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Author Topic: Best TFI/Big Cap Upgrade Best Practices?  (Read 12783 times)

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Offline drock87

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Best TFI/Big Cap Upgrade Best Practices?
« on: August 13, 2014, 04:43:35 PM »
My car needs a tuneup as it is, and I think it is time to do TFI/Big-Cap. I have found COUNTLESS articles on which coil to use, to use the "TFI" style coil or cylinder-style, which wires to splice, whether or not to even splice wires, etc.

I am fine doing a basic tune up. Wiring is NOT my best forte, and I would like something that is extremely simple. I do have the ECM Test (I now just type 'ECM test' instead of the n.u.t.....er, haha) done and a Motorcraft carburetor.

Here is what I know and appears to be gospel: I need a set of 8mm wires, cap, and cap adaptor from a Ford 300CID, early 80's era. The plugs need to be gapped to .045

The coil is what has me confused. The article in the Eaglepedia calls for the Accel coil, but it seems like many have had issues with this coil despite it appearing to be the easiest. While this is technically my "extra" car, it goes on several hundred mile ski trips in the dead of winter and will soon be hauling my jetski. I can't have an ignition go bad unexpectedly.....mine has been extremely reliable since doing the ECM Test.

Best practices?
My list of my cars/toys (or toys at my disposal!)

1985 AMC Eagle Sportwagon
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I like to to tell people my Eagle is like a Ferrari. It's quirky, tempermental, border-line exotic, and something you don't see everyday.  See? Makes perfect sense....

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Offline carnuck

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #1 on: August 13, 2014, 04:57:46 PM »
You can use the Ford coil or a Napa IC12 as long as you have a good quality cap.

Want truly simple? The HEI coil in cap dist is the one. One wire unless you have a tach.
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Offline Mernsy

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #2 on: August 13, 2014, 06:14:17 PM »
I've been using the Pertronix coil for years with no issues. I had to bypass the resistor wire and feed system voltage to it.

Offline AMCLOVER258

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #3 on: August 13, 2014, 06:23:58 PM »
http://www.summitracing.com/parts/crn-730-0020/overview/year/1982/make/jeep/model/cj5 I was using this here coil and it seems to be rather effective if you plan on keeping for current set up. you can either get Male/female converter to run 8mm wires or try and find some 8mm female wires like the stock one and that'll do ya pretty good.

Offline Draekon

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #4 on: August 14, 2014, 12:36:10 AM »
I've been using the Pertronix coil for years with no issues. I had to bypass the resistor wire and feed system voltage to it.

I have also had my Pertronix coil for years, although I haven't actually put that many miles on it...

Offline eaglefreek

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #5 on: August 14, 2014, 12:50:04 AM »
I bought a 3 ohm Petronix coil and it only lasted 6 months. I've had an MSD coil on there for about 6 or 7 years without any trouble.
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Offline Billman

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #6 on: August 15, 2014, 04:27:16 PM »
I did the Skip White HEI and wires for a 77 chev 250 http://www.skipwhiteperformance.com/detail.aspx?Item=6511-R
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Offline carnuck

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #7 on: August 15, 2014, 05:23:39 PM »
Don't forget the HEI dist gear has to be swapped and the one from the Eagle Motorcraft dist is too big and will wobble around till the cam and cam gear are destroyed too! MSD AMC V8 gear works as does AMC points dist gear and Prestolite (gone after '78)
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #8 on: September 11, 2014, 01:58:22 PM »
So at this point, I have done it all.

TFI:
The TFI is a good upgrade for your Duraspark ignition system. Start with a quality cap, rotor, and adapter. Then make sure you get the best set of wires you can find, because good wires are very important to a quality ignition. I'd recommend a make-your-own set of MSD Street Fire wires. They are simple to make as long as you have a vice handy (I actually crimped mine with a bottle jack and the subframe of my car while I was at school).

For the coil, either buy a 1.5 Ohm canister coil OR buy a 3.0 Ohm canister coil and bypass the stock resistor wire in your harness. I used the 3.0 Ohm coil/bypassed resistor for a couple years somewhat reliably.

As far as I know, most of the TFI style "E-core" coils have very low resistance and would probably need a resistor added to them. These work better if you're installing a "Stealth HEI Module" in place of the Duraspark ignition module. Otherwise, you will probably have some kind of failure, be it coil or module. Keep in mind, absolutely NONE of the replacement/aftermarket Duraspark modules are made in the US, and many have reported problems with replacements. I used a 4-pin HEI module wired with stock connectors for a couple months and the car ran great, but unfortunately I believe it got a little water on it and shorted the module.

HEI/Skip White Distributor:

The HEI distributor can be convenient, if you do your research. Skip White sells one that drops right into the 258 for ~$60, and all that is required to hook it up is a single 20amp fused wire. However, the gear it comes with is reportedly hardened steel, and it could potentially eat the gear on your camshaft within a year costing you a fortune in repairs. In this case, you would need to buy an AMC V8 distributor gear (~$30), and a couple thrust washers to shim the HEI shaft to something like .030" end play. In addition, you'll probably have to adjust the mechanical curve with new advance springs, and you might need to get an adjustable vacuum advance canister. I ran an HEI like this in my 4.0 for a few months, and while it was reasonably reliable, I struggled with spark knock and finding the right timing advance. It never ran quite right. Furthermore, there is no provision for timing retard while you are starting the car, so the starter really drags until you get it going.

CDI:

I know, these are expensive and can't be trusted as a stand alone ignition. Hear me out.

 I installed an MSD Street Fire 5520 CDI box with MSD Blaster TFI "E-Core" coil on my Eagle last night. Though of course I can't yet say anything on reliability, the car has never ran better! These are hooked up with my TFI cap set, all waterproofed heatshrink connections tucked away with wire wrap, and it idles stumble free at 600 rpm in drive. It even got down to 450 rpm due to my carb adjustment and wouldn't stumble like it was dying! It even has a rev limiter, though I doubt my auto trans would ever need it, and it couldn't have been easier to install.

This setup cost me right around $200 with the wiring harness to plug right into the Duraspark distributor, plus I get a $25 rebate through Summit. The best part is, I left the Pertronix coil and Duraspark module alone so my ENTIRE IGNITION can be swapped by quickly unplugging and plugging in 3 wire connectors. That's right, a redundant ignition! I'm a hair away from being able to flip a switch 8)

If you can afford it, I would strongly recommend this route for reliability and even safety sake. An ignition is not something that should be failing, take for instance GM's $1.3 billion recall because of faulty ignitions  ::)
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #9 on: September 11, 2014, 02:10:11 PM »
As an additional note on the Street Fire line from MSD, apparently some of the components from the 5520 CDI in particular are made in China. That (and a slightly reduced output) is the difference between this "budget" line and the 6 series CDI units.

However, these boxes are assembled in the U.S. and made to MSD's specifications, which are quite strict btw, as well as tested rigorously for a 4 hour burn in period before they are shipped. The Street fire boxes must meet the same testing requirements as their other products. They also back their products very well, give tons of thorough setup and troubleshooting info, and include a supposedly great warranty.

I certainly hope this ignition lasts in my application, but you can decide for yourself. If it continues to run like it is, this was entirely worth it. I'll try to get pictures later.
« Last Edit: September 11, 2014, 02:11:22 PM by Baskinator »
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Offline eaglefreek

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #10 on: September 11, 2014, 03:01:09 PM »
I've had the MSD Streetfire CDI in my Eagle for over 3 years and it has been very reliable. I did have to install a diode in the exite wire to the alternator, because the car would continue running once in a blue moon when the key was turned off.
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #11 on: September 11, 2014, 03:46:31 PM »
I was wondering if I'd have to install the diode, as I've seen it was necessary when converting to the mopar fuel injection harness. It hasn't run on for me yet, but I'll probably use the diode anyway. Did you notice any mileage gains when you first switched?

Glad to hear it's been reliable for you, that's very reassuring.
« Last Edit: September 11, 2014, 04:05:58 PM by Baskinator »
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Offline captspillane

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #12 on: September 11, 2014, 05:16:38 PM »
That's right, a redundant ignition! I'm a hair away from being able to flip a switch 8)

Oh that would be epic. You have my attention. I'll have to check this out when you're by next.
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Offline eaglefreek

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #13 on: September 11, 2014, 06:44:04 PM »
Did you notice any mileage gains when you first switched?

No, but it does seem to start easier.
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #14 on: September 12, 2014, 11:47:54 AM »
Fair enough. I also need a better electric fuel pump that puts out 4-5 psi, and my accelerator cable is stretched, so I'm sure my mileage will increase after those issues are taken care of. My car started fine with the TFI, but I think it's even better with the CDI.
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #15 on: September 12, 2014, 02:50:27 PM »
FYI, there are also a couple other brands with CDI units in the same price range.

Summit sells one (made by Mallory): http://www.summitracing.com/parts/sum-850610

-This also has an adjustable rev-limiter and weatherpack connectors

Intellitronix just came out with their own that has a lifetime warranty: http://www.ebay.com/itm/301203963601?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

-This does not have a rev-limiter or the convenience of connectors, but it is significantly more powerful, even more so than the MSD 6A, and made in the U.S.

I was considering the Intellitronix, but it's too new to have reviews and I liked how the MSD was basically plug and play. However, Intellitronix offers $100 + a brand new box if for some reason yours fails, and they even offer a $100 upgrade service for MSD or Mallory 6A units.
http://www.intellitronix.com/150D-CD-Ignition-System.html
http://www.intellitronix.com/Ignition-Rebuild-Services.html

I just recently came across one of their universal digital 5-gauge panels for really cheap on ebay and I can't wait to set it up.
« Last Edit: September 12, 2014, 03:25:50 PM by Baskinator »
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Offline AMCLOVER258

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #16 on: September 15, 2014, 07:43:03 PM »
So im trying to find an msd cap and rotor for the tfi i just put in. does anyone have any links for just the cap and rotor? everything i keep coming across is the v8 cap and rotor

Offline eaglefreek

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #17 on: September 15, 2014, 08:57:47 PM »
So im trying to find an msd cap and rotor for the tfi i just put in. does anyone have any links for just the cap and rotor? everything i keep coming across is the v8 cap and rotor
None that I know of. Not a lot of performance stuff for the Ford 300.
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
Click for Fayetteville,TN Forecast" border="0" height="100" width="150

Offline AMCLOVER258

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #18 on: September 15, 2014, 10:11:16 PM »
 :censored: Guess im going hei soon, and it sucks cause i learned the hard way not to pay for the team rush when all the parts a advanced are like 30.00 total...

Offline carnuck

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #19 on: September 15, 2014, 11:45:29 PM »
Napa FA136 is the brass cap and FA159 is the better quality rotor.
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #20 on: September 16, 2014, 12:44:39 PM »
Cap and rotor don't have to be MSD brand to be quality. As long as they have brass terminals they're fine. MSD only makes them for V8s.
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Offline carnuck

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #21 on: September 16, 2014, 01:13:05 PM »
Actually, they make them for inline 6 and 4.3 V6 Chevs too.
« Last Edit: September 16, 2014, 01:13:22 PM by carnuck »
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Offline Baskinator

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #22 on: September 16, 2014, 01:29:50 PM »
I meant the TFI cap and rotor, not HEI
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Offline AMCLOVER258

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #23 on: September 16, 2014, 02:06:24 PM »
HAH, So buying the msd brand for the tfi wouldn't have even done much anyways... i soooo over think stuff.  :banghead:

Offline carnuck

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Re: Best TFI/Big Cap Upgrade Best Practices?
« Reply #24 on: September 16, 2014, 11:14:49 PM »
They only have the small cap version for ford 6 cyls.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

 

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