First rebuilding of some coils
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Jevil
Topic author - Posts: 6
- Joined: Thu Sep 25, 2025 5:41 am
- First Name: Jens
- Last Name: Willeke
- * REQUIRED* Type and Year of Model Ts owned: 1927 Tudor Sedan
- Location: Wenden, NRW, Germany
First rebuilding of some coils
Hello all.
As I was not feeling confident with keeping my distributor (see here: viewtopic.php?t=49977) I am now on my way back to the roots. I was able to get a 26/27 coilbox on ebay with four coils in it.
I disassembled all the rusty points and made some measurements (LCR-meter, L-measuring frequency was 1kHz).
Hoping to find out that the windings are okay.
But I am not quite sure about my results in comparison with the original "datasheet facts" I found ("origin" line).
My results: Primary windings seem to be okay for all of them. Secondary resistance of #3 ist relatively low.
Inductance measurements are all far away from original values.
Maybe somebody can help me to figure out which one ist rebuildable without changing windings (which ist not reasonable in my opinion).
Greetings from Germany,
Jens
As I was not feeling confident with keeping my distributor (see here: viewtopic.php?t=49977) I am now on my way back to the roots. I was able to get a 26/27 coilbox on ebay with four coils in it.
I disassembled all the rusty points and made some measurements (LCR-meter, L-measuring frequency was 1kHz).
Hoping to find out that the windings are okay.
But I am not quite sure about my results in comparison with the original "datasheet facts" I found ("origin" line).
My results: Primary windings seem to be okay for all of them. Secondary resistance of #3 ist relatively low.
Inductance measurements are all far away from original values.
Maybe somebody can help me to figure out which one ist rebuildable without changing windings (which ist not reasonable in my opinion).
Greetings from Germany,
Jens
1927 Tudor Sedan - black (of course)
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Dan Hatch
- Posts: 5293
- Joined: Tue Jan 08, 2019 7:31 pm
- First Name: Dan
- Last Name: Hatch
- Location: Alabama
Re: First rebuilding of some coils
Get Ron Patterson coil rebuilding coil video or cd. Tells you all you need to know. Dan
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TXGOAT2
- Posts: 8061
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: First rebuilding of some coils
Error deleted.
Last edited by TXGOAT2 on Thu Nov 13, 2025 7:36 pm, edited 1 time in total.
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Scott C.
- Posts: 849
- Joined: Sun Jan 06, 2019 11:44 am
- First Name: Scott
- Last Name: Clements
- Location: Waynetown Indiana
Re: First rebuilding of some coils
I have rebuilt several coils. Here is what I have used to determine whether a coil is good or not. Most of the time the only problem is the capacitor. You will definitely want to set the cushion spring gaps on your new points. That will make them easier to adjust and run much better. I have come across a few that checked bad but was able to resolder the wires to the contacts on the side, or bottom of the coil. What are you planning to use to check for double spark and adjust the amperage? I have a Strobo Spark from Fun Projects, but they are no longer available.
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Jevil
Topic author - Posts: 6
- Joined: Thu Sep 25, 2025 5:41 am
- First Name: Jens
- Last Name: Willeke
- * REQUIRED* Type and Year of Model Ts owned: 1927 Tudor Sedan
- Location: Wenden, NRW, Germany
Re: First rebuilding of some coils
For setting up I plan to use a 4-channel DMO and current clamps. I think this will do the job.
1927 Tudor Sedan - black (of course)
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Chris Barker
- Posts: 327
- Joined: Sun Jan 06, 2019 5:08 pm
- First Name: Chris
- Last Name: Barker
- * REQUIRED* Type and Year of Model Ts owned: 1926 Coupe
- Location: Somerset, Eng;and
Re: First rebuilding of some coils
They are all rebuildable.
The only measurement that matters is the secondary coil resistance and yours are all within the normal range.
I have never seen references to T coil inductance and so don't know what you do with the numbers.
There is a huge amount of info on line about T coils.
And for setting up, see also this long thread:
viewtopic.php?f=2&t=9072&hilit=arduino
The only measurement that matters is the secondary coil resistance and yours are all within the normal range.
I have never seen references to T coil inductance and so don't know what you do with the numbers.
There is a huge amount of info on line about T coils.
And for setting up, see also this long thread:
viewtopic.php?f=2&t=9072&hilit=arduino
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TXGOAT2
- Posts: 8061
- Joined: Sun Feb 14, 2021 10:08 pm
- First Name: Pat
- Last Name: McNallen
- * REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
- Location: Graham, Texas
- Board Member Since: 2021
Re: First rebuilding of some coils
If the resistance is normal the inductance value is likely normal also. Somewhere, there is a table of the magneto AC frequency at various engine speeds. The "buzz" frequency can vary from one coil to another when they are correctly adjusted.
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Charlie B in N.J.
- Posts: 776
- Joined: Mon Jan 07, 2019 7:40 am
- First Name: CHARLIE
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- * REQUIRED* Type and Year of Model Ts owned: "27 Tudor / "23 Touring
- Location: Brick N.J.
- Board Member Since: 2010
Re: First rebuilding of some coils
Watch the video by all means. Plenty of tips there. After viewing come back here with any questions.
Forget everything you thought you knew.