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GRutter · 09-19-2020, 09:59 PM

Don't confuse crankshaft degrees with distributor degrees.
The mechanical advance of the B distributor was 8.5 degrees (17 crankshaft degrees)

If you had a Model B timing cover, the initial timing would be 19 deg BTDC.
The mechanical advance of the distributor would add 17 degreees to that, giving you a maximum of 36 degrees advance.

Set your initial timing at 19 degrees.

Other considerations:
The model A distributor initial timing is at 0 deg BTDC, but the manual advance would allow you to move it to 40 deg. That is why it is always recommended to not advance the spark all the way... it is too advanced for an A engine. But it's lower compression was more tolerant of over advancing.

The Model B engine had a higher compression head and a better cam. It's max advance of 36 deg was perfect for that combination.

09-19-2020, 09:59 PM	#8
GRutter Senior Member Join Date: Sep 2017 Location: Mint Hill, North Carolina Posts: 386	Re: B Distributor Initial Timing Don't confuse crankshaft degrees with distributor degrees. The mechanical advance of the B distributor was 8.5 degrees (17 crankshaft degrees) If you had a Model B timing cover, the initial timing would be 19 deg BTDC. The mechanical advance of the distributor would add 17 degreees to that, giving you a maximum of 36 degrees advance. Set your initial timing at 19 degrees. Other considerations: The model A distributor initial timing is at 0 deg BTDC, but the manual advance would allow you to move it to 40 deg. That is why it is always recommended to not advance the spark all the way... it is too advanced for an A engine. But it's lower compression was more tolerant of over advancing. The Model B engine had a higher compression head and a better cam. It's max advance of 36 deg was perfect for that combination.