coil blowing up

Hi all I havn't been on for a while although I am still working on my austin k8 so far Ive done all the sheet metal work on the body made up a lot of panels inside the cab. Now im trying to get the motor going on petrol { instead of aerostart ] the problem I have is the other day I had the k8 hooked up to my hilux [ jumper leads ] for about 20 minutes trying to get the electric fuel pump to get fuel up to the motor and starting it a few times on areo start and the top half blew off the coil I was hoping someone could explain why thanks in advance cheers geoff

Voltage of coil ????

no it was brought from the british parts importer at mulgrave about 4 months ago

...ignition switch turned on, but engine not running.....That'll do it ol' mate

As above, oil filled coils don't like sitting around for long with the ignition on with no engine running. Make sure you have the correct voltage coil for the ignition system. Continuously pumping 12 volts through a 7.2 volt points ignition coil will end its life quickly.

...it's all to do with the points being shut whilst the ignition is on...it's not always that situation will occur, but when it happens the coil just can't handle it...

...can anyone give a proper scientific reason for this.....??

With the ignition on and the points closed there would be a constant current/amps flowing through the coil. As a coil is only designed to have current flow for short durations rather than a constant current, excessive heat is generated causing the coil to blow up if left long enough. There is a formula for heat and current over a certain duration. Hope this helps.

thanks for your replys fellas we are just using an original button [ignition ] to turn over the starter motor which I was doing on a regular basis wilst checking that the starter motor wasnt getting hot. By the way I just have the motor sitting in the chassis so it is not wired up properly it is just wired up enoough too get it started and run for a bit thanks again geoff

...they wont just blow up for no reason..something must've been a bit awry ??

...Is the Hi Lux 24 volt ?

If it's the round style canister coil it will be oil filled. There is usually a relief hole which may have failed. The coil gets hot, the oil expands and it needs somewhere to go.