Champion spark plugs 18mm

[Rogerpugs]

Hi does anyone know the difference between Champion D16 and D16J spark plugs?
Many thanks 
Roger Pugsley

[Tony Press]

All the references seem to indicate they are basically the same.

[Russlin]

Champion D 16 spark plugs are pre gapped at .025" (0.64mm), installed height 2.34". New Champion number is 516.

Champion D 16 J plugs are pre gapped at .030" (0.78mm)' installed height 2.25". Champion number is 564.

Both spark plugs are classified as Champion Agricultural Plugs.

The differences may relate to specific engines for which the plugs are designed.

[John Cornforth]

Hi

The only difference I can find is that the D16 (516) is pre-gapped at 0.025 inch and the D16J (564) is pre-gapped at 0.03 inch. I guess if you have a factory making thousands of engines it saves valuable time to be able to just screw them in without tweaking the gap.

[Rogerpugs]

Many thanks Tony Russ and John
Much appreciated
best regards
Roger