hot ignition coil, texas t distributor,12 v system

W

wbs

Senior Member
hello- my new coil boiled the oil out of it - manufacturer said coil had internal resistor-i'm running 12 v . all ohmages were open ckt in coil ckt as they should have been and no spark plugs were shorted out.

iwas told not to throw the ignition switch until the last moment of start up so as to reduce current thru coil when points may be closed and use additional extern. resistor in addition to the intern rest. , etc .

has anyone else had this problem and if so how did they solve it? is there such a thing as a heavy duty coil? i notice that teaxas T sells a coil for $15, so i guess that in general, a heavy duty coil is not needed.
 
wbs said:
hello- my new coil boiled the oil out of it - manufacturer said coil had internal resistor-i'm running 12 v . all ohmages were open ckt in coil ckt as they should have been and no spark plugs were shorted out.

iwas told not to throw the ignition switch until the last moment of start up so as to reduce current thru coil when points may be closed and use additional extern. resistor in addition to the intern rest. , etc .

has anyone else had this problem and if so how did they solve it? is there such a thing as a heavy duty coil? i notice that teaxas T sells a coil for $15, so i guess that in general, a heavy duty coil is not needed.
Click to expand...

Coil get hot based on low resistance . The 12 volt coil should have 1.5 ohms minimum resistance. A shorted spark plug will not have any effect on the coils primary windings.
Leaving the switch on can cause a heat build up however we all do it a lot. Proper primary circuit resistance will help this issue.
The best ever coil for the Bosch distributor used with the T kit is a Bosch Blue # 0012 coil. Its 3 ohms and i have never sen a defective one. The one on my T has ran with a Bosch distributor for over 9 years.
You can buy these on amazon.com...

Your coil died because the resistance was too low......
 
I've never heard of this happening unless there's a dead short of some kind. It's a 12 volt coil correct? You should be able to leave the car sitting with the ignition on and not have a coil cook off. Not that I'd do it mind you but still. OK, you need a new coil and the Bosch is a good one. Check that the voltage is correct and if it has an internal resistor. You don't need an external one if there's one inside. I think your old one when bad on it's own IF there's no other short in the circuit.
 
The el - cheapo made in China coils fail early and often, it is expected. We have a fellow who tours on the Texas T party every year, he gets about 100 miles per coil.

Do yourself a favor and buy a coil for a 1969 Volksbuggen from your local auto part store. Carry a spare under the seat, along with spare points and condenser.
 
Royce P said:
The el - cheapo made in China coils fail early and often, it is expected. We have a fellow who tours on the Texas T party every year, he gets about 100 miles per coil.

Do yourself a favor and buy a coil for a 1969 Volksbuggen from your local auto part store. Carry a spare under the seat, along with spare points and condenser.
Click to expand...

The 69 VW Beetle coil is a Bosch # 0012 available on Amazon at a good price. I have never seen a bad one.
 
wbs said:
thanks -does anyone know how many watts and ohms the external power resistor is?
Click to expand...

Somewhere around 10-12 watts at 1.5 ohms when used by its self. However usually the coils internal winding has a resistance of 1.5 ohms as well. Overall current flow would then be lower (cut in half) and wattage ( heat build up) would be shared for less current and less heat ...

The problem is that the cheap coils sometimes have a much lower resistance like .6 ohms and ask for 20 plus amps , that where the oil gets hot and boils out!!!! Close to 120 watts could heat a small room almost with that kind of wattage..
 
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thanks again- i'm going to take my spare coil to a friend who has a accurate ohmmter and measure its ohms. i take it from bubba's post, current should be 4 amps -so i would need a power resis. = 3 -[whatever primary coil res. is]--watts would be 24watts[1.5 ohm x4 ampsx4 amps] at most but prbably less--------
and


i need order 0012 coil for regular usage---

----for spare p0ints and capacitor , i ask for 69 vw beetle, correct?
 
Correct. Get one made in Germany or USA if you want it to last.

wbs said:
thanks again- i'm going to take my spare coil to a friend who has a accurate ohmmter and measure its ohms. i take it from bubba's post, current should be 4 amps -so i would need a power resis. = 3 -[whatever primary coil res. is]--watts would be 24watts[1.5 ohm x4 ampsx4 amps] at most but prbably less--------
and


i need order 0012 coil for regular usage---

----for spare p0ints and capacitor , i ask for 69 vw beetle, correct?
Click to expand...
 
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