Oil pressure on 454s

Here it goes again, last time it took out all the mains and rod bearings. Rebuilt it now engine running good, then here it goes again. The alarm goes off, look down, no oil pressure. What am I missing, is there a pressure relief valve that`s bad

Not sure, but I'd take off the distributor and drive the oil pump using the drill/drive shaft technique. Find out if the pressure builds up normally. What was done at the last rebuild besides the bearing work? Was a problem found? A sudden, total loss of oil pressure is usually due to a broken oil drive coupler. The stock ones are plastic. Another possibility is the oil pump pick-up fell off. They should be spot brazed on to the pump.

This is the second time around, First time it took out all the main and rod bearings, I had it rebuilt , crank 20/30 under, rods reconditioned, line board, new pistons, rings, cam/bearings/lifters, new oil pump, heads done and new oil pressure sender and manul gauge , Only ran it for an half hour and its doing it again. Go down and oil level is good. No oil leaks. Start it back up, runs good, good oil pressure and then does it again.I don`t want to wipe out the crank again. Yes it has a pressure alarm and it works and goes off when the drops to O..

So, the engine went thru a total rebuild, and no defect was apparently discovered. This is interesting. OK, exactly how much oil is in the engine? Does it use the "standard" Crusader remote oil filter? How old is that oil hose?

We can safely now exclude the oil pickup falling off, probably the drive rod, and the oil pressure relief is new with the new oil pump. Were the engine block oil gallery pipe plugs removed and cleaned out with at least compressed air during the rebuild?

this first half hour of run is at about 1800 to 2000 rpm, correct? It goes into a no pressure situation, you shut down, restart, it comes up to pressure, and then at some odd time later, it repeats this? Was the old oil pump pickup reused? It's like a piece of debris is floating around in a very bad place.

Sender, low pressure switch, and gauge installed in the galley plugs of the block, right above the oil pan?

OK it took out all the rod bearings, mains look runable, So that`s 2 times won`t be a third, just got 2 low hour 454`s ,

Doug:

did you have the block checked before the most recent rebuild?

Yea, but what`s eating at me is I didn`t blow out the oil passages in the crank when I got it back from the shop. If that`s what did it , Ok live and learn, and don`t get in a big rush. Anyway I have the new motor in and it`s running great, Got next week off and I`m going fishing. ;<}