installed my new 383 and had to take it to the shop because the motor was running bad. the car was backfireing because the lifters were bottoming out and not filling with oil or something??? the shop told me that the topend was not getting oil to it. they tried a few things and decided to give me the car back because they could not figure it out...
i took off the manifold and rented a priming bit form Autozone. I started t to prime for 5 min and nothing still with 60lbs of oil pressure. I took out each lifter individually and saw oil traveling threw the lifter galley at a good velocity, almost enough to reach the other side, is that good enough??? i can see the lifter very slowly allowing oil to pool on the area where the puchrod would sit and thats about all. my drill is a Dewalt 18v.
I was told maybe the freeze plugs fell out in the front of the motor but i pulled the timing cover back enough to see them sill in place, they said if they were out my oil pressure would be low too and it is not.
The lifters are LS7 and they came right out of my old block straight into my new motor. they are all still soft and not allowing my valves to open all the way. should i get new lifters and try to prime again??
for oil to move up through the pushrod the engine has to be running. there's a metering disc in the lifter which normally locks in oil, as in hydraulic lock because it's a hydraulic lifter. as the lifter comes down off the cam lobe, the oil should shoot up through the pushrod to the head. i believe you'll need all lifters in and pushrods in with rockers tightened down and correct preload on the lifters, then crank engine via starter with ignition disabled. you should see some oil make it to the head. if you have one lifter out you'll have no oil pressure in the lifter galley and not get oil pressure to allow oil to make it up the pushrod. Other than that, only other thing I can think of is cam bearings might not be lined up 100% and you're not sufficient oil to the lifters, or you have the wrongs lifters and the oil hole in the lifter is not lining up with the hole in the lifter bore so oil isn't making it properly into the lifter.
But just with all lifters in run your oil priming tool and oil should ooze up around the lifters and you should measure at least 30-40 psi on a mechanical pressure gauge. If that happens then you should be good to go. crank the engine, idle it for a couple seconds with rocker cover off and you should see oil. hope that helps.