Major Pertroix Woes



Hi, I am new to this forum, but have been lurking for several months. I have a 66 Mustang Coup with an inline 6 200. It is basicly stock. The only mod was the Pertronix. Like I said I have been lurking, and have scanned through the threads of others who have had problems. I originally had a Pertronix I, and hooked it up straight to the coil. It worked for about 200 miles, then as the car would warm up it would run, well like crap, then just plain die. I then connected up a switched 12V from the IGN switch before the resisiter wire, and the same thing. I thought maybe the module, so I got the Pertronix II, hooked it up, and the same exact thing! Right now, it is a stock 200, with the Pertronix II, and the Flamethrower II. I would appreciate any help on this issue. I am just about ready to put the points back in. BTW, I have gotten a great deal of good advice from these threads as I was rebuilding the engine in Nov, and Dec.

Thanx Much,
I know this may seem's the timing?

Also, what did you set the gap for on the pertronix? It also sounds like your carb may be out of adjustment. I found that when I went to Pertronix, a lot of other problems became more apparent.

The carb seems to be ok. I pulled the plugs after 200 Miles, and they looked good. The timing is another story, however. When I try to run at 12 deg BTDC, it runs terrible. It seems to like around 20-25 deg (Which is way way too much). I am running a reconditioned 67 dual advance, single vac dizzy, with an Autolite 1100. The dizzy is connected to the ported vacuum source on the carb. I am running a stock radiator and fan with a 185 deg Tstat. When I installed the Pertronix, I used the clear plastic shim they provide to gap it.


When I first got my car, it was running at 25-30* advanced at idle. WHen I installed the pertronix, it cleared some of the problems. I too could not get it to run down to 6* (MT). I found it was a combination of an old carb, vacuum leak, and improper timing. I replaced the vacuum line to the carb, and then spent about 30 minutes running the RPM down and resetting the timing as I got the RPM lower. I could only do it a little bit at a time. I want to say that your timing is way off. If you are running 25-30 initial, you at speed will be around 50* advanced. Did you check your timing mark with TDC and make sure the mark was right? I also found mine was off a bit.

IIRC, and I may be getting some of my facts mixed up here, but I thought that the dual advance dizzy would not work on an 1100 unless you have a manifold vacuum source for the dizzy. I may be wrong there. Hopefully someone can answer that one for sure.

You said your plugs were fine, so it isn't the carb getting the wrong mixture. Maybe check your wires. Usually if the car is firing badly then at least one or two plugs would show signs.

Maybe try putting the points back in and see if you have the same problem.


I think you may be onto something with the ported vacuum. Tomorrow, I will put the points back in and see what it does, but before that I might plug up the ported vac, and connect dizzy to the manifold, see if that cleans it up at all. As far as valve timing is concerned, I used a dial indicator to acheive TDC, but this is easy enough to check. I will also purchase a rebuild kit for the carb. Plug wires are new, but I will di a resistance test on them as well. I will let you know how it goes. Thanx for the help.

You have to remove the spark control valve and install a plug in its place to be able to use the 1100 with the dual advance dist.
I am not very familiar with the Autolite 1100, is that the small sensor looking thing right by the vacuum port?

Yep. From what I've been told, you need to unscrew it and plug the hole when using the dual advance dist. with it.
Thanx! I will plug up the hole tomorrow, and switch the dizzy to manifold vacuum. Let ya know how it goes.
BTW, will my current condition let the engine run smooth when cold, and degenerate as it heats up. That is what is happening.

Hi Mustang66,

Sorry to hear about your frustration. Sounds like you are dealing with several issues. Need to break this down to one at a time. Let's start with the ignition since that seems to be the number one headache.

First, the Pertronix II and Flamethrower 2 are a very good upgrade. However, as you know the the electrical source is key. So is being sure you have the correct unit for the dizzy, thermactor or not. Call Pertronics and verify with them that you have the correct part number. The '67 dizzy could be either one (91266 or 91261 - "D" drive or "KEY drive and I don't remember which is which).

Did you remove the Ballast Resistor?? Have you checked the voltage at the + (red) side of the coil. The PII with F2 are designed to run w/o the resistor, i.e., 12 volt coil and dizzy. Remove the resistor, be sure you have 12 volts at the coil, and hook the red dizzy line to the + side of the coil. Be sure all connections are clean / tight. Be sure the PII is gapped correctly (.030). Replace your cap and rotor as worn parts don't stand up to 45000 volts very well. New / good plugs should be gapped at 45 for starters.

Timing. The 200 I6 likes a lot of initial advance. 20* with a stock cam is not shocking. The problem is that with 20* initial you will very likely have an overadvanced condition under accelleration. The all-in advance should not exceed 34* - 38* at 2400 - 2600 rpm. If you are sure you have the dual advance dizzy (single vac), try this. Disconnect the vac advance, i.e., plug the vac at the dizzy and the carb. Set the timing at 20* at 600 rpm (in gear if you have an automatic). The slower the better (500 - 600) so as to insure that the mechanical advance has not kicked in. After set increase the idle to whatever seem best setting (mine likes 700 in gear). Do not hook up the vac sustem. Drive the car. If you get ping under load (WOT accelleration) back off the initial advance until it goes away (set & drive, set & drive, etc - my car likes 16*). It is entirely possible that the vac system is overadvancing the car. See this sight

I am a strong supporter of the mechanical advance only system primarily because it is the only way to know exectly what your timing advance curve and rate are going to be under all driving conditions. The vac system introduces to many variables. In your case, however, I am concerned that the vac system on the 1100 carb may not be compatible with the dual advance dizzy. The best way to check is to bypass it. I suspect you will see the benefits as soon as you try this. The only down side is that we don't know which advance weight limit you currently have (see www.bob2000). If the dizzy you purchased has a 15* weight, you will have 30* at 2500 rpm B4 initial or vac advance is introduced. If you find that you have to reduce you initial to something on the order of 5* - 6* to eliminate ping, you have the wrong weight for a mechanical advance only system (www.bob2000). Also, at 5* initial your car will idle like C..p. If this is the case, however, this is the exact reason for the vac system. If hooked to a ported source the vac advance should add approx 10* at idle. Then, in theory, as the throttle is opened (WOT accelleration) the vac deminishes and the car gets only the initial + the mechanical (5* + 30* = 35*). The problem is that you can't be sure what the vac is actually doing at any point in the rpm / load cycle. But that is how it is intended to work. So, if you get down to 5*, you should see idle improve when you hook up the vac. However, the 1100 vac system was intended to run with a dual vac dizzy. It, therefore, has a valve in the vac port that could interfer with the advance signal your dizzy needs, + or -. The fix is to run the car with mechanical advance only so long as you stay with the 1100. Actually, I like the mechanical for any carb application. To convert, you simply need to put the 10* weight limit in the dizzy and set the initial at the highest possible "no ping" level.

If ignition and timing adjustments alone don't correct your issues you will need to consider the carb, value adjustment and timing (rockers and chain), etc. But with a newly rebuilt motor I doubt etc is an issue. At any rate, take these systems on one at a time.

Hope this helps. I had a very similar problem with my '66 200. The process was expensive (many mistakes) amd frustrating, but when it all comes togather it feels GOOD.

Enjoy the trip - Steve

Steve again. Boy , you sure got a lot of good info while I was word smithing my response. The reason I'm back is that when I tested the bob site connection in my post it would not bring up the site. However, the site address is correct. Go to it through your net connection. It is a very helpful site.

You're right. You have put a lot of great info in your post. Thanx. As far as the Pertronix: I ran a new wire to the coil and Pertronix unit from the IGN switch. Getting 13.75 volts while cold, 12.2 at idle warmed up. I have the "D" drive or the Non-Thermactor type (91266). The dizzy is the rebuilt from Cal Mustangs. I don't know the * of the wieghts in the dizzy. Is there a way to tell? The Pertronix is gapped and installed correctly. Falcon64 was telling me that the spark control needs to be removed from the 1100 carb. I am going to try that. You have also given me much to think about. I do think that you are correct about the over advance situation. I also think that Slade, and Falcon64 may be correct in pointing out that I may be dealing with multiple problems. I have re-verified TDC so the problem is not the valve timing. I have verified the plug wires. I have verified the voltage to the coil and Pertronix. I am sure that the mixture is correct based on the plug condition. So that leaves me with the following:

1. Spark Control on Carb needs to be removed and plugged
2. Ported vacuum on carb needs to be plugged
3. Dizzy may or may not get connected to manifold vacuum
3. Centrifigal Advance may have incorrect wieghts.
4. Bad Pertronix Module (Unlikely. What is the likelyhood of 2 bad modules in a row)

The degree limit of the weights is stamped into them. You can easily tell what you have. And they are not to difficult to change. But B4 you open up the dizzy try the method I outlined. Plug the vac ports and set initial at 20*. When you test drive don't give the car to much throttle. Get on stright flat piece of road in third gear and puy you foot down smoothly. You don't have to be moving all that fast. Just put the engine under load and don't let the car downshift. If you can get to the floor without any pinging you are set. With 20* of initial you will probably get ping. Even with the 10* weight you would have 40* of advance by 2500 rpm. That's a little high. If you ping, try 18*. Then 16*. When the ping stops, you can estimate you weight stop by subtracting the initial from 35*. Example: 35 - 15 = 20. 20* at the crank means 10* in the dizzy (dizzy turns 1/2 crank speed - so 10* of weight = 20* at the crank). 35 - 5 = 30, or 15* weight stop. All-in advance will need to be 34 - 38. You want all the initial you can get without ping. Be sure to yake a look at

Good luck - Steve
By the way. Value adjustment can have a significant impact on idle as well as performance. If you don't have adjustable rockers, consider them. If you have to buy a set, get 1.6:1.

Pertronix are onto a good thing. They sell a product line, and others create terabytes of data trying to get their cars running smoothly!

Mustang66, what happened to the supply voltage as the car died?

What is your manifold vacuum at idle, on a warm engine?

My wagon used to not idle after warming up. You had to give it some to stop dying. I'm changing the engine (flogged out 170) - easier in the long term... But I suspect both my problem and yours require a look at the fuelling, too. Sorry to throw more irons into the fire.

Hey addo,

You need to review the info more closely. The Pertronix and smoothly are to different subjects. Not putting 12 volts to the unit is not uncommon. Once that is done the discussion is over. How many DSII posts have we seen with the same or similar issues.

As for smoothly, anyone who hasn't lived through the exercise of sorting out a Autolite 1100 / dual vac dizzy set-up that isn't working cannot possible understand the frustration. The carb and the dizzy are a interdependant systems. Change in one impacts the other. The 65 - 66 automatics seem to have a unique set of problems in this area. The only way through it is to separate the two and sort them out one at a time. Having spent six months and hundreds of dollars on this "problem" I am I don't think "terabytes" of assistance is something to make fun of. Simply trying to help. I HAVE BEEN THERE. HAVE YOU?

Here is the latest:
Plugged up the Spark Control, and thePorted Vacuum on the 1100...No difference. Rebuilt difference. Cleand and regapped plugs to smaller gap of difference. Current determination...Incorrect valve adjustment in #1 and #4. This was determined by performing a running compression test. Between 55-60 on 2, 3, 5, & 6. 30-32 on 1 and 4. Will be removing valve cover and performing cold valve lash adjustment durring the week.

Let ya know how it goes. I do want to say thanx to everyone who helped. You guys, and this forum are great. Also, Steve, I looked at the plate for mechanical advance. It says 6-1. I will assume it is a 6* plate.


Once again, I don't have my numbers memorized, but your compression numbers (all of them) seem really low. But 1 and 4 are really off.