[redmuley]

1966 Pontiac 389. I rebuilt my engine last summer putting in all new components. I adjusted the rockers to specs and after a while of cranking with “no compression” I realized that I forgot to let the lifters set in oil for a while before installing and so when the lifters pumped up, they crammed my valves wide open. Once adjusted properly the engine was broke in, receiving oil in all correct locations. When doing a double check on the rocker adjustment I noticed that the push rods were semi close to the hole in the head, toward the stud, so I took the heads off and had them drilled larger with guide plates and hardened push rods installed. I checked to make sure that I had put the original size rocker on and I had, even though the new rocker rollers are just a tad bit different than original. This summer I installed the heads back on and adjusted the rockers, I could tell that some of the lifters may not still be pumped up, I started the engine. The rockers/lifters were very noisy so I pulled the valve covers off and checked the rockers adjustment and noticed that some of the lifters were having a hard time pumping up. There was oil all over the top of the head so I new that I had been getting oil up there, but when I fired it up a second time hopeing that some of the remaining lifters would pump up I noticed that I was not getting any oil from any of the push rods. I have about 40psi pressure up by the distributor, but not getting any oil to the top of the heads. Earlier in the day I would have had to have some oil come up to the top because there was oil everywhere, then no more. I don’t know if the oil on top of the heads is from just what the lifters had inside them or whether they wear working until something plugged up one of the oil gales. I would try to say that some of the lifters are bad from not soaking them in oil before the initial brake in last year, but I am not getting any oil out of any of the rockers. I would also try to blame the alignment of the rockers but I have gotten oil up on top before so I know that oil can pass up there. I’m not sure where exactly the oil flows, whether in is getting blocked before it even hits the cam or whether the oil is somehow going around the lifters? I don’t think that a bearing has slipped because I would still be getting oil to some of the rockers. I have no idea as to where to even attempt to find or fix the problem. I heard that if I take off the oil filter and apply air pressure that I may be able to “unstick” something, but I don’t know and am very lost as to what to do. Thanks for any ideas as to what to look for, or any approaches that may help.

[Jack Gifford]

I thought this sounded familiar- yep! It's a duplicate of his 6/21/07 post here.
I also thought I remembered him getting some help with his problem- no?
I'm no help- I can't imagine what could cause oil to flow, and then later not flow.

[Firebob]

Was this a rebuild? One thing you might check is if all the oil passage plugs were reinstalled. If the threaded plug in the back of the block or the one(s) in the front(behind the timing cover) are not installed you will get pressure but not enough to force the oil up to the rockers.

Robert