Bubbles in, and gurgling sounds from the oil

[MikJac]

Hello, I need some advice about a 3.5-litre engine, as I have no experience with these engines myself.
I’ve bought a rebuilt Rover 3.5L V8. It’s now installed in my car, but I have a few questions about the engine’s lubrication system.
Before first start-up, I packed the oil pump with petroleum jelly and spun it using a drill through the distributor hole. The engine builds oil pressure, but there’s also a gurgling/bubbling sound, as if the pump is drawing in air. At the rocker arms, you can also see bubbles in the oil. The bubbling noise continues for a few seconds after I stop spinning the pump. (Spun the pump at 500 rpm -> 30 psi after a few seconds, ran the pump for about three minutes, but there was no difference... the bubbling continued)
I’ve removed the sump and checked the pickup screen, pickup tube, and the gasket between the tube and the block. I’ve replaced the oil pump gasket and checked the mating surfaces. I packed the pump with petroleum jelly again, but I get the same result.
Those of you who have experience with these engines— is this normal? what could be causing this, and what should I do?

 

[harveyp6]

Only other place that the suction side of the oil pump can draw air apart from all you have checked already is the timing case gasket. It's rare but it can happen.

 

[MikJac]

Hi!
But is this a problem, or does this usually happen when you spin the pump through the distributor hole?
If I run the engine with the starter motor, the same problem does not occur. But I can't get the oil pressure up either...

 

[jp928]

Distributor not properly connected to the oil pump drive? The Oring on the dizzy can be hard to get into the hole....

 

[Gargo]

Hi!
But is this a problem, or does this usually happen when you spin the pump through the distributor hole?
If I run the engine with the starter motor, the same problem does not occur. But I can't get the oil pressure up either...

I'll answer the 2nd first; I've always got a smooth flow (no bubbles) when spinning the pump via the dizzy hole.

Is it a problem? Personally I'd be happy to run the engine with no load (don't drive fast), until I was rid of the bubbles. As long as you have oil flow the engine should be lubricated OK for no load.
As Harvey suggested a leak in the suction side of the oil pump system from the timing case gasket or the pickup tube itself etc. will result in air in the pressurized oil.