MTFCA Forum

Now that coils are getting harder to find, is anyone still using the TrueFire system and finding it satisfactory?

Some sort of an update to that system might be worthwhile now!

The internet is loaded with people selling model t coils made by Ford.

I can see a shortage in KW made coils because Bob Bergstat sold the KW coil setup to that great business who shall not be named where parts go to die.

James.... True-Fire manufacturing ceased quite a few years ago, the upgrade you are asking will not be available by the company since it no longer exists.

Inst this just another issue when veering from stock?
No mfg support.
Restored coils (better than new & will outlast the buyer) Are available from a handful of dedicated hobbyists.
New period timers are being manufactured. (several types)
We have the technology to tune our ignition systems to perform like distributors while retaining originality.
No problem needing a solution.

Years ago there was a young guy who's name I forget was dabbling in converting regular coils into electronic coils. I have a set from him, they do work and put out a heckuva hot spark. Currently I'm not using them. I may again. The only caveat is they require 12V and must NOT ever be hooked to the mag. Took him forever to get them to me..was also a college student and overwhelmed. But maybe he's still doing them..who knows. Of course an alternative is..well..you know what!

TrueFire support is lost and gone forever. If one fails, there are a few people around who generally understand them and might be able to answer questions. No, I'm not one of those.

I've used stock coils off and on since 1984, only briefly had good use from them and that included time with professionally rebuilt coils as well as electronic goodies to solve any ills I might encounter. I think they are lovely for those who need their cars to be correct (bless you, we need you around) but I'm not one of them.

Since '88 I've been using Bosch 009 distributors with modern coils. 6 or 12 volt, always worked fine for me on my 25ish touring car and the speedster. Yes, I have changed a coil, points, condensers, caps and rotors a couple of times in my garage. My cars get driven and I figure my repairs are right in line with maintenance I did on my cars back in the '60s and '70s. I carry those ignition bits with me as spares should I need them but that hasn't happened yet. Should I get another stock, driver, T, it will likely get a distributor fairly early in it's time with me.

Use a system you understand that works for you and be happy driving your T.

The coil inside the Truefire unit is a commonly available part, number 26266, for a Ford Ranger pickup if I recall. I bought a spare for myself years ago in case I ever need it (so far I haven't).

Mr. Bittner chose to use a unique setup for wiring the secondary output wires to put them in the correct positions to attach to the stock Ford ceramic terminals, here is a pic of one of his units:

For the sake of those reading this forum in the future, the Tru-Fire is basically the same system as was used on the Ford Tempo and some other Ford four cylinder engines of the same vintage. The system uses a Hall effect sensor with a magnet replacing the rotor in the commutator. The coil pack has two floating secondaries with cylinders 1-4 and 2-3 firing with every revolution of the crankshaft utilizing a waste spark which fires into the dead cylinder. The “brains” of the system is a TFI (thick film ignition) module which was originally secured to a “gutless” distributor containing only a rotor. This evolved to the module on a heat sink and the 4 spout coil pack. As of this writing, the innards of the box remain easily available in spite of the system being over 30 years old. I have not looked inside the Tru-Fire system so I cannot say what parts were used in the commutator shell.

These are personal memories and I do not speak on behalf of the Ford Motor Company.

I heard and hence thought of course the coils were from the Ford Taurus but very well may have been in the Ranger also. Doesn't matter. It works great when it works. I've had 3 cars with them over the years and all were great runners. I'm back to cars with all stock...for now anyway.

Jim Golden
Ford delivered over 60 million Model T ignition coils and the after market suppliers added another 5 million?
Perhaps your looking in the wrong places for Model T coils.
Ron Patterson

Ron, I was not looking, but I found 35 this week.

The guy wanted $10 each though.

I personaly know of 4 Truefire systems in New Zealand (my dad's is one of them). One has since been removed from the car, but the other three cars go very well. However, all 4 have needed coils replaced at least once (definitely a weak point). I have repaired two of the units myself, and for us in New Zealand, the auto electricians know it as a Ford Mondeo part. Presumably the same part, although it does need modifying slightly to fit in the Truefire box.

I-timer & stock coils, problems solved.

That part is available and common here.

The only problem is to make sure the wires are firmly attached and properly covered to prevent an arc over.
Note the availability source.

I’ve been running one in my 13 for over 20 years. He made one to fit my 13 coil box. I charge a 12 volt battery from the magneto

When my supply of working Heinze coils dwindled down to 3 working units, Ed Bittner mad e a special Truefire unit to fit the Heinze wooden coilbox in my 1912 chocolate van. He had to alter the contact points and add spacers to the box to make it work. That had to be in the late 1990's. It has worked flawlessly the whole time. I sold the units for him for a while in Australia, and he sent me a few spares to trouble shoot with. I still have all of those, including a spare coilpack.

Allan form down under.

The only problem that had shut down a lot of those systems was the Switching Transistor in the Timer box that has no identification and cannot be replaced or substituted.

I have a few systems here that were given to me and that only lack a good switching transistor to properly function.

They work fine, if you can get 5 to 5.5 volts to the box while powering the starter.

A standard T engine will turn over with a starter while only reading 3 to 3.5 volts at the starter terminal, but that is not near enough for the TrueFire to make any sparks.

Made my own TruFire copy last year, used a VW smart coil to fire the plugs and a Anderson timer. It worked but not the best, the smart coil's dwell is set by the ECM. I tried my best to mimic the dwell I needed but I don't think it was right.

When I bought my center door, it had TrueFire in it. It worked very well for about a year, and then one day it started backfiring terribly and quit. I mess with it couldn't do anything with it got my hands on another you sit and couldn't do anything with it when it works. It works great when they're dead I don't know but I have two of them if somebody's looking for any make you a good.

Since when are coils getting hard to find? Read posts above!

TMiller6 wrote: ↑

Thu Feb 01, 2024 6:37 pm

For the sake of those reading this forum in the future, the Tru-Fire is basically the same system as was used on the Ford Tempo and some other Ford four cylinder engines of the same vintage. The system uses a Hall effect sensor with a magnet replacing the rotor in the commutator. The coil pack has two floating secondaries with cylinders 1-4 and 2-3 firing with every revolution of the crankshaft utilizing a waste spark which fires into the dead cylinder. The “brains” of the system is a TFI (thick film ignition) module which was originally secured to a “gutless” distributor containing only a rotor. This evolved to the module on a heat sink and the 4 spout coil pack. As of this writing, the innards of the box remain easily available in spite of the system being over 30 years old. I have not looked inside the Tru-Fire system so I cannot say what parts were used in the commutator shell.

These are personal memories and I do not speak on behalf of the Ford Motor Company.

The big difference with a coildriver in modern cars is, that the coil is constantly sparking during the time the hall sensor in the timer is activated. Inside the box are two circuits with a 555 chip at around 250 Hz which drives a transistor.

TMiller6 wrote: ↑

Thu Feb 01, 2024 6:37 pm

For the sake of those reading this forum in the future, the Tru-Fire is basically the same system as was used on the Ford Tempo and some other Ford four cylinder engines of the same vintage. The system uses a Hall effect sensor with a magnet replacing the rotor in the commutator. The coil pack has two floating secondaries with cylinders 1-4 and 2-3 firing with every revolution of the crankshaft utilizing a waste spark which fires into the dead cylinder. The “brains” of the system is a TFI (thick film ignition) module which was originally secured to a “gutless” distributor containing only a rotor. This evolved to the module on a heat sink and the 4 spout coil pack. As of this writing, the innards of the box remain easily available in spite of the system being over 30 years old. I have not looked inside the Tru-Fire system so I cannot say what parts were used in the commutator shell.

These are personal memories and I do not speak on behalf of the Ford Motor Company.

The big difference with a coildriver in modern cars is, that the coil is constantly sparking during the time the hall sensor in the timer is activated. Inside the box are two circuits with a 555 chip at around 250 Hz which drives a transistor.

I have a TrueFire test set, but I have never been able to find the switching transistors in the Timer Cover.

The box is more reliable than the Timer cover.

The Test Set is simple to make.

A big wing nut, not shown, on the left rotates the Timer Rotor.

The metal uprights represent the block.

J1MGOLDEN wrote: ↑

Wed Apr 30, 2025 6:35 pm

I have a TrueFire test set, but I have never been able to find the switching transistors in the Timer Cover.

The box is more reliable than the Timer cover.

The Test Set is simple to make.

A big wing nut, not shown, on the left rotates the Timer Rotor.

The metal uprights represent the block.

TrueFire Tester Top.JPG

In the original mechanical rollertimer the coil is activated during (almost) 90 degrees on the crank and it often occurred that the engine started on only a turn of the key. I never had that with the TrueFire. Jim, did you ever measure the activation angle on the test set?

NO, but it is a lot less than the original.

I found a simple way to measure the angle. Quite stupid I never thought of it, but better late than never. I measured angles at the crank handle. I measured the angle at the point where the buzzer starts buzzing and the angle when the buzzer is silent again. It appears to be slightly less than 45 degrees. So that is half of the original angle, so you have half of the sparks too. I think that has a purpose, because it is a wasted spark system where two cilinders get a spark. One around TDC and the other at BDC. If the angle would be 90 degrees like original and you have set the ignition late, like when starting, the cilinder that is inhaling would get a spark when there is a lot of fresh mixture in the cilinder. That would cause a serious backfire.