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What is your opinion? Which do you find/hear/know to be more accurate?
Reason: my new 408 has an undetermined oil pressure.
My two electric gauges say that the pressure is ~8 PSI at warm idle (800 rpm), and ~35 PSI max at 2k rpm ish. Gauges are-new Autometer electric with matched sensor, and old Equus electric with matching sensor...both read within ~2 PSI of eachother.
My new Equus mechanical oil pressure gauge says that the ~8 PSI mark on the electric gauges is actually 19-20 PSI, and that the ~35 PSI mark on the electric gauges is actually 40 PSI. (I tested this after I removed the motor again, while using a drill to prime/drive the oil pump...actual max pressure is unknown using mechanical gauge)
These pressures are measured using a Melling M83, standard volume pump.I'm probably going to put an HV pump in it as my clearances are on the loose end of OK with new bearings. I'm also going to use my new mechanical oil pressure tester I bought to check things. And lastly I'm going to check the accuracy of the mechanical ones as best as I can via metered air pressure.
I am old school and tend to trust mechanical guages more, but if you have two electric gauges reading whithin 2psi, I would tend to side with the electric gauges. There are situations where electric gauges will vary, mainly at high temps, so I always install my mechanical gauge and take those numbers as my baseline.
Life is hard, it's harder if your stupid.
Final results point to the motor not being any good.
Hot at 160*, where I keep it, it will idle at 13 psi with a known working/accurate mechanical gauge. Max pressure is 35.
Cold it started out at 45 psi. Within 10 minutes it was down to 17 psi at idle. After a 3/4 mile drive it was down to 13 at idle, and 35 psi under a load @ ~3,000 rpm...so I parked it.
The pressures are measured while using a new Melling M83HV, high volume, oil pump. The oil is Rotella 15w40.
Don't know what happened when the machine shop put it together...but they missed something. Now I don't have anymore time to work on it. Heck, I've put in over 50-60 hours in the car this week over spring break...just working on the motor. Now it looks like this is the final result. The dang machine shop has goofed this deal up from the start when the motor was dropped off. I let their reputation sway me into thinking they would do a good job. I should have just put it together myself.
Yeah, I'm pretty bummed myself. The pressure just kept dropping and dropping, so I don't trust it a bit. I'm taking the car off the insurance policy for a while now...I don't have time to work on it much now that spring break is over. Not sure what will happen with the motor.
I'll probably leave it in long enough for me to move the car around and out of my way.
Mine has a cheap Mech one installed on it from the PO, I hate them because the oil like has to run to the gauge & if it springs a leak it can be so messy..
Prosport offers good quality & reasonable priced gauges. I highly recommend them. I used them on my DSM cars without any issues at all. It is what I will be converting over to myself in the near future.