The Ford Barn

rockfla · 06-04-2025, 08:21 PM

I am trying to help a fellow Barn memeber, he has a 37-41 helmet distributor, has tried several avenues to get his car running (which it was prior to purchase) but was having no luck. He sent me his distributor so I could check it and set it up on my Sun machine. I have the right set of points dead on 22, pulled the left blocker and set the dwell at 35. Timing is set 2dgr advanced. I figured I would stick it on my 39 Mercury and test it out…..and I get NO fire at all!!! None. Using my coil and condenser which on “my” distributor fire my Mercury off “immediately”!!!! I can put my distributor and coil back on and like clock work, My Mercury fires immediately! Double check the other distributor back on the Sun, all dwell is dead on, timing still 2dgr, good strong arrows, put it back on my Merc, nothing, no start, no fire.
I verified the correct rotor for the 37-41 spark plug plates, it’s the correct rotor.
Suggestions or ideas???

KiWinUS · 06-04-2025, 08:47 PM

Is inside of rotor to shaft insulated?

koates · 06-04-2025, 09:13 PM

Does the dist have the original FORD coil on top like original or an adaptor set up for the remote coil. You have to do some testing with a voltmeter and ohm meter. Test for power to the coil primary terminal through the ignition switch. Original column switches wear inside and cease to pass current through them. Some of the remote dist plates are made from a fibre material and bend around and make bad connections to the inside of the dist. The bakelite plates are much better. Testing with a meter or test light is the only way not guessing and asking everyone else what they think because they dont know. Auto electricians test and dont guess. Regards, Kevin.

mcgarrett · 06-04-2025, 09:15 PM

Quote:

Originally Posted by rockfla

I am trying to help a fellow Barn memeber, he has a 37-41 helmet distributor, has tried several avenues to get his car running (which it was prior to purchase) but was having no luck. He sent me his distributor so I could check it and set it up on my Sun machine. I have the right set of points dead on 22, pulled the left blocker and set the dwell at 35. Timing is set 2dgr advanced. I figured I would stick it on my 39 Mercury and test it out…..and I get NO fire at all!!! None. Using my coil and condenser which on “my” distributor fire my Mercury off “immediately”!!!! I can put my distributor and coil back on and like clock work, My Mercury fires immediately! Double check the other distributor back on the Sun, all dwell is dead on, timing still 2dgr, good strong arrows, put it back on my Merc, nothing, no start, no fire.
I verified the correct rotor for the 37-41 spark plug plates, it’s the correct rotor.
Suggestions or ideas???

To clarify, are you saying you have the points "dead on 22" meaning .022" ? The instructions that came with my KR Wilson timing fixture says to gap the points at .012".

koates · 06-04-2025, 09:21 PM

Nope, he is talking 22 deg. not thousands of an inch. Regards, Kevin.

mcgarrett · 06-04-2025, 09:26 PM

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Thanks for the clarification.

Brian · 06-04-2025, 10:08 PM

I'm with kiwiinus on this...the rotor is shorted out...electricity will take the shortest route to ground...

rockfla · 06-05-2025, 02:53 AM

Thanks guys

I’ll check it out when I get back home from my trip. When I got back In from my shop and started thinking the process through, all I came up with was the rotor and personally, In all my life, have never heard of this or been around a rotor that was bad.
Kevin, the coil and condenser and all of the wiring, switch and connections are ALL good as I am using my 39 Mercury as the test mule……I can get in it, pump the accelerator three of four times, pull the choke and it’s running within 5 seconds. I drive it pretty regular, so the whole system is working very good. After I set this distributor up. I was gonna test drive it and make sure it performed before I sent it back.

Thanks again.

35fordtn · 06-05-2025, 08:57 AM

Do you have a coil installed on the sun machine? Either the contact for the coil is grounding out or the most likely scenario is the rotor has a crack on the inside. If so replace the rotor and insulate the shaft. This is actually a common problem there are two service bulletins regarding this. That’s why for undersized the shaft in the middle

Bored&Stroked · 06-05-2025, 10:50 AM

Curious . . . what do you guys use to isolate/insulate the shaft from the rotor? I've come up with a variety of methods to solve "spark to ground" issues with Harman-Collins dual-coil distributors - so I'm always looking for tips and tricks that others use.

Thanks in advance!

Side Note: Given the above, I have equipped my Sun distributor machine with a setup to run/test the secondary portion of the ignition --> with coils, plugs and a variable "spark gap" mechanism to put load on the system and see how it performs as such.

Here are some links to an article and video from quite a few years ago:

https://www.jalopyjournal.com/forum/...ke-one.628039/

https://www.youtube.com/watch?v=3xduaVyzx10

KiWinUS · 06-05-2025, 11:26 AM

Shrink sleeve Dale.

Flathead Fever · 06-05-2025, 11:46 AM

Seems like the points are shorted to ground or the voltage is prior to it getting to the points. I would hook up an ohm meter to the points and the case and see if they show they are opening and closing. The voltage might be going to ground before it gets to the points. That's the only thing that makes sense if the coil will work on another distributor. A cracked rotor might do it, but you should be able to see the crack. Swap the rotor to, swap everything and if still won't start I'd looked for a short to ground in the distributor housing. Make sure to disconnect the battery when using the ohm meter, your just checking stuff for continuity and shorts and not for voltage. Having the battery hooked up could damage the meter on the ohms stetting.

When I was a kid, we had a '65 Mustang. One day my mom took it to the store and then it wouldn't start. She called my dad, and he brought a spare rotor down and that was it. He always kept the old service parts he changed as emergency backups. That's only time I'm ever seen a rotor completely fail, not even at work as a mechanic for the phone company for 30-years did I see a rotor completely fail. They still run just not very well. On the Mustang the rotor broke into two pieces. I hate to say it, but my dad only used Motorcraft parts, and he did a tune-up and the recommended mileage. It was just a defective part. What are the odds of that happening on your personal car but never seeing it happen as a mechanic. He had bought the Mustang new and that was the only time it left us broke down in 20 years. Those were good dependable cars.

I wonder why I can remember a broken rotor on a Mustang from 50-years ago but I'm looking at parts I bought for a '34 pickup project and wondering what the hell I bought them for. Damn stroke!

Flathead Fever · 06-05-2025, 11:57 AM

Also, why in the hell do I keep posting twice. I deleted it. Damn stroke

Bored&Stroked · 06-06-2025, 09:16 AM

Quote:

Originally Posted by KiWinUS

Shrink sleeve Dale.

Hey Tony - what type of sleeve (material, etc).

I've used heat-shrink material on a lot of other electrical stuff - but never on a distributor/rotor shaft?

Chris in MA · 06-06-2025, 02:17 PM

I just went through two helmet distributors. The one I took off the car was rebuilt by Jim Linder (RIP) in about 2011. The other one I bought was a rebuild from someone on here a while back. Both shafts had some type of insulation. Bubbas had shrink wrap and the other a couple of wraps of black electrical tape.

06-04-2025, 08:21 PM	#1
rockfla Senior Member Join Date: Mar 2014 Location: Jacksonville FL Posts: 5,164	Distributor guru suggestions I am trying to help a fellow Barn memeber, he has a 37-41 helmet distributor, has tried several avenues to get his car running (which it was prior to purchase) but was having no luck. He sent me his distributor so I could check it and set it up on my Sun machine. I have the right set of points dead on 22, pulled the left blocker and set the dwell at 35. Timing is set 2dgr advanced. I figured I would stick it on my 39 Mercury and test it out…..and I get NO fire at all!!! None. Using my coil and condenser which on “my” distributor fire my Mercury off “immediately”!!!! I can put my distributor and coil back on and like clock work, My Mercury fires immediately! Double check the other distributor back on the Sun, all dwell is dead on, timing still 2dgr, good strong arrows, put it back on my Merc, nothing, no start, no fire. I verified the correct rotor for the 37-41 spark plug plates, it’s the correct rotor. Suggestions or ideas???

06-04-2025, 08:47 PM	#2
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 3,418	Re: Distributor guru suggestions Is inside of rotor to shaft insulated?

06-04-2025, 09:13 PM	#3
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,218	Re: Distributor guru suggestions Does the dist have the original FORD coil on top like original or an adaptor set up for the remote coil. You have to do some testing with a voltmeter and ohm meter. Test for power to the coil primary terminal through the ignition switch. Original column switches wear inside and cease to pass current through them. Some of the remote dist plates are made from a fibre material and bend around and make bad connections to the inside of the dist. The bakelite plates are much better. Testing with a meter or test light is the only way not guessing and asking everyone else what they think because they dont know. Auto electricians test and dont guess. Regards, Kevin.

06-04-2025, 09:21 PM	#5
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,218	Re: Distributor guru suggestions Nope, he is talking 22 deg. not thousands of an inch. Regards, Kevin.

06-04-2025, 09:26 PM	#6
mcgarrett Senior Member Join Date: Dec 2013 Location: Corsicana, Texas Posts: 1,551	Re: Distributor guru suggestions Sponsored Links (Register now to hide all advertisements) Thanks for the clarification.

06-04-2025, 10:08 PM	#7
Brian Senior Member Join Date: May 2010 Location: Masterton, New Zealand Posts: 4,097	Re: Distributor guru suggestions I'm with kiwiinus on this...the rotor is shorted out...electricity will take the shortest route to ground... __________________ Unfortunately, two half wits don't make a whole wit!

06-05-2025, 02:53 AM	#8
rockfla Senior Member Join Date: Mar 2014 Location: Jacksonville FL Posts: 5,164	Re: Distributor guru suggestions Thanks guys I’ll check it out when I get back home from my trip. When I got back In from my shop and started thinking the process through, all I came up with was the rotor and personally, In all my life, have never heard of this or been around a rotor that was bad. Kevin, the coil and condenser and all of the wiring, switch and connections are ALL good as I am using my 39 Mercury as the test mule……I can get in it, pump the accelerator three of four times, pull the choke and it’s running within 5 seconds. I drive it pretty regular, so the whole system is working very good. After I set this distributor up. I was gonna test drive it and make sure it performed before I sent it back. Thanks again.

06-05-2025, 08:57 AM	#9
35fordtn Senior Member Join Date: Aug 2010 Location: McMinnville, TN Posts: 2,468	Re: Distributor guru suggestions Do you have a coil installed on the sun machine? Either the contact for the coil is grounding out or the most likely scenario is the rotor has a crack on the inside. If so replace the rotor and insulate the shaft. This is actually a common problem there are two service bulletins regarding this. That’s why for undersized the shaft in the middle

06-05-2025, 10:50 AM	#10
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,906	Re: Distributor guru suggestions Curious . . . what do you guys use to isolate/insulate the shaft from the rotor? I've come up with a variety of methods to solve "spark to ground" issues with Harman-Collins dual-coil distributors - so I'm always looking for tips and tricks that others use. Thanks in advance! Side Note: Given the above, I have equipped my Sun distributor machine with a setup to run/test the secondary portion of the ignition --> with coils, plugs and a variable "spark gap" mechanism to put load on the system and see how it performs as such. Here are some links to an article and video from quite a few years ago: https://www.jalopyjournal.com/forum/...ke-one.628039/ https://www.youtube.com/watch?v=3xduaVyzx10

06-05-2025, 11:26 AM	#11
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 3,418	Re: Distributor guru suggestions Shrink sleeve Dale.

06-05-2025, 11:46 AM	#12
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,492	Re: Distributor guru suggestions Seems like the points are shorted to ground or the voltage is prior to it getting to the points. I would hook up an ohm meter to the points and the case and see if they show they are opening and closing. The voltage might be going to ground before it gets to the points. That's the only thing that makes sense if the coil will work on another distributor. A cracked rotor might do it, but you should be able to see the crack. Swap the rotor to, swap everything and if still won't start I'd looked for a short to ground in the distributor housing. Make sure to disconnect the battery when using the ohm meter, your just checking stuff for continuity and shorts and not for voltage. Having the battery hooked up could damage the meter on the ohms stetting. When I was a kid, we had a '65 Mustang. One day my mom took it to the store and then it wouldn't start. She called my dad, and he brought a spare rotor down and that was it. He always kept the old service parts he changed as emergency backups. That's only time I'm ever seen a rotor completely fail, not even at work as a mechanic for the phone company for 30-years did I see a rotor completely fail. They still run just not very well. On the Mustang the rotor broke into two pieces. I hate to say it, but my dad only used Motorcraft parts, and he did a tune-up and the recommended mileage. It was just a defective part. What are the odds of that happening on your personal car but never seeing it happen as a mechanic. He had bought the Mustang new and that was the only time it left us broke down in 20 years. Those were good dependable cars. I wonder why I can remember a broken rotor on a Mustang from 50-years ago but I'm looking at parts I bought for a '34 pickup project and wondering what the hell I bought them for. Damn stroke! Last edited by Flathead Fever; 06-05-2025 at 11:56 AM.

06-05-2025, 11:57 AM	#13
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,492	Re: Distributor guru suggestions Also, why in the hell do I keep posting twice. I deleted it. Damn stroke Last edited by Flathead Fever; 06-05-2025 at 12:03 PM.

06-06-2025, 02:17 PM	#15
Chris in MA Senior Member Join Date: May 2010 Location: Newburyport, MA Posts: 133	Re: Distributor guru suggestions I just went through two helmet distributors. The one I took off the car was rebuilt by Jim Linder (RIP) in about 2011. The other one I bought was a rebuild from someone on here a while back. Both shafts had some type of insulation. Bubbas had shrink wrap and the other a couple of wraps of black electrical tape.