• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Coil

Share this page

D

Darrel

Member
Offline
While fiddling in the engine with a carburetor problem, I touched the coil - and nearly burnt my arm! The coil was so hot I could not hold it for more than 2 seconds. I assume this is not normal. I know they get warm, but should not cook. Apart from a faulty coil, could anything else be causing this issue?

Distributor is a Lucas 25D with Lumenition electronic module and the Lumenition coil spec'ed for this setup.

Any advice appreciated.

Thanks!
 
Hi the coil getting hot will not give you the symtoms of every 500 miles having to retune carbs and change plugs ,it will play up giving misfire or non starting everytime you use it and no amount of engine tuning will hide it.It could have overheated if you've had the ignition on for a long time,there are various posts on checking the coil that can be looked at.how you getting on with the carbs?
 
As a quick check, why not fit a set of points (temporarily) along with a standard (parts store generic) 12V coil. If you find the problem goes away, you have choices: fit a new electronic ignition and matching coil, fit a Pertronix ignition and keep the cheap generic coil, or leave the points and cheap coil on.

I've never worked with Lumneition but I have been told that you do need to follow their coil recommendations.
 
The coil was fried. This coil came with a ballast - which I fitted initially. However, she was a real cow to start in the mornings. So on testing it was found that the spark was too weak. So I removed the ballast. This meant that a coil that was menat to get 9V was now getting 12V and it did not like that. The coil had since gone to happy coil hunting grounds. The ignition system in my Mini was not designed to have a ballast. After some research - it seems that when cranking the coil is supplied 12V from the starter relay and reverts to 9V when the engine is running - so bypasses the ballast on cranking. As my car was not designed for a ballast - this was not happening - so on cranking I wass till getting 9V and the spark was too weak. I checked with Lumenition and was told that the module did not need a ballast, only the Lumenition coil if used. So, put in a Bosch hi-energy coil and the problem is solved - a coil that is designed to receive 12V. The coil now gets warm, as expected, not cooking hot.

In response to the fuel issue - a new needle and seat valve cured the problem - so thanks for the help on that one. Has taken some time and some fiddlng - but I have a car that goes well again. :yesnod:
 
For future reference if you want to add a ballast coil, you can do so if you fit all three of these components at the same time: 1) the ballast coil, 2) the ballast resistor, and 3) a 4-terminal solenoid.

The ballast resistor is wired in series between the ignition switch and the connection to coil (+). (Negative ground cars). The 4-terminal solenoid will replace the original 3-terminal one. From the 4th solenoid terminal you run a length of wire to coil (+). This will deliver full system voltage to the coil when operating the starter and drop back to lower voltages during normal running.

The 4-terminal relay was used on some Minis in the U.K. until electronic ignition was added. In the U.S. you can use the solenoid from cars like a Mk4 and early 1500 Spitfire. However, I'm confident if you go to a parts store where the clerks are not computer dependent, you could ask for a 4-terminal solenoid for early 1970s Fords or Chevys and do equally well.
 
Back
Top