Beetle Coil Failure

[bus71]

The bug lost power, but still ran however. The coil was very hot compared to the engine, too hot to touch. Points looked fine. I put the spare coil on, and it ran fine. The bad blue coil was a Bosch, made in Portugal, marked #932 547. I don't know the age of this coil. I checked it with my vom and it reads o.k. However, it was cooled off by then. Ratwell mentions avoiding coils that "slosh", this one does. I thought blue coils were epoxy filled. I now have a black, short coil for a spare. Anyone have any thoughts on this? Thanks!

[Amskeptic]

The bug lost power, but still ran however. The coil was very hot compared to the engine, too hot to touch. Points looked fine. I put the spare coil on, and it ran fine. The bad blue coil was a Bosch, made in Portugal, marked #932 547. I don't know the age of this coil. I checked it with my vom and it reads o.k. However, it was cooled off by then. Ratwell mentions avoiding coils that "slosh", this one does. I thought blue coils were epoxy filled. I now have a black, short coil for a spare. Anyone have any thoughts on this? Thanks!

The advance of coil technology was from oil-filled to epoxy, and most new VW coils are the epoxy blue Bosch jobs. But perhaps you have a weird one there. The heat sounds like a winding short where you still have current flow through the coil, but the insulation between adjacent windings has broken down. You get less magnetic field and more current-induced heat.
Colin

[bus71]

Thanks for the replies. The only other problem I had with a coil was one that started to leak on a very hot day. I also found another coil like the one that failed in my parts stash. It is identical. Most of my parts date back at least 20 years. Maybe that explains the oil. Shorted windings makes sense to me.