Oil pressure fluctuating

[rick2116]

Hello all
I have a question about my oil pressure issue I’m having. I have a non turbo Aerovee with 320 hours on the engine. I have a manual oil pressure gauge. I’ve had this set up for about 120 hours. Approximately 3 or so flying hours ago, I noticed the oil pressure fluctuating from 45 psi to 35 psi. Over a min, it will move 5 or 6 times. I’ve changed the guage. I’ve removed, cleaned and made sure the oil bypass valves would move freely with no change. Oil temp doesn’t change during flight. Cruising at 3200 rpm. I’ve contacted Sonex tech and Kerry saying basically there’s nothing he can think of that would cause the oil pressure to do that. I can’t think of anything either. One would think if something was failing, it would cause a low oil pressure. If something was stopped up it would cause a high oil pressure not fluctuating from normal to low then back up to normal. I know I’ll have to do some trouble shooting but not exactly sure where to start. May have to change to a different oil pressure set up. If anyone has any ideas or may have had this happen to them and solved the problem, please let me know. Oh. And yes my oil level is where it should be. My oil cooler is on the bottom.
Thanks,
Rick Owens

[tx_swordguy]

Rick,
I would pull the relief valves again and get some very high grit wet/dry paper from an autobody shop 2000-2500 grit and polish the pistons. Also check for grit in the valve cylinder. I was just working on a revmaster having high psi and had to take the prv out a couple of times until I found a small piece of grit that I think was hanging up against the piston(even though the piston slid fine). get a flashlight and qtip etc and clean the cylinder as well as polishing the piston. I was also having oil fluctuations (on a jab) and poslishing/cleaning the prv fixed it.
Mark

[rick2116]

Mark,
I’ll try that. I didn’t do any polishing just cleaned them up a bit.
Thanks
Rick