How to make a Model T coil tester. aka Buzz Box

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Model T Ford Forum: Forum 2013: How to make a Model T coil tester. aka Buzz Box
Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Thursday, October 31, 2013 - 10:04 pm:

Let me pass the benefit of my experiences to others on this subject.
Model Trs, (being the unique people they are), most should understand this. I love you guys and gals and wouldn’t go to the extensive efforts to prepare all of this for anyone else.

If electrical systems are ‘Greek’ to you and you would like to build your own tester, maybe my instructions will help you. I have made and sold many coil testers at Hershey and on eBay.

How is a tester wired? Pictures are better than words. (the 1000 words thing, don’t ya know). Schematics can be confusing. By looking at my pictures you should be able to know what to buy and what you will need to do to put one together. Some woodworking expertise and imagination and with experimentation will certainly help.

Understanding the route of the current as it goes through the wires.
Follow the wiring. (The color of the wires is not important.)

Let’s start with the Positive (+) current starting at the wire nut marked X. picture1. It goes through the on/off switch to the + post of the ammeter… through the ammeter and through the hole marked C. The wires at C go to a contact that touches the button on the bottom of a coil. The other wire coming from the contact goes to post X which is one of the points on the top of the tester. When the points are close enough, the spark jumps to the other point and comes down post Y. From Y it goes to the contact that touches the bottom (side) button on a coil. The current goes through the coil and out the top button on the coil and through the wire at hole B and to the negative (-) wire of the battery cord.

As you position the wires make sure that none of them come close to each other. Sparks could cross over where they shouldn’t.

The brass points and other contact pieces can be fashioned with tin snips. The brass from which I fashioned the various contacts and points is available at Taylors, True Value, Ace or similar hardware stores. Our store displays them in a little ‘stand-up” box and is located near the selection of aluminum panels for storm doors and other selections of metal strips and tubing.
The points and contacts that touch the coil buttons are of different thicknesses than the points. The button contact pieces have to be thin enough to have some flexibility. See what they look like in picture #9.

The brass screws, washers, nuts and knurled nuts are available in little drawers at the True Value/Ace types of hardware stores. You just have to hunt through a lot of drawers. MAKE SURE THAT ALL THREAD SIZES MATCH. 8/32 THEAD. See the last picture for a list of parts needed.

My 3rd picture should give you some idea of where the ammeter sets in the line of events. (consider the whole tester as being my unit and picture (in your mind) the ammeter as being installed in it.)

The Model T purist will tell you that the huge heavy coil tester is necessary to set your coils correctly. So what about the hundreds of thousands of guys who got by and only used a Buzz Box?

SO WHERE DO I GET A SUITABLE AMMETER? Look on eBay. Look for: ammeter dc 0-3 or ammeter dc 0-5 (always specify dc). 0-5 is OK… 0-3 would be better. So what if it doesn’t look antiquish… who cares as long as you can adjust a coil to 1.3 amps?


There is an ongoing question, which way does direct current flow? If you Google the question… it seems that no one is really sure.

I will be glad to answer any questions and help you in any way that I can. Contact me by clicking on my name. I am nearing 89 and I still love helping people. If you successfully make a tester, I hope you will send me a picture of it.
Add this Forum post to your favorites for quick recall.
See the website at the very bottom.
Have some serious fun.
signaturevirginiabeach
1underneath
2top
3ammeterinline
4woodpiecessmalltestee
5woodpiecesLGtester
6picofpost
7picofparts
8brassparts
9coilcontactshaping
10myoriginalbox
11partslist

Here is a post that put on the 2009 Forum with pictures of different types of boxes. Also note all of the ensuing discussions.
http://www.mtfca.com/discus/messages/80257/105769.html?1253136251

Bonus https://www.youtube.com/watch?v=uoABty_zE00 1 min

and The Empty pickle jar http://play.simpletruths.com/movie/the-empty-pickle-jar/store/ 3 min


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Thursday, October 31, 2013 - 10:19 pm:

Sorry about that. I was warned that I had 3 pictures rejected. I wrote down what to correct and Xed the page down. Sooo... it goes through anyway. I'll be back.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Thursday, October 31, 2013 - 10:50 pm:

I hope my pictures go through tis time.
1underneath
2top
3ammeterinline
4woodpiecessmalltestee
5woodpiecesLGtester
6picofpost
7picofparts
8brassparts
9coilcontactshaping
10myoriginalbox
11partslist


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Thursday, October 31, 2013 - 10:59 pm:

OK... I got it right this time
signature


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chuck Hoffman - Gold Country of Calif. on Thursday, October 31, 2013 - 10:59 pm:

Good luck Gene. I built one of these a few years ago and posted some pictures on the forum. All I got was a lot of flak and criticism because it wasn't a HCCT and therefore useless. Hope you do better.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Thursday, October 31, 2013 - 11:26 pm:

I love a project like this. Thank you for showing all the details. Is there any way I tell if the coil is double sparking with this tester? Looks like a lot of fun to make.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Thursday, October 31, 2013 - 11:43 pm:

Gene, can you show how to add a spark plug checking feature to the above machine?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Friday, November 01, 2013 - 12:29 am:

Chuck,
Yes, I “know about the buzz box flack. So I will ask the question again, “So what about the hundreds of thousands of guys who got by and only used a Buzz Box?”

Erich,
I don’t see any way that the buzz box will check for double sparking. I took the build of a buzz box as a challenge; and it was fun!
Testing a plug doesn’t show any degree of value of a plug. With all of that current going through it, you will certainly see if a plug is shorting out.
testingapludg

Make yourself a signature at http://www.gif-mania.net/animated-signatures/
To select a pen or pencil click the little box ‘shared figurines’ and select Artist/pencils. Then move over to the left and experiment.
Once you click Create, click Download this signature (give it a moment) Click ‘Open’ to see it. Right click and Copy and stick it somewhere where you can go get it later.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Randall Strickland on Friday, November 01, 2013 - 12:57 am:

I like it!nice work!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Friday, November 01, 2013 - 12:58 am:

Thanks.



Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, November 01, 2013 - 07:32 am:

Not trying to start anything. Just curious. Do you believe double or missing sparks affect performance?

If one were to assume they do affect performance, one might also surmise that the use of a buzz box could lead to owners getting frustrated that their T doesn't run on coils (even though they've been tested), and install a distributor, and as Ron Patterson says....Declare victory.

My personal opinion: A coil set up on a buzz box will run great on battery, but it may or may not run great on mag, just depends on whether it has missing or double sparks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, November 01, 2013 - 07:36 am:

Like Hal said your buzz box pretty much can only allow you to tell if the coil can buzz. It is of no use in properly adjusting a coil. Even if your T only runs on battery you are just plain missing the boat.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Tillstrom on Friday, November 01, 2013 - 09:07 am:

Don't get me wrong, I am not anti-buzzbox. I made one and used it for a long time with great results. To me, if a buzzbox gets a T out of the garage and on the road it has worked.

I have set coils on a buzzbox that ran on mag and the car would scoot down the road 45 MPH if I wanted to. What I honestly noticed after building and setting them on a HCCT was that there was less vibration and the engine just ran smoother.

This is why. There is a delay built into the points by function of the limiting rivet. The points stay in contact with each other until that rivet is reached which allows the current to build. When a coil double sparks it is because the points aren't staying together as the cushion spring tension isn't correct. The result is a weaker spark that occurs sooner than it is supposed to. If the next cylinder occurs at the correct time the result is the difference is something other than a span of 180 degrees.

This is what the buzzbox cannot detect (double spark).

Just as important to smooth running as getting single (full energy) sparks is getting them at the correct time. The distance of the limit rivet should be the same between coils.

I am all for the guy who is getting a T running do what he can. I am also all for chapter members assisting them in smoothing things out as best as they can be made to.

This is why I offered the HCCT plans in hopes that chapters would take the project on and thereby helping said new members.

If I lived out in the middle of nowhere and needed to get a T running, you can bet I wouldn't blink to set them on a buzzbox. I also wouldn't blink at the chance to set them on a HCCT or Strobospark if the opportunity arose.

The important thing is, once set up correctly that the owner not fiddle fart around with them again on the buzzbox.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Friday, November 01, 2013 - 10:45 am:

I ran this picture on the Barn site and it's all I use now for checking to see if a coil operates. I use a train transformer with an AC output. I've built (and sold on T-Bay) a number of buzz boxes and I'm not knocking Eugene's project. It's a fun build but I didn't bother going any further in testing coils for years until Bob J. contacted me and came over with his HCC tester. The car started cold on mag the first time we tried it after HCCing. I've only done about 15 coil re-builds and out of those only 2 didn't need any further adjusting so it's (slimly) possible to get it right with a buzz box but you'll miss more often than hit it right. You HAVE to get them HCC'd. You'll never go back.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, November 01, 2013 - 11:34 am:

Charlie,

I would not let a coil jump a gap more than about a 1/4". No doubt it will do it, and it's quite impressive, but it can lead to internal arcing inside the coil. It's not very good for them.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Friday, November 01, 2013 - 11:41 am:

Hal: try taking a pic with one hand & keeping the sucker sparking with the other at the same time! LOL.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, November 01, 2013 - 01:16 pm:

I can see where that would be a problem.:-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jared Buckert on Friday, November 01, 2013 - 04:52 pm:

Pretty neat little build. I'll add it to my already growing list of projects.

I seem to remember some talk of a smaller version of these buzz boxes that ran off a 9V battery. It didn't have a gauge, but it would make a coil buzz if it was a good coil. That way you could test your swap meet finds before shelling out the cash for them, without hauling around a bulky buzz box unit. Does anybody remember this project and what became of it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Garnet on Friday, November 01, 2013 - 05:08 pm:

That would be the coil beeper sold by one T parts supplier. The down side to using it at an auction sale is that it also tells everyone standing within an hundred feet of you if the coil is good. It should have come with a headphone circuit instead ... test it, swear and throw it back in the pile with all the others you swore at, and then buy them all later !! Good fun.

I used to do this with radio tubes at auctions. I just used a battery and placed two contacts in an the thumb and first finger of an old glove and the battery was wired in series with the headphones. Pick up the tube with the contacts on the filament and if I heard a click in the headphones there was a good chance the tube was good. Anyone standing beside me at an auction wouldn't have known what I was doing and just thought I was listening to music!


Garnet


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, November 01, 2013 - 05:21 pm:

If you have a coil beeper then put your index finger over the hole in the black thingee and it won't make much more than a very weak murmur of a beep that you can hear but outside you can still offer the guy $4 for the entire box of "no good" coils but remember that a T guy is notoriously cheap so he may hold out for $4.50 in his counter attempt at preserving his $.50 profit in the whole deal.

I got a grin out of the signs at Hershey that said the coils in a certain box had been "checked with a Fun Projects Beeper" already ha ha.

In truth most T guys are like me - "old farts" who can't hear high pitched tones anyway.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jared Buckert on Friday, November 01, 2013 - 06:10 pm:

I wouldn't use it at an auction, because most of the auctions I go to aren't packed full of T owners. That's how you pick up a Universal Rim Tool for 7 bucks. Be the only one in the crowd that knows what it is. I'm sure Steve Jelf can attest to that as well.

I just thought it would be handy to test a coil I find at a swap meet. So many people claim parts are tested good, but watching you pull your own tester out of your pocket can make some of the less honest ones a little nervous. I'd rather test it and find out it doesn't work before I pull out the billfold.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Friday, November 01, 2013 - 07:31 pm:

Jared,
Here is a picture of a simple tester that shouldn't be too hard to make.
tester


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Friday, November 01, 2013 - 08:13 pm:

I'm with you Jared. The best T buys I ever got was at no name flea markets where they just don't know. I got a Ford screwdriver for $2 at one place and recently picked up a bras top coil for $5. Sellers see the Ford name on tools and their up a bit but you can find bargains. At the recent Englishtown Show/Swap meet there was a guy with about a dozen beat up coils. $20 each and he wouldn't move a cent so I did. Away from there. I seem to do better if I'm "sluming". I think if you're looking for something specific, say at Hershey, you might not be bothered by an inflated price.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Friday, November 01, 2013 - 09:09 pm:

I guess I'm missing something here about coils , buzzboxes and HCCT's. Two years ago I started to get my 15 touring (barn find) into shape. No one within a hundred miles had a HCCT so I rebuilt the coils and carefully adjusted to them according to the "MTFCA's electrical system" pamphlet (using a homemade buzzbox). Done right - it takes a while.

The car starts easily on mag or battery, idles smoothly and will do an easy 45mph if I want.

So, not to start an argument, but exactly what would I gain adjusting them on a HCCT? Would I get 47 mph? (don't go that fast anyway). Would it run smoother? (it already runs as smoothly as others I've ridden in).


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Friday, November 01, 2013 - 09:58 pm:

I am going to try and shed some light on this. Testing a coil is not the same as adjusting a coil. A buzz box will test a coil - sorta. It may or may not be adjusted correctly and the test won't tell you. If you adjust it to 1.3 amps reading on the BB meter you may have adjusted it to 1.3 or 2.6 or .65 amps. If the unit is single sparking then your setting of 1.3 is accurate. If the unit it double sparking you have set the coil to .65 amps but it reads 1.3 because the "duty cycle" of the coil is basically double and the ammeter is measuring total current. If the coil is misfiring it may measure 1.3 but in fact be producing sparks at any duty cycle up to 1:1 and your current could be actually set to 2.6 or higher depending on the duty cycle since a 2.6 current event that occurs half the time gives a 1.3 reading.

Since I make and sell new coils I have had the opportunity to setup somewhere between 1500-2000 coils so far although my daughter-in-law Angela has done some of those and she is faster at it than I am. I have the advantage of having coils that all have perfectly flat Hard maple wood tops that are not soft. They also have brand new correct capacitors and I have both an HCCT and Strobo-Spark available. I use the strobo spark since it is a bit easier for me even though I really don't need the capacitor check feature since I have installed new capacitors to start with. I take a set of points out for a coil and wash them in lacquer thinner and blow them dry. I then install the vibrator (lower part) to the coil followed by the Bridge (upper brass part). I align the points and tighten the hardware all of which is new. I set the point gap to 1/32" and then put it in the Strobo-Spark. I have had times when almost an entire batch of points will need almost no adjustment and even had one day when 24 out of 32 coils basically just "worked" and I was done in almost no time. That only happened once. I have had other times when I have had to fiddle with both the vibrator tension (to correct the current setting) and the cushion spring tension of the upper bridge (to get single sparks only) and then back and forth a couple of times. Sometimes I have had to give up and install a second set of points because the upper point was rubbing on the limit rivet and the points could not be adjusted to work. There are no published specs by Ford as to starting tension on the vibrator or cushion spring. There is only a drawing and some general notes as to materials and dimensions of the points. The present vendor doesn't have the dimensions perfectly right but some points work perfectly anyway with little or no adjustments. Why am I presenting this? Imagine that the tester you plugged your coil into was a buzz box and I think it would explain the entire thread(s) about buzz box versus HCCT. It all depends on whether the points you have need much adjustment or not and there is simply no way to tell by looking at them since it is a balancing act between 2 springs and a coil winding mounted to a wood platform. If you understand what I am trying to explain - there is not real argument in my mind about what is going on. Will a dead coil work in a BB - no. Is the current setting of 1.3 in a BB then a valid reading??? Reread the above. I am not against the use of a BB if that is all you have since it will tell you if a coil is at least firing some of the time but if your car has a miss or doesn't seem to run very smooth and you have ruled out coils based upon a buzz box test - well......

Hope this helps for a better understanding of what is going on. I firmly believe that 95% of fixing anything is knowing first what is going on and then how it all should work.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Saturday, November 02, 2013 - 09:41 am:

Bud you sound exactly the way I did. Pre HCC that is. The fact is that if no tester is available and you're satisfied with the cars performance that's that. If you get the chance though have them done. There might be a surprise waiting for you.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Saturday, November 02, 2013 - 10:13 am:

Bud,

You will be shocked and amazed at the difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, November 02, 2013 - 10:39 am:

If I can get to someone (perhaps on next vacation roadtrip) I will definitely have them adjusted on a HCCT.

Who knows, maybe I've been eating vanilla ice cream and haven't found the Bluebell peppermint stick yet !


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Saturday, November 02, 2013 - 11:28 am:

Bud,
You are absolutely correct…I got by for decades with nothing more than a little this/a little that and occasionally tossing one in a box for one that worked better. Then one day someone offered to stop by with a Strobo-spark to tune what was in the car and a good bunch in the box also came back to life.

A while went by again and a newer car that was cranky added and this time the offer was with a HCCT and he was really in Goldilocks mode as to setting and persistence, but they are absolutely beautiful when done, can move car to car, start on mag or battery, and haven’t had to be touched in eons!

I don’t know how many have pianos…but it’s like the piano tuner. I knew one guy that used only a 12 point deep socket and his ear….another who used an actual tuning wrench and a 440 hertz tuning fork for that one note, followed by his ear for everything else…another who used a tuning lever, had a gizmo box that could set one octave by machine, the rest by ear…and there was the guy who came in with a full spectrum analyzer, a series of tuning levers of different lengths, and a mute set that looked like he was about to do open heart surgery.

For the Spinet…any one of the 4 could tune it and it worked, or seemed to work good enough. Move over to the Mason & Hamlin Grand and the first two would be wasting their time (and me wasting my money) as it either would never have come in for the full range to begin with or would not have stayed in.

I now sort of think that coils are the same way. Drive slow and easy…don’t expect much…you get by with almost any method. Want to push the envelope as to charge build time etc. and expect the best possible performance with sustainability? Go top end or the one below it…your individual skills will vary. :-):-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Carnegie on Saturday, November 02, 2013 - 12:08 pm:

When I set my coils up for the Montana 500, I observe their action on a triggered sweep oscilloscope and spend a lot of time getting four perfectly balanced coils. One year, I was surprised to see one of the competitors at the 500 "adjusting" his coils by sparking them against the fender with a set of jumper wires and twiddling with the points, presumably to get a "fat" spark, or maybe to get them all to scream at the same pitch. He actually ran well and finished 5th.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Saturday, November 02, 2013 - 12:52 pm:

Tom,
I think your observation of someone adjusting a coil by sight or sound and that coil performing well in a group of high performance T's carries more weight then the commonly reported seat of the pants comparisons. It would be interesting to set up a dyno test with coils set from "experts" in both camps.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Saturday, November 02, 2013 - 01:17 pm:

Tom, I wonder what he had done with those coils previously? Had he used more precise tooling to find/create 4 matched coils? Even so, I am surprised he did so well. I wonder what words that guy would use do describe his method and thinking regarding the pre-race fender arc coil adjustments.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Saturday, November 02, 2013 - 01:19 pm:

I love my strobo-spark for the ability to very precisely adjust coil function. I try to match the 4 coils as much as possible. Even so, they do not sound the same to me. If I were using sound as part of my adjusting, I am not sure I could trust what results I would get.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Saturday, November 02, 2013 - 03:16 pm:

When I first bought a StroboSpark Coil Tester, I was about ready to send it back, as every coil I tested had a bad capacitor. Most of the coils had excessive capacitor leakage and almost as many had the wrong size capacitor.

Then I happened to call Coilman and discuss my problem with him. He told me that he had rebuilt over 5,000 coils and about 100 had good capacitors. He always uses the StroboSpark for a quick preliminary test and a final check.

The Buzz box will tell you if the coil is bad, but will not and can not verify if the coil is good.

The Hand Crank Coil Tester will tell you if the current is correct and if you do not have random mis-fires or double sparks, which can often happen.

You really need the StroboSpark to test the capacitor for size and leakage and to make the final adjustment.

You need the HCCT to display the 16 sparks and verify that there are no missing or double sparks.

You don't really need the Buzz box for anything, except for a quick go - no go test.

If you only have one of the three items, go get a StroboSpark!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Saturday, November 02, 2013 - 03:20 pm:

While you guys are digesting what's on this post, remember to set your clocks back an hour before you go to bed. I will set a clock on the supper table as a reminder.
Here is something you can play with in the meantime. If your computer will be on this evening, set it to go off during that time and get up and change all of your timepieces. I have about 17 things to change. Don’t forget the VCRs and the clocks in the cars.

With your pointer, move the red hands (there is one behind the other). By all means, you have my permission to play with it now.
Turn your volume up and then minus the page down and let it set till the clock goes off.
http://www.poodwaddle.com/clocks/alarmclock/
alarmclock


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jared Buckert on Sunday, November 03, 2013 - 12:30 pm:

I met with the Coil Doctor during Chickasha last year, and he used a Strobo-spark and a HCCT to test all his coils. Kind of a double insurance policy. I've had him rebuild my coils before, and they made a world of difference in how nice my car ran. I'm sure the Coil Man has the same results, but I've personally never worked with him. I would like to learn how to rebuild coils, but at least there are some very qualified rebuilders out there. I wouldn't mind having a buzz box or beeper for checking swap meet finds, though. Maybe someday I'll have enough pennies saved up for a Strobo-spark.


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