Leakage at plug in cylinder #4 - '40
 

When I bought my '40 2 years ago.....the car had sat around a number of years and not really driven much. The engine was rebuilt in 1987. When I started driving it....I started to have some leakage at the #4 plug. I would spray some cleaner on it and wipe it away. It just dawned on me that this year there's no leakage ! Anyone have an idea of what was causing it in the first place ?

Thx...Mike