wiring and gauges. Here are some photos of the tank as it was received and along the way of the restoration.

 

 

 

 

 

 

 

 

 

 

[Belesarius]

Oh god. Jeeps is gonna have a heart attack.

[LostCosmonaut]

I'm not sure if he has the info you need specifically, but Meplat is the guy to talk to around here about working on old armored vehicles. He has quite a bit of experience in that area.

[Meplat]

It depends on what kind of resto one wants.

 

I'm not up on the Izzy conversions, though an 8v92 is quite a skosh wider than a GAA. (IIRC).

The GAA is like 33" (35"?) and the 8V92 were ~50"..

[Jeeps_Guns_Tanks]

'Jumbo'?

 

 

Yes, a dead Jumbo. it's in one of the Zaloga books, I'll find the caption.