MSD help

[usdart]

Has anyone here hooked up an MSD 6tn in an A body?
The MSD site was little help. The wire colors don't match and after I hooked it up the way they said, it cranked but would not start.
I think it has to do with the 'run' circuit and 'start' circuit being wrong.

Was hoping someone here had done a 6tn and worked it all out.

Thanks

[sumpholergv]

Just send it back and go get yourself a stock Mopar orange ignition box
Chrysler had a top notch ignition system During their time period so what i would do is convert to the stock electronic ignition and use the orange box.

[dave571]

The orange box is marginally better than a stock box.

Yes the stock stuff was good when they built it, for that matter breaker points were quite the thing when they thought them up.

There is much better these days. MSD is a good system, but I'm not fond of how hard it is on ignition parts.

Wasn't there a diagram in msd kit? The only two wires you should need from the stock ignition are the 2 pickup wires from the distributor. The power is diirect to the battery with a keyed source to turn the unit on. Most msd's work that way. I haven't installed the box you are talking about.

[mhenesian]

MSD components are top-notch. All serious racers run MSD ignitions and distributors, in all classes. I threw all my old Mopar distributors, wires, etc. in a box to be buried in a "time capsule". Wire up the 6TN as per the instructions. It think they use a special NASCAR weather-tight connector, so this could be causing you some grief. Not sure. Generally, use the "white wire" trigger with points, and the "violet" wires for a mag pickup. Pay attention to the polarity of the Mopar pickup and its connection to the MSD trigger wires - as per MSD instructions. The most important item is the ground wire. The MSD box requires a very solid ground connection (the black wire). You can also easily trouble shoot the box by momentarily grounding and then lifting the white wire off of ground. This will trigger the box and create one spark. Also check the MSD users forum on their web site, you can also call them by phone last I checked,

Mark H.

[Kevin Garceau]

"Just send it back and go get yourself a stock Mopar orange ignition box
Chrysler had a top notch ignition system During their time period so what i would do is convert to the stock electronic ignition and use the orange box."

Now thats funny.... I dont care who you are!

[usdart]

Thanks mhenesian:
I did hook it up according to their instructions. The Tech also said they only used these colors for a short time and now they are different.
The connector has '6' wires and the batt and ground wires come out the other end.
I don't know where the OLD neg wire on the coil goes. Do you tie the Ballast resister wires all together?
I would like the 'multi spark' function to help with smog here in Nevada.

[mhenesian]

Hi usdart,

From your last post, the MSD 6TN box seems to have connections like the NASCAR box, the MSD 6HVC. The usual MSD series 6 instructions don't adequitely cover the 6TN ! The 4-pin connector is for a Rev limiter. Just leave it unconnected, or tape it over. The heavy red and black wires on the left side are the battery + and - (or ground) connections. The 6-pin connector contains the following wires (from the HVC instructions):

pin F: violet mag (+) trigger wire, goes to Mopar orange pickup wire (M+)
pin E: green mag (-) trigger wire, goes to Mopar black pickup wire (M-)
pin D: orange wire, goes to coil +
pin C: black wire, goes to coil -
pin B: brown wire, goes to an MSD compatible Tach, or a Tach adapter
pin A: red wire, goes to ignition switch (+) or to ignition switch side of factory ballast resistor.

If you're using a points type Mopar distributor, don't connect the violet and green wires, just remove the distributor wire from the coil (-) connection and connect to the white wire that comes out of the left side of the MSD box.

As for the ballast resistor, just wire across it since the MSD 6 series ignitions don't require a ballast. Also disconnect whatever factory wiring goes to the Mopar ignition box, coil and ballast resistor.

Once you get this working, you won't be disappointed. Gap a new set of plugs to 0.050 ~ 0.060" and you'll be all set for better engine performance, gas mileage and lower emissions !

Good luck,

Mark H.

[usdart]

That is what I call help indeed

Now I feel like taking another stab at it

You gave better info than the MSD site without sarcasm too..

My deepest thanks and respect go to you sir!

By the way, I have the FBO ignition installed, I believe the MSD multi spark may work better for me.

[dave571]

Originally Posted by mhenesian

Hi usdart,

As for the ballast resistor, just wire across it since the MSD 6 series ignitions don't require a ballast. Also disconnect whatever factory wiring goes to the Mopar ignition box, coil and ballast resistor.

The advice in the post is all straight up except for this bit which is ok, but unneccessary, and will make no difference in performance..

One of the most common misunderstood thing swith msd is that it doesn't use a ballast resistor. True it doesn't, no debate here. The thing is this....With the factory wiring ,the balast resisitor is part of the existing ignition primary wire system on the car. The ignition primary circuit is the circuit that provides power to the coil.

When msd is installed, the coil is powered directly by the msd box.
The msd box is powered directly from the battery....

The ballast resisitor has already been eliminated. No need to bypass or bridge the ballast, since it is already no longer paret of the primary system.

The existing poitive wire on the coil (which has the ballast in line with it) is only used to turn on the msd, the same way a switched wire would on a relay.

It does say in the msd instructions that the switch on wire, does not need to be 12 volts, and that the existing wire for the ignition primary, with reduced voltage on it, will work fine.

Lots of racers don't use MSD, and lots do. Chevy guys love thier HEI, while alot of mopar guys stick to the chrome box, gold box, or something like the
FBO stuff.

I use the FBO stuff to run 11's, so although I think MSD is decent stuff, I question it's reliability, and necessity on a street car.

my .02

[usdart]

Thanks Dave571..

Here in Nevada we have to Smog cars newer than 1967. I was thinking the multi spark would provide a more complete burn of fuel resulting in better results for Smog.
I passed Smog with the FBO but, I had to lean out the Carb and back down the Timing until it ran like crap. This is with a fresh new engine too!
The idle side is fine due to a little invention of mine I added to the PCV system,and, I am runnuing a little smaller Carb this time too.

wish I had an exhaust anaylizer to experiment with.

[dave571]

MSD may help with idle speed emissions.

Only two places in all of canada have emissions tests, and I don't life near either, so I've never tried.

Hope it works out for you.

[mhenesian]

Dave,

Thanks for the nice comments and additional advice. I agree with you 100%.

It's too bad we all have to put up with the unreasonable emissions B.S. in most of the US. Here in CA we now have to smog all cars newer than 1976, including 1976 models, to standards that I swear are much tighter than the factory specs. My daughters '78 Trans AM has dual cats, smog legal headers, air pump, no exhaust smell, and it can barely pass the CA Smog II tests. It's ridiculous since you usually can't find emissions components (EGR, air pumps, manifolds, etc.) for any of the late '70's cars or early '80's cars. You're really lucky if you can find any functional "smog part" at you're local "pick and pull".

I thought California was bad. It must be worse in Nevada ! Let's hope that Canada doesn't adopt California or Nevada smog laws,

Good luck to usdart !

Mark H.

[George G. Leverette]

dave571, I have the MSD6AL installed in a 72 Duster with 340 and a 74 Duster with 360 engine. The cars will not run if the ballast resistor is disconnected. "Wiring across the ballast resistor" begs a question. Which color wires should be connected, I am assuming the blue with white stripe and the brown wires, is this correct? The 74 Duster will start with the key sometimes, I have a new neutral safety switch and ignition wiring harness. The seat belt interlock has been by-passed any ideas?

[B1owner]

I agree with sumpholegv. If you spend 400 bucks on a MSD distributor, and then spend another 200 bucks on a 6t or 6a, your car wont go a tenth (or a hundreth for that matter) faster. But hey, you could save your money and run you 32 year old electronic ignition like me but why not spend your money needlessly? Take your MSD to the track and race the car. Then dial in your old junky low tech mopar ignition and find out why the car runs exactly the same.

[pcrmike]

It is the 60's all over again. There are HEMIs running amok, and they are only required to have mufflers, that's all, to be legal. You can ditch the cats, and run an expansion chamber, and that is all that is required. There are certain advantages to living in redneck country (though I am not a redneck myself.) and that is one of them. My soon-to-be-completed D100 440 4bbl Club Cab will be equipped with driveshaft tube stacks fabbed after the chambers for a true straight-shot, street legal exhaust. I will post pics of it.

Now, to the matter at hand. I hae used MSD products for a long time and agree they have their place. The HV coils and boxes are not so great on carbed, moderate compression engines. It will require a fattening of the jets, and/or a backing off of time, or raising the octane. There are certain tradeoffs, and if your mean mopar is in the 10:1 to 13: range, you will likely experience a benefit. BEWARE of the silent detonation. I would use EFI or a stoichiometer to monitor AF mix until everything is dialed in at least. This can prevent things like broken ring lands, etc. My .02 :-) PCRMike

[powerdodge]

Originally Posted by George G. Leverette

dave571, I have the MSD6AL installed in a 72 Duster with 340 and a 74 Duster with 360 engine. The cars will not run if the ballast resistor is disconnected. "Wiring across the ballast resistor" begs a question. Which color wires should be connected, I am assuming the blue with white stripe and the brown wires, is this correct? The 74 Duster will start with the key sometimes, I have a new neutral safety switch and ignition wiring harness. The seat belt interlock has been by-passed any ideas?

well,they probably get the power through the ballast? you have to jump the ballast, or disconect at both sides, and solve them toghether! the coil will have hard time crating the lightnin if ther's too low voltage!

[dave571]

Originally Posted by George G. Leverette

dave571, I have the MSD6AL installed in a 72 Duster with 340 and a 74 Duster with 360 engine. The cars will not run if the ballast resistor is disconnected. "Wiring across the ballast resistor" begs a question. Which color wires should be connected, I am assuming the blue with white stripe and the brown wires, is this correct? The 74 Duster will start with the key sometimes, I have a new neutral safety switch and ignition wiring harness. The seat belt interlock has been by-passed any ideas?

If the msd was wired as per the wiring diagram supplied with the msd, the circuit that runs through the existing ballast on the car, turns on the MSD unit. It is the switch wire to turn on the main power feed, inside the msd box, which is drawn directly from the battery on the ehavy red wire.

If this is the case it won't run disconnected, simply because the msd is not being turned on.
As mentioned earlier, the existing ballast resistor will not interfere with the performance of the msd. When MSD says "..a ballast is not used with msd.." they mean between the coil and the msd box. If you have wired it the way the diagram says, the ballast is not part of the msd circuit. You would have to ADD one between the msd and the coil for there to be a loss of performance.

If you really want to bypass it, so you don't have to carry a spare or whatever, I'm not sure off hand which wire you want to by pass. It would be the power lead on one side, and the lead that used to go to the coil on the other.

The thing to remember is, that bypassing it serves no real purpose. Operation is unchanged, output voltage unchanged.

Hope this helps...

Dave

[George G. Leverette]

Your explaination sounds logical, I wnat to eleminate some of the wiring that is not necessary for satisfactory operation of the vehicle.