Adjusting spark coils by sound

[jiminbartow]

When I was concluding my 2 year long restoration of my 1926 coupe in 1972, I was putting it all back together and looking forward to starting it. Back then, before the internet, and before meeting anyone that knew about Model T’s, I pretty much had to wing it. When I got it all together, I had no idea that a special piece of equipment was needed in order to adjust the spark coils, so, I adjusted each coil in the car, by ear. I would turn the crank to a coil then adjust it by sound. I would adjust it until it had the strongest, smoothest sound then went to the next coil and did the same until I did all 4 coils. When I added water, oil and gas, I was ready crank it. I choked it and believe it or not, it cranked on the third try and ran beautifully and has not run so good ever since. Back in the day, how did the average Model T owner adjust their coils? Could they have done it by sound like I did back in 1972? Why is it not an accepted practice to adjust the coils by sound when I had such good luck when I did it and is there a downside to adjusting by sound? Jim Patrick

[Steve Jelf]

I'm not a coil expert, but I suspect you were just lucky.
How does the Service Manual tell you to do it?

[jiminbartow]

I was very lucky…always. I was only 16 when I started the restoration on my Model T in 1970, but after working on lawn mowers, go carts, my buddy’s Cushman scooter and my Grandpa’s old Evinrude outboard motor, I was pretty mechanically inclined. If I was not sure of something, I used common sense and I almost always did the right thing throughout the entire 2 year restoration. I did have the green Model T Ford Service Manual, which provided guidance, but there were some things I had to do differently to accommodate my budget, when what the book said to do was impossible due to the tools they used that I did not have and could not get. When I think back on it, I am lucky the thing ran so good, much less even started, which is a testament to the resiliency of the Model T. If only you knew…. For instance, while I dismantled the engine, I removed the magneto coil, the cloth bindings were shredded and soaked in black oil and caked in dirt and hard oil. Since I was unable to rewind the coils, I had to make due with what I had and hope it worked. I took a big pan and filled it with mineral spirits and soaked the magneto coil in it for a week, changing the mineral spirits each day when it turned black, doing this many times until the mineral spirits remained clear. I then let the magneto coil dry for a week. When it was totally dry, I coated it with several layers of red Glycol. I installed it in the car when I reassembled the engine without testing it. Believe it or not, it worked after I started the car and switched it from BATT to MAG and it worked perfectly for the next 40 years until I rebuilt the engine in 2010. Another thing I did was when I was installing the crankshaft, I discovered the main bearings babbit was oxidized into a grey powder about 1/32” deep, but I could scrape off the powder down to the shiny good babbit. I could not pour the babbit, so I had to figure out how to salvage what I had, so, using a flat razor blade, I carefully scraped off the soft grey babbit of the main bearings and cap, until I reach the hard, shiney good babbit, then, one bearing at a time, turned in each bearing by hand, with the crank by wrapping a piece of 220 sandpaper around the crank shaft bearing surface so the rough side was facing the babbit, then using the shims, I turned in each bearing separately until it fit the newly exposed babbit, then I would do the next and the next until they were all done. Again, I was very lucky because it worked like a charm. It went like this all throughout my restoration experience. Each challenge was confronted and met, with success. It taught me a lot. Just use common sense and trust your instincts. Had I had the forum and you guys to ask back then, I don’t think I would have learned as much or gained so much confidence in my abilities. I have sort of lost that because I now find myself asking a lot of questions that, in 1970-‘72, I would have had to figure out for myself. Jim Patrick

[Kerry]

Man! if you scraped that much off the babbitt, the cam gears must have been well and truely worn out

[JohnH]

Some early literature does actually describe coil adjustment without instruments. For example, "The Model T Ford Car" by Pagé from 1918, says that, "The tension of the vibrator spring should not be too light or too heavy, and the vibrator should work rapidly enough to make a sharp, buzzing sound when contact is established at the timer."
The Ford Instruction Book from 1913 says, "It is important to have all the units adjusted alike and with a little experience you will be able to "feel" by the explosions when the point is reached at which the motor develops the maximum speed".

The reality is that a car will run and drive as long as a spark is produced, when the relevant timer contact makes connection. However, unless one has been extremely lucky, performance won't be as good as that obtained with a proper tester. There is no audible way of adjusting for equal firing time or multiple spark elimination, or for that matter if the coil current is too high or too low.
Having said that, back in the day when a car would have had its original coils, which came off the production line at the same time, and therefore had similar characteristics, it may have had a better chance of producing tolerable results.

[John iaccino]

When I first got into Model T's, we adjusted the coils the same way as the first post. We looked for the highest, even pitch of the buzz and tried to match them all. The cars may not have run perfect, but they ran well. I have always been amazed how everyone has been convinced that we now need a $750 HCCT in order to set our coils.

[DanTreace]

As a teen, I set new points by adjusting tension on the vibrator spring, and looked for a hot spark. The buzz sounds didn't seem important as long as the coil buzzed! So sight is what I used, and a high or low frequency buzz didn't matter.

Back in the day, if the owner read his "Ford Instruction Book' the message is there, "trouble probably lies in the spark coil and the car should be driven (good thing 3 of the coils still worked ) to a Ford dealer who has special equipment for testing and adjusting units...."


Or they could just get this gizmo and have a sparking good time adjusting coils! Think it worked the same way as adj. the tension, as that cylinder is a weight that is calibrated for that measure?

It was only later I got a set of coils that were adjusted on the HCCT. Then found that the '24 would really run, even idle down on 'Mag...... because until then I thought my magneto was putting out poorly, the car would run on mag, after starting on bat, but slowing down to low speeds would want to stall, so I would switch to 'Bat' for those times. All I did was get a set of properly adj. coils and my magneto instantly fixed itself

[Sheri]

It was always my understanding that this was how the phrase “tune up” came into the popular lexicon of automotive language. Since the coils produce a pronounced pitch the thought was that making them all produce the same pitch produced a better running engine. This was especially true of the heinze coils which really sing compared to the KW design. It does seem to make sense that given the lack of any other tools this approach might produce good results. Since i play guitar i could try putting one of my tuners on a coil to dial in the pitch but it probably wouldn't work due to all the rf coming out of the coil and the likely interference it would generate in the tuner electronics. Years ago one of our club members was asked about replacing the coils in his car with a distributor and i loved his response: “ I find the sound of the coils very reassuring” he said. I do too. One thing seems true, no pitch means no spark.

[John kuehn]

I didn’t know about or ever heard about any kind of coil testing device that you used to adjust the coils until the 1980’s.
In the 60’s when I got my Grandfathers Coupe running I adjusted the coils for a good buzzing sound and the engine ran pretty well. My Grandfather had two boxes of coils in various states of condition. He never threw any T parts away and what I found he swapped coils when one went bad and used others for pieces and parts.

Sometimes I think this is one area of Model T that’s gets over thought out. AND YES I know there is more to it than just the sound BUT all I know is I got my Coupe running pretty good without using any kind of coil adjustment device.

The average T owner back in the T era kept his Model T going by what he had and most didn’t have a HCCT coil setting device.

Twenty years ago I bought a few coils from a guy at Chickasha and he was setting the coils he sold out of the back of his truck with a HCCT. I was watching him do it and the coils were buzzing with the same sound when I was setting my old ones at home.

Since then I bought rebuilt coils from Brent Mize and I’m glad he’s doing it. Haven’t had any issue with his coils.

[TXGOAT2]

If a T coil is in working order, it will buzz and throw an impressive spark without any fine adjustment. But that's not to say that a set of 4 will work together properly in the car. I've found that attempting to adjust the coils by sound is futile. Yes, the engine will run, but it won't run as it should. I did better by running the engine and adjusting the coils by how the engine sounded than by how the coils sounded. I got the engine to run OK, but after adjusting the coils with an ECCT, it runs MUCH better, and it can now be started easily by hand cranking on MAG, and it no longer eats timers. It's important to realize that the fact that a particular coil can be shown to throw a good spark and "sounds good" does NOT indicate that it is in proper adjustment, or anywhere near it. A Model T engine can be in a very poor state of tune and still run, but they run much better when in tune. A Model T engine can run without any cylinder missing and still run very poorly.

[varmint]

No special tools here.
Once I get it all together, I will probably listen to the coils, follow the book, and perhaps use a music tuner to observe the vibration.
Then ask for help.

66 car and horse.jpg (50.66 KiB) Viewed 3884 times

[John kuehn]

The guy on the horse can’t even get it right! Guess he didn’t know the car he was next to wasn’t a Model T! But wait it does look like it’s black!

[varmint]

The guy in the car is asking the man on the horse where his Model T is ?

The guy on the horse is the Model T owner.

[TXGOAT2]

If the coils could be readily adjusted by ear, Ford would never have brought out the HCCT.

[TXGOAT2]

Running and running right are two different things. I'm sure many people back in the T era drove Ts every day and never drove one that actually ran right.

[John iaccino]

Happy to be a dinosaur

[TXGOAT2]

I'm happy to let the ancient lizards ride in the fuel tank.

[Norman Kling]

Pat must use Sinclair gas! When I take my car to the station, I say I am getting dinosaur gas for my dinosaur car!
I have been on tours where a member would adjust the coils by ear. He got it to running on all 4. That got him home.
I have never tried adjusting them that way, but I do use a buzz box and get 1.5 amp on each coil. First I hook up my tester to see if the capacitor holds a charge, then I adjust the point gap and then bend the back of the bridge until I get 1.5 amp with a good spark. I do this first on 6 volt and then connect my box to the magneto of an engine which is running on battery but has a good magneto. When I get 1.5 amp on the magneto and battery, I try the coil in the car and if it runs smoothly on both battery and magneto that coil is good.
I do realize that I might get a very small improvement on the coil tester. But I carry a couple spare coils and a spare timer and a few spark plugs with me and so far have not had to be on a trouble truck on tours. The engine is stock even the cylinder bore has been sleeved to standard. The head has been resurfaced only enough to make the surface flat. My car keeps right up with the others except for some with speed equipment on their engines.
Norm

[TXGOAT2]

You can carefully adjust 4 typical T coils to sound good and throw a good spark, then put them in the car and it will most likely start and run OK. However, it is almost certain that the actual spark timing will vary from cylinder to cylinder. For instance, you might be running at 1200 RPM with the spark lever set to give 18 degrees BTDC. In fact, you might have 14 degrees BTDC on cylinder # 1, 21 degrees BTDC on cylinder # 2, and 17 degrees BTDC on cylinder 3, and 11 degrees BTDC on cylinder # 4. This causes needless vibration, power imbalance, and reduces performance and mileage.

[Scott_Conger]

"Tuning a coil" stopped being a thing when coils came out with cushion springs and proper (for the day) testing equipment surfaced in large numbers. It certainly disappeared from Dykes and other reputable manuals of the day shortly after that improvement to coils occurred. Technology is not static, and improved throughout the entire production period of T's. To point to a text that was "state of the art" in 1912 to justify the use of an outdated and irrelevant procedure to perform service on a vehicle for which the technology has surpassed the outdated advice is simply ignorance; either honest or willful, but ignorance of the subject none the less. Travel advice in the travel Blue Book of the period suggests that the tourer "do not take directions from a farmer, as he does not know the road very far". Not only did the farmer not travel very far, neither did he travel very quickly on the road, either, as it was often neither a physical nor emotional possibility given road conditions of the day (and likely often supported by the ailing performance of a car tuned by ear).

Since we often must drive our cars at nearly twice their designed speed, "running" and "running well" are two distinctly different things. My experience with "tuning by ear" is this: those that firmly believe in it either have never driven another T, or have only driven T's owned by similarly inclined individuals (likely the guy that taught them how to tune by ear). Absolutely NO ONE who has hand cranked or driven a T with properly tuned coils would ever go back to "ear tuning". You may think your car runs "fine" on ear tuned coils, but driving a properly set up car can be an epiphany.

For folks who simply and certainly know better, instead of using tools readily available, and techniques considered best practices, I might suggest the following (or not!) to be sure to get lots of attention and make new friends with the trouble truck driver or AAA:

1. tune every coil to the same pitch regardless of cushion spring travel or tension
2. when changing out parts, set the distributor or timer to the same general place as it was before, regardless of the brand it replaced - heck, the spark lever is adjustable, so who cares where the distributor or timer is set?
3. Air gauges are for scaredy-pants...fill the tires with air until they resonate one octave above the sound made when you hit your head hard on the fender.
4. run 100% concentrated coolant (hey, if 50/50 is good, 100% is better). Science and facts be damned, it's all or nothing
5. if the choice above is "nothing", run whatever water you have available to you. It was good enough for Grandpap 80 years ago, and we all know HE never rusted through a block
6. spend lots of time using reverse for a brake on long down-hill runs and save the brake and low gear bands for use later
7. use the brake band for those times when you really need it - after all, brakes are made for slowing down regardless of your speed.
8. Qwik-Poly or other thin epoxy resin is not just for body wood...in fact very spectacular results can be expected if it is used on rotted spokes
9. use the low gear band that you saved, for lots of slipping with the engine speed as high as possible...clutches are made to be slipped
10. don't bother restoring your light reflectors - 12V and halogen bulbs are the only way you're going to get enough light to see by

I could go on, but am sure I don't know all of the "fixes" that a T might need, nor the breadth of creativity that a really inspired "expert" mechanic can bring to the party. Their work can be found on every T for sale that "ran when parked".

[varmint]

Scott, you have 10 great captions for cartoons. All you need now are illustrations to go with them.

[Been Here Before]

Do I detect a minor uprising against the microchip coil adjusters?

[TXGOAT2]

You don't need no microchip, all you need is is a Slim Whitman record and a pair of pliers.

[varmint]