Chas
Measured my
oil level in the pan and compared to your measurements.
My full mark and
oil level is 1/8" higher than your 7 qt level. I am using a Canton 810 pan - 8 qt system so the pan is designed for 7 qts, which I used and measured for my dipstick mark when I built the engine.
At approx 1qt low (6 qts), my
oil level is approx 1/4" lower than yours. Size of reservoirs would account for this differential.
At that lower level, the probe is still in the oil and I get temperature indication. The probe is 1 5/8" long from its sealing point to the end of the bulb. Assume the engine retains two quarts when running, with the oil level "one quart low" there would still be four quarts in the sump and that level is approximately half way up the probe. Maybe windage would move the oil from that area but I still think the tip of the probe would be submerged in oil.
The only thing I can come up with is my assumptions are incorrect. Either the block has more oil in circulation, thereby exposing the probe or the windage creates a void in this rear corner.
I think my only alternative is to put the probe into the oil stream as it moves to the remote filter. At least there, it would always be submerged.
May have to put this project on hold till I can finish some others and get the car down off the stands.
Paul