A Gen2 oil pump is a crescent design with vanes on the gear and a spring on the crescent lever. The crescent has 2 modes. The system operates in "high oil pressure mode" most of the time. and when the engine is fully up to temp and at idle or very light load it decides to save fuel... the ECM sends a 12V signal that switches the solenoid to rotate the crescent mechanism into "low oil pressure mode". This is to reduce pumping losses and improve fuel consumption. If the +12V signal wire or solenoid are damaged / not functioning, the oil pump has a spring on the crescent lever so it will stay in high oil pressure mode.
Is the Melling M390HV Oil Pump really an upgrade? I've heard of people using it, but don't know if it offers more than just more oil pressure. Or I should say, I've not heard if the design itself is more robust or just a spring pressure change.
-> Have you truly heard of people using the M390HV on a Gen2 Raptor engine?? I can not find any evidence of this although it seems like it may be "an upgrade" in that it removes the solenoid and the crescent/vane pack. I plan to spend time on trying this over the next couple of weeks. I have oil-pickup and p06da mil questions for anyone thats actually tried it already! here is my understanding:
1/ The M390HV is Melling's $150 pump for Ford's Generation 1 3.5L Ecoboost and comes with an overly stiff spring rate installed. They also supply a softer spring rate that IMO should be utilized in all 3.5L installations This is an interesting pump because it uses a traditional Gerotor oil pump design and a simple pressure relief. I consider it to be reliable and simple. Is the gear the same powder metal as Ford OEM? (I think so). I may have some spare pumps to sacrifice for science
2/ The M490 is Melling's $350 pump for Ford's Gen 2 and Gen3 3.5L Ecoboost. Melling claims to upgrade the M490 to a stainless steel gear, I doubt that and will confirm my suspicions shortly. From what Ive seen the Melling is quite literally the identical tooling casting as OEM ford, but with the fomoco logos removed with a grinder. you can see the grinder marks in their photos below.
Overall, the bolt pattern appears to be similar. I will take some measurements this weekend when i have a little more time
