Mysterious drop in oil pressure

[chepsk8]

I've got a problem I have not seen here before.

I pulled my stock 5.0 out over the winter to fix my car after the crash. The only motor work was to sleeve the rear of the crank, and tighten/re-seal the rear oil galley plugs (one was seeping). The car had a bad oil leak from the rear, it was the crank & seal. I also run an oil cooler using the sandwich adapter inbetween the filter & the block. I also replaced the oil pump a few years ago with a high-volume pump, as the motor has alot of miles, so I wanted alot of oil running through it. I also did head gaskets last summer, the P/S had a chunk out.

I put in fresh 20-50, since I race the car, and started driving it. Tons of oil pressure when cold, 80+ at start, and it gradually drops off as it warms up. Once hot, I run 15 psi (mechanical gauage) at idle, and it tops out at about 40-45 at full revs. Last year I had 25 or more at idle,and 55-60 at speed.

Any ideas on this year's loss of pressure? When out, could something have shifted internally? Or must I face the music and just admit this motor is very loose? If you have had this experience, did your motor live for a while?

Many Thanks for your input!

 

[DMAN302]

Type of filter? Try replacing first if all the standard items of the check list come back ok....things like checking gauge and sender for issues. I have 'heard' a bad filter can cause issues with pressure. Was the pan damaged at all?

 

[chepsk8]

Pan is un-damaged, though it is a canton racing pan. Could a pick-up too low in the pan, or hitting the bottom cause this? I have a mechanical guage, and am wondering if I need to burp it? I'll change the filter.

 

[JimBowy]

Although 15psi hot idle isn't great, its just at the bottom of the acceptable Ford hot idle oil pressure limits. As long as your pressure doesn't drop much more the engine will be fine. At idle the engine requires very little oil pressure to keep everything properly lubricated.

 

[DMAN302]

BUT running 20w50 weight..I'd want to see more pressure at hot idle..at least 25 IMO.