Model B Distributor

You will need a model B timing gear cover or a good ear and understanding of the idea behind timing the A & B.
 
i tuned mine the same way i do a standard model a, which is pretty much by ear and it works great. Simple start, locate TDC with your front timing pin and make sure your rotor is pointed towards #1 lug in the distributor body. loosen the rotor cam and turn your rotor til you see the points are just about to open. run it and see how it feels. if needed advance or retard from there.
 
1. With an A timing cover on a Model A or Model B engine block, one can time the Model B distributor with geometry, using a hand made fixed sheet metal pointer securely fastened to the timing cover and pointing over 12:00 o'clock on the crankshaft pulley.

2. When the pin slips in at top dead center, (TDC), on the Model A timing cover, mark the top rear of the crankshaft pulley with (3) a corner file at 12:00 o'clock.

3. To obtain a mark for determining degrees before top dead center, (BTDC), a similar mark can be provided on the top rear of the same pulley on the pulley's driver's side of the first mark; but how far away should this second mark be from the first (TDC) mark measured in inches? Let's call this distance in inches on the Circumference of the crankshaft pulley Z .

4. Next, first determine: D = Pulley Diameter; Pi = 3.141; C = Pulley Circumference; N = Number of Degrees in a circle or in the pulley Circumference = 360 degrees; Number of degrees desired before top dead center = (XBTDC) or X .

5. if D = 5"; then C = Pi x D or C = 3.141 x 5", hence C = 15.706" for a 5" pulley.

6. If X = 16 degrees (BTDC); & N = 360 degrees, we can find the percentage of N that X is of C, or in other words that 16 degrees is of the whole circle or the percentage of C; call this percentage of the Circumference Y. Therefore, Y = X / N; hence Y = 16 degrees divided by 360 degrees & 16 / 360 = .0444, then Y = .0444.

7. Now that Y = .0444, we can convert this percentage into inches on the Circumference of the pulley to find Z ; hence, if C = 15.706", then Y x C = .0444 x 15.706" = .698". Therefore Z = .698"

8. If 11/16" = .6875"; & 3/4" = .750"; with Z being near 11/16", one can see that Z will be very close to 11/16".

9. Provide a (BTDC) mark on the crankshaft pulley approximately 11/16" on the passenger's side of the (TDC) mark, if 16 degrees (BTDC) is desired.
 
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