Well, I've upgraded my ignition, coil, plugs, wires, and distributor (pertronix). Thought it went well until it ran a bit. Idle was just terrible. Messed with the timing a bit, all pretty fruitless...and depressing!

I wired the distributor directly to the coil. Realized the pertronix distributor needs 12V to operate correctly. My multimeter shows approx 3V when running across the coil. Obviously I wired it wrong.

Based on what I've read, I believe I need to wire the negative directly to the coil and the positive to a "switched" connection.

To any pertronix users or otherwise, how would you recommend wiring??? I'm such a novice with electrical, so be kind.

Thanks in Advance!!!

 

Unless there something quirky about Jags, it's a switched 12V source to the + on the coil, red wire on the Pertronix to the same + terminal on the coil, and the black Pertronix wire to the - terminal on the coil.

Reading voltage across the + and - terminals won't tell you much.

 

Thanks, I think you are correct. To verify a low voltage issue. I ran a jumper from the + to the battery. Started right up, but no difference the running.

Unless you guys think I'm missing something here, I think I may just put the Lucas distributor and coil back on. I will say the power improvement was noticeable, however, that idle quality is unbearable...worse than ever.

 

You sure the timing at idle is correct? No vacuum leaks? Vacuum advance canister?

 

I've got a related question, that may or may not shed light on the question above:

For our Series III a Pertronix D177600 distributor is correct. Pertronix recommends a 3-ohm-resistance coil be used, not a one- or 1.5-ohm coil, which is stock.

Which ohm rating is correct? I've never understood this well.

Thanks, Andrew

 

If Petronix recommends 3.0 ohm, that's what's correct for their ignition system.



Cheers
DD

 

You almost certainly are ! That's not intended as an insult. If you missed something then you're in good company with all the rest of us, and vice-versa

Pertronix system are well regarded and popular. There is no reason the idle should get worse unless something was overlooked, or accidentally disturbed....or perhaps a faulty component.

Sleep on it and retrace all your steps with a fresh outlook. Pay particular attention to the brittle wiring along the water rail....especially the single white/black wire that run aft along the rail.

Make sure the ducting between the air flow meter and the throttle body didn't get disturbed.

Cheers
DD

 

All the posts I've read indicated:

Pertronix D177600 Flame-Thrower Plug and Play Vacuum Advance Cast Electronic
PerTronix 40011 Flame-Thrower 40,000 Volt 1.5 ohm Coil

This is what I purchased, but based on my success so far, I'm probably not the right guy to ask!! :-)

As for the issue. At cold, the idle is rock solid better than ever. Starts almost instantaneously as well. As it warms up, the idle gets worse and worse. Everywhere else in the rev range is excellent.

Doug, you are right. I found and cleaned up my timing marks, re-did my connections, and double checked various vacuum lines/grounds. Tomorrow I'm going to confirm the timing is in spec and take it from there.

 

Pertronix does recommend the 40511 or another 3-ohm coil. I checked again to refresh my memory before posting earlier. (See page 2 of the instructions here: http://www.pertronix.com/docs/instru...ts/D177600.pdf). That could have something to do with your trouble!

Andrew.

 

Possibly the plug wires are not in the correct sequence?

 

Fixed it! Amazon had free overnight shipping and I opted for the correct 3 ohm coil. It did the trick. Between the OEM specs, Amazon showing the 1.5 ohm in their "bundle" and multiple pertronix posts that indicated the 1.5 ohm, it didn't even cross my mind.

Thanks for helping and having my rethink think my issue!!

 

Glad it's fixed!

I'm curious as to why the resistance of the coil made such a difference. I found the following in the Pertronix FAQs :

What type of coil can I use with the Ignitor™? How do I check my coils resistance? (12V negative ground only)

To determine if your systems coil is compatible with the Ignitor, some measurements should be taken prior to installation of the Ignitor. Caution… While performing this test, never leave the ignition switch on for more than 30 seconds at a time.
Set your voltmeter to a 15 or 20-volt scale. Attach an 18 or 20 AWG jumper wire from the negative coil terminal to an engine ground. Attach positive (red) lead of your voltmeter to the positive side of the coil, and the negative (black) lead to an engine ground. Turn the ignition switch to the run position. Now read the voltage at the positive coil terminal. Turn the ignition switch off. If the voltage measured is approximately 12 volts, no resistance wire is present. A typical resistance wire will provide 9 - 6 volts.
The next step is to determine the resistance in the primary ignition. Label the wires attached to the coil terminals and note their appropriate location. Make sure that the ignition switch is off and disconnect all wires from the coil. Adjust your meter to the lowest ohm scale. If you are using an analog style meter make sure to zero the needle.
Measure from the negative terminal to the positive terminal. Write your measurement down.
Now the maximum system amperage can be determined, divide your voltage measurement by your coil resistance measurement. This will give you the system current or amperage.
Four and six cylinder engines should not exceed 4 amps. Eight cylinder engines should not exceed 8 amps. If the total amperage in your system is higher than the amount recommended for your application, you should install a ballast resistor.
Example

Voltage 12
Resistance 1.5
12 / 1.5 = 8
Total amperage 8


Which means in your case, presuming there was no ballast resistor, the 1.5 ohm coil was drawing double the amps permitted. The present 3 ohm coil gives a 4 amp load which is OK.

I know with traditional points and condenser a high load will shorten the life of the points, but I wonder why the Pertronix unit is so sensitive?

 

This really got me thinking too. I know there's a lot of discussion that the ballast resistor isn't all that necessary especially on a vehicle without points, but perhaps it was intentional to increase the resistance at the coil.

In the case of the Pertronix, it just happens to be more sensitive to the lack of resistance.

I have no idea, just spitballin!