Coil information

[Rod C]

Need some advice on the coil in my 1980 924 turbo. Car came with the inner contents of the coil exploded all over the engine bay so my question is does the turbo use the same coil as a N/A engine and what would cause a coil to get that hot that it boils and explodes?

Thanks in advance.

[Peter M]

Rod,

In the absence of any experts speaking up could I suggest that the coil could overheat and burst from being powered up continuously for a long long time. 

This could occur from a wiring fault such as the ballast resistor being shorted or jumped maybe the ignition switch being left on for a long period while the distributor points being closed maybe?  I'd suggest you use a voltmeter just to establish when the coil is powered up and when it is not just to check all is well with the wiring.

Alternatively and much more likely it could have been just old age causing the insulation in the coil windings to break down and short causing the overheating and failure.

As for coil types, I would think they would be the same but if you check the PET parts manual - downloadable from the Classic Porsche website - for that model, you will be able to compare part numbers between the NA and the turbo. 

I reckon you should be able to source a suitable replacement coil from Repco reasonably cheaply.

 

Good luck with it all.

[Buchanan Automotive]

924 & 924 Turbo >  1980     =   046 905 105

924 Turbo   1981 >              = 211 905 115 B  ( Siemens digital ignition system )

[Peter M]

There you go!  The facts from someone who has hands on experience!  Thanks Bruce.

[tazzieman]

The old coils have cooling oil that can leak out. Not sure if early 924s did , but early Boschs in Benzes fail. Beware the sloshy sounding coil!

When yours burst , was it an oily mess?

[Rod C]

Thanks guys for your imput it is very much appreciated.

Tazzieman the car was like it when I purchased it and the hood must have been up when it exploded as there is hard black goo splattered over the engine bay and on the front section of the body.The owner was 85 yrs old and abit of a tinkerer and as a result there is a mysterious blue wire running from the positive terminal on the coil and goes back to the ignition barrel where it has been spliced in so Im wondering if this maybe the culprit!

As suggested time to get the multimetre out and check a few wires.

[Redracn]

Sounds like he bypassed the ballast resistor. Probably to get a better spark. Not a good move as with points and early transistor system you had to have a ballast resistor either an external one or built into the coil.