A local company specializing in rebuilding Broncos had an older Pertronix module that I think will work on my F100. It was a model 1261, which I think is the earlier version of the 91261 that Summit Racing said would work on my engine - 240/300 CID, motorcraft distributor. Can't find a definitive answer. I will pick up a good set of points and a condenser to keep in the glove box as well (when I get this truck up and going).
Have a slow speed/idle miss and on acceleration. Had planned on replacing it anyway. Just not die-hard enough to want to support points.
If anyone can tell me different on the module please advise. The instructions I got with the module were severely lacking.

 

Sorry I can't answer your module question but I can tell you I think your problem is in the carb. Carbs have 4 curcuits. Idle,cruise,power,and choke. The idle curcuit is still working higher RPM than most people think. It slowly falls off as the cruise curcuit is kicking in. So I think something wrong with your idle and power curcuits. I'd rebuild the carb. Soak it's metal parts in some good carb soak solution. Clean out all it's internal passages.

 

Did a carb rebuild about 1 month ago. That included a pretty good cleaning. Truck ran fine for a while after that. Now that is not to say that did not make a mistake on rebuilding the carter YFA.

 

If it ran fine for a while after that it sounds like some more crap got sent to the carb. Dirty fuel filter,rubber hose breaking down on the insides somewhere,sediment from in the gas tank,etc.

 

will take a look. replaced all rubber between the fuel tank and the engine. I believe with the mechanical fuel pump, there is a filter in that housing I can check.
I did noticed that one time this truck had the smog canister on the passenger side of the engine area. the disconnected line that runs back to the cab is all that remains.

 

Try blowing out the fuel lines with compressed air. Check the flow from fuel pump to be sure.. At least a pint in 30 seconds.

Pertronix is excellent, but more importantly check the end play on the distributor itself. Once they get a few miles on them this wear will cause missing at idle. About that time they also become worn inside, too much slop in the pins and weights, so the mechanical advance is erratic as well. If there is more than 40-50k on the distributor itself something to consider. A solid state module in lieu of points is a lot more forgiving of a worn dizzy, but no substitute.

 

without consulting my chilton's or my ford service manual, is swapping out the distributor a major chore on these straight sixes?
You know the truck only shows about 80K on it, but I am surmising 180K or more.

 

Should be a piece of cake? The trick is to be sure and get one curved for your application and not a dump truck or something like that (or set it up yourself.) then; with a Pertronix and a hot 12 volt coil like a flamethrower or accel you can open up the spark plug gap to about .050 and improve idle even more. When I swapped points out it was a big improvement, tho not as much as a new dizzy. Can still reinstall points if required.

 

C4AZ-9365-B .. Corrogated Paper Cartridge Fuel Filter (Motorcraft FG-1A) / Available from Ford.

Fits inside metal canister that threads onto the fuel pump / Applications: 1964/72 myriad FoMoCo vehicles.
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I doubt the following has anything to do with the problemo.

Evaporative Emission (Evap/Em) introduced in 1970 Passenger Cars, F100's, Bronco's and Econolines and thru 1972 was mandatory in these vehicles sold new in CA.

It's possible that other states mandated Evap/Em as well in 1970/72.

In Cab (and if so equipped optional auxillary) fuel tank(s) have a round hole for the fuel vapor valve.

Vapor line routes from the fuel vapor valve along the inside of the right (passenger) side frame rail to the round steel charcoal canister located in engine compartment or in front of engine crossmember.

But...does your truck have the optional auxillary fuel tank? If so, its fuel tank sending unit has a "sock" (D1AZ-9A011-A ~ plastic meshed filter screen) that slips onto the end of the pickup tube.

The little charmer could be plugged up with rusty scale. You have to drop the tank to gain access to the sending unit.

 

NumberDummy, no aux fuel on my short-bed flare-side. Loved having the dual fuel tanks on my first pickup, the 1972 Ranger Xlt. As a kid running on my parent's nickle I would sometimes go through two full refills in a week.

 

Have you checked for any vacuum leaks? If auto tranny check all rubber line. Are the carb nuts tight? not sucking any air around base. Is carb opening all the way when choke is off.?
Orich

 

Manual trans. No power brakes. Only have two vacuum lines. Spare vacuum ports plugged. Believe carb is tight on manifold.

 

How about the Vac. advance on the dizzy when those get old and the inner diaphragm leaks.

A fast way to check it, put a long enough length of rubber tubing/hose on the nipple and suck in the other end.

It should pull in and hold in once you suck out all the air if you don't mind putting your mouth one the hose.

Or have a friend do it, id no go their then buy a hand held Vac. Pump that has a Vac gauge on it.

Edited Also the older Pertronix units will cook and do a melt down if the ign. key is left on with out the engine running,
for more then a few minutes. The newer Pertronix ll did not have this over heating problem.
Orich

 

To be fair leaving key in the run position will roast points, too, if they happen to be closed at the time.

With Pertronix, it seems to work best with an aftermarket or flamethrower low ohm coil. That is, bypass any resistor wire and feed a full 12.x volts from battery to coil to both module and coil. The instructions are good but they are a bit unclear why/when this is OK and when it isn't. With the charging system both the coil and ignition module would see 14 volts? In this case more seems to cause fewer problems than less.

Like any ignition system it pays to make sure every connection and cable is rock solid and clean.

You can get away with a stock ford distributor cap and good wires but the higher 40k voltage means stuffing some dialectric grease in the boots to prevent arcing across the towers. Aftermarket caps are usually pretty good diameter to avoid this....and everything has to be clean of carbon and grease or oil, including the coil itself. Use heavy copper wire for the bypass at coil and ignition.

 

1957/76: There are two different V8 dizzy caps.

B7A-12106-A (Motorcraft DH-6): 1957/74 dizzy cap is black, except HiPo engines that used the B7AZ-12106-A H/D cap that was tan.

D5AZ-12106-A (Motorcraft DH-354): 1975/76 dizzy cap is blue, this cap replaced the tan B7AZ-12106-A HiPo dizzy cap.

You can use the blue cap on all 1957/76's.