Chry 318 Ign. coil burning up
 

I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run fine
for another few months. Any help or suggestions with this problem would
be GREATLY appreciated.

Thanks
Ronnie

Check to make sure there is a good ground to the coil case.

wrote in message
ps.com...
I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run fine
for another few months. Any help or suggestions with this problem would
be GREATLY appreciated.

Thanks
Ronnie

On 19 Dec 2004 19:24:09 -0800, wrote:

I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run fine
for another few months. Any help or suggestions with this problem would
be GREATLY appreciated.

Two things - one is you could be charging the coil with more voltage
than it can handle - you might want to go with a heavier coil.

Second, as Calif Bill mentioned, you may have a loose, as in very
loose, ground.

Later,

Tom

On 19 Dec 2004 19:24:09 -0800, wrote:

I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run fine
for another few months. Any help or suggestions with this problem would
be GREATLY appreciated.


Sounds to me like your coil is being "fried" because there is too much
voltage being run through it. Most coils are designed to run at the
full 12V when starting, but then switch in a dropping resistor which
drops the voltage down to about 8V when running. If this dropping
resistor is absent, the coil will get the full charge at all times.

Another thing to check is your charging voltage. If your alternator
regulator is acting up, and the charge voltage runs up to 16 or 17 V
the same thing could happen. Although, you'd probably notice your
batteries boiling over and very bright lights as well.

Dave

Adding to what K said. The easiest way to see if the ballast is wired
correctly and working is to disconnect one end of the resistor while the
engine is running. The engine should quit. The resistor value should be some
where around 1.2 ohms.
JIMinFL
"K. Smith" wrote in message
...
wrote:
I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run fine
for another few months. Any help or suggestions with this problem would
be GREATLY appreciated.

Thanks Ronnie



2 years ago the coil might have just died of old age, we all will:-) but
then ......

The rewire ??? Hmmm check the ballast resister is actually in the circuit
when the engine is running, the coil is designed to run on 7-8 volts via
the resistor, save when the starter is engaged the resistor is supposed to
be left out of the supply so the coil can get extra for start or at least
whatever is left over after the starter is fed.

If the rewirer goofed then the coil will start OK all the time of course
but once the engine is running the supply voltage won't be getting cut
back to 7 or 8 volts. Giving the coil 12 volts all the time will kill it
over time.


K

Dave Hall wrote:
On 19 Dec 2004 19:24:09 -0800, wrote:

I have an early 1980's modle 318 Chrysler engine installed in a
mudboat. About 2 years ago I developed a problem with the Ignition
coil burning up. The engine has the original electronic ignition
system installed, but has been completely rewired by a Dodge
dealership, the control module, ballast resistor, and the
distributor
pick-up assy. have been replaced. However, I continue to have the
problem. The engine runs perfectly for about 3 months and then
without
any warning, will backfire and die. There will be no ignition fire
until the coil is replace, then the engine will start up and run
fine
for another few months. Any help or suggestions with this problem
would
be GREATLY appreciated.


Sounds to me like your coil is being "fried" because there is too
much
voltage being run through it. Most coils are designed to run at the
full 12V when starting, but then switch in a dropping resistor which
drops the voltage down to about 8V when running. If this dropping
resistor is absent, the coil will get the full charge at all times.

Another thing to check is your charging voltage. If your alternator
regulator is acting up, and the charge voltage runs up to 16 or 17 V
the same thing could happen. Although, you'd probably notice your
batteries boiling over and very bright lights as well.

Dave

I appreciate all the responses very much. The resistor resistance is
app. 1.2 ohms and running voltage is 8.2 volts. Alternator output is
14.4 volts. The coil is mounted directly to the block and the bracket
seems to be tight and clean, no signs of corrision. I tried install a
higher resistance resistor and dropped the running voltage to 7 volts,
but that made the ign. fire too weak. I have tried using Mopar coils
as well as aftermarket coils with no noticeable differance. Someone
suggested using a HEAVY DUTY coil, where can I buy one and what do I
ask for? This problem certainly has myself, the Dodge dealership and
several local independent mechanics scratching our heads.
Thanks again
Ronnie

On 20 Dec 2004 16:52:07 -0800, "wtbuck12"
wrote:

~~ snippage ~~

I appreciate all the responses very much. The resistor resistance is
app. 1.2 ohms and running voltage is 8.2 volts. Alternator output is
14.4 volts. The coil is mounted directly to the block and the bracket
seems to be tight and clean, no signs of corrision. I tried install a
higher resistance resistor and dropped the running voltage to 7 volts,
but that made the ign. fire too weak. I have tried using Mopar coils
as well as aftermarket coils with no noticeable differance. Someone
suggested using a HEAVY DUTY coil, where can I buy one and what do I
ask for? This problem certainly has myself, the Dodge dealership and
several local independent mechanics scratching our heads.

Auto parts places can come up with a heavier duty coil. Might want to
try a speed shop also.

BUT.....

I wonder if this is a heat related problem. Based on what you just
posted, it all sounds normal. Which makes me wonder what is breaking
down the insulation (which is what normally happens with a coil).
There is a lot of internal heat in a coil from it's normal
functioning, but perhaps it's located close to a heat source like
exhaust manifold? The only other thing I can think of is that the
coil is inducting a external charge by being located too close to a EM
source - perhaps a generator or something?

Just shots in the dark.

Later,

Tom

On Tue, 21 Dec 2004 01:02:20 GMT, Short Wave Sportfishing
wrote:
I wonder if this is a heat related problem. Based on what you just
posted, it all sounds normal. Which makes me wonder what is breaking
down the insulation (which is what normally happens with a coil).
There is a lot of internal heat in a coil from it's normal
functioning, but perhaps it's located close to a heat source like
exhaust manifold? The only other thing I can think of is that the
coil is inducting a external charge by being located too close to a EM
source - perhaps a generator or something?

======================================

All of that, plus you should also check your alternator and voltage
regulator. 14.4 volts is a bit on the high side and may be
contributing to the problem. 13.8 is a more normal "float" voltage
after the batteries are fully charged.

Maybe wrong coil. Maybe should be an internal resister coil and you are
putting in a no resister coil. They both need external ballast resistors.
Petronic's makes a coil that will work with electronic ignition with no
ballast resistor. The ballast resistor is to reduce peak current flow
through the points, adding a lot of lifespan to them.

"Short Wave Sportfishing" wrote in message
...
On 20 Dec 2004 16:52:07 -0800, "wtbuck12"
wrote:

~~ snippage ~~

I appreciate all the responses very much. The resistor resistance is
app. 1.2 ohms and running voltage is 8.2 volts. Alternator output is
14.4 volts. The coil is mounted directly to the block and the bracket
seems to be tight and clean, no signs of corrision. I tried install a
higher resistance resistor and dropped the running voltage to 7 volts,
but that made the ign. fire too weak. I have tried using Mopar coils
as well as aftermarket coils with no noticeable differance. Someone
suggested using a HEAVY DUTY coil, where can I buy one and what do I
ask for? This problem certainly has myself, the Dodge dealership and
several local independent mechanics scratching our heads.

Auto parts places can come up with a heavier duty coil. Might want to
try a speed shop also.

BUT.....

I wonder if this is a heat related problem. Based on what you just
posted, it all sounds normal. Which makes me wonder what is breaking
down the insulation (which is what normally happens with a coil).
There is a lot of internal heat in a coil from it's normal
functioning, but perhaps it's located close to a heat source like
exhaust manifold? The only other thing I can think of is that the
coil is inducting a external charge by being located too close to a EM
source - perhaps a generator or something?

Just shots in the dark.

Later,

Tom