top dead center, Model B

A. Correction: Per reply #17, timing gear is turning half as fast as the crank gear. Thanks!

B. Per reply #18, why discuss ignition timing on a subject heading of: top dead center, Model B?

Humble opinion:

1. On Model A forums, "TDC" is mentioned "often" often as well as added on timing cover timing devices used to locate "TDC", & as well as differences in ignition timing with A & B timing covers with recommended 19 degrees BTDC timing for Model B's.

2. It may be mentioned on Model A forums to set the engine's crankshaft "TDC" vee mark at 9-1/2 degrees "BTDC" on a timing device as opposed to setting it on the often mentioned 19 degrees BTDC when using a Model B distributor; however, I never could locate mentioning this 9-1/2 degree BTDC setting when using timing devices and/or timing lights.

3. So often we see a Model A forum connecting rod shim discussion for example with a message heading of Bull frogs in my tail pipe -- so if one is looking for shim discussions he overlooks the bull frog heading.

4. I figured if someone is researching "TDC" & B timing, this "TDC" Model B heading may be read.

5. But in addition, the real reason for posting same is the never or seldom mentioned timing set at 9-1/2 degrees BTDC setting as opposed to trying a 19 degrees BTDC setting which could prevent one from stripping starter bolts or worse, while trying to hand crank, possibly breaking an arm because of too far advanced timing.

6. If this discussion violated forum police rules under this heading, I apologize for thinking of the safety of fellow forum guys.

7. At least the guys in reply #17 & #18 appreciated this effort at 2:00 a.m. this morning. Thanks Rex A Lot & Patrick L.
 
Also, in trying to discuss "TDC" & this "B timing" cover matter in simple laymen's terms, I forgot to mention that with the timing gear rotating at half speed of the crankshaft's rotational speed, & with the B timing pin location positioned at 9-1/2 degrees advanced when using a B timing cover, that this 9-1/2 degrees x 2 engine crankshaft revolutions is equal to the 19 degrees BTDC often mentioned.

Could have missed it under "Search" or in other Model A archives, but I never saw written on a Model A forum that a Model B distributor's advancement requirement measured on the A or B's engine's crankshaft's pulley is set with the timing device's 9-1/2 degree mark BTDC when using a timing cover degree timing device with or without using a timing light.

At about age (10) I saw the original owner of my 1930 Coupe come to church with his arm in a sling after a Model A hand cranking experience -- never forgot it.
 
At about age (10) I saw the original owner of my 1930 Coupe come to church with his arm in a sling after a Model A hand cranking experience -- never forgot it.
end quote

I broke both bones in my arm/wrist crank starting an A. A Farmall A, that is. Its a long story, I did it wrong and knew it while I was doing it, but 12 year olds do some stupid things.
 
This vintage tip may or may not help someone one day -- if on a tour or whatever, & one has a Model A dead battery & you need to "quickly" move the Model A by hand cranking with unknown "A or B ignition timing", my Dad showed me this years ago.

Stand on the Model A front bumper, make a simple, single loop around the hand crank with a rope, & pull the crank upwards -- if it kicks back, the rope just slips out of your hand(s) -- then enjoy Christmas & New Years without a cast & a drink in "both" hands.
 
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