Finally got around to installing an electronic pressure sender. Little bit of an endeavor on this car that requires taking off the intake to access the front of the block. Also took the opportunity to inspect intake valves, as well as the PCV hoses and oil separator. See this thread for that discussion: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4802182/1
Because I didn't want to add more points of failure or leaks by using a T fitting, I completely removed the factory oil pressure switch. It was the classic idiot light switch set for around 6 to 8 psi. If the warning light ever illuminated while driving, the engine would already be dead. Sensor threads were M14x1.5, requiring use of an adapter to fit the sensor's 1/8 NPT threads. I used a high temperature thread sealant suitable for exposure to hot oil.
Because I ran the sensor through my Arduino data logger and gauge screen, I could make a little circuit to allow the Arduino to switch the oil pressure warning light. I used two setpoints, with a steady light to indicate oil pressure caution and flashing light to indicate oil pressure warning.
Once I had everything back together, I found some very encouraging signs when I started it back up. Oil pressure comes up very quickly - by the time the engine fires pressure was already climbing past 40 psi. 84 psi of oil pressure at cold idle, and 22 psi at hot idle in gear with oil temp at 100C / 212F. Minimum spec for hot idle at 100 C is apparently 14 psi on this engine. By 2000 rpm, oil pressure is around 40 psi, and nearly 70 psi by 3000 rpm. Minimum spec at 4000 rpm is 50 psi. Overall looks like pump and bearing clearances are quite healthy. Data log graphs coming soon when I have time to process them.
I think I'll set the caution to illuminate at 20 psi and the warning flash at 15 psi. At least will give the engine a fighting chance if there's a sudden leak on the highway and I somehow fail to keep track of the number on the gauge dropping.
Vacuum is low in this pic because engine is cold and the AC is on. Warm engine in neutral without AC shows around 21 inHg.
Because I didn't want to add more points of failure or leaks by using a T fitting, I completely removed the factory oil pressure switch. It was the classic idiot light switch set for around 6 to 8 psi. If the warning light ever illuminated while driving, the engine would already be dead. Sensor threads were M14x1.5, requiring use of an adapter to fit the sensor's 1/8 NPT threads. I used a high temperature thread sealant suitable for exposure to hot oil.
Because I ran the sensor through my Arduino data logger and gauge screen, I could make a little circuit to allow the Arduino to switch the oil pressure warning light. I used two setpoints, with a steady light to indicate oil pressure caution and flashing light to indicate oil pressure warning.
Once I had everything back together, I found some very encouraging signs when I started it back up. Oil pressure comes up very quickly - by the time the engine fires pressure was already climbing past 40 psi. 84 psi of oil pressure at cold idle, and 22 psi at hot idle in gear with oil temp at 100C / 212F. Minimum spec for hot idle at 100 C is apparently 14 psi on this engine. By 2000 rpm, oil pressure is around 40 psi, and nearly 70 psi by 3000 rpm. Minimum spec at 4000 rpm is 50 psi. Overall looks like pump and bearing clearances are quite healthy. Data log graphs coming soon when I have time to process them.
I think I'll set the caution to illuminate at 20 psi and the warning flash at 15 psi. At least will give the engine a fighting chance if there's a sudden leak on the highway and I somehow fail to keep track of the number on the gauge dropping.
Vacuum is low in this pic because engine is cold and the AC is on. Warm engine in neutral without AC shows around 21 inHg.