no oil pressure on start up

[ty901]

The patient is a 2.7L carb’d w/ pressure fed tensioners & ‘72S cooler system all in a ’66 tub. ‘72S oil console was opened up to accept an OEM case-based thermostat.
Engine built on a used short black of unknown history. seller pulled it from a ‘71 (that I don’t believe he ever drove) to install a 3.6L vario-ram. PO he purchased the car from claimed it was “…blowing oil”.
More recently I posted a question about pre-charging the oil system in preparation for initial startup. Part of that process had about half of the oil in the reservoir draining into the case… a situation that continues.

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1059478-oil-priming-getting-ready-fire-up.html

After a series of brief start ups the oil pressure gauge was not indicating any pressure. Suspecting the used sender, I replaced it with a new unit but still “no soap”. Cracked the cam feed lines… dry. Pulled the OP sender … dry. Oil filter ? you guessed it… dry.
I’ve read through the Ultimate Oil Pressure Relief Valve thread and a few others relating to no oil pressure. Pretty sure there are no blockages in the lines between the reservoir and the case or cooler. I’ve triple checked the orientation of the hoses at the ‘72S thermostat. I don’t recall addressing the pressure relief and / or safety valves, but I’m guessing that I at least refreshed both seals.
Input appreciated.

[stownsen914]

Oil filter is on the scavenge side, so it may be OK that it's dry at this point.

You mention about half of the oil from the reservoir getting into the sump. I assume reservoir = oil tank? (Just confirming you aren't referring to some other reservoir you used for pre-charging the oil system.)

So there is oil in the feed hose that connects at the bottom of the oil cooler? You're sure there are no blockages in that hose (like a rag or paper towel stuffed in there to cover it when the engine was out)?

[ty901]

yes, reservoir = tank.
if I loosen the nut on the hose going to the cooler there is oil... not a lot... coming from the cooler not the hose.
this hose comes from the '72S thermostat.

[stownsen914]

Hmmm, the hose that attaches to the bottom of the cooler is the main oil feed to the engine. It's gravity fed from the tank, so should always be full of oil. There should not be anything between the tank and the nipple / feed line on the bottom of the cooler. You mention it's routed from a thermostat?

[stownsen914]

Here's a diagram from an old Grady Clay post. The file name suggests it's for a '72. Not sure if that's true, but the oil feed should be the same either way. The on-engine oil cooler is "2" in the diagram. Note the other end of the feed hose attaching to the bottom of the tank.

[ty901]

after studying the engine side of the plumbing I now see the issue. I have the hoses that connect the engine to the rest of the system reversed.
so... time to make up 2 new hoses & all should be well with the world.
I shot myself in the foot (once again) by selling off all my "spare" fittings so hopefully I can rustle up the 2 (or 3 ) ends I need.
damn... if I was a plumber my house would be pretty smelly
thanks for the help!

[winders]

How long did you run it with the engine oil lines reversed (engine getting no oil)?

[ty901]

hose from the pump line up to the thermostat / console rerouted with the reusable fitting.
sorting the other path will be a bit of a chore, but doable.

[ty901]

@Winders ... a few short blasts and one less than 10 seconds. I'm hoping I didn't cook anything in the lower end.

[ty901]

this is the image where the light finally went on;

[jpnovak]

Yes, Hardline 32 comes straight across from the bottom of the tank. It is connected to the oil cooler with an S hose and to the tank with a short hose. Basically, gravity does a lot of the work for you. BTW, most of the oil will just drain into the engine sump.

Here is my 72 oil system pic.