B Distributor Initial Timing

[DBSHELTON]

I have read a little about the B distributor and I am using one on my 30 Huckster. What I am not sure of is what initial timing I should set it up on. I have a Nurex Timing timing tab set with the pulley marked on TDC so I can check things with a timing light. Right now I have the initial set at 9.5 degrees but the engine wants to run hotter than it used to. Should I try more initial timing? What is everyone else running who is using the B distributor on their model A?

[J Franklin]

I time mine by ear since I still have the A gear cover. I will note your answers for reference.

[wmws]

What is the timing at 1500-2000 RPM.

[DBSHELTON]

Originally Posted by wmws

What is the timing at 1500-2000 RPM.

No idea. No tach.
Approx what should the timing be there?

[Synchro909]

Originally Posted by wmws

What is the timing at 1500-2000 RPM.

I would expect that at those speeds without a heavy load like pulling up a steep hill or towing, you would be at maximum advance. (lever all the way down.)

[CWPASADENA]

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Set the initial timing at 17-18 Deg. That will get you in the ball park. The "B" distributor only has about 12-13 Deg. of mechanical advance. The mechanical plus the initial will give you about 30 Deg. total which is where you want to be. This is assuming that your "B" distributor is in good condition.

Chris W.

[DBSHELTON]

Originally Posted by CWPASADENA

Set the initial timing at 17-18 Deg. That will get you in the ball park. The "B" distributor only has about 12-13 Deg. of mechanical advance. The mechanical plus the initial will give you about 30 Deg. total which is where you want to be. This is assuming that your "B" distributor is in good condition.

Chris W.

I was wondering if 17-18 was too much initial, but now you mention it, I am only getting about 12 or so advance. (I actually have 3 Model B distributors that I have refreshed and they all top out at about 12 degrees advance) Sounds like a plan. Thanks.

[GRutter]

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.

[DBSHELTON]

Thanks. I was thinking the B timing cover was 9.5 crankshaft degrees. That's why I earlier set mine on 9.5 degrees. I will try 19 and see how that works.

[Patrick L.]

I would not recommend setting base timing more than 12º. Any more than that and the engine could kick back while starting.

A distributor advance putting out 12º equals 24º at the crank. So 36º total is plenty.

So if you have TDC marked on the pulley just raise the engine speed to a good cruise RPM and then guesstimate the amount of timing advance with the timing light. Or add a timing strip and you'll know for sure.

[Joe K]

Originally Posted by GRutter

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.

This description is closest to Vince Falter's description at http://www.fordgarage.com/pages/bdistributoradvance.htm

Joe K
Who is currently going through converting a Model A block for use as a Gordon-Smith compressor using Model B distributor & timing. (Gordon Smith kind of relies on centrifugal variable timing to compensate for the automatic loading/unloading of the engine.)

[Jack Shaft]

Model A or model B engine timing..one degree of advance per thousand rpm is what you are shooting for.
diameter of pulley x3.1416 divided by 360 gives you degree spacing.On a model A stock crankshaft pulley 5 degrees is a bit over 1/4 "..or use your nurex timing grid and TDC mark.hook up timing light and cheapie garage sale tach and dwell meter (40 bucks on Amazon) start engine,at 500 rpm either move the breaker plate or turn the distributor cam (pain,you have to shut off the engine and fiddle with it) to be 5 degrees advanced at 500 rpm,10 degrees at 1000,15 degrees at 1500 and so on check up to 2000 rpm.Basically as rpm goes up you can see the mechanical advance rise,basically 'mapping' the advance,this tell you if your advance is working correctly.the b works well,what get confusing is static timing it,so dont,use a timing light.

[Y-Blockhead]

Originally Posted by Jack Shaft

Model A or model B engine timing..one degree of advance per thousand rpm is what you are shooting for.
diameter of pulley x3.1416 divided by 360 gives you degree spacing.On a model A stock crankshaft pulley 5 degrees is a bit over 1/4 "..or use your nurex timing grid and TDC mark.hook up timing light and cheapie garage sale tach and dwell meter (40 bucks on Amazon) start engine, at 500 degrees either move the breaker plate or turn the distributor cam (pain,you have to shut off the engine and fiddle with it) to be 5 degrees advanced at 500 rpm,10 degrees at 1000,15 degrees at 1500 and so on check up to 2000 rpm.Basically as rpm goes up you can see the mechanical advance rise,basically 'mapping' the advance,this tell you if your advance is working correctly.the b works well,what get confusing is static timing it,so dont,use a timing light.

???

[Jack Shaft]

Be sure to rill a hole in the cam screw to get oil the upper shaft,thats the weak point on the B distributor

If the engine runs up to 500 degrees toss a steak on the head..

[DBSHELTON]

Was playing around with timing. Not hard to start until almost 30 degrees. I now have the initial set on 19 degrees. No problem starting at all, sounds very good but it is raining so a test drive is out.

Jackshaft, One degree of advance per thousand RPM? Surely that is not right.

[Jack Shaft]

Originally Posted by DBSHELTON

Was playing around with timing. Not hard to start until almost 30 degrees. I now have the initial set on 19 degrees. No problem starting at all, sounds very good but it is raining so a test drive is out.

Jackshaft, One degree of advance per thousand RPM? Surely that is not right.

One degree per 100 rpm..24 degrees at 2400 becareful,check full advance make sure you don't exceed

[DBSHELTON]

That is what I thought.
Thanks.

[GRutter]

If you have initial timing at 19 degrees, you should be spot on.

[CWPASADENA]

Originally Posted by Patrick L.

I would not recommend setting base timing more than 12º. Any more than that and the engine could kick back while starting.

A distributor advance putting out 12º equals 24º at the crank. So 36º total is plenty.

So if you have TDC marked on the pulley just raise the engine speed to a good cruise RPM and then guesstimate the amount of timing advance with the timing light. Or add a timing strip and you'll know for sure.

The Model "B" distributor has only 12 Deg. mechanical advance as measured at the crank shaft, (or 6 deg. Distributor shaft deg.). You could hand crank Model B's with 18-19 deg. initial without a problem at all. Time it the way Henry said to do it and it will be fine.

If you do not have enough initial timing when using a "B" distributor, the engine will be too retarded and will run hot and be down on power.

If you are running a 6.0 high compression head, it is not a good idea to have more than 28-30 deg. total timing at 2000 rpm.

My opinion,

Chris W.

[Patrick L.]

OK, I was wrong. I should have looked it up. I thought there was a 9.5º difference between the A and B front covers.

Apparently Model B base timing is 19º with minimal distributor advance totaling 36º.

http://www.fordgarage.com/pages/bdistributoradvance.htm


I know in 'more modern' cars I don't want base timing any more than 12º for kick back reasons.

[Bob-A]

I'm not much of a "guru" when it comes to anything Model-A or B. Especially concerning timing degrees or what ever. But, when I rebuilt a "B" distributor to run on my "B" block (with a "B " timing cover) replacing an "A" distributor. I could never find anywhere any instructions on Timing a B distributor!?! Eventually I found on the ..'Barn here, from 05-04-2013. A message from fellow FordBarn'er H. L. Chauvin. The thread was titled: "B Distributor in a Model-A and how to set the timing perfect?" Mr. Chauvin stated: "This may not be what you where looking for, & some may disagree, however, the following is a vintage detailed description from an original copy of: 'Motors Handbook of Specifications, Interchangeable Parts Service Instructions for 1934'......which covered many specifications for most automobiles made in the US from 1927-1934." I don't know how to quote the thread and place it here in my message. But it should be easy to find in the archives like I did. I could not believe how easy it was to time the distributor after reading the vintage instructions! The only change I made was to set the gap at .020 and not .018.

I hope this might help.


Bob-A

[DBSHELTON]

OK, since it will be raining for the next few days, I decided to go ahead and install my new Snyder 6:1 head. After I got everything apart and all cleaned up, I wanted to find actual TDC since it is real easy with the head off. Sure enough, after getting it all setup and checked, the timing mark was 3 1/2 degrees retarded. Kinda surprised that the Timing Dimple on the new laminated cam gear is that far off. Now I feel much better knowing that everything "Jives"! So there is another 3 1/2 degrees of advance I was leaving on the table for the B Distributor.

[aermotor]

This may be off topic, but how do I set up a Mallory distributor? The timing cover appears to be the same as an A cover and the Mallory advance appears to be the same as a B distributor. The piston is at TDC with the pin dropped into the flywheel dimple and that is the way things set now. BTW, I had a distributor drive shaft made to put the slot in the center in order to mesh with the Mallory distributor.

John

[Synchro909]

Originally Posted by DBSHELTON

OK, since it will be raining for the next few days, I decided to go ahead and install my new Snyder 6:1 head. After I got everything apart and all cleaned up, I wanted to find actual TDC since it is real easy with the head off. Sure enough, after getting it all setup and checked, the timing mark was 3 1/2 degrees retarded. Kinda surprised that the Timing Dimple on the new laminated cam gear is that far off. Now I feel much better knowing that everything "Jives"! So there is another 3 1/2 degrees of advance I was leaving on the table for the B Distributor.

If the head is off like during assembly, I never use the timing pin. It is much easier to use the valves on #4 cylinder to get TDC on #1. Let me explain:
#4 is at TDC after the exhaust stroke at the same time #1 is TDC on compression. At the top of the exhaust stroke, the intake valve begins to open 7 1/2 degrees BTDC and the exhaust closes 4 1/2 degrees ATDC. That means that at TDC, both valves are open, the inlet a little more than the exhaust. If you set the motor with both valves open (equally), you will be 1 1/2 degrees BTDC. At this point, the valves are "rocking". That is, if you turn the motor a little forward, the inlet valve will open more and the exhaust will close more. Go back the other way and the reverse happens.
If you stop the motor with the inlet valve a little more open than the exhaust ON #4 CYLINDER, #1 is very close to TDC and your are ready to set the cam on the distributor shaft. Even with a wildest guess at which valve is more open, you will be within a degree or so of TDC - plenty near enough when you consider that while driving, we change the timing by up to 40 degrees according to ear.
These timing angles are crankshaft degrees.
I always instal a timing scale on the front of the engine and put a mark on the front pulley at this stage and never use the timing pin even if I do have to check the timing (VERY rare).

[DBSHELTON]

After rechecking everything the cam gear dimple is only about 1 1/2 degrees off. I do feel much better knowing that TDC is marked on the pulley with a scale using the piston stop method. Much easier using a timing light like a more modern car.

[DBSHELTON]

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Originally Posted by aermotor

This may be off topic, but how do I set up a Mallory distributor? The timing cover appears to be the same as an A cover and the Mallory advance appears to be the same as a B distributor. The piston is at TDC with the pin dropped into the flywheel dimple and that is the way things set now. BTW, I had a distributor drive shaft made to put the slot in the center in order to mesh with the Mallory distributor.

John

Never used a Mallory, but I would think you would need some initial timing to start out. I would get a timing scale and maybe start with 12 degrees or so initial and see what the advance curve is. Maybe adjust to 30 degrees total by 2,000 rpm and go from there. Adjust for max timing with no pinging while driving.

[Jack Shaft]

30 degrees at 2000rpm with a 6 to 1 head is in the danger area for banging out the center bearing.the engine at 4.2 to 1 compression is way more tolerant of spark advance.

[DBSHELTON]

Originally Posted by Jack Shaft

30 degrees at 2000rpm with a 6 to 1 head is in the danger area for banging out the center bearing.the engine at 4.2 to 1 compression is way more tolerant of spark advance.

True. I didn't know he had a 6:1 head.