The Ford Barn

JimZ · 05-11-2021, 12:09 AM

My ‘31 coupe came to me through my dad beginning with my grandfather’s purchase of it in 1934. At some point in the past 90 years the original distributor was replaced with a model B version. As far as I can tell everything else on the engine is 1931 Model A. It runs pretty good with the timing set by ear but I would like to attempt to set it to some kind of specification to achieve its full running potential.

Can anyone give me information or identify a previous post on properly setting the timing of a Model A with a Model B distributor? Thanks!

Patrick L. · 05-11-2021, 04:06 AM

It'll depend on the timing cover, they are different. If you could post a pic of the timing pin boss. If it's a B cover then set it just like an A. The timing should be advanced more.

jwmckenzie · 05-11-2021, 05:30 AM

The Model B is timed at 19degrees BTDC.

If you have a Model A timing gear cover, the crankshaft has to be backed up 19degrees, after the pin drops in the camshaft gear.

If you have a Model B timing gear cover, rare. The pin will drop in at 19degrees BTDC.

Jack Shaft · 05-11-2021, 07:56 AM

Or you can use a pointer and mark TDC, then you can use a timing light.You can buy a degree scale or just use your eye,5 degrees advances is 1/4" at 500 rpm...the engine likes 1 degree of advance per 100 rpm max at 24 degrees.by rigging a tach dwell meter and using a timing light you can 'map' the advance...5 degrees at 500,10 degrees at 1000,ect..

JimZ · 05-11-2021, 08:53 AM

I think the cover is a Model A. I will follow your instructions. Thanks very much!

Ruth · 05-11-2021, 09:33 AM

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Quote:

Originally Posted by Jack Shaft

Or you can use a pointer and mark TDC, then you can use a timing light.You can buy a degree scale or just use your eye,5 degrees advances is 1/4" at 500 rpm...the engine likes 1 degree of advance per 100 rpm max at 24 degrees.by rigging a tach dwell meter and using a timing light you can 'map' the advance...5 degrees at 500,10 degrees at 1000,ect..

Jack, you mention a dwell tach. Do you happen to know the dwell setting that would equal the points set at ~.020"?

Someone on Ford Barn suggested a setting but I can not find it now. I thought I would try setting my points with my dwell tach.

bruceincam · 05-11-2021, 09:45 AM

Quote:

Originally Posted by Ruth

Jack, you mention a dwell tach. Do you happen to know the dwell setting that would equal the points set at ~.020"?

Someone on Ford Barn suggested a setting but I can not find it now. I thought I would try setting my points with my dwell tach.

The dwell for a four cylinder at 0.020" point gap should be 30 deg. or so. Low 30's should be the expectation.

Ruth · 05-11-2021, 10:04 AM

Quote:

Originally Posted by bruceincam

The dwell for a four cylinder at 0.020" point gap should be 30 deg. or so. Low 30's should be the expectation.

Thanks Bruce. I seem to remember the other member mention he found 32° was optimal but I was not sure. Thanks for confirming that to me.

I'll write it sown this time.

ursus · 05-11-2021, 11:59 AM

Quote:

Originally Posted by bruceincam

The dwell for a four cylinder at 0.020" point gap should be 30 deg. or so. Low 30's should be the expectation.

The OP says he has a Model B distributor. If it has the Model B cam, then the dwell should be 42-43 degrees. The stock Model A distributor cam will have less dwell, at 32-33 degrees. Many are now using the improved Model B cam and it seems that may be all that the vendors now sell.

Ruth · 05-11-2021, 12:42 PM

Quote:

Originally Posted by ursus

The OP says he has a Model B distributor. If it has the Model B cam, then the dwell should be 42-43 degrees. The stock Model A distributor cam will have less dwell, at 32-33 degrees. Many are now using the improved Model B cam and it seems that may be all that the vendors now sell.

Well, ya see. That's where I was confused. I have a B distributor cam so I'll try 42° then check the gap. Thanks Ursus.

JimZ · 05-11-2021, 01:21 PM

How can you tell if you have a Model B cam without pulling it out?

Greg Jones · 05-11-2021, 01:54 PM

I think we are talking about the distributor cam, the thing the point open and shut against. Or at least I think we are.....

JimZ · 05-11-2021, 02:05 PM

You’re right, sorry.

Charlie Stephens · 05-11-2021, 02:16 PM

Quote:

Originally Posted by JimZ

I think the cover is a Model A. I will follow your instructions. Thanks very much!

Model B cover with pin at top of elongated boss for comparison.

Charlie Stephens

Charlie Stephens · 05-11-2021, 02:28 PM

Quote:

Originally Posted by JimZ

My ‘31 coupe came to me through my dad beginning with my grandfather’s purchase of it in 1934. At some point in the past 90 years the original distributor was replaced with a model B version. As far as I can tell everything else on the engine is 1931 Model A. It runs pretty good with the timing set by ear but I would like to attempt to set it to some kind of specification to achieve its full running potential.

Can anyone give me information or identify a previous post on properly setting the timing of a Model A with a Model B distributor? Thanks!

Another handy thing if you are looking for a condenser for the B distributer buy the best Model A condenser you can find from a place like Bratton's. Elongate the hole on the bottom and add a short wire as in the pictures.

Charlie Stephens

JimZ · 05-11-2021, 04:07 PM

I backed up the crank 19 deg from tdc, set timing with method using a lamp attached to hot side of points and ground. It ran terrible and with backfire upon acceleration. Reset to previous setting with #1 at tdc and it ran ok again.

Is it possible I have an auto advance breaker plate and a Model A distributor cam.

JimZ · 05-11-2021, 04:14 PM

Also, gap between rotor and distributor pin is .040. This sound correct? The rotor photo is positioned just prior to points opening timed with #1 at tdc. Does this look correct.

Russ/40 · 05-11-2021, 06:51 PM

Rotor to pin should be .025" That is a "B" distributor.

JimZ · 05-11-2021, 07:07 PM

Any idea why my gap there is too large? Neither the rotor nor cap is burned or worn to the amount of .015. Likely poor quality aftermarket parts?

Greg Jones · 05-11-2021, 08:16 PM

In my experience, rotors are never ready-to-go out of the box. If you find one that is, you just got lucky. You almost always need to tweak this clearance. By this I mean you may need to judiciously bend the end of the rotor tab either up or down to adjust the clearance. Sometimes, I have had to do some slight filing on the contacts in the distributor cap to get the 0.025" (or close to it) gap consistently on all four points. Most times on new parts, I have to do both. Make sense?

katy · 05-12-2021, 10:58 AM

Quote:

Originally Posted by Greg Jones

you may need to judiciously bend the end of the rotor tab either up or down to adjust the clearance.

How does one do that w/out breaking the rotor? I've never been able to figure that out.

jwmckenzie · 05-12-2021, 12:02 PM

JimZ, can we get a wider view of your timing pin location, like in the picture Charlie Posted?

I have seen those elongated bosses on commercial engines and have been told they were aftermarket, wondering if your timing gear cover is a "B" but without the elongated boss. Just a thought.

Is the auto advance working in the distributor?

Bob C · 05-12-2021, 12:59 PM

According to Vince's site it looks like the Model A service replacement and all the
Model B timing covers had the elongated timing pin boss. The 1933-34 had just
a round boss. http://www.fordgarage.com/pages/timingcovers.htm

JimZ · 05-16-2021, 09:03 AM

I’ll get a better photo in a little while. Even though the advance seems to be working fine, getting it timed per a proper procedure is unachievable. The best I can do is set it so it doesn’t backfire. I have no idea if I’m getting optimum performance. I’m thinking about putting a Model A distributor in it. Then I can enjoy the true Model A driving experience. I wonder if I’ll need to change the body or are the A and B bodies the same?

JimZ · 05-16-2021, 09:46 AM

Best I can do for the photo.

jwmckenzie · 05-16-2021, 10:55 AM

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Quote:

Originally Posted by JimZ

I wonder if I’ll need to change the body or are the A and B bodies the same?

The bodies are different. Your pic looks like an "A" cover.

Have you tried a timing light? I have one that has a dial on the back that you can move to see where you are at. If you are running a 6v System simply power the 12V timing light with another battery.

Of course you would have to get to TDC and put an indicator and mark on the crank pulley. NuRex makes a timing indicator.

https://www.nurex.com/extra-crankshaft-degree-indicator

Here is what I did. White dot on crank pulley is TDC, the yellow mark is 19 BTDC.

JimZ · 05-16-2021, 01:41 PM

I will try it with my timing light.

shew01 · 05-16-2021, 02:42 PM

Quote:

Originally Posted by jwmckenzie

The bodies are different. Your pic looks like an "A" cover.

Have you tried a timing light? I have one that has a dial on the back that you can move to see where you are at. If you are running a 6v System simply power the 12V timing light with another battery.

Of course you would have to get to TDC and put an indicator and mark on the crank pulley. NuRex makes a timing indicator.

https://www.nurex.com/extra-crankshaft-degree-indicator

Here is what I did. White dot on crank pulley is TDC, the yellow mark is 19 BTDC.

I’m curious. How did you know where to put the yellow dot for 19 degrees?

Sent from my iPhone using Tapatalk

JimZ · 05-16-2021, 03:21 PM

Well my 35 year old $15 timing light won’t work. Funny, it was fine 20 years ago! Going shopping for a new one.

shew01 · 05-16-2021, 08:14 PM

Quote:

Originally Posted by JimZ

Well my 35 year old $15 timing light won’t work. Funny, it was fine 20 years ago! Going shopping for a new one.

I guess they “don’t make them like they used to.” [emoji23]

Sent from my iPhone using Tapatalk

jwmckenzie · 05-17-2021, 06:34 AM

Quote:

Originally Posted by shew01

I’m curious. How did you know where to put the yellow dot for 19 degrees?

A little Geometry and an internet calculator, I able to calculate the distance of between the dots (Chord Length), given a 19 degree angle and the radius of the crank pulley.

JimZ · 05-17-2021, 02:50 PM

New $50 timing light shows that I had the timing set at exactly 19 deg. BTDC with my Model B distributor. I knew it was running ok but didn’t realize I could get 19 deg. by ear. Too bad I had to tear up the packaging to get the timing light out or I’d think about taking it back.

jwmckenzie · 05-17-2021, 04:15 PM

Quote:

Originally Posted by JimZ

New $50 timing light shows that I had the timing set at exactly 19 deg. BTDC with my Model B distributor. I knew it was running ok but didn’t realize I could get 19 deg. by ear. Too bad I had to tear up the packaging to get the timing light out or I’d think about taking it back.

Excellent. Now you know... We all need a new tool from time to time....

California Travieso · 05-17-2021, 06:37 PM

Quote:

Originally Posted by JimZ

New $50 timing light shows that I had the timing set at exactly 19 deg. BTDC with my Model B distributor. I knew it was running ok but didn’t realize I could get 19 deg. by ear. Too bad I had to tear up the packaging to get the timing light out or I’d think about taking it back.

Keep it. You might need it in another 35 years. 😇

David Serrano

Jack Shaft · 05-17-2021, 06:46 PM

Static timing a B distributor isn't the best way to go...shoot for 1 degree advance per 100 rpm.. according to the math .255" on the circumference of the pulley is 5 degrees..so,at idle,or if you use a cheapie tach dwell,at 500 rpm is should advance a skossh over 1/4 inch...at 1000 rpm it should be hair over a half...3/4 at 1500,1 " at 2000 rpm..

05-11-2021, 04:06 AM	#2
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Model B Distributor in a Model A It'll depend on the timing cover, they are different. If you could post a pic of the timing pin boss. If it's a B cover then set it just like an A. The timing should be advanced more.

05-11-2021, 05:30 AM	#3
jwmckenzie Senior Member Join Date: Feb 2014 Location: Boston, MA Posts: 213	Re: Model B Distributor in a Model A The Model B is timed at 19degrees BTDC. If you have a Model A timing gear cover, the crankshaft has to be backed up 19degrees, after the pin drops in the camshaft gear. If you have a Model B timing gear cover, rare. The pin will drop in at 19degrees BTDC.

05-11-2021, 01:21 PM	#11
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A How can you tell if you have a Model B cam without pulling it out?

05-11-2021, 01:54 PM	#12
Greg Jones Senior Member Join Date: Jul 2010 Location: Aiken, South Carolina Posts: 695	Re: Model B Distributor in a Model A I think we are talking about the distributor cam, the thing the point open and shut against. Or at least I think we are.....

05-11-2021, 02:05 PM	#13
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A You’re right, sorry.

05-11-2021, 12:09 AM	#1
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Model B Distributor in a Model A My ‘31 coupe came to me through my dad beginning with my grandfather’s purchase of it in 1934. At some point in the past 90 years the original distributor was replaced with a model B version. As far as I can tell everything else on the engine is 1931 Model A. It runs pretty good with the timing set by ear but I would like to attempt to set it to some kind of specification to achieve its full running potential. Can anyone give me information or identify a previous post on properly setting the timing of a Model A with a Model B distributor? Thanks!

05-11-2021, 04:07 PM	#16
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A I backed up the crank 19 deg from tdc, set timing with method using a lamp attached to hot side of points and ground. It ran terrible and with backfire upon acceleration. Reset to previous setting with #1 at tdc and it ran ok again. Is it possible I have an auto advance breaker plate and a Model A distributor cam.

05-11-2021, 06:51 PM	#18
Russ/40 Senior Member Join Date: May 2010 Location: Santee, California Posts: 3,505	Re: Model B Distributor in a Model A Rotor to pin should be .025" That is a "B" distributor. Last edited by Russ/40; 05-11-2021 at 06:57 PM.

05-11-2021, 07:07 PM	#19
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A Any idea why my gap there is too large? Neither the rotor nor cap is burned or worn to the amount of .015. Likely poor quality aftermarket parts?

05-11-2021, 08:16 PM	#20
Greg Jones Senior Member Join Date: Jul 2010 Location: Aiken, South Carolina Posts: 695	Re: Model B Distributor in a Model A In my experience, rotors are never ready-to-go out of the box. If you find one that is, you just got lucky. You almost always need to tweak this clearance. By this I mean you may need to judiciously bend the end of the rotor tab either up or down to adjust the clearance. Sometimes, I have had to do some slight filing on the contacts in the distributor cap to get the 0.025" (or close to it) gap consistently on all four points. Most times on new parts, I have to do both. Make sense?

05-12-2021, 12:02 PM	#22
jwmckenzie Senior Member Join Date: Feb 2014 Location: Boston, MA Posts: 213	Re: Model B Distributor in a Model A JimZ, can we get a wider view of your timing pin location, like in the picture Charlie Posted? I have seen those elongated bosses on commercial engines and have been told they were aftermarket, wondering if your timing gear cover is a "B" but without the elongated boss. Just a thought. Is the auto advance working in the distributor?

05-12-2021, 12:59 PM	#23
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 8,747	Re: Model B Distributor in a Model A According to Vince's site it looks like the Model A service replacement and all the Model B timing covers had the elongated timing pin boss. The 1933-34 had just a round boss. http://www.fordgarage.com/pages/timingcovers.htm

05-16-2021, 09:03 AM	#24
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A I’ll get a better photo in a little while. Even though the advance seems to be working fine, getting it timed per a proper procedure is unachievable. The best I can do is set it so it doesn’t backfire. I have no idea if I’m getting optimum performance. I’m thinking about putting a Model A distributor in it. Then I can enjoy the true Model A driving experience. I wonder if I’ll need to change the body or are the A and B bodies the same?

05-16-2021, 01:41 PM	#27
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A I will try it with my timing light.

05-16-2021, 03:21 PM	#29
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A Well my 35 year old $15 timing light won’t work. Funny, it was fine 20 years ago! Going shopping for a new one.

05-17-2021, 02:50 PM	#32
JimZ Junior Member Join Date: Mar 2021 Location: Bell County Texas Posts: 24	Re: Model B Distributor in a Model A New $50 timing light shows that I had the timing set at exactly 19 deg. BTDC with my Model B distributor. I knew it was running ok but didn’t realize I could get 19 deg. by ear. Too bad I had to tear up the packaging to get the timing light out or I’d think about taking it back.

05-17-2021, 06:46 PM	#35
Jack Shaft BANNED Join Date: Dec 2019 Posts: 1,196	Re: Model B Distributor in a Model A Static timing a B distributor isn't the best way to go...shoot for 1 degree advance per 100 rpm.. according to the math .255" on the circumference of the pulley is 5 degrees..so,at idle,or if you use a cheapie tach dwell,at 500 rpm is should advance a skossh over 1/4 inch...at 1000 rpm it should be hair over a half...3/4 at 1500,1 " at 2000 rpm..