AA Truck engine

[smittykid]

What if any are the differences between the 4 cyl. Ford put in the AA trucks and the standard cars? Thanks

[Kurt in NJ]

Clutch is larger with heavier springs

[2manycars]

With the earlier multi disk clutch, a stronger spring was fitted. Later the difference was eliminated, probably when the single disk clutch came out. One other rare difference was a rear main bearing drain tube that had a ball check valve for trucks that were used in industry that used a huge dumping mechanism that unloaded the whole truck by tipping up the truck. The ball check was to keep oil from running up the tube when the truck was tipped up on it's back. These things are documented in the Service Bulletins. Other than that, the engines are the same.

[flatford39]

The serial number...

[Steve Plucker]

When Ford started production, the A clutch spring was a 420 pound spring and the AA clutch spring was a 455 pound spring. Starting with about engine number A-26268 (February 1928) the AA prefix on the engines were dropped due to the fact that all clutch springs were to be the same weight of 420 lbs thus ALL vehicles had the A prefix, car, light commercial and trucks. More than likely the use of the smaller 420 pound spring for AA truck use was just not suffecient enough for the heavier loads so in May 1928 Ford decided to go back to the 455 pound spring and continue those engines with the AA prefix. Not sure of the engine number for which that occured.

[smittykid]

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Thank you everyone!

[CarlG]

When I was a teenager, I took the engine out of an AA and installed it in a sedan. Used the flywheel and clutch from the truck, mated it up to the sedan bell housing and transmission. Even used the radiator and shell from the truck on the sedan.