Oil Pressure with no oil up to rockers?
 

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.

A couple of questions: Do you have a stock valve train? If so, you rocker adjustment is very different that that of a Chevrolet motor. Pontiac rockers are torqued to 25 lbs and done. Second, are your push rods new or the original. You should check and see of you have a hole through the middle of the orignal push rods and compare to what is in the engine now. Third, your breaking for the valve train is to run it for 20 minutes when you first fire it up. Did you do that?

Those would be my first two suggestions. I'm sure you'll get a lot more feedback from the other folks on the forum.

-r-

How long did it run for?

When I did my '66 389 recently I used stock pushrods, which I cleaned & checked for open passages, & it took a VERY long time priming with a 1/2" drill & a chopped up distributor before getting any oil out of the pushrods. We had filled the lifters etc. I know we primed & rotated crank for 20 minutes before there was enough oil coming to the top to satisfy us. That was with over 60 PSI.

I would try to prime it with a drill for a good long while & rotate the crank some while doing so to see if you get any oil out of ANY of the rods. That will give you a little more info to work with. I always want too think some disasterous Sh*t has occurred like I have left a shop rag in there or something, but usually it is something less dire. Take your time & you will figure it out.

After that & the cavitation we experienced that somehow showed 0 PSI, I would never fire an engine without seeing all that the way I wanted it first. You put so much time & $ in that it has got to be right before firing it.

the first question i'll ask is you did put the plug in the end of the oil passage that feeds the lifter galley didn't you? it's under a plug back by the distributor.

prime the system with a drill and see if you get oil thru the pushrods.

mike

[QUOTE=mike nixon]the first question i'll ask is you did put the plug in the end of the oil passage that feeds the lifter galley didn't you? it's under a plug back by the distributor.

I've seen this oversite too many times to count, causing the problem.

OK. I have heard/read about this plug being left out often, but if it is not put in wouldn't you have oil sputtering all out the rear of the block, running down all over the place? With the size of that hole it seems like you would HEAR it blowing out of there at 40-60 PSI.

Just curious since if it is a common mistake I am bound to do it sooner or later.

bruce, the oil runs down the inside of the block by the dist shaft. the plug i'm referring to is located in the rear end of the lifter galley.

mike