Does any of this have to do with the hall effect?

 

Ya not sure you would feel any benefit with the TFI in normal operation in the deep south. Where you might notice a difference is with worn plugs and possibly longer plug life.
That was one of the unexpected benefits of the TFI coils "seemed" to give longer longer plug life. But plug technology was changing so much in that era it is hard to say if it was the coil or the construction of the plugs that made the difference..

If you get the opportunity give it shot again some time with the TFI coil.

 

Pardon me for asking, but why would I want to do that?

If I am *not* in an area that experiences subzero cold starts, and temperatures NEVER even come close to -30, what would I gain by swapping to a TFI E-Core coil?

 

Potential extended spark plug life, in hot climes better coil performance. E core coils are much less likely to break down and fail so longer life, they run cooler and are more efficient as the lamination's stop eddy currents and the heats generated that comes with it and the associated losses, this means hotter spark as you are you are not getting the resistance loses, remember these coils are designed to handle a full 12V and in the dura spark applications it is being run at reduced voltage so coil life is way way extended over regular coils and even stock TFI applications.
It may not be something you feel under foot but it may pay off at the pump.

Every one did not switch to them cause they were inferior to the old iron bar core coils. That tech is over 100 years old. The Coil is just a transformer, they moved away from bar core transformers in electrical applications before WWI. GM had the right idea with the HEI, just the execution was lacking.

 

I read through here and am leaning towards the DS2 conversion as it seems simpler than rewiring things to get 12 volts to a HEI distributor; I did a DS2 conversion years ago and will have to refresh my memory on what to buy to make it work.

But, since you all have experience with both, which is simpler?

My 1986 F-150, with the 4.9 liter 6, doesn't have a ballast wire so I'll have to get a 1.1 ohm ballast resistor... does anyone happen to have a link to the correct part and/or a part number I could search? Last time, I ended up buying multiple resistors and checking resistance when power was applied... Finally finding one that was 1.1 ohms.

The junk yard DS2 harness I bought is gonna need to be redone and I'm lazily contemplating the idea of HEI as it would be awesome to just run switched power to a big ugly GM distributor and sending a vaccum hose between the tree and the distributor.

Thanks all for your help... since I put the non-feedback carb in my fuel economy has gotten better... now if I can get an ignition that advances installed I'll be golden!

 

I installed a skip white hei on a 351w, works good, but it is huge and ugly. It interferes with stock intake manifold heater hose outlet, so setting timing is rough, you have extremely limited amount you can turn distributor. On a straight six, it wouldn't bother me I guess, it wouldn't be right in your face, like a V-8, so you might not notice it being so large and hideous and clunky. I only did it on my 351 because it had all that feedback crap all over top of motor and it had been badly butchered, and I do mean bad. If I had it to do over, I'd have done as I did with my 68 ranger when I converted it and went junkyard and gathered up stock duraspark setup.

 

Look on page 27 in this link Start & Ignition - Gary's Garagemahal (the Bullnose bible) you do have a resistor wire in your harness. They were running the duraspark trucks along the same assembly line as the EECIV trucks apparently, and they had provisions in the harness for both systems.

 

Awesome link! Thank you, the schematic on page 27 indicates the "R/LG" wire is a resistor... I found an extremely thick wire that is red w/ a lime green stripe and I'm thinking this is the "run" power I'll hook to the coil (I'll voltmeter it and see if it puts out less than 12 volts).

Thank you again

 

Yes, what you are describing sounds like the ballast resistor wire that was used on the DSII ignition systems. When I converted my own truck from a feedback carburetor/TFI ignition to a conventional carburetor with DSII, I was pleasantly surprised to learn that Ford included the ballast resistor wire in the truck's main wire harness from 1980 - 1986. This way, Ford could plug in either the DSII wire harness or the EEC-IV wire harness into the truck's main wire harness. When the EEC-IV harness was plugged in, the ballast resistor wire was simply bypassed.

If you can find a stock Ford DSII wire harness from a 1980 - 1984 truck, I would do that over any HEI system. In addition to the DSII harness, you will need a DSII ignition module, distributor, and coil. (I suppose you could re-use your existing TFI coil, but I would not recommend it; I would use the coil that was designed specifically for the DSII.) Performance will be about the same, there will be no fitment issues, no cutting or slicing of wires, and it will still look completely stock. No one would be able to tell by looking at your engine that it did not originally come from Ford with a DSII ignition. And if you use the stock Ford parts, any mechanic can reference a shop manual to troubleshoot any sort of problems that may arise in the future.

 

There is nothing wrong with using the TFI coil with the DS II system, no splicing is required. The spade connectors will unplug from the iron bar coils horse shoe connector and plug in to the TFI's connector. They are the same spade terminals.

The older style canister coils are oil filled with a simple iron bar for the magnetic flux amplification. The TFI coils use a laminated iron E core that is more efficient than the simple iron bar used in early coils, this allows for a hotter spark a the same power (amp draw) or equivalent spark out put at reduced (amp draw) power usage. This also allows e core coils to run cooler negating the need to be oil filled. Using the TFI coil with the DS II system will not negatively impact the lifespan of any of the DS II components and may actually help increase the life span of the module.

This swap is well documented and has been around since the TFI coil was introduced in the 80's .

Since you already have the TFI coil and it's mounting bracket I would retain it. This will allow you use all of your existing ignition wires wires and save you the trouble of trying to source a decent aftermarket canister coil which can be a real crap shoot in today's world.

Although the TFI coil can handle a full 12V the DS II ignition module can not reliably handle switching that voltage as a general rule. Regardless many people do feed a full; 12V to TFI coils on DS II systems with no ill effects.

If you want a DS HEI system then swap to a DS I set up this is a true HEI system unlike DS II.

 

I didn't catch earlier, the last part of your post about checking the voltage. Your tester is always going to say 12v, even if you have the correct resistance wire. The reason is your voltmeter does not pull enough current through the resistor to create enough voltage drop.

The amount of voltage a resistor "resists" or drops, depends on how much current is flowing through it. The formula is E=IxR were E is voltage, I is current, and R is resistance. In the normal Ford system, if they designed it to average 9v at the coil, and they are using a 1.1 ohm resistor, that means 9v=?current x 1.1 resistance. 9 divided by 1.1 = 8.2amps. So the factory was expecting a average current running through the resistor of approx 8 amps, and that would give them 9v.

Your meter doesn't draw hardly any current at all. All meters use some current out of the circuit they are measuring, so they cause some error. So the better and more accurate meters(more expensive), use the least amount of current out of the circuit.
I did a google search, and found a common resistance between the probes on a digital multimeter is 10 meg ohms or 10 million ohms. So when you put your digital meter onto the resistance wire, you are completing the circuit with the meter, essentially you have a 1.1 ohm resistor in series with the 10meg ohm meter. So basically 10 meg ohm. 12v=?current X 10 meg ohm. 12 divided by 10 million = .0000012 amps in the circuit. .0000012 amps x 1.1 ohms = .00000132 volts. This would be the amount of voltage drop across the resistance wire you would have when using the meter. So the meter would read 12v minus .00000132. So the meter would read 11.99999 volts.

In other words, you will not know if you have the right wire until you get everything hooked up and the engine is running.

 

I agree with you about trying to source a decent aftermarket canister coil in today's world. NOS Ford Motorcraft coils *do* turn up on Ebay from time to time. I picked up a spare one still in the box about a year ago. His best bet would be to grab the coil and mounting bracket from the same vehicle he gets the DSII harness from.


It will be a LOT harder (and expensive) trying to source original or even decent aftermarket parts for a DSI system over the much more common DSII system, Chief. I don't think DSI was even offered past 1979, and certainly not on the F-Series truck, so I don't know why you would even make that suggestion. And didn't you say in an earlier post that the DSI system was very problematic?

 

When new, the DS I was problematic just as DS II.and electronic ignition was problematic when new. That does not apply any longer to either today.. And getting a DS I Module is no more difficult than a DS II module. And he can retain the TFI coil with no wiring changes, as the coil is fed a full 12V with the DS I system. DS I is a true HEI system unlike DS II So again it comes down to if you want an actual HEI system and you can utilize factory Ford bits to do it. And the install is identical to DS II utilizing a DS II harness and distributor. DS I is way over looked for these sort of changes, if you are swapping to a DS system why not just go all the way and swap to the HEI DS I as it is the same amount work as DS II..

I do not know why anyone would push DS II when swapping to the HEI DS I is exactly the same amount of work. The only difference, the extra cost for the DS I over a DS II module. And that is still way way cheaper than any aftermarket HEI system......

 

It will be extremely difficult to find a California-only DuraSpark I wire harness for his truck.

 

Same harness as DS II is used. The only components that are really different between DS I and DS II are the ICM and coil.
Hence if swapping to a DS system not going to the HEI DS I is kinda silly.