I passed on the first couple reports of this problem, thinking it may have been a rare unique faulty part, and maybe not much wrong with the masses. But the reports continue from multiple sources, and some cases of multiple successive failures.

Photo from Lindsay Sampford, Cambridgeshire, UK

On 20 October 2010, Andy Bounsall in Ontario, Canada wrote:
"I had one that did exactly the same thing a year or two ago. I contacted Lucas about it at the time and they seemed quite surprised.

D Sjostrom, in Massachusetts, USA, wrote:
"After my fourth Lucas coil in 12K miles I switched to a Flamethrower with no more issues at 20+K".

Seems like the photo tells most of the story. This is a modern issue (2008-2010) Lucas Sport Coil. The coil is filled with oil. There is a seal ring under the molded plastic top, and the works is crimped together. Perhaps the crimping is faulty, or maybe the oil was over-filled with no air space to allow for thermal expansion. Whatever the cause, it is definitely a manufacturing defect, as there have been a lot of these failures reported.

On the flip side, I have been running a Lucas Sport Coil in my MGA since February 1996 with only one problem (not exploding). The first one lasted 13 months and 23,000 miles, then start arching across the output end. I managed to tape it up enough to get home. I think it had a small crack in the HT tower end. The second one has been in service since March 1997, 13-1/2 years and 140,000 miles to date with no problem.

On 20 October 2010, Andy Bounsall in Ontario, Canada wrote:
"It's the new ones that are failing. I also have a mid-1990's Lucas Sports coil which still functions fine and is now the spare that I carry in my boot.

Steve S in California, USA, wrote: "The Lucas Sport coil I purchased in the early 90's weighs about three times what the current ones do. Quality has surely gone downhill since then. The older Sport coils, made into the 90's, are slightly shorter and fatter than the newer ones and have gold stickers. They seem to last forever unlike their newer replacements. Mine also has a white top but I don't recall if they all did or if they came in black as well".