Kiene Valve Threads and Pressure Sensors

APPLICATION NOTES

If only I had a bigger wrench...
Indicator ports for engines and compressors are made by Kiene Detroit Diesel in Addison Illinois. These are standard indicator port valves common on almost every engine and compressor around the world today. They come in several shapes and sizes to fit the application. One thing in common on all these valves is the 1-1/4 10 British Whitworth thread for the pressure sensor attachment.

A common complaint heard is "The pressure sensor will not go on, the nut is too small" or "If only I had a bigger wrench, I might be able to get the sensor off". The problem is two fold.

First, the indicator valves have had two versions of the thread, one with peaked threads and one with rounded threads. Somewhere around the late 50's the style changed. So pre 195X the threads were peaked. This gives a tighter feel to the nut being placed on the indicator port and making it harder to get off once hot.

Second, the indicator port threads, over time have become corroded and/or painted to the point of clogging the thread where it is hard to thread the pressure sensor nut onto the valve.

The solution to both issues is to run a die (shown below) over the threads prior to placing the pressure sensor on the valve. This may need to be done once or possibly every time depending on the time between uses. Some plants paint on a regular basis or corrosion occurs over the time span.

Nu Thread Die

Windrock always purchases the nut and plug assembly from Kiene Detroit Diesel to assure uniformity in the material used. Kiene assures us that the material used will fit the indicator valves they sell to the OEM's and end users for their machines.