Carbon track in wood coil box?

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Model T Ford Forum: Forum 2015: Carbon track in wood coil box?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Townsend ; ^ ) Gresham, Orygun on Wednesday, February 04, 2015 - 12:57 am:

I have a wood coil box that has been modified to accept rebuilt 1914-1927 coils. However there is a slight miss when running and the car will not accelerate. It just does not have the power.

I've tried different coils.

If I put on a metal coil box with the same rebuilt coils in it, it runs great! So there is something going on with the wood coil box.



I adjusted the contacts inside the box so they make perfect contact, so I'm sure that is not the problem.



There is varnish on the inside on the inside of the coilbox. The wires on the bottom are insulated with varnish.



I know carbon tracking happens with the laminated layers of wood in the metal coil boxes, but how about in a wood coil box?

I'm thinking maybe I could drill out the holes for the terminal bolts and put in some plastic sleeves for better insulation? Would the "leaks" likely be around the spark plug terminals?

How can I test for "leaks?"

I know I could get a new wood coil box for the "modern coils" but am not ready to admit defeat yet. I'm frustrated...

: ^ {

Keith


Top of pagePrevious messageNext messageBottom of page Link to this message  By George n Los Angeles CA on Wednesday, February 04, 2015 - 02:02 am:

At night, open garage door start up, turn off lights, use a flash light to help get around the floor jack you left in a bad place, turn off the flash light and look for jumping sparks, then proceed to the engine see if anything is jumping around the firewall,cables and plugs. What's your spark plug gap? I had exhilaration prob with a too wide a gap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Wednesday, February 04, 2015 - 10:11 am:

Keith

After checking in the dark as suggested, you might what to re-check the terminal contacts again, and alignment of the box contacts to the coil contacts.

Had similar problem, this box was retro fitted for later coils, but the contact spacing was off, an the coils sometime didn't contact. Even with wood spacers that held them from slop fitting. The issue was the box contacts, and spacing.

And the wiring was solid core, so changed that to multi strand as it takes better rough handling, and was able to be sure the wiring was done right.





Former contacts, repro, and fitted incorrectly.



re-spaced two rows of contacts to get in alignment with the coils.



Finished with original contacts, note how they stand proud of the wood grooves to strike the coil contacts firmly.



Done, worked great!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Wednesday, February 04, 2015 - 10:50 am:

It's very easy to install those contacts the wrong way. I expect you can guess how I know that. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Hjortnaes, Men Falls, WI on Wednesday, February 04, 2015 - 01:42 pm:

Dan

What you are showing in the picture is that the two in the middle are aligned toward the middle of the box and the two outer ones are aligned toward the outside of the box. Is this correct for every coil box?

I will have to check the one I just finished.

Thank you.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Wednesday, February 04, 2015 - 04:44 pm:

Dave

This box pictured in the thread was for the big older coils, and was told it worked for the little newer coils, but the alignment was off. So I re-did it to fit the coils better.

Here is a drawing sketch from FordOwner showing the proper Ford metal coil box w/switch layout for the contacts in the box.





The original contacts come in lefts and rights, and both rows on each side use the same, so that two rows are lefts and two rows are rights, as divided in the box, 2 rows on one side, two different rows on the other.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, February 05, 2015 - 12:36 am:

What does the underside of the lid look like since most of these larger wood coil boxes have no provision for holding the coils DOWN so they can jump around. It also appears that you have powered the bottom strip by the center rivet and have soldered a wire into the rivet which may or may not be making a good connection with the bottom strip. Ford did it that way too and it caused trouble. The boxes like this that I have seen have not been carefully laid out with holes being way off in both side to side measurements and up and down. Notice there is a groove down the center of the back and front. It is wide. Notice in the metal box that the coils all sit exactly side by side with no wide groove. If that groove was not accounted for in the contact spacing ...well.... The contacts themselves seem pretty distorted and might not be making a good connection to the bolts. I would remove the top row of contacts and buff and solder them to the bolts I would do all 8 of them if it were my box but the top 4 are most important since they provide the power INTO the coil units since the output HV will arc over from contact to bolt but I like to solder them anyway so that the bolt cannot come loose. Spend some time cleaning up the connections and reshaping them. Look at the pictures of the contacts on my web site since that is exactly how they are supposed to look. Make up a stick with horizontal spacing marks at 2-5/16 on centers and place that stick horizontal inside the box to check the dimensional alignment of the contact MOUNTING BOLTS because these contacts are offset. If the box were using 26/27 contacts without offset then the spacing is different. Check the switch contacts by bypassing the switch with wire from mag post to the bottom strip on one or both of the end rivets. They too might not have good connection but probably at least one of the 3 does. I would use an ice pick with wire wrapped around its tip and the other end connected to the mag post and touch the end rivets underneath while the motor is running to see if that makes the miss go away. If yes then its the center rivet or the switch that is intermittent.

I have to also advise you that somehow it is thought incorrectly that only the laminated coil box woods have the carbon tracking issue. That is simply wishful thinking. If it IS wood then it can carbon track unless the wood you are using doesn't contain any carbon :-) Some of the MTBC coil box lining is made of material with higher carbon content than wood but hey it IS cheaper and with enough work with file and some redrilling you can get it to fit and pretend its better than wood :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd, ............Red Deer, Alberta on Thursday, February 05, 2015 - 12:05 pm:

Was going to ask what MTBC stands for, but thought I would just do an online search. Came up with a lot of meanings but nothing relating to a product that could be used for coil box lining.

Here's a partial list of the meanings I came up with:

Music Therapist Board Certified
Mean Time Between Callback
Mariners Temple Baptist Church
Mycobacterium tuberculosis complex
Medical Transcription Billing Corporation
Malaysian Tenpin Bowling Congress
Mountain Biking Club
Margaret Thatcher Business Center
Master Time Base Control
MEASAT Teleport and Broadcast Center
Maximum Time Between Change-out
Mechanical Trades Bargaining Committee
Mean Time Between Call
Metroplex Technology Business Council
Mean Time Between Changings
Mitsubishi Trust and Banking Corporation
Mean Time Between Cleans
Mean Time Between Coincidence
Mean Time Between Collisions
Million Title Book Catalog

So, the question remains: What does MTBC refer to in relation to coil box lining materials?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, February 05, 2015 - 12:26 pm:

It is a name given to copycats who steal the research and marketing and provide something that is only cheaper but not researched with regard to materials or diimensions. It may even violate copyrights and be illegal. It means "Me too but cheaper".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Townsend ; ^ ) Gresham, Orygun on Friday, February 06, 2015 - 02:19 am:

Here is the underside of the lid:



The extra piece of wood holds the coils snugly so the don't float up. The notches are now slightly larger and clear the points.

On the bottom strip, if I remember correctly, I made a loop in the stranded wire and soldered it. I sandwiched the (cold) loop between the contact strip and the wood on the bottom with one rivet going through the loop. The three rivets are aluminum pop rivets. I could drill out the pop rivets, solder the loop onto the contact strip, then re-rivet it to the bottom.

While I am soldering, I will solder the all 8 contacts to the mounting bolts. While I have the bolts out, what do you think about drilling out the mounting bolt holes and putting in a plastic "sleeve" (about a 1/4" OD and 3/16" ID the thickness of the box, about 3/8")? IF there is carbon tracking from the mounting bolts, my thought was the plastic inserts (which would not be seen) would isolate the mounting bolts from the rest of the wood.

I will also massage the shape of the contacts a little. Because the bottom of the box is slightly higher, I had to raise the point of contact on the contacts so it matches the contacts on the coil.

I will also try a jumper wire from the input wires to a rivet on the bottom of the box and see if that makes any difference.

The car sure runs well with the metal coil box.

It will be a while before I can do the modifications and re-test it. The car is currently on display in the lobby where the Corbett Children's Theatre is doing a production of The Music Man. Since the play is set in 1912, the 1911 car fits the setting perfectly.

: ^ )

Keith


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd, ............Red Deer, Alberta on Friday, February 06, 2015 - 11:33 am:

Thanks John, I learn something every day, never heard that one before.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, February 06, 2015 - 10:02 pm:

The plastic sleeve is not likely to help much since when dealing with High voltage the carbon is already a fairly high resistance but the HV jumps across cracks and insulation points. To do any good you would need to drill out the terminal holes by about 3/4" to keep the HV then 3/8 away from places it might want to jump. Did you address the contact alignment with regard to BOTH of the contact fingers being centered on the side and bottom contacts of the coil? If the coils are not original KW or Ford they could be off a bit themselves and not enough to get in trouble with the metal box coil box but off enough to not match the all wood one. I frankly tell people to consider just putting a metal coil box on their car equipped with waterproof kit and drive since that way you really don't have to worry about water. Since the metal coil box is exactly the same footprint as the earlier boxes, just hang the all wood box on the shelf for the next owner and have fun in the mean time since you do not have to modify the dash or wiring to use the later box. T guys might know it is from a later year but most folks won't and you will still have coil and timer ignition to tell folks and to show them how it was different. All wood box is just too much trouble but I think I would address all of the points raised at this point to find out what it is then decide if a later box is the fix. Does the car run on magneto or is it a battery only set up?

(Message edited by piewagon on February 06, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, February 06, 2015 - 10:09 pm:

Duplicate posting - sorry.

(Message edited by piewagon on February 06, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Townsend ; ^ ) Gresham, Orygun on Saturday, February 07, 2015 - 11:29 am:

The contacts in the box line up well with the contacts on the coils (both up and down and side to side.) It is hard to get the camera lined up for a good shot, but here is the best view I have:



I have tried both rebuilt original Ford coils, and new Bittner coils. Both exhibit the "miss" in the wood box, but perform flawlessly in the metal box.

I will solder the contacts to the mounting bolts first, then do a switch test.

With the metal coil box, the car runs well on either magneto or the new 12v lawn & garden battery.

: ^ )


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