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post #10 of (permalink) Old 09-07-2005, 09:39 PM
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Re: TFI and HEI what\'s the difference?

Since this subject comes up every month or so... I find it impossible to believe that absolutely nobody has suggested using the search function and doing your own research.

And then there is the fact that it's not the first time you asked pretty much the same question.

<u>'82 cj7 ignition question.</u>

"RANT ON" It looks to me like you just post up a question and then don't read the replies or follow any of the links provided and surely don't try to use search to find other threads. Could be that just bothers me more than it should. "RANT OFF"

You do have a strange ECM location since it's a 1982 and I don't know what that does to the wiring harness. Maybe John can help with that since there's a thread on JeepsUnlimited on the subject.

Start with this page that gives part numbers for the Ford large cap adapter, cap and rotor. You will also find different part numbers for TFI coils and even spark plugs. Be sure to change over to the 8mm plug wires, I really like the Motor Craft set.

<u>Ford Ignition Parts</u>

The distributor cap adapter, cap and rotor are a direct fit with no modification required - just a screw driver. I would suggest dielectric grease.

You can run the TFI coil by simply wiring it in place of the old coil using the coil harness in the part numbers. Here's where we will have some discussion about the TFI coil running at less than full voltage due to the resistor wire.... bla bla bla.... It will work, might be better other ways... It will work.

I have four Jeeps to deal with, all are 1983 to 1985 vintage originally with Dura Spark ignitions.

One is a 304 and the other three are 258's.

Everyone of them has the Ford cap/rotor and plug wires from that parts list.

The 304 has been running an Accel full voltage coil (no resistor or resistor wire) and a Dura Spark for the past five or six years. It will get a TFI coil and HEI module at some point.

Two of the 258's are running John's Stealth HEI with full voltage to a TFI coil.

Then there's my CJ7, has a TFI coil but not only is the resistor wire still in there so is all of the crazy plumbing that was originally built into it. The ECM still controls the Carter and even the spark. Vacuum advance is still manifold sourced. It has overdrive and will run 31" tires @ 70 MPH on the highway for hours then go trail riding often revving over 3,000 RPM and then turn around and drive for hours home (several board members will be happy to confirm that).

The typical reason stated to do the Nutter bypass is that the motor wouldn't rev above 2,800 or 3,000 RPM without bogging down. But if everything is working correctly, NO VACUUM LEAKS and you spend some time tuning it 3,500 RPM isn't a problem (likely higher if you trust your 20 year old motor that much).

Here's the famous Nutter Bypass info:

<u>The Ignition Bypass</u>

<u>John Nutter explains how he improved performance by modifying his Jeep CJ-7 ignition system</u>

<u>Pre-1983 Ignition</u>

<u>The "Nutter" Bypass with the HEI Ignition Upgrade for the AMC 258</u>

If you go the TFI coil/HEI module hybrid route you will need to disconnect the ECM (aka Nutter it).

Likely no one here can tell you how to get away with that in California, but maybe. I'm betting that if it's running well it will pass testing. Aren't the standards lower for older vehicles? The guy doing the test likely wasn't born when your Jeep was made so how the heck would he know what it should look like?

There is no emissions testing in Indiana, we wreck them first so it doesn't matter.

Back to USE THE SEARCH! (or just click on the links below):

<u>Anyone done the TFI upgrade on a 401?</u>

<u>Stealth HEI added, What the heck? Mystery Solved!</u>

<u>Rough Running continued...</u>

<u>258 TFI Upgrade Question</u>

<u>My attempt at the HEI conversion</u>

<u>V8 TR TFI HEI Upgrade Completed Another winner</u>

<u>Prestolite to Duraspark Distributor Swap</u>

<u>Timing with TFI Upgrade</u>

<u>Rough idle when cold, Air/Fuel?</u>

A few of those threads are about V8's... you might think that isn't related. It is.

Other threads are about problems and how they were solved, read those twice.

That's just the tip of the iceburg... But... If you have looked at every thread above and still have some questions.... post em up (just be sure to use a couple of those threads as a reference).

I still might just do my own search and post a few links that cover your new question.... so save me the time and try that first.

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