magnet clamp plates

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James kitchener
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Joined: Mon Mar 04, 2019 12:36 am
First Name: james
Last Name: Kitchener
* REQUIRED* Type and Year of Model Ts owned: 1914 touring 1923 touring
Location: British Columbia Canada

magnet clamp plates

Post by James kitchener » Mon Nov 11, 2019 7:08 pm

Can someone tell me if using 1912-13 long style clamp plates on my flywheel and the newer single stack mag ring could cause any problems with mag output or timing? I know this seems like a strange question but I am trying to figure out a strange problem with my mag out put. My magnets are strong, mag ring rebuilt, gap correct, little to no crank shaft end play, mag puts out about 8v at idle but never goes over about 15 at wide open throttle, with 1157 bulb, and never burns out the bulb. I have rebuilt many T engines and of course mine is the only one with this problem.
James Kitchener.


Scott_Conger
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Re: magnet clamp plates

Post by Scott_Conger » Mon Nov 11, 2019 7:24 pm

The longer keepers were designed to be used with round poles with widly spaced coils, of course, and the later short keepers were used with oval poles and very closely spaced coils. I know you know that, but am repeating for benefit of newer members here. I do not know for certain, but I really wonder if the long keepers in tandem with larger oval poles are somehow altering the sine wave of the AC output and it is not a clean or true waveform. If you have access to an oscilloscope it would be interesting to compare the wave form of a normal mag and yours.

For everyone else, here is a thread that shows the difference in coils and keepers: http://www.mtfca.com/discus/messages/59 ... 1452261264

If Ron Patterson (or other knowledgable people) is/are lurking, he'll debunk me if I'm wrong. I'm not an EE.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


Topic author
James kitchener
Posts: 5
Joined: Mon Mar 04, 2019 12:36 am
First Name: james
Last Name: Kitchener
* REQUIRED* Type and Year of Model Ts owned: 1914 touring 1923 touring
Location: British Columbia Canada

Re: magnet clamp plates

Post by James kitchener » Mon Nov 11, 2019 8:54 pm

Scott Conger, thanks for the replay I have been questioning this for a long time. My engine is apart right now do to some teeth breaking off of a reproduction trans driven gear so i will probably install the small rectangular ones.Would be really interesting to know if it makes a differance or not.


J1MGOLDEN
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First Name: James
Last Name: Golden
* REQUIRED* Type and Year of Model Ts owned: 1926 Model T Roadster
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MTFCI Number: 13562

Re: magnet clamp plates

Post by J1MGOLDEN » Mon Nov 11, 2019 9:27 pm

The most important measurement is the spacing between those magnet pole pieces and the pickup coil pole pieces.

If the spacing is close to .040 you will only have about 8 volts out of the Magneto.

.025 to .030 is ideal or fine, if the engine has new main bearings.

That is all I had on the first engine I did, as I thought the most important point was to have enough clearance so the pole pieces did not touch.

A WRONG ASSUMPTION!


Scott_Conger
Posts: 6431
Joined: Sun Jan 06, 2019 11:18 am
First Name: Scott
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* REQUIRED* Type and Year of Model Ts owned: '13, '15, '19, '23
Location: Clark, WY
Board Member Since: 2005

Re: magnet clamp plates

Post by Scott_Conger » Mon Nov 11, 2019 9:37 pm

Jim Golden

I have always been of a notion exactly as you have just described. Research today turned up this: http://www.mtfca.com/discus/messages/33 ... 1376366658

I have a lot of respect for Royce's opinions and experiences and as of the date of: Royce in Dallas TX on Monday, August 12, 2013 - 07:51 pm he was changing his tune as to what was necessarily prudent vs effective.

I don't add or detract from his conclusion here; I only document that he gave it.

James K

try to get original clamps. The repros are too soft and flexible.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured

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Corey Walker
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* REQUIRED* Type and Year of Model Ts owned: 1914 runabout, 1921 homemade truck, 1921 Speedster
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Re: magnet clamp plates

Post by Corey Walker » Tue Nov 12, 2019 12:24 am

I had a clamp screw break in my 14 and it damaged one of the longer style clamps so I put an ad in the classifieds for one along with this picture. Somebody noticed the later mag ring and gave me a reason as to why it would work, just not as exactly intended. I replaced the longer style with the later ones when I put it back together. The main difference is that it’s like my 21 now. You can notice the difference in the positions on the quadrant more. The magnets weren’t recharged when I was running the longer clamps which might have had a lot to do with it but it was like a gradual advance.
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Corey Walker, Brownsboro, Texas

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