I've got a '67 with a 352 that just started running bad on me a couple weeks ago. The symptoms are that while I'm driving it will start missing, spitting and sputtering, and back-fireing some as well. At this point I can't tell if it's heat related or not, but here is what happened this morning: Drove it approximately 20 miles (on hwy) then it started missing a little, like it was loosing fire to the plugs or something. Within a few minutes it started to miss a lot and I could barely get it to the nearest gas station. While idling it would just spit and sputter for several minutes, then run smooth, then start missing again.

Here's what's been done to this point: Replaced ignition coil, set points, adjusted timing, and checked plug wires.

Any other suggestions as to where I should be looking??

Please help me....

 

Ignition is usually the first place to check, but it sounds like you've got that covered. The next place to check is usually fuel delivery. Sounds like might have a bad fuel pump, or something might be clogging the fuel line or filter. Check those next. If you have access to a vacuum gauge, you should also hook it up and see what happens -- you might have an intermittent vacuum leak somewhere that is causing your symptoms.

 

Thanks for the input. I'll go over those things tonight. Shouldn't be the fuel pump, cuz it's only about 8 months old, but it's worth looking into allong with the filters and what not. I'll also see if I can get my hands on a vacum gauge and see what happens.

BR

 

I just had another thought. Did you check the vacuum advance on the dizzy? A cracked diaphragm could cause those symptoms.

 

I changed the vaccum line to the dizzy, bu that was about as far as I went with that. I'll have to take a closer look there. Thanks again!

 

sounds like a fuel problem. I hope you used a ford fuel pump or at least napa. my experience with rebuild crap from from lesser franchise 'auto'parts stores is just that. crap. plugged fuel filter,maybe?

 

 

Well, I've checked all the fuel areas and did find a problem in the carburator, but it wasn't the root of the problem. Just a result of the problem from earlier in the week when the engine backfired and caught the oil bath on fire, it burned up several gaskets in the carb.

We pulled the coil wire out enough to see if it was loosing fire and it was. Everytime the engine would miss, we lost fire. Since the Ignition coil is new and I went ahead and replaced the points, there wasn't much left to check. Which leads me to ask, since this is before my time, exactly what the heck does the 'Condenser' do. I figured I might as well replace it for $2.50. Although I haven't gotten to drive it much, I haven't had a problem since I placed it. Can anyone enlighten me on exactly what it's purpose is?

Thanks

 

I’ll take a shot. When the points are closed the current is flowing through them. When the points open it is supposed to stop the current flow but the coil in series being an inductor resists this starting and stopping action. So if you didn’t have a condenser, when the points open there would be an big arc across them from the current not wanting to stop until the points opened wide enough that the arc could not jump. This arc is the same as the points being closed so effectively is retards the timing by several degrees. Also, most of the energy from the coil is lost in the arc across the points instead of transferring to the secondary windings of the coil to produce the high-voltage. So the condenser is a temporary storage place for the arcing instead of just going to ground. Now when the points open the current is interrupted with only a small arc and the secondary voltage builds up much faster for a hotter spark. The energy that is temporary stored in the condenser is released back into the primary windings after the plug fires and just bounces back and forth in the circuit until the points close again for the next firing.

If I remember, there is a way of knowing if you have the right value of condenser. I believe it goes like this: Minus material on the minus point (the stationary one) means minus capacity on the condenser. In other words, you need a higher value of capacitance.

Barry

 

Great explaination Barry. Makes sense to me, of course being a electronic engineer helps .