Guys, i have an EAA biplane with an o320 a3b i believe is the model number. It was rebuilt around 2000 when the plane was built. I bought it 2 ish years ago and it has always had warmish hot oil temps of 215-220 and relatively high oil pressure at cruise. The builder had red line psi at 90 and it would routinely stay at or slightly below 90 during cruise. He also had an inverted oil assembly installed. I just recently put the oil system back to stock and bypassed the inverted stuff because eventually I will remove the engine for use in a fokker triplane I am building. After removing the inverted stuff I am seeing psi of 110 in cruise. I removed the short bodied non adjustable oil pressure relief valve, cleaned it and took out the only washer in the valve. As expected it dropped my psi by about 5. Not enough so I ordered a second crush washer to try in addition to the one on there for a little more drop. The actual spacer for it is $170. The spring appeared to have a purple marking coating. My question is are there different compression springs available and how do I go about finding what the strengths are. All the parts houses list lycoming part numbers and no other info. No length or strength of compression. There is an adjustable valve that does not come with a spring $215. Not sure if my current spring would work on that or not. I just bought an oil psi test gauge to verify the plane gauge is accurate. I have not tested it yet. In current configuration it hits 90 psi at about 1700-1800 rpm. Any advice would be appreciated. Only flew it for about 10 min this way to see if heated oil would bring psi down. It did not appreciably reduce the psi and I didn’t want to damage the engine with excessive oil psi.
Mark
Mark
