oil pressure LOST, and then 24 hours later BACK

[Pete Munroe]

All,

Guessing not enough oil vs. too much here caused pressure drop. Overfilling can create problems...AVIAD is quite wide. Think it takes a relatively more oil to get the level high enough to where you are in the crank windage compared to a overfilled narrow stock type pan...? But, my pan DOES have the fence/scraper removed to accommodate a main bearing support...maybe that created more problems than I thought.

Had pressure gone back normal I was going to add 1 qt...AVIAD has always surprised me as to how much oil it NEEDS to be stable...thought it offered more margin of error. I have to have 8 qts "in the pan" to be stable...thinking I misread the dip stick, actually closer to ~7. Will re-check marks on dip-stick when refilling to make sure which mark 8qt is...drilled 3 holes in dip stick last time, but now second guessing myself which one is 8qts...dumb. Can not find my notes...!

Foaming...last minute on the track drove slow due to the 20 PSI. after parking it sat for 5-10 minutes. Restarted psi still 0. If foaming, how long would to go back to essentially liquid? Oil is Castrol 10-30, fwiw.

On assembly (16,000 miles and 10 years ago) while on the test stand the guys pulled the pan to shim pump to lower pressure. Too high at 100+.

After shimming runs 80 cold, 60-70 hot. At idle 40 cold, 25 hot.

Guessing its a high volume pump (do not think they have gone with high pressure unit). Looked in the Ford engine book by Pat Ganahl and no info on oil pumps other than # M68HV for the high volume pump. Will check that.

A diagram of the relief valve setup would help. Push out a roll pin and remove a spring/piston? Looking for flashing, grooving, to cause it to stick. Especially after unusually high psi pushes it deep it to the passage.

Best guess, relief valve stuck open, bleeding off pressure. After cooling and the trailer ride home for 2 hours, it freed itself.

SO, 24 hours later, all seems normal...cold idle is at 40, psi responds instantly to throttle. Assuming then gauge OK (a SW mechanical).

Have intended to run a ACCUSUMP. The ERA 289 it is hard to put under the hood. Take 5 ft hose to get to the pass footbox. Better sooner than after scoring a crank.

For today...

cut open the filter (should be a flippin' mess), look for debris, check the pan for debris and trap doors free, and pull the pump/screen.

Guys...thanks for the input, any other ideas on oil pressure relief valves, etc welcome. Will get back on what I find asap.

Pete