Flamethrower Coil

ledslinger29

Well-known member
Hey fellas,
Which part number flamethrower coil is recommended for a 170 with loadomatic with pertronix upgrade? I was at Jegs and noted that there are several different part numbers....
 
If you are using the resistor wire to feed the coil use the 1.5 ohm coil, otherwise use the 3 ohm coil is how I understand it.
 
Econoline":cnbm3j0k said:
If you are using the resistor wire to feed the coil use the 1.5 ohm coil, otherwise use the 3 ohm coil is how I understand it.
I know the oil filled, metal case is good or better but isn't there a ohm difference pre & post '75/7 systems (a change w/the DSII)?
 
Yes, but that brings in a whole nother subject and we're talking about points systems. Even the DSII coil is going to be 1.2-1.5 ohms and must have a resistor wire to be reliable. It's basically the same coil with a different connector, lol. With a modern ignition module you can run straight voltage(12-15v) @ .4 ohms with a TFI type coil. 'Modern' meaning a late 70's HEI 4-pin module.
 
"...Which part number..."
Just pick one up from Matt @ VI, eh?
 
Just an update, found on hotrod.com. Chad I don't believe Matt has flamethrowers.
Im pretty sure my pertronix is the standard ignitor one.
For specific recommendations we contacted our pal, Don Lindfors, at PerTronix to get the straight story on coils. As he explains, PerTronix offers three oil-filled, canister-style coils and they are identified by the ignition system they are suited for:

The Flame Thrower 40,000V coils have internal resistance rated at 1.5 or 3.0 ohms. The 3.0-ohm coil should be used on PerTronix Ignitors installed on four- and six-cylinder engines while 1.5-ohm coils should be used for eight-cylinder applications. These coils can be used on virtually any inductive (non-capacitive discharge) ignition system.

Flame Thrower II coils have lower resistance, 0.6 ohms for use with Ignitor II ignition systems as well as many other high-energy ignitions. The low resistance helps to produce up to 45,000 V. This higher voltage allows larger spark plug gaps for added power and better fuel economy.

Flame-Thrower III coils were developed for use with the new Ignitor III electronics. The extremely low resistance of 0.32 ohms results in 45,000 V and a coil that charges to peak, current typically 30-70 percent faster the other coils. It should be noted that these coils are compatible with Ignitor III electronics only.
 
So I did some figuring and some testing, and the old coil was getting 6V. Ford used a resistor wire on my vehicle to keep the voltage supply to the coil at 6 instead of 12. A little more research and some advise from another forum revealed that anytime you replace the points with Pertronix it is recommended that you send 12V to the coil. I had the Pertronix put in about 10 years ago, and never knew I was running 6V all this time. So i replaced the resistor wire from the ignition switch with a 12ga normal wire so my coil would get 12V, and folks let me tell ya. I rebuilt the motor last year, many of you will remember giving me advice, and I was pretty disappointed with my power given the upgrades I did. Ran her tonight and laughed running down the road! What a difference! I don't know how much is from upgrading to a Flamethrower and how much is from providing the Pertronix with the voltage it was supposed to have all along, but this little 170 is a beast! I could probably break the tires loose if I wanted to (I don't). The fun factor of driving this old truck just increased big time. Thanks all!
 
Thats good news on your modernized ignition system.
The Ford TFI coil also has very low primary resistance. Another advantage it is solid state, not oil filled.
The down side is mounting it.
I use one with my MSD-6al & it works to perfection. Thats the reason i have several MSD Blaster coils for sale.
 
For us from in the points, condenser and oil filled coil era , what's makes it TFI coil? . Do you ever need a resistor with a Ford late model coil and GM HEI module for trigger?. Any advantage over standard ford 12V Dura-Spark II coil?

PS: the term 'Condenser' dates from a time before 'Capacitor" became standard term in electronics..


thanks
 
(I'm really ignorant on ele/whole ign systems)

Sorry if this is seen as a thread jack:
powerband crosses a Q I've always had...
the TFI is avoided by many of the ol timers round here as unreliable.
Is it cuz the over all system in which it wuz used or just that coil itself?
 
Hi, Ford TFI 3, and TFI 4 ( thick film ignition) are the first computer controlled ignitions. They had no vacuum and maybe no centrifugal advance. TFI 4 was good, but now the modules get a bad rap because many of the aftermarket replacement modules suck. We always had a spare Motorcraft module in the tool bag. Good luck
 
my preference is the full DSII system but at some point I may swap out the 'box' (I have the "blue strain relief") for a lill HEI module. I like the cleaner lines (small sz, cost/availability, easier to keep a spare onboard) it would give.

* Would I need to change out the coil @ that time (lower/higher volts or whatever it needs)? *
 
powerband":3vib2fao said:
For us from in the points, condenser and oil filled coil era , what's makes it TFI coil? . Do you ever need a resistor with a Ford late model coil and GM HEI module for trigger?. Any advantage over standard ford 12V Dura-Spark II coil?

PS: the term 'Condenser' dates from a time before 'Capacitor" became standard term in electronics..


thanks
Since the system operates on reduced voltage i assume the Ford DS11 coil is a high resistance unit on the primary side. The voltage is probably 35K. Correct me if i am wrong.
My TFI coil is rated at 45K.
The MSD box slams 400V into it since it is the capacitive discharge system. Thats how it produces 3 sparks up to 3K rpms.
So far so good yet.
 
ledslinger29":mdemw51l said:
So I did some figuring and some testing, and the old coil was getting 6V. Ford used a resistor wire on my vehicle to keep the voltage supply to the coil at 6 instead of 12. A little more research and some advise from another forum revealed that anytime you replace the points with Pertronix it is recommended that you send 12V to the coil. I had the Pertronix put in about 10 years ago, and never knew I was running 6V all this time. So i replaced the resistor wire from the ignition switch with a 12ga normal wire so my coil would get 12V, and folks let me tell ya. I rebuilt the motor last year, many of you will remember giving me advice, and I was pretty disappointed with my power given the upgrades I did. Ran her tonight and laughed running down the road! What a difference! I don't know how much is from upgrading to a Flamethrower and how much is from providing the Pertronix with the voltage it was supposed to have all along, but this little 170 is a beast! I could probably break the tires loose if I wanted to (I don't). The fun factor of driving this old truck just increased big time. Thanks all!

:beer: congrats on getting a decent working ignition system so you can now really enjoy driving your Bronco! This is also why me and so many other site members will usually recommend ditching the old LOM Distribitors and upgrading at least to the latter points distribitor with its centrifugal and vacuum advance (which your 68 Bronco should have stock) or just going all the way to the better still latter model Ford DuraSpark II ignition system. As with a DS II is electronic plus also has both the centrifugal and vacuum advance systems it is an easy swap to really wake up the performance and economy of these early Ford Six engines. Good luck you proved that there is another way to make these six'es run good too. (y) :nod:
 
Good demonstration on consulting an expert for the ignition system. And encouragement for those wanting to mod a 170 for a Bronco which had always got my advice of more cubes. Which cant hurt of course.
 
Back
Top