hei distributor and 3 wire gm alternator swap

[prodents69]

I have an 85 f 150 with a 5.8. I am trying to convert the distributor to hei and the alternator to a 3 wire gm alternator. Any idea where i could get a diagram of how to do this? And What car would be a good donor for the 3 wire alternator?

[cep62]

An '85 should have a HEI ignition.
Why do you want a 3 wire gm alt?
If I was going to swap I'd get a 1 wire gm.

[Dragon]

An 85 351 would be a Duraspark II and I would get a 1 wire 3g or 4G alternator with Ford mounting already on it,

[fmartin_gila1]

Go to Http://www.gofastforless.com There you will find an article to install and wire in a 3 wire GM Alt on a ford. I converted mine about 6 years ago and has been working fine since.

Fred

[fitzwell]

Duraspark II with a T.F.I. coil & a 3G alternator...done.

[Dragon]

Simple and reliable

GM HEI is no better than Fords Duraspark 2 and no higher energy than the TFI coil. And it is all Ford.

[DGrant09]

T.F.I. coil? What are these??
Sorry learnin curve here..
Thanks
Dan

[Dragon]

TFI = Thin Film Ignition the next step after Duraspark II. The coil is also called an e-coil due to it's coil core shape that looks like an E. The TFI coil is very hot with less current and more voltage than a can coil. The current is only slightly lower yet the voltage reaches over 50K and on the race versions over 100KV. That is why the spark gaps got wider.

My Super Stock Accel coil is 42 to 45K and the spark will jump about 2 inches easy. The 100K coils punched 5 holes in my hand and the longest arc was 3 feet. why in my hand you ask. I blipped the brand new engine and oil pressure went over 160 psi and blew the oil filter can apart. I yanked the coil wire to kill the engine.

[DGrant09]

TFI = Thin Film Ignition the next step after Duraspark II. The coil is also called an e-coil due to it's coil core shape that looks like an E. The TFI coil is very hot with less current and more voltage than a can coil. The current is only slightly lower yet the voltage reaches over 50K and on the race versions over 100KV. That is why the spark gaps got wider.

My Super Stock Accel coil is 42 to 45K and the spark will jump about 2 inches easy. The 100K coils punched 5 holes in my hand and the longest arc was 3 feet. why in my hand you ask. I blipped the brand new engine and oil pressure went over 16 psi and blew the oil filter can apart. I yanked the coil wire to kill the engine.

OUCH, I've only been zapped by a lawn mower and that woke me up! I was glued to the metal handle until the bleepin thing stopped..
I can't imagine a coil with that much power..

[Dragon]

oops a correction 160 psi that is what happens with a 427 sideoiler High Volume pump in an FE with no cam galley pressure relief. I don't get glued luckily, into my right hand and out the front of my thighs were they were pressed up to the fender.

I have had several the Accel Super coil and the early Mallory Large coil, the the TFI racing coils and 1 HEI coil in cap that pulled 100KV. And the test LASER firing circuits at NWC China Lake. (been more than 25 years.)

[DGrant09]

Back to the post:
What are the benefits to a T.F.I. vs. the standard coil when using Duraspark II?

[Dragon]

The more voltage the farther the spark travels so the wider the gap is. The wider the gap the more flame ignition front is exposed to the fuel air mix. That means the flame builds faster. If you have a 4 side electrode plug and a 20K coil it will only use one electrode. But if you have 100KV it will jump all over the place.

The more voltage the more paths it will find. The reason: the first arc burns it's landing spot, so the arc jumps to a clean spot. On and on this goes until the arc drops due to the loss of source power. If your Dwell is 25 degrees the coil charges for 25 degrees of rotation or until the coil reaches saturation. When the points close the coil charges. Saturation is the point at which an electrical coil cannot absorb anymore power.

A coil only fires because of a change in voltage levels. It is an autotransformer with one end tied to the coil positive and the other end tied to the rotor through the wires and plugs to ground. As the coil charges up It reaches positive saturation. When the rotor turns to the right place to fire and the dizzy opens the coil circuit. This fires the spark.

An E coil has a faster rise time so it reaches saturation prior to firing faster. The faster the rise time the higher the rpm that can be reached. 8 cylinders gets 45 degrees of rotation prior to firing after the last cylinder so the total charge can be built and then discharged.

The 45 degrees at 8000 rpm is .008 of a second. If you can fully charge a coil to 100k in less than .004 (time to charge at 8000 rpm before firing) of a second you can keep the dwell going for 27.5 degrees and the coil will be fully charged before the system discharges. This applies to point systems and electronic system single discharge systems. MSD systems are different in that they trigger once on time and then rapidly fire and recharge the coil.This requires an e-coil because of the faster rise time.

The next type of system is the EDIS and it uses 1 coil for every two cylinders so the coils can charge for 180 degrees minus the ignition discharge time, about .0005 out of the .030 of a second per 4 cylinders. This coil can charge with the same very high voltage but another benefit is it can develop very high current allowing it to fire in the most adverse conditions.

[fitzwell]

in addition, the TFI coil needs no ballast resistor. Changed both of my rigs over, used the motorsport 9mm wires & never looked back.

[Dragon]

6V systems points systems don't use resistors, all 12V point systems & Duraspark I and II require resistors but TFI does not as stated above.

The resistor is to prevent coil burn out and reduce the arcing on the points in point systems. The condenser (capacitor) is matched to the coil's inductance (resistance of the windings). When the condenser and the inductance are matched the points burn evenly on both sides. When they burn towards the stationary arm (metal gets higher on that side) The inductance is too low or the capacitance is too high.

In the first electronic ignition school I went to before the Duraspark came out Ford told us they were leaving the resistor in the system to simplify the parts required between vehicles.

[prodents69]

I have an 85 f 150 with a 351w. I am changing the distributor to an hei and the alternator to a 3 wire gm ?alternator. Any idea where I could get a wiring diagram of how to do this? Any idea what would be a good donor car to get the gm alternator?
Please Help!