272 oil pump prime

I did all that, but will the pump draw oil from the pan with the pump dry from being installed dry or should I pack the pump with grease or try to fill it with oil? It's difficult to install into the block and the fill tube at the same time keeping the hex drive in place!
 
I'd fill it with oil, 90 wt gear oil. If dry it will eventually pick up oil from the pan but it cold take 30+ seconds. The small amount of gear oil won't hurt anything in the engine.
 
Yes, counter clockwise (or anti-clockwise if you prefer). Remove the valve covers and spin the pump until you see oil at the rockers.
 
Yeah I was turning counter clockwise with the valve covers off, but the pump was spinning but not picking up oil, I double checked the hex rod was installed correctly. I just figured it didn't have the power to pull oil from the pan when dry. So, Vaseline won't cause a problem in the engine even after changing the oil? What is the nut with the plunger and spring do on the pump? Is that an adjustment?
 
No problem with Vaseline, it will just dissolve when the pump starts pumping oil. The nut w/plunger and spring is the pressure relief valve. It is not an adjustment.
 
I've primed a couple of Y's just using a socket and speed wrench connected to the drive rod. Put down the distributor hole. 1/4 " deep socket, 1/4 drive (need a slim socket). Tape the socket to the speed wrench. Turn counter clock wise. You will feel the drag when it starts pumping
 
well that didn't work either, no oil up top. I'm going to remove the rocker shafts and try to blow some air either down the oil galleries or up from the oil filter tube. Will a hanger or other type of object fit down the oil gallery under the rocker shaft to loosen up any debris? Happy Easter!
 
A hanger will fit depending on what gauge wire it is, but the problem is the oil passages to the rockers aren't a straight shot to the center cam bearing. They make a dogleg under the heads about 1 1/2" long. If you can find a brass bristle rifle bore brush small enough and flexible enough you might be able to work it into the slots in the heads but it won't make the bend down to the cam bearing. Unless the passages are completely plugged blowing air down them won't tell you much, been there, done that. Best to pull the heads and inspect. Also spin the pump with the heads off to see how much, if any, oil comes up from the center cam bearing. The worst case scenario is you have a grooved cam bearing with soft babbit that has restricted the groove. Best case scenario is the rocker shafts are plugged with sludge, easy to fix by complete disassembly and cleaning them out.
 
JSRTUDOR said:
well that didn't work either, no oil up top. I'm going to remove the rocker shafts and try to blow some air either down the oil galleries or up from the oil filter tube. Will a hanger or other type of object fit down the oil gallery under the rocker shaft to loosen up any debris? Happy Easter!
Click to expand...
How much work has been done on this engine? Is it well-used or rebuilt?

Has the rubber sleeve on the pickup tube into the oil pump been replaced?
If not, or if it was over tightened, it may be sucking air. (last photo)

You can remove the oil pressure sensor and spin the pump or crank the engine over to see if you're getting oil out of the pump. With the sensor out of the block the pump will also have a better chance at picking up oil.

Blowing high pressure air into the oil supply holes under the rocker stands may force debris into the center cam bearing.

The oil passages down thru the heads each make a 90 degree turn at the head gasket, with a shallow groove in each head. Then another 90 degree turn down into the block. The flow of oil can easily be blocked at these small turns around the head gaskets.
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Correct and if the heads have been planed much groove needs to be enlarged. I would check connections between pump and pan. Vaseline worked ok in the Buick engine I rebuilt and they seem to have a temperamental oil system also.
 
A pressure gauge is necessary also as it will tell if the pump is functioning. If pressure is developed and no oil to the heads, either the center cam bearing or plugged passages.

Do you know the exact year of the engine?

It was a very poor design (IMO).
 

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Yea! I finally got oil up top! I reinstalled the pump, after trying to blow air through the system, then spun the engine over by hand and removed the rocker shafts and spun the pump with the drill and got oil up top. It was intermittent at first, but got more steady as it spun. I cleaned out the rocker shafts before reinstalling them.
 
Make sure the shafts are installed correctly so the oil holes in the stand/shaft matches the oil hole in the head
 
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