1974 ford Problems

[molinebob]

I have a 1974 ford f250 highboy 4x4, just wondering what would cause it to eat a set of points up in not even ten miles of driving? Just bought the truck to haul firewood with, and snowplow once i get the plow mounted. Had a bad distributor in it when i bought it so bought a new one from Napa, put it in with the points set at 20 thousandths.Acted up yesterday like a carb prob, but then i remembered from my younger days that i had a 302 act like that and it was the points so I checked them and sure enough they were fried. Put another set in today and will run it till they fry i guess, just wondering what would cause it to go through the first set so fast. Thanks Bob

 

[Dick K]

Not sure about about ford, I have always ran GM. GM used a resistor in the ignition feed when the motor was running, dropped the ignition voltage to 6 volts. Only had 12 volts when starting. If the resistor went out the vehicle would rapidly burn up a set of points. Might pay to check your wireing.

 

[Dean]

Most likely the ignition resistor or the condensor.

Much less likely, the coil.

Dean

 

[evilboweivel]

check the voltage to the points
sounds like no resistor

 

[Anonymous-0]

I haven’t had anything with points for a long time: but if my memory is correct if the ballast resistor is wired incorrectly the points will turn blue/black but will not pit. If it is a bad condenser one side of the point set will crater and the other side will have a little peak on it.

 

[molinebob]

it was like one side was completely gone, the other side was good, coil was just replaced, but it did have an aftermarket electronic ignition on the old distributor that was all hacked off before i bought it, so i just replaced it with a point style back to original, did notice though that they had a wire ran from the resistor to the positive side of the coil, and on that side of the resistor there was two wires coming off of it, thinking it had something to do with the aftermarket elec conversion that was on it, i just now cut that extra wire and it started and ran fine so im thinking that might of had something to do with it. Time will tell..Bob

 

[Butch(OH)]

Yup, as they all said you very likely have full time 12V feeding the coil, condensor is a possibility. GM used a resistor wire, Mopars had a resistor on the firewall. Cant say I ever had to find it on a Ford so dont know where to tell you to look. All of them had switching from the starter solinoid to give full battery voltage when cranking. On the Ford it comes from your fender mounted solnoid. One of the small wires is the pull in for starting, the other feeds 12V to the coil when it is energized. If somebody had been "creative" with your wiring you can always add a resistor in the coil feed wire.

 

[barnE]

Lincoln I had in 69 used resistor wire. Hard to tell from regular wire without ohm meter. Dave

 

[John Garner]

molinebob --

I agree with the earlier posters, that your truck's ignition system is probably incorrectly wired so that the points are switching 12 volts all the time. Other possible contributors to the point burning could be a really low-grade point set, a bad ignition condenser, or severe contamination.

Ford used a high-resistance wire between the firewall solenoid Ignition (I) terminal and the coil terminal, a plain copper wire between the solenoid Start (S) terminal and that same coil terminal to bypass the resistance wire when cranking the engine.

The intent of the "starting bypass" wire is to supply whatever battery voltage there is (for the most intense spark) while the current draw of cranking the engine cuts the available voltage.

The intent of the "running" resistance wire is to reduce the voltage at the points while the engine is running to a level that the points can withstand for hours on end.

A missing or broken running resistance wire can be safely replaced with a new resistance wire OR a length of plain wire AND a firewall-mounted ballast resistor.

John

 

[JMOR]

I can't determine what you mean here, "coil was just replaced, but it did have an aftermarket electronic ignition on the old distributor that was all hacked off before i bought it, so i just replaced it with a point style back to original, ". But if you are still using an EI coil, that is your problem........too much current for points.

 

[juniur]

coil is wired backwards. points go to neg side switch feed to pos side. will burn points very quickly

 

[JMOR]

(quoted from post at 07:57:58 09/08/11) coil is wired backwards. points go to neg side switch feed to pos side. will burn points very quickly

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