Ford GAA 1100 Cubic Inch WW2 Tank Engine

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This is a picture of the Ford GAA, 1100 cubic inch tank engine used in some Sherman tanks, and in some newer tanks during WW2. It was an all aluminum block and cylinder head, double overhead cam, 4 valve per cylinder monster of a V8. It produced "only" around 500 hp due primarily to it's very low compression ratio for the lousy automotive gas of the time. It made prodigious torque at very low RPM. It began life as a V12 that Ford designed and built hoping to win an Army Air Force contract for an aircraft engine. Ford lost that contract to Allison. When the Army issued an RFP for a tank engine, Ford lopped 4 cylinders off the V12, and the GAA V8 was born.
A question I've always had tho is why Ford didn't scale the GAA down to around 300 cubic inches or so after the war and put it in some of their automobiles. The basic tooling already existed. Would have only been a matter of scaling the existing design down. It was way ahead of it's time design-wise. Instead, Ford continued to use their largely obsolete flathead V8 until some time in the early, maybe mid 50's, I'm not sure.
A 300 CI version of the GAA would have easily tripled the anemic output of the old flathead v8. As the quality and octane levels of post WW2 gasoline climbed, a smaller GAA's output, with higher compression and more aggressive cam timing, would have soared.
Had Ford done that, IMO, the horsepower wars that began in the mid 50's and continued until 1971, would have come to an early conclusion, unless similar designs from GM and Chrysler were developed.
The above is only a mental exercise, but something I've wondered about from time to time.
 
I’ve seen some articles on that engine. I’m GUESSING the production costs would have been too costly for the day. Governments can afford engines like that. Joe Q. Public wouldn’t pay for it.
 
never heard of this beast ! an advanced engine for the times , i wonder how reliable they were in the field.
 
never heard of this beast ! an advanced engine for the times , i wonder how reliable they were in the field.
I read that on average, american tank units had better operational strength than the germans at least, as the tanks were newer simpler designs for mass production and serviceability, had spare parts available, and I read that the average american tank crew just had more experience with cars and machinery, and could fix more things in the field.
But on flip side, many Shermans never lasted through the break in period as they took heavy losses from upgraded german tanks, and often only won a battle though overwhelming numbers.
 
The engine's ignition was all magneto, and the cams were completely gear driven. I disagree with the complexity argument, as Chryslers 331 CI original hemi was itself rather complex, and was never really a high volume motor, offered only in higher end Chryslers, and spin-off's in select Dodges, and Plymouths. Poor sales of those models led to the dropping of the original hemi in the late 50's. Economies of scale reduce or increase unit cost.
The gear driven camshaft assembly was probably the least efficient to produce, and could have been converted to a much less expensive chain drive set up. Aluminum casting was not something that was new at the time. Numerous automakers even back in the 1920's offered fledgling V8's of various design in which the blocks were cast aluminum, but not unit blocks; the blocks of those early v8's were build in two halves, split at the crankshaft centerline and bolted together.
It's all moot now. The GAA never caught on in automotive racing post WW2, as it was way too large, tho I've seen several unlimited tractors used for pulling competition use them, but not many, as parts are rare and expensive.
 
Ford probably judged, most likely correctly, that the post war domestic auto market didn't support such a complex and consequently expensive engine.
Then Cadillac and Oldsmobile and Chrysler (HEMI) made modern OHV V8 and Ford was stuck with flat head for awhile. They eventually caught up.
 
Ford was only a little late, introducing the Y-Block in 1954 (the Lincoln Y block came earlier, but was a different engine). They were popular in boats, we had a few.
- The Ford branded 239ci version was 130HP (0.54HP/ci)
- The Merc branded 256ci version was 161HP (0.63HP/ci)

The GAA was 0.45HP/ci, I assume due to the low compression.

The Y-block was a good engine, so I'm not going to knock Ford for going that route instead.

It was 3 years behind the first HEMI (1951) which was the 180HP 331 (0.54HP/ci).
 
The Y-block was a good engine, so I'm not going to knock Ford for going that route instead.

Yea, until you try to do a camshaft change with the block in the vehicle. Clothespins, anyone? ;)
I'll actually be rebuilding a 292 Y-block this year for my 1960 panel van. Pieces for this engine are scarce and expensive for quality components. This isn't just an engine where parts are purchased on a price point.
Getting back to the 1100 c.i. tank engine, I bet the government didn't give Ford a huge contract because the engines were having problems with their cam phasers. :ROFLMAO:
 
Actually, from what I've read, Ford lost the aircraft engine contract to Allison due to logistics concerns; parts and a logistics system for Allison aircraft engines were already in place, albeit for an earlier model powerplant. The newer Allison V12 was an evolution of an existing design. At least the huge investment in engineering and design Ford expended creating the GAA was offset by it's use as a tank engine in V8 form.
The Allison V12 is another sometimes maligned WW2 aircraft engine. Actually it is considerably more robust and less complex than the Rolls Royce Merlin V12. The advantage the RR engine had was in the dual stage supercharger it employed giving it more power at altitude than the Allison could produce with it's single stage supercharger. Why the US couldn't duplicate a version of the two stage supercharger the Merlin used is unknown. At lower and medium altitudes, the Allison could safely endure WEP (war time emergency power) levels of boost and fuel delivery considerably longer than the Merlin. The most famous aircraft which employed the Allison was the P-38, and also the P-40, of Flying Tiger fame.
 
Yea, until you try to do a camshaft change with the block in the vehicle. Clothespins, anyone? ;)
I'll actually be rebuilding a 292 Y-block this year for my 1960 panel van. Pieces for this engine are scarce and expensive for quality components. This isn't just an engine where parts are purchased on a price point.
Getting back to the 1100 c.i. tank engine, I bet the government didn't give Ford a huge contract because the engines were having problems with their cam phasers. :ROFLMAO:
We had a couple of 312's, the first was bone stock in a decapitated tug boat, the 2nd in a 1931 Chris-Craft Cadet 22' runabout, heavily worked with a high RPM camshaft, balanced rotating assembly, dual Offy intake with those lovely Carter side drafts, and I have no idea what was on it for heads, but it breathed well enough past 6,000RPM (in a boat!) that they were obviously very capable. It fed dual 3" exhaust with Shephard flaps on the stern, no mufflers. It made one heck of a song.

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