Photos of 12 roadster Magneto and magnets with drill spots...

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Model T Ford Forum: Forum 2008: Photos of 12 roadster Magneto and magnets with drill spots...
Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael W. Herndon on Sunday, November 16, 2008 - 06:17 pm:

Here are photos of both the magneto and the magnets, plus a few others..

The engine is 1913, the magneto part has a starter notch and appears to be single wrapped.

Note the drill pits, in the magnets, what we have been talking about.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Sunday, November 16, 2008 - 06:50 pm:

Michael, I don't see what you are saying here, but you have a coil ring used from 1919 to 1927 with the starter engines. The magnets are probably later too and a little thicker, otherwise you would have an excessive Mag gap and the Magneto would not work.

You did not have enough clearance for some reason. There are a few likely causes of your problem identified here. 1. The engine was excessively worn and let the magnet pole pieces contact the coil ring. 2. A brass pole piece screw broke or backed out and made contact with the coil ring. 3. The oil pickup funnel made contact with the magnets, came loose and did the other damage. 4. A piece of debris in the transmission got between the magnet pole piece and coil ring and tore a pole piece loose.

I turned on the lights so we could see the photos better.

1

2

3

4

5


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson on Sunday, November 16, 2008 - 10:07 pm:

Michael
I have a different take after looking at all the photos.
Clearly the later style field ring and flywheel were used in the early engine which is commonly done.
I see no evidence of insufficient magneto gap causing the failure.
What I do see is the failure of two magnet clamp screw heads allowing two magnet keepers to become loose inside the engine and causing damage to the cotton tape wrapping on one of the field windings.
Apparently a used flywheel was installed during the rebuild process and that is where the trouble started? Original flywheels must always be completely disassembled and checked for crystallized clamp screws and cracked magnets.
Here is a photo of a failed clamp screw head. Failed clamp screw head and here is a cracked magnet. Cracked magnet
Frankly, I think you are lucky you found this when you did or the damage could have been very much worse. If you look closely somewhere inside the engine you will find the magnet clamp screw heads and two very beat up magnet keepers.
Given the propensity of used Model T flywheels to have these type of problems it is beyond me what anyone would reuse one with out completely rebuilding it.
I heard a story this week of a Model T while running where a broken magnet half departed it's flywheel mounting breaking out the top of the hogshead severing the side of the gas tank causing a Model T fire.
Why anyone would spend the obligatory $3500+ to FULLY rebuild a Model T engine and omit the step of an additional $50 to fully rebuild the flywheel and preclude this type failure is a mystery to me?
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson on Sunday, November 16, 2008 - 10:08 pm:

Michael
I have a different take after looking at all the photos.
Clearly the later style field ring and flywheel were used in the early engine which is commonly done.
I see no evidence of insufficient magneto gap causing the failure.
What I do see is the failure of two magnet clamp screw heads allowing two magnet keepers to become loose inside the engine and causing damage to the cotton tape wrapping on one of the field windings.
Apparently a used flywheel was installed during the rebuild process and that is where the trouble started? Original flywheels must always be completely disassembled and checked for crystallized clamp screws and cracked magnets.
Here is a photo of a failed clamp screw head. Failed clamp screw head and here is a cracked magnet. Cracked magnet
Frankly, I think you are lucky you found this when you did or the damage could have been very much worse. collision If you look closely somewhere inside the engine you will find the magnet clamp screw heads and two very beat up magnet keepers.
Given the propensity of used Model T flywheels to have these type of problems it is beyond me what anyone would reuse one with out completely rebuilding it.
I heard a story this week of a Model T while running where a broken magnet half departed it's flywheel mounting breaking out the top of the hogshead severing the side of the gas tank causing a Model T fire.
Why anyone would spend the obligatory $3500+ to FULLY rebuild a Model T engine and omit the step of an additional $50 to fully rebuild the flywheel and preclude this type failure is a mystery to me?
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael W. Herndon on Monday, November 17, 2008 - 12:54 pm:

Hi Ron...

I bought the 1912 T about 2 months ago... Apparently it had been previously rebuilt, and probably a number of times considering that the cylinders are already about .060 over.

You are right, I did find two keepers but only one screw head, crystalized.

So, I don't know if this was used and not inspected, etc. prior to rebuild, but whatever the reason, I am rebuilding now. I have had many suggestions that are appreciated by the group, including what you have said. For sure, I will do it completely to avoid this problem later!

I am planning to have the magneto rebuilt (suggestions as where?) and the magnets checked or replaced/recharged.. (same question..) Some of the magnets have the marks on them from drills, supposedly for balance? Suggestions have been to toss them.

Thanks for the input! Lots for me to learn and am learning!

Michael


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Humble on Monday, November 17, 2008 - 05:04 pm:

Ron,
Would you recommend replacing the magnet clamp screws whenever the engine is apart, or is this to correct a problem with original Ford screws and need only be done once? My clamp screws were last replaced in the late 1970's and I will have my engine out soon to replace the small timing gear.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Lorentz K Lorentzen on Monday, November 17, 2008 - 05:36 pm:

The end of the brass screws are supposed to be hammered (peened) against the starter gear. So when you remove them again you have to chip off the end and then you will not have enough to peen them again even if they are in good overall condition. Therefore you MUST ALWAYS replace brass screws that have been peened when you put it all back togehter. I also recomend thet you run a tap through the threads. One of my holes kept eating up the brass threads until I re-tapped it. It is an odd tap that I can not remember the number for. Ron knows for sure.
As for the early cars with non starter flywheel it's a little bit different, I think the screws are not peened but secured with a wire. Someone else need to give full comments on that issue... In that case I would assume that the screws can be reused if they pass your inspection.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Garnet on Tuesday, November 18, 2008 - 12:37 am:

Don't know why the magnets were drilled unless it was a dumb attempt at balancing the entire assembly. Either that or they were taken out of some farm invention and put back into a T.

Garnet


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Tuesday, November 18, 2008 - 12:06 pm:

Clamp screw threads are #14-24TPI.
The screws were also peened on the earlier non-starter flywheels.
It looks like they used a special hammer w/cross hatching on it to peen them, and they only shmucked them once. Maybe it was a trip hammer?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Peterson on Monday, January 12, 2009 - 07:51 pm:

I found large chunks of brass in the oil of my 1912. After pulling the engine and removing the hogshead and pan, all I find wrong is maybe loose drums on the transmission. My rebuilder thinks it may be a brass thrust washer from the transmission?
This is a rebuilt powerplant with only 4 miles on it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Tuesday, January 13, 2009 - 02:19 pm:

John,

I suggest you reprint your question as a new thread and maybe include some pictures of the brass chunks. There really isn't that much brass/bronze in a T engine that can easily come loose.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stan Howe on Tuesday, January 13, 2009 - 02:23 pm:

I also have some of those magnets with holes in them. I dunno why.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Tuesday, January 13, 2009 - 03:19 pm:

Most metals including brass are crystalline in their metal microstructure. When a metal fails in fatigue the surface appears to be "cystalline" on a macroscale. The term "crystallized and broke" is a misnomer as the metal,at the microscopic level, has a crystalline structure both before and after failure.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael W. Herndon on Tuesday, January 13, 2009 - 04:23 pm:

By the way, I have removed the magnets at the start of this thread several months ago... 6 were cracked. The drill spots really are not drill spots at all, they are indentations that appear to have been made, perhaps at the construction phase, and are indentation, not drill spots (to be redundant..).

They do not appear such that they will have a deleterious effect on the strength of the magnets. I am looking for 6 more magnets and then will have Ron Patterson recharge them.

Michael


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