worf928

If the o-ring at the top of the oil pick-up tube is dislodged, faulty, or the wrong part, you will get the exact symptoms described. Guess how I know?

Frank? History of the oil pan gasket? Recently changed?

Dr Bob, lets assume that one has the oil-check valve components in hand: plug, spring, ball. How do you know if they're 'good' or not? How do you test the valve to make sure it's doing its job?

dr bob

The missing component in your hand is the dirt/varnish/whatever that might prevent the ball from seating perfectly with only the pressure of the spring and the weight of the column of oil providing the seating pressure. If the ball isn't damaged and the seat is intact with no scoring, it really takes minimal spring pressure to get a seal. To much spring pressure means that oil won't flow forward at all until pump pressure exceeds spring pressure. So go easy on added spring pressure.

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As others mention, good filters now include a rubber-flap anti-drainback valve arrangement. You can see the rubber when you look through the outer ports on the top of the filter. A leaking or missing anti-drainback valve will allow about 30% (SWAG based on angle of the filter)of the filter contents to drain back directly from the filter, plus any oil sitting higher than the filter including the stuff in the external cooler.

That brings up another point, the oil thermostat/pressure bypass regulator. Normally a cold engine allows oil to bypass the external cooler for earlier flow to the engine and for faster warm-up. If that valve/regulator is sticking, it might take a while to get oil flowing around through the cold cooler, and back to the sender and switch.


I guess I'd change the filter first just 'cuz it's cheap and easy.

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I had a F-car (the Italian type, not a ford and loosely related to the other Italian F-car, the Fiat...) that used a pair of spin-on filters standing vertically on top of the engine. Better than the two removable elements in previous models. The filter was the same size and threads as the one used on the American F-cars, ie: Fram PH-8A, Motorcraft FL-1, etc. The difference was the anti-drainback valve incorporated in the end. Fram made the PH-2850 for this application, for about 4x the price of the same filter sans rubber valve. I'll take two per oil change, please. Without the valves, a couple quarts of oil would bleed back down through the pump, and starting from cold would be an ordeal until the filters filled and the pressure rose enough to feed the crank. Solid lifter buckets so no top end rattle anyway. Use the right filter and the problems disappeared.

FCSFrank

Thanks for all of the suggestions - Worf - no new pan gasket.
Oil filter - There has always been instant oil pressure in the past? Filters from Pelican Parts?
Dr. Bob - Oil check valve - okay - Now your scaring me.

Thanks
Frank
91S4

WallyP

dr. bob said
"I had a F-car (the Italian type, not a ford and loosely related to the other Italian F-car, the Fiat...) that used a pair of spin-on filters standing vertically on top of the engine. Better than the two removable elements in previous models. The filter was the same size and threads as the one used on the American F-cars, ie: Fram PH-8A, Motorcraft FL-1, etc. The difference was the anti-drainback valve incorporated in the end. Fram made the PH-2850 for this application, for about 4x the price of the same filter sans rubber valve. I'll take two per oil change, please. Without the valves, a couple quarts of oil would bleed back down through the pump, and starting from cold would be an ordeal until the filters filled and the pressure rose enough to feed the crank. Solid lifter buckets so no top end rattle anyway. Use the right filter and the problems disappeared."

And if you use the cheap filters, the really high oil pressure on start-up of a cold engine can blow an oil filter apart, making an incredible mess on the wrinkle finish.

worf928

Whenever I've got cam covers off, I pull the check valve components, check for crud, and inspect the seat with an inspection mirror. I've yet to find seats that didn't look just fine in the inspection mirror. I've yet to pull a ball that isn't bright shiny silver. I haven't found a spring that isn't springy. I'm left wondering if I'm just wasting my time. Hence why I asked about a positive (or negative) method of actually testing the function of the valve. I really like testing things that are deep before putting everything back together.