Coil Box Cover - Skipping

[mpetitjean]

I am experiencing skipping when I am under load in high gear. Starting, idling,and low gear are fine. When I go into high and accelerate or climb even a small incline I get repeated skipping. I have adjusted spark advance and GAV. Ultimately, when I remove the coil box cover and drive under the same circumstances it goes away completely.

Below are pics of the inside of the box, the lid, and the coils.

What would cause this?

Matt
1914 T Touring

[John kuehn]

A coil shorting out against the inside of the coil box cover? Maybe the sheet metal piece inside the cover hitting one of the coils?

[TWrenn]

Looks to me like the wrong year coils for that metal box. As John said I think its the metal strip shorting it out. I temporarily tried similar coils in my '26 could box and had same issue when I put the lid on it. Regular KW wood top coils don't do that.

[mpetitjean]

Interesting. I have a back-up set of wood top coils, I'll try those.

Matt

[TWrenn]

Interesting. I have a back-up set of wood top coils, I'll try those.

Matt

Let us know how it went!

[John kuehn]

Weren’t the brass top coils used mostly in the earlier wood coil box? I think the common wood top were in the 14’s. I might be wrong. The cars I have are the later 19 and up T’s so not sure.

[speedytinc]

Try covering the coil holder ledge with some electrical tape. Experiment. That bar is there to keep the coils down. I have added a strip of .062" plastic to add extra tension on the coils.
The lid is correct for that box. I believe the brass top coils are also correct for this box/lid. I could be wrong.

[Fire_chief]

Those brass topped coils, with the 6 screws, are correct for that '14 coilbox.
As mentioned, check for the coils shorting against the box or lid. Also make sure the coils are pushing forward against the contacts. I use business cards to keep the coils tight.

[John kuehn]

Fire Chief is right. According to Bruce’s Encyclopedia the brass top coils are correct for T’s until 17 when the wood box coils came out and were used thereafter. With the metal lid made the way it was that must have been an occasional shorting issue with the metal hold down piece so close to the brass tops of the coils. Interesting enough 1917 was when Ford moved away with so much brass on the Model T’s. Something to think about I guess. Maybe it started with the coils but what do I know.

[MichaelPawelek]

Fire Chief is right. According to Bruce’s Encyclopedia the brass top coils are correct for T’s until 17 when the wood box coils came out and were used thereafter. With the metal lid made the way it was that must have been an occasional shorting issue with the metal hold down piece so close to the brass tops of the coils. Interesting enough 1917 was when Ford moved away with so much brass on the Model T’s. Something to think about I guess. Maybe it started with the coils but what do I know.

WWI metal shortage?

[RVA23T]

WWI metal shortage?

Bingo! my though exactly.

[John kuehn]

Probably so! Think of all the brass that was used in ammunition both BIG and small! Same in WW2.

[Drkbp]

It appears that your coil point adjustment nuts near the firewall are too high.
I just took this picture of the coil box in my July 1913 Touring a few minutes ago
that have been in that box for 6 or 7,000 miles. Poor light but the knurled nut near the
firewall on each of my coils appear to be lower than the setup you have. Please note the
piece of cedar shingle "coil adjustment" wedged against the #3 and 4 coils. Just
happens to be three Six screw and one Four screw brass tops. The six screw tops
appear to be black finished brass and the four screw is just brass. Runs like a bandit with
what appears to be the same flat top and wood coil box panels you have.

[TRDxB2]

From the encyclopedia about the Coils
1913
4706 1383 Kingston. Used 4713 coils, 5-3/4 x 2-9/16 x 2-5/16”
4600 ----- Heinze. Used 4611 coils, 5 x 3-1/16 x 2-5/16”
----- ----- K-W. Used 4681 coils, 5-3/8 x 3-1/4 x 2-1/4”. This was a wooden box and the coils had the contacts in a different location from the later types.
4725 1383 K-W and Ford. Metal box, non-sloping lid. Individual coils supplied by K-W, Heinze, and Ford. Used 4732 or 5007 standard-size coils, 5 x 3-1/2 x 2- 1/8”

1913-1914
4725 1383 Ford. Same as 1913 Ford/K-W box. Used standard Ford “brass-top” coils, 5 x 3-1/2 x 2-1/8” supplied by K-W, Heinze or Ford. Switch cover was brass with black background.

Perhaps the semicircular cutouts on the shelf to hold the coils down were added for a purpose (to eliminate shorting coils) on the later lids.
Is the lid an original or repro? I have no pictures of the underside of a 1914 lid (except yours)

[mpetitjean]

It appears that your coil point adjustment nuts near the firewall are too high.
I just took this picture of the coil box in my July 1913 Touring a few minutes ago
that have been in that box for 6 or 7,000 miles. Poor light but the knurled nut near the
firewall on each of my coils appear to be lower than the setup you have. Please note the
piece of cedar shingle "coil adjustment" wedged against the #3 and 4 coils. Just
happens to be three Six screw and one Four screw brass tops. The six screw tops
appear to be black finished brass and the four screw is just brass. Runs like a bandit with
what appears to be the same flat top and wood coil box panels you have.

Yes they do appear lower on yours. Mine have an additional lock nut in addition to the knurled nut. Removing that may help or at least be the point where there is an issue. Thanks for your input.

[mpetitjean]

From the encyclopedia about the Coils
1913
4706 1383 Kingston. Used 4713 coils, 5-3/4 x 2-9/16 x 2-5/16”
4600 ----- Heinze. Used 4611 coils, 5 x 3-1/16 x 2-5/16”
----- ----- K-W. Used 4681 coils, 5-3/8 x 3-1/4 x 2-1/4”. This was a wooden box and the coils had the contacts in a different location from the later types.
4725 1383 K-W and Ford. Metal box, non-sloping lid. Individual coils supplied by K-W, Heinze, and Ford. Used 4732 or 5007 standard-size coils, 5 x 3-1/2 x 2- 1/8”

1913-1914
4725 1383 Ford. Same as 1913 Ford/K-W box. Used standard Ford “brass-top” coils, 5 x 3-1/2 x 2-1/8” supplied by K-W, Heinze or Ford. Switch cover was brass with black background.

Perhaps the semicircular cutouts on the shelf to hold the coils down were added for a purpose (to eliminate shorting coils) on the later lids.
Is the lid an original or repro? I have no pictures of the underside of a 1914 lid (except yours)

Super helpful, thank you. I don't know for sure if the lid is original but it seems to be the same wear and tear as the rest of the car. I picked up a coil box off the forum a few years ago, I'll look at that one and see if it has the semicircular cut outs. This would have been a good Hershey item to hunt for....

Thanks
Matt

[Ron Patterson]

Matt
It appears your coils do not have the manditory insulating washers between the adjusting thumbnut and the coil point upper bridge. Without these the stamped metal top is ("hot" and) part of the coil primary winding high current circuit making it prone to shorting to the coil hold down (without releif) on your type coilbox lid.
Tim
The design of the Improved Car coilbox lid has spring tabs that are supposed to lightly push down on the coil wood top to hold the coils in place, and if not properly aligned will short to the vibrator spring will easily short to the vibrator spring which is part of the coil secondary winding circuit. These tabs will deform if you use them with metal top coils in and Improved" coilbox.
Ron Patterson

[Drkbp]

Matt,
I have the same lid you have and it is the original style. I attach a photo of a very nice
repro 1913-14 lid with cutouts to clear the knurled nut. I couldn't tell from your photos,
but the bolts that hold the metal coil box to the firewall have a "flat" side on them.
It's to aid in installation because your coil box has four mounting holes in it and
they are round. Your bolts should be like the top row. My bolts were raven finished
(black) but the nut and washer on the engine side of the firewall were brass plated.
Also, the four coils in my touring and all of my other 4 and 6 screw brass top coils have
just the knurled nut on top. Maybe not original but I don't know. On the 4 and 6 screw
brass top coils, I believe the brass finish were by Ford and raven anodized were KW.
The knurled nut seems to be self-locking. Maybe Ron P will chime in because he would know.

[greenacres36]

My 15 has the coil lid with the cut outs and they were not big enough. I had to put them on the mill and make them bigger. It was doing a similar thing when the vibration was right the coil would just happened to hit the shell but after, making them bigger I’ve had no problems.

[mpetitjean]

Matt
It appears your coils do not have the manditory insulating washers between the adjusting thumbnut and the coil point upper bridge. Without these the stamped metal top is ("hot" and) part of the coil primary winding high current circuit making it prone to shorting to the coil hold down (without releif) on your type coilbox lid.
Tim
The design of the Improved Car coilbox lid has spring tabs that are supposed to lightly push down on the coil wood top to hold the coils in place, and if not properly aligned will short to the vibrator spring will easily short to the vibrator spring which is part of the coil secondary winding circuit. These tabs will deform if you use them with metal top coils in and Improved" coilbox.
Ron Patterson

Ron
Here is a close-up of the points. I see the grey insulator between the spring and bridge. If I understand your description, it should be on top of the bridge?

Matt

[Ron Patterson]

The metal top coil MUST have a insulating washer on top of the spring and on top of the upper coil point bridge to prevent the metal top becoming part of the Primary winding electrical circuit.
If you don't have two washers and run only on magneto things work ok, but if you use a battery wired to the coil box for starting the vibrator may lock to the metal top placing a continual high current load across the primary winding, causing the coils to get very hot very fast leading to "real" trouble.
The first larger Wilson design KW coil was used for a short time the the last half of 1913. The Ford standard sized Wilson design metal top coils first appeared and were joiuntly made by Ford and KW. KW six screw tops first (black oxide coated) and then KW soon dropped the extra two screws and the Black oxide coating. This went on with Ford and KW in lockstep until 1917 where the metal top was dropped and in late '17 and '18 Ford experimented with the cast wheat gluten coil which was soon dropped in 1918 because cast wheat gluten case was dimensionally unstable. The came the Ford wood cased coil with no branded logo till 1919 when Ford insisted his name in script be on everything and the logo branded first appeared on the wide side and later on the top edge.
All these details are in our three part Ford/KW coil article. I have these in electronic format if anyone wants a copy.

[Ron Patterson]

PS; all the thumbnut locknuts pictured in the metal top coils in this thread are incorrect. The correct locknut is very thin.
Ron Patterson

[Ron Patterson]

Attached is a photo of a set of properly rebuilt KW 6 screw black oxide metal top coils.
Ron Patterson

Furstnow-Small.JPG (31.9 KiB) Viewed 4695 times

[jab35]

Ron: Will you please post a link to the coil article you mention? But if I'm the only one needing it, you can email to jab35(at)cornell(dot)edu thanks, jb

[Moxie26]

mpetitjean..... Any progress to report on your problem?

[Dan Hatch]

Now you know why 14 Coilbox lids are so hard to find. They all got thrown out in some ditch back in 1914.

[Moxie26]

Dan and Matt.... I'm just curious if someone used a post 1918 or so wood coil , dressed it up with the earlier brass plate and hardware, so the sale of would be priced a hell of a lot higher. Those four point posts look awfully short compared to the original manufactured metal top coils.

[John kuehn]

When the thread was started I commented that maybe the coil box lid was the issue. It was a guess but with the brass top coils and the lid really close to them that had to be a hassle more than few times and causing issues. I would imagine that the dealers heard about it too.

[TRDxB2]

Now you know why 14 Coilbox lids are so hard to find. They all got thrown out in some ditch back in 1914.

My guess is that the coil box lids, all years, were scrapped metal for the war effort. The coil wasn't because of the attached wood required some effort to remove it. In my Barn Find lots of coils & coil units but no lids

[1925 Touring]

Ive got a few stray lids, all metal, but do not know one year from the next.

[TRDxB2]

Ive got a few stray lids, all metal, but do not know one year from the next.

[John kuehn]

After a while the coil box lids were thrown in a corner along with the engine pans. Not every time but a lot of the time.

[mpetitjean]

mpetitjean..... Any progress to report on your problem?

I had a coil box cover with the cut outs in the metal strip that fits, but not perfectly. With that cover there wasn't any skipping. I ordered thin brass nuts and the insulating washers from McCaster-Carr. I think with those swapped and the original cover it should be resolved. I'll follow back up with results. Thank you everyone!