Hey Roger, interesting, did these aircraft also lose oil pressure the higher they climb? It's consistent how I lose pressure about 1-2 psi every 1000'. Yesterday I replaced all my oil lines with stiffer line (AER FBN0800) as well as the thermostat to a P6-H-205. I now have better oil pressure at high altitude, I always have good pressure on the ground or low altitude but lose pressure the higher I climb, ground level its 50, 1000' - 45psi, 10,000' -33psi, 15,000' 25psi, these numbers are from today after flying the new oil lines. I had 23psi at 10,000' before this. I found many zip ties were crimping the lines, they were installed way too tight from factory. I might consider trying a radiator with built in thermostat, this would reduce oil lines significantly, but still doesn't make sense how I lose pressure the higher I climb, not to this extent at least. Again when I go to idle or low rpm at high altitude my oil pressure instantly increase to good values 45-50 but drops as soon as rpm is set to cruise.
