Here is what I did to get an
oil temp reading in the sump of my 460 crate engine that uses a 14mm x 0.5 thread metric drain plug, yours may vary.
I wanted to avoid removing the sump pan and installing a dedicated weld-in bung which was way too much work since the motor is complete and in the chassis.
I had to use a *onda drain plug (it uses a larger hex head) and uses an aluminum sealing washer.
My "el-cheapo off-shore" electric
oil temp gauge came with a 1/8 NPT- 27 sensor, just the right size for installing it into most drain plugs.
I drilled it (using a lathe) and tapped the 14mm drain plug such that the sensor tip extends past the end of the drain plug about 3mm. Used telfon thread sealant paste to seal the sensor to the tapped drain plug and installed using the AL sealing washer.
Low cost effective and easy solution.
CAUTION this solution is only used to monitor the
oil temps during my intial fire-up and test/tune sessions. The sensor would get ripped out/damaged from the first big pot-hole if left in for everyday use due to inadequate ground clearance.
Later, once I add an oil cooler, I can relocate the sensor into the oil cooler circuit if needed where the sensor is safely up inside the chassis rails.
