I'm glad your issue is resolved, William, but I'm not sold on the "one tooth off" theory. It doesn't work that way- period. You probably had a loose or disconnected ground wire that you straightened up and didn't realize it. I'm not trying to discount your find, but as stated earlier, you can be several teeth off when stabbing a distributor- as long as the housing is turned so that #1 fires when it is supposed to, the truck can and will be timed correctly. The engine doesn't know that the distributor is off several teeth so how is it going to tell a timing light to read as if the ignition timing were advanced?

A running engine is nothing more than a series of simple mechanical principles- one can easily complicate things by overlooking the basics.

Congratulations!!!

Joe

 

William, great! At least you found the problem and also solved a potential problem by getting the Pertronix hooked up correctly now.

Just to clarify, I guess I wasn't clear in my previous post about why my timing was advanced when I was fighting the Pertronix problem on my truck (I knew what I meant, I just didn't say it right!). When I installed my Pertronix and had it hooked up wrong the engine ran like crap. The unit itself will not change the timing, it just acts like a set of points in that respect. I had to advance the timing on mine to get it to stay running as it would just die after idling for a few seconds.

The thing with mine was i KNEW it had to be something I did with the Pertronix that created the problem as that was the only modification I did at the time. It had run super on the set of points I pulled out!

 

Joe, thanks for the diagram. I'm on the work puker today so pdf's are no problem now. Hey, something interesting, your page 13 is different than the page 13 in the link you posted earlier. Where it talks about removing the ballast resistor, I think they are referring only to the XR3000. Compare the two pages, count the step numbers and you'll see where the heading for the XR3000 balast resistor notes is in the wrong place. It should be before the gray box with the ballast note.

Anyway, a call to Crane can't hurt.

Barry

 

Won't you feature that!!! I looked a little closer at Crane's site- there are two versions of the XR700- one with a diagnositic LED, and one without. The instructions for the one with the LED give a little added info and it looks as if when they added the info at the beginning, it threw off the format of the rest of the PDF.

At any rate, I called Crane- TWICE. I wanted to make sure I didn't get two stories from the same source. To make a long story short, I had them both pull up their installation instructions for the XR700. I then asked them to tell me the difference in hook-ups between an XR700 and a coil with external resistance, and an XR700 and a coil with internal resistance.

Are you following me?

The hook-up, according to the diagram, for an XR700 and a coil with external resistance (ballast resistor installed) shows the power source for the control box to be the decreased value given at the "+" terminal on the coil after the resistor. Now, don't let me shake you. In a setup where a coil is used with internal resistance (by the way, according to both reps, this is the prefered setup), there is no balast resistor used, so therefore, the voltage at the "+" terminal on the coil is 12V - where the control box is powered from.

SO- my next question was: would the control box benefit from receiving its power source BEFORE the balast resistor as opposed to AFTER? Guess what the answer to that was.

YES!

I asked them what it would take to update their installation instructions to clarify the power source for the control box and they both responded, "I dunno." IT'S UNANIMOUS.

Anyway- I'll be going out there shortly to do some fiddling. I'm not convinced this will help the timing advance issue with my hoopie, but it should help with the feeling I have that it lacks a little power due to a weak spark.

Thanks Barry, for your input.

Joe

 

Hey that's what I was thinking, power the unit off 12v but leave everything else the same, just like the Pertronix. Check the temperature of the unit after a while just to be safe. If your truck has the factory ammeter it's a cinch to get power under the hood that's switched on only during start & run.

It's funny those tech guys, a long time ago I called Pertronix twice about the same thing and they finally gave me a similar answer after talking to their specialist.

Barry

 

It's a done deal. Rewired the control box to 12V before the ballast resistor and my hoopie came to life. My rear end slid out from under me twice while making turns with moderate acceleration- not really getting into it.

I don't have a temp gun so I laid an A/C thermometer across the top of the control box before the mod and let the truck run for 15 minutes. After the mod, I laid the thermometer across it again and let the truck run for 30 minutes while I gabbed with the neighbor. No change in temp. I figured if the control box burnt up, that would give me an excuse to by the XR3000 control box and I wouldn't have to worry about any ballast resistor.

Oh... I checked my timing with a light after I set it by vacuum and adjusted the carb- 20* BTDC. After checking and re-gapping the plugs last week, I'll leave it alone. This thing is running good.

Joe

 

It sounds as if maybe you have a problem with the petronix or your installation somehow affected the advance mechanisms. If you don't have a dialback timing light then you will need to have marks on your damper to 30 degrees or so. You will most likely have to do some measuring and mark them on. I do not know the specs for your dist. but if you run the engine up to around 2500 you should see around 30 drgrees total advance with the vacuum line connected and maybe 20 with it disconnected. These are just ballpark figures. If you want to get it spot on then get your distributor specs and check it against them. If you don't have a hand held vacuum pump get one. They aren't that expensive and double as a vacuum guage which no mechanic should be without.
With your pump in hand you can connect it to the dist. and watch the timing mark as you pump. Most vacuum advance units start in around 4-7 inches of vacuum and are all in at 15 inches. You can adjust the vacuum advance by putting an allen wrench in the tube where the hose goes on. If it's stuck you need to replace the vac. advanc unit. I get all my specs out of an old Motors manuel. I also had a very good tuneup specs book that Motorcraft used to put out.
The total advance will vary from 28- 36. If you want to do it by ear you can run it up until you just hear a ping under heavy load then back the timing down until the ping dissapears. The base timing is only a guideline that was established 35 years ago when gasoline was a lot different than it is today so don't be too concerned with it if you get the truck to run right. Ford even revised alot of those settings on different recalls over the years.


OOPS! Sorry I never got to the end and didn't realize you had the problem solved.
I didn't hear mention in your discussion about the wiring just how the resistance that Ford used in the feed wire to the coil was dealt with. I would think adding a ballast or internal resistance coil while using the original coil feed wire would be redundant resistance.