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3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 1:23 pm
by BuzzBumbleBee
We were out with the T the other day for a local car show and it rained hard in the afternoon.
On the drive down the car was behaving very well (best it's ran in a long time)
But after the rain we went to start it up and nothing.... Would not start. But what it would do was send a very noticeable shock through my hands whenever I touched the key or the handbrake .....
I read online that it's quite common for the coils to short through the wood in the coil box when wet (especially with carbon build up)
So I decided to print a new back and base for the coil box (pictures below) in some PETG. Would anyone else find the STL files helpful? (Do note that these where made using the old box we had as a template, and I have no idea how close this was to stock.)
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 1:30 pm
by JTT3
That’s AWESOME. I wish we had a tab for storing this type of data to be used as an adjunct to restoration of current & future hobbiest. Thanks ever so much for your innovation.
Best John
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 2:36 pm
by Mike Silbert
While I love 3d printing and have made many prints but in this application I have some concerns.
Over the years I have discovered that most 3d printing is porous (leaky).
They will fail vacuum leak tests, weap chemicals when plating, and not hold pressure. When installed on a vacuum leak tester it will suck liquids through the plastic parts. Cool to watch but not good if it is supposed to seal.
There are ways to seal 3d printed parts but you have to know that it is needed to be done.
If it is properly sealed it should work fine.
I make my own waterproof parts for my cars out of solid plastic pieces. I have been caught in some terrible rain storms forcing me to pull over due to flooding. See my MTFCI Hamilton Ohio tour picture if you want proof. The car ran fine and did not miss a beat.
I recommend every driver car be retrofitted with waterproof box parts. It is no fun to break down due to wet coil box wood.
Happy Motoring
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 3:03 pm
by Dan Hatch
A few years ago you could buy that part of the shelf made out of plastic. Was made from the Ford print, fit and worked like it should.
Too bad it is not being made today.
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 3:31 pm
by BuzzBumbleBee
Mike Silbert wrote: ↑Thu May 30, 2024 2:36 pm
While I love 3d printing and have made many prints but in this application I have some concerns.
Over the years I have discovered that most 3d printing is porous (leaky).
They will fail vacuum leak tests, weap chemicals when plating, and not hold pressure. When installed on a vacuum leak tester it will suck liquids through the plastic parts. Cool to watch but not good if it is supposed to seal.
There are ways to seal 3d printed parts but you have to know that it is needed to be done.
If it is properly sealed it should work fine.
I make my own waterproof parts for my cars out of solid plastic pieces. I have been caught in some terrible rain storms forcing me to pull over due to flooding. See my MTFCI Hamilton Ohio tour picture if you want proof. The car ran fine and did not miss a beat.
I recommend every driver car be retrofitted with waterproof box parts. It is no fun to break down due to wet coil box wood.
Happy Motoring
I can see your point around 3D printed parts not being totally water tight, however in this case it's just to improve on the old wooden box. Main advantage here is that its far less likely to absorb water from a quick downpour than the wood.
If you exposed the printed parts to enough water then it could fail, but I suspect at that point water would have passed through the mounting screws ect before the printed part becomes an issue.
The best option I guess at that point is to seal everything up so water never gets anywhere near the HT side of things
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 3:53 pm
by Moxie26
If you can find a period made coil box, save those internal contacts. Clean them up and put them in your new application. The original contacts were made of a better metal that held tension a lot better than what's being put out today.
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 4:18 pm
by RajoRacer
Dan - I purchased one of Snyder's plastic c.b. kits not too long ago - it fit perfect & was a mirror image of Fun Project's kit.
Re: 3D Printed Coil Box (Back and Base)
Posted: Thu May 30, 2024 8:24 pm
by jiminbartow
While 3D printers are amazing innovations the surface of the product they make is composed of hundreds of rough layers. Maybe one day amateur 3D printers will evolve to a point where they produce finished products with a smooth surface like it should be.
Regarding the coil box parts featured here, I think it could be made waterproof with a coat of polyurethane or POR 15. Jim Patrick
Re: 3D Printed Coil Box (Back and Base)
Posted: Fri May 31, 2024 7:29 am
by TXGOAT2
Would a wooden replica made of marine-grade plywood be non-hygroscopic?
Re: 3D Printed Coil Box (Back and Base)
Posted: Fri May 31, 2024 11:04 am
by Oldav8tor
Nice job with the 3-D printer. If it's waterproof you have a winner!
We've had a couple of instances in our club of sputtering cars due to water infiltrating the coil box. While the plastic replacement kits available from the vendors may not be quite as polished as the ones sold years ago by Fun Products, they do the job. Re-use your contacts if you can. If you need to replace them, the two main vendors sell contacts of different quality so you should check them out before ordering. You want the ones that look like this. They're closest to the originals.
If your contacts have lost their "spring" you might try what I and a couple of other fellows have done.....Double them up! Blasphemy I know, but it works....problem solved.
A friend replaces coil box wood with a material designed for outdoor signs. Me, I'd just get the plastic box kit. When putting it together, be sure all wires and connections are well insulated from the metal box. We've had two instances recently of bottom wires shorting that way. It's also a good idea to solder the contacts to the bolts that run thru the insulators. Speaking of which, we recently had trouble on a tour with one of our cars because the nuts holding two of the insulators were loose. Tightened up and the car ran fine.
The attached photo shows carbon traces on the wood of a coil box from a '22. Got wet and never worked properly again.
Re: 3D Printed Coil Box (Back and Base)
Posted: Fri May 31, 2024 5:42 pm
by Mike Silbert
To seal a 3d printed parts they can be sealed using you choice if insulating coatings. Spray clears or brush on and let it soak in. For those that have access to it conformal coatings work great. For better results vacuum or pressure chambers push it deep in the pores. Black paint can be used with excellent results as long as it does not contain too much carbon pigment to be conductive.
When choosing plastic to make your own pieces be careful and test black plastics for conductivity. Slick surfaces help make the coils easier to slide in and out also.
Anything that is ESD safe is conductive and no good.
My favorite material is smoke brown plexiglass when I can get it. Clear plexiglass is a good choice for a demonstration 26-27 engine. If you want an authentic look add sand scratches for simulated grain effect. Then a light coating of black paint to finish it off.
A few other details to make a better box:
Ford installed an insulating cardboard sheet in the bottom of the box. Make sure something is there. The best replacement is to use a sheet of thin plastic since it cannot absorb water. Thin plastic is available for free salvaged from many places.
When installing the white insulators I use soft nylon washers instead of the cardboard ones.
And a place sometimes forgotten is the unused hole when the switch is on the dash and not the box. Seal it with black RTV to keep driving rain out.
With some care the coil box water problems will go away forever.
Happy Motoring