July 16th/17th - Coil/King Lead Modification

Over recent weeks, the Jeep engine hasn't been quite right, sometimes running a bit rough and down on power. I wondered whether the cylinder head gasket was failing again or whether the valves needed adjusting. All the plugs were a bit sooty, the front two more so than the others. A compression test showed the cylinder pressures all ok, though the front two were a little lower than the rear two. The valve cover came off and the valve clearances adjusted.

The French Solex carburetor mixture can't be adjusted. It's not designed to be adjusted, presumably so soldiers in the field don't mess around with it, so why did it appear the engine was running rich? A poor combustion would do it, but what would cause poor combustion? All the plugs were fairly new and the leads tight on the plugs and also tight into the distributor. The king lead from the distributor was also ok, but then I realised that it was loose in the coil.

On removal, I found the coil socket and lead were all covered in carbon. It wouldn't firmly click into place and it was just the friction of the rubber cap holding it in, but obviously not making firm contact, hence the arcing in the end of the coil. It was all cleaned out and put back together with a drop of glue on the rubber cap, holding it onto the lead.

A test drive to get some fuel, showed the engine running fine and with perhaps a bit more pull than before. So the problem seemed to have been fixed, but how to stop the lead creeping back out.

The following day, I made a composite glass/ply/glass bar that slotted over the king lead. Two springs from the bar, attached to holes in the coil bracket, pull this bar with a little downward pressure to maintain positive contact of the lead into the coil. I may yet paint this black, but will eave it alone for now for further testing.