Engines A or B

[Wisconsinjimmy]

What is the difference between the two engines and is there a way to tell them apart, reason is my dad has a bunch of engines laying around.

 

[Kurt in NJ]

The "B" engine has a place for a fuel pump
The "A" engine has a oil return tube from the valve cover to the block

 

[Tiny]

B's have a 3 bolt water pump.
A's have a 4 bolt water pump.

 

[Dave Mellor NJ]

The B oil fill pipe is fatter

 

[H. L. Chauvin]

Hi Jimmy,

Also, if parts are laying around, or if the oil pans are not installed one can observe that the B crankshaft journals & diameters of Babbitt connecting rod bearings are larger in diameter than that of the A.

 

[DougVieyra]

B's have a 3 bolt water pump.

Another way (besides no oil return pipe and the opening for the '32-'34 'B' engine mechanical fuel pump) to tell a 'B' block, is that the engine's valve side cover is significantly and noticeably wider (top to bottom).


ALSO NOTE : Anything other than the basic short block must be viewed with skepticism in determining if a block is an 'A' or a 'B'. As heads are often changed around, the Head/Water-Pump is not a good indicator of the type of engine. Because of the higher compression and the much easier to install / replace, 'goose-neck' / water-pump ( a combined one-piece unit ), of the 'B' (marked 'C') head, they are often installed on an 'A' engine, in place of the original 'A' head. Also, as the timing-gear cover (used to mount the front of the engine to the frame) also can be changed from a 'B' engine (as mounted to the significantly different '32 frame) to the 'A' cover - this indicator also is flawed.

 

[1931 flamingo]

HOLE in the right side of the block for fuel pump. Definitive.
Paul in CT

 

[Purdy Swoft]

The advantages of the B engine is larger bearings on the crankshaft and mild oil pressure to the mains. The slightly higher compression head adds nearly seven horsepower more than the 4.22 compression model A head. The camshaft has more lift and duration and gives a 600 RPM increase over the model A engine. The B engine is rated at 50 horsepower. On the negative side, the model B blocks are thinner and most will have cracks in the valve seat area.

 

[Charlie Stephens]

The B oil fill pipe is fatter

Dave,

Except for the early "B" that had the same diameter pipe as the Model A but was longer. Look for the provision to mount the fuel pump, it's something that can't be changed.

Charlie Stephens

 

[ratamahata]

Later model B engines came with counterbalanced crankshaft...
A more bigger intake with a model B zenith carburetor...

 

[Wisconsinjimmy]

Wow!!!!!!!!!!!!! Lots of info on that question, thank you very much.

 

[dave in australia]

If you post a few pics of what you have, a lot of knowledgeable people on this forum can inform you what is what.

 

[Wisconsinjimmy]

One more question if you do not mind, what is a fair price on an engine if it turns over or stuck, I am going over to dads on Saturday and have a look see.

 

[Purdy Swoft]

The least price for a complete stuck B engine with a marvel carb, that I have found nearby was $500.00 . I've seen B long blocks that were said to be free offered as low as $800.00 as a core.

 

[Wisconsinjimmy]

It likely sounded as though I need to make a lot of money "NOT", I am going to see what I can dig up there are even a couple Flatty's, one is hooked to a military welding machine and the other is in a truck. I had better try and get them before the stepmother sells it all off, I offered her 3 grand for the 30 coupe a month ago and then sells it to some picker for the same amount. I am not liked