Model B Engine

[wmws]

Does anyone know if a Model B engine will bolt right into a Model A.

[pat in Santa Cruz]

you will have to change the flywheel housing to an A housing. Some cut off the B housing part of the oil pan in order to do this, but you can probably find one that has already had that done.

If you want to stick with the original B oil pan and flywheel housing, you will need a B transmission. You will also need to modify the rear engine mounts or use float o motors designed for a B, and get an adaptor kit for the pedals and radius arm ball.

Bob Bidonde use to sell a booklet on doing this. Maybe he still does. Hes on this message board.

[Kurt in NJ]

If you chop off the back part of the oil pan that forms part of the bellhousing on the B it will bolt in using all the original A parts

[quickchange]

B trans pedal mount & radius rod mount which allows you to run B engine & B trans in an A avalible from Clings & AZ Model A Parts for LHD & RHD,vehicles . A very nice kit ,
Derek in a hot NZ

[Bob Bidonde]

Sponsored Links (Register now to hide all advertisements)

The simplest approach is to use the Model "A" transmission, Model "B" flywheel, Model "A" flywheel housing and modify the Model "B" oil pan by cutting off the flywheel housing just aft of the spot welds.

Another approach is to modify a Model "A" oil pan by hammering dimples into it to clear the Model "B" connecting rods, and to enlarge the rear semi-circular opening to accommodate the larger Model "B" rear bearing and cork seal.

You can transplant the Model "A" distributor and continue to run the Model "A" timing gear cover. However, if you run the Model "A" timing gear cover, you will need to advance the timing by 1.5 holes. An better alternative is to use the Model "B" timing gear cover as it has the timing pin hole in the advanced position (+9.5 degrees).

Run the Model "A" intake and exhaust manifolds, and the Model "A" carburetor. However, if you want more torque via better breathing, run the Model "B" carburetor. Open the throat in the Model "A" intake manifold to match the Model "B" carburetor throat diameter.

As for cylinder heads, the Model "B" head has a slightly higher compression ratio than the Model "A" cylinder head (4.2:1 vs 4.6:1). If you run the Model "B" head, then use the Model "B" 3-bolt water pump. Model "B" water pumps are not plentiful and there is not a plethora of parts available for the Model "B" water pump. The Model "A" cylinder head enables keeping the 4-bolt Model "A" water pump.

Use the Model "A" motor mounts front and rear. Also use the Model "A" throttle assembly, and be sure to shim the gaps closed between the ears on the flywheel housing and the engine. Assume 2 shims at each ear, but measure the gaps and shim accordingly.