Model B ignition question

S

Simonpie

Senior Member
I have a 31 model A that came with a Model B centrifugal advance ignition. It ran well and I plan to keep it, but I now need to retime it. Is there a book out there that gives timing instructions for the B? I also have a pulley with degree scribes, so if anyone knows the correct idle firing point and advanced firing point, I could do it by timing light.

Thanks,
Simon
 
If'n it's a A engine I would set it the same as a regular A and go from there, see how it runs, etc.
 
Timing a B-distributor is dependent upon the point of reference which, if timing by the original method, requires that you determine if the timing cover and pin is from an A or B engine. The B timing cover pin location has 19 degrees of initial advance and another 13 or so degrees available from the centrifugal advance. The Model A is set with zero degrees of initial advance and has up to 40 total degrees controlled by a lever.
 
Ursus,

That's what I needed! Thanks.
It is an A engine and cover. I thought the 0 degree idle setting seemed odd.
Simon
 
Hi Simon,

Many ways to achieve this B distributor timing.

Just one (1) way to insure accurate B distributor timing with crankshaft pulley degree markings:

With an A engine, with an A timing cover, and if your crankshaft pulley is accurately marked with proper degrees advanced:

1. Rotate "A" engine clockwise until the timing pin slips into the timing gear through an "A" timing cover. (You may want to double check through No. 1 spark plug hole, (nearest radiator), to insure piston is raised to top dead center, (TDC); and degrees marked on your crankshaft pulley is registering "0 degrees. This is (0) degrees is used for setting manual advanced timing for an "A" distributor.

2. After achieving "0" degrees as indicated above for an "A" distributor, rotate engine clockwise such that the crankshaft pulley now is advanced 9-1/2 degrees; followed by adjusting the distributor cam such the points just begin to open when rotor is positioned near no. 1 distributor body contact pin. (Same as for an "A" distributor).

3. The larger diameter timing gear turned by the half sized crankshaft gear will be set at the required 19 degrees advanced for a centrifugally advanced Model B distributor.
 
Just in case one has a "B" distributor they would like to use or try with an "A" timing cover, and .............. if one does not have degree markings on one's crankshaft pulley or a similar device, and .................. if interested in using such a degree indicator device ....... E-bay currently has the following timing indicators for about $17.00 with shipping ..... others also sell similar timing indicator devices.

Model A Ford Ignition Timing Indicator - Degree Indicator Only
 
H. L. Chauvin said:
Just in case one has a "B" distributor they would like to use or try with an "A" timing cover, and .............. if one does not have degree markings on one's crankshaft pulley or a similar device, and .................. if interested in using such a degree indicator device ....... E-bay currently has the following timing indicators for about $17.00 with shipping ..... others also sell similar timing indicator devices.

Model A Ford Ignition Timing Indicator - Degree Indicator Only
Click to expand...

This is the one I have:

http://www.ebay.com/itm/FORD-MODEL-...hash=item3f503eeeeb:m:mjSljea9uuI5HP8oBAX6E8w
 

Attachments

  • Timing Indicator.jpg
    Timing Indicator.jpg
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Hi Carl,

I have the same one for my B distributor ...... file a small vee in the crank pulley, paint bottom of vee with "typewriter-white-out- paint", and see the B centrifugal advance doing its job with increased RPM's while holding a timing light.
 
Double checking. Wouldn't 9-1/2 degrees on the crank make 4-3/4 on the cam? Or to put it another way, 19 +13= 32 crank degrees, which sounds very reasonable compared to a lot of other cars. 9-1/2 + 6-1/2= 16 crank degrees, which sounds very retarded.

Simon

H. L. Chauvin said:
Hi Simon,


2. After achieving "0" degrees as indicated above for an "A" distributor, rotate engine clockwise such that the crankshaft pulley now is advanced 9-1/2 degrees; followed by adjusting the distributor cam such the points just begin to open when rotor is positioned near no. 1 distributor body contact pin. (Same as for an "A" distributor).

3. The larger diameter timing gear turned by the half sized crankshaft gear will be set at the required 19 degrees advanced for a centrifugally advanced Model B distributor.
Click to expand...
 
Use a timing light with a degree wheel or button, most of them all have it now and then all you need is the crank pulley marked O to the timing cover. Throw away your engine mounted degree scale...
You can determine timing, total advance etc
 
Mitch//pa said:
Use a timing light with a degree wheel or button...
Click to expand...
I looked on my 1965 Sears Penske timing light and I couldn't find that wheel or button.

Guess I'll have to keep my timing degree thingy. It was cheaper than a new timing light.
 
CarlG said:
I looked on my 1965 Sears Penske timing light and I couldn't find that wheel or button.

Guess I'll have to keep my timing degree thingy. It was cheaper than a new timing light.
Click to expand...

Time to move into the modern era like your Lincoln air grease gun:D

The motor will look better JMO.. Maybe Some don't agree

We like tools don't we
 
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That scale only goes to 30... An A can achieve somewheres around 40 fully advanced... The light can show you exactly what you have above 30.
 
Hi Simon,

A. The two (2) slightly different "Ignition Timing Degree Indicators" shown above are both very simply designed to set timing with a regular "Ford" crankshaft pulley.

B. The regular "Ford" crankshaft pulley used with this device conveniently has same diameter as the Model A and Model B timing gear.

C. Nine and one-half (9-1/2") degrees, (or 1/2 of 19 degrees required Model B advanced timing), marked on the circumference of a "Ford" crankshaft pulley measures just under 7/16" inch, more like between 13/32" - 27/64".

D. The timing pin slips in the timing gear every other engine crankshaft revolution; and, the piston rises to the top of the engine block every engine crankshaft revolution.

E. On one engine crankshaft revolution the distributor rotor should be adjusted to be pointing towards 4 o'clock when the timing pin slips in, i.e. at TDC; and, with said timing, on the other engine crankshaft revolution, (when the timing pin cannot slip inwards), the rotor is pointing towards about 10 o'clock.

5. The key term is ignition timing of the rotating rotor in the Model A or Model B distributor.

6. Some may prefer to use a timing light, some not; some prefer a degree dial as indicated above, some not; and some prefer to use a timing pin to time one's Model A .................. however, questions appear now and then about timing a B distributor with an A cover.

Hope this helps.
 
Simonpie said:
Double checking. Wouldn't 9-1/2 degrees on the crank make 4-3/4 on the cam? Or to put it another way, 19 +13= 32 crank degrees, which sounds very reasonable compared to a lot of other cars. 9-1/2 + 6-1/2= 16 crank degrees, which sounds very retarded.

Simon
Click to expand...

I agree.

As Simonpie has stated, you want to set INITIAL timing at idle @ 19 (crankshaft) degrees. The distributor has another 13 (Crankshaft) degrees of centrifugal timing built into it resulting in 32 (Crankshaft) Degrees total timing which is a good place to start.

Starting with 9-1/2 (crankshaft) degrees of initial timing will result in severely retarded timing.

Forget that the cam gear and distributor cam turn at half speed relative to the crankshaft. Ignition timing is measured relative to the Crankshaft rotation and referenced from TDC (Top Dead Center) of #1 piston.

On my "B" engine with a "A" front cover, I made a pointer for the front pulley. With the engine at TDC, I filed a notch in the pulley adjacent to the pointer. I then measured the circumference of the pulley which is equal to 360 Degrees of rotation of the crankshaft. I then calculated what part of the circumference was equal to 19 degrees. I filed a second notch in the pulley 19 degrees before the TDC mark. This 19 degree mark is where you want to set the timing at idle. You only need a simple timing light to set initial advance. Instead of making a pointer, you can purchase one of several offered by the parts people.

That is my opinion and what I did.

Chris W.
 
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Hi Simon,

Wouldn't 9-1/2 degrees on the crank make 4-3/4 on the cam?

Forgot to address your above question and to mention that if one looks at Mr. Foster's photos and explanations in reply # 5 above, one can roughly measure on his photos and see that the timing pin location on the B timing cover is moved upwards and advanced (clockwise) 9-1/2 degrees more on the B timing gear cover than that of the timing pin location on the A timing gear cover.

2. Then, as Mr. Foster further explains, this 9-1/2 degrees timing pin advance on the B timing gear cover means that the crankshaft timing is advanced 19 degrees.

3. This noted difference is because the crankshaft makes two (2) revolutions every time the timing gear makes one (1) revolution.

4. Also, in a parts catalog, one can see 25 teeth on a smaller diameter crankshaft gear, and 50 teeth on a larger diameter timing gear.

5. Some get confused with camshaft 9-1/2 degrees vs. crankshaft 19 degrees vs. 9-1/2 crankshaft pulley degrees, with all three (3) compared to the ignition rotor degrees.
 
Re-locating the hole in the timing cover 9 1/2 degrees will advance the crank 19 degrees. The crank rotates twice as fast as the cam.

Or to put it another way, if you were using a "B" timing cover (or a re-drilled "A" timing cover), you would have to rotate the crank to 19 degrees Before TDC to get the cam gear to move 9 1/2 degrees so you can get the timing pin to fall into the detent in the cam gear.
An engine with a 3 7/8 bore usually needs in the neighborhood of 30-40 degrees total advance to run right.

Chris W.
 
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