Hello glow plug experts. Here's the thing. I've got a series 111 converted to a 15J probably from a FX-4 taxi. Checking the glow plugs because of longer starting and find - three of one type and one of another! The three are really old by the look of them, no markings visible, one has failed, one looks cracked and the other has a scar. The fourth one, in cylinder 2 from the front is a Champion CH63, the normal fit for a 2.5 N/A. However, this type won't go in the other cylinders! The ones that do have a narrower probe that is knotched. I'm wondering if they are CAV originals. I'm searching around for replacements but the "specialists" seem to have never heard of a 15J. Anyone out there hit this problem before?