no spark - what is wrong?

CP

CP

Senior Member
ok, i had skip convert a coil to 12 volts. worked but spark was week. put on another coil and worked fine. so i sent the coil back to skip and he of coarse fixed it at no cost. he said i burnt it up and must have left the ignition on. i only had the ignition on during first startup, but...whatever. my new coil worked. anyway, i got the "rebuilt" coil from skip today and fired it up. started up no problem and ran for 10 seconds since i had the gas off.

anyway.....now i have no spark again. its very "week". it does spark, but barely. what the heck is going on?

i have a 10 ga. wire direct from the battery to the resistor. one wire from the resistor to the "batt" terminal of the rebuilt 12v coil (48 type). the other terminal goes to the distrib. pretty simple.

i took my coil off my running engine and dont have strong spark either.

"week" spark, what is it?

no cut wires...engine on stand.

resistance of wire is .2 ohms

resistor (i tried two) one is .6 ohms and one is 1.5 ohms

it ran with the 1.5 on for like i said 10 seconds and sounded great.

changed from the ,6 because i figured maybe that is why my coil burnt up.

however, not geting spark from a coil that i know is good is what is getting the best of me.

i have new wires and bought another set of wires....tried both. week spark.

help? cp
 
im getting week spark from the coil wire grounded to the head studs.

if i attach coil wire to the distrib, i get nothing.

i attached a mallory 3772001 (2-bolt elec) "bran new" and nothing changed.

checked the ground wire.

new resistor (at first start, it smoked a little) i assume thats normal for the resistor when it first gets juice. only had switch on for 5 seconds or so.

new cap new rotor. no points, now what?

i can put in the stock crab in again that was running with the other coil. ill try that tomorrow i guess.

i just dont understand how u can have spark for one minute and then none.

is 10ga wire too heavy?

know the original coil was 6v pos ground. skip said he rebuilt for 12v neg ground. so i asked him, do u reverse the terminals and he said no. where it says "bat" connnect to the battery (switch) and where it says "dist", connet to the distrib.

i dont see how i can screw this simple wiring up.

anyway, im hittin the shower...hot and muggy as heck up here. thanks though....CP
 
Like Bubba said, if the coil is good, the condenser is REALLY suspect. I'll guarantee you that the 10 ga. wire is not the issue. Does the new rotor match the cap? If you're using a crab style cap, the original "46 - '48 style rotor is too short. Just a thought. Good luck.
 
If you have a 12 volt coil and have no resister it may run for a short time like out of gas.12 volt coils need a resister around 1.5 ohms.If on a test stand HOT ROD it and get a Ford 12 volt coil and resister for a car or truck from 56 to early 70s. If it still doesn't run get a new condenser.
 
well, i got rid of the unilite and put the crab back on. the reason i got the unilite is because i could not get the timing right (or so it sounded to me). anyway, i found an old borg warner condenser in a box and put it on. Holy Moly. Not only did she fire up, but no noks and farts and excellent throttle response with the trip carbs (none blocked off). engine sounds great. Im into the unilite for 300 and now want to get that working. im told i need the coil 29219 and some spiral wires (not solid core).

Im gonna see if i can get the unilite working with the new wires and coils and keep then go back to what i have now. ( a great sounding engine). Ill keep the unilite, coil, and wires in the trunk in case of problem on road trip.
 
thanks for your help. If someone could explain what the condenser does (in simple terms), that would be great.

I really hate electronics, but im forced to learn more.

Thanks again, CP
 
Food for thought: The stock 59AB dual point distributor is a really good piece of equipment. Properly set up and with a good coil and condenser, it might be all you need.
 
thanks alot Bubba,

i actually found your web site last week and was liking how u showed the pictures of how you rebuild the distributors and the cost seams reasonable as well.

you definately helped me out big time.

i have another distributor that is a little sticky. Ive been lubing it up and it spins "ok" now. im thinking of sending it your way to have a spare. you definately deserve some business from me from your "right on" response.

im a rookie big time when it comes to these things. and i really appreciate your and others input.

cp.
 
The condenser is a capacitor. In operation it starts charging when the points close. It charges like an accumulator in a hydraulic system. When the points open again, the built up charge bursts out at high velocity. This electrical spike causes the coil primary winding to unduce a high tension voltage into the secondary winding. If all is functioning corrrectly and insulation is good, the high voltage procedes to the path of least resistace at the spark plug gap. Then it starts all over again. Amazing that it will do this task millions of times if it was made correctly. Most aren't made correctly in this day and age. We are lucky if one in three works correctly.
 
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