Oil pressure idiot light sender thread pitch and size?

1/8 NPT "National pipe thread'is most common on sensors and switches.

BSP "British standard pipe"is what gets mixed up with our standard JIC flare fittings on hose ends, the thread pitch is real close and will thread together but the angle of the flare is a few degrees different they will seal together but need to be tightened up more and will generally start rolling the threads a bit.

At the mine i work at we see this all the time with hitachi / John Deere equipment we run, seems the Japanese love the British standard fittings.

Here is some technical reading for those who may find it interesting.

http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

http://www.engineeringtoolbox.com/iso-threads-d_752.html

NPT threads may look similar to ISO 7/1 threads. However, ISO and NPT threads should not be mixed. ISO threads have 55o taper angle versus 60o for NPT. The NPT root and crest configurations are also different from ISO. For ISO threads pitch is usually measured in millimeters (may be expressed in Inch). The pitch are different.