Mystery model B engine
 

My brother bought a model B engine with a strange number stamping. The number is stamped on the flywheel housing, as B engines are, but the number is odd. This engine also has a raised boss on the left side, where the model A engine has the serial number stamped, but the boss is about 2 inches by 3 inches, and it is thick, and has two tapped holes in it. We are wondering if this was some industrial application.

Re: Mystery model B engine
 

It appears your number starts with ☆AIB5xxxxx, which is early 1932 industrial engine, but not with the heavy clutch.

I am not sure what made it 'industrial' compared to a stock engine.

If you give me the whole number, I will add it to my list of unusual engine numbers on my web site.

The boss with two threaded holes is for a vacuum clutch canister mounting which was cancelled before start of production. Is is commonly found on early blocks, but was never used for anything.

Re: Mystery model B engine
 

AB 5???? If that is AB followed by a number in the early 5,000,000 range it is a normal early B, early in 1932 with AB that was shortened to just B for most B's.
Early B's had several features to accommodate a vacuum assist feature that was planned but never produced. Tapped holes might relate to that?

Re: Mystery model B engine
 

Thanks very much for the replies. My brother is happy.

Re: Mystery model B engine
 

The tapped holes Bruce is talking about are on a boss below the oil fill tube. The boss is approx. 2.5" x 3.5" (from memory) The other feature meant for the vacuum assist was on the firewall to mount linkage or ???

Re: Mystery model B engine
 

Please post pix of the boss area with tapped holes and of the vacuum clutch canister. Thanks, George.

Re: Mystery model B engine
 

That will need to wait for a while. My brother is on vacation.