random lifters not pumping up

[flatbed200]

Hello guys
I'm working on a 392 in my 74 200. We have just rebuilt the engine. All the oil galleries are clean. A comp 260 cam installed along with new cam bearings that we made sure were installed correctly, all oil passages are open. The lifters are from comp also. The push rods have adequate pre load.

We just started the engine and assumed cam break in procedure. It still had a little bit of lifter noise after 15 minutes of running about 2k rpm. The oil pressure is around 45 to 50 during this run. This is with straight 30 weight non detergent oil.
We shut it down and pulled the pass. Side valve cover. #8 exhaust rocker had quite a bit of lash to it. Pulled it back into the shop and had to stop for a while. About 3 hours later, I rotated the engine over and checked out all the rockers for lash. There were 7 altogether that had excessive lash, this is between both drivers and passengers side.
Next day I started and idled for about 20 seconds, still had a little valve noise and those lifters still had lash. I could see oil oozing out around the top of them while running. These soft lifters are random, the ones next to them have yet to develop any lash.
This re build has gone on over the course of 4 years and the lifters sat around in their box for probably 2 years. Could that have damaged them or could I have gotten a bad batch of lifters?
I primed them with the oil pump drive thoroughly before I first started it.
Any ideas? I'd really hate to junk my new cam by having these lifter problems.
Thanks,
jim

 

[Robert Kenney]

Numerous reports of bad lifters have been written about in the past so that would not surprise me. However that does not mean yours are bad.
Where did you get the lifters? What maker are they.
Sitting on the shelf won't cause a lifter to fail if kept clean and dry.

The problem with turning the engine and unloading any lifter is that while they sit, the valve spring causes the lifter to loose its charge of oil. While it is unloaded it can suck air in unless there is a solid supply of oil present in the gallery while it unloads.

If you have any concerns regarding a lifter being ok or not, I recommend removing theme one by one and pumping them up in a container of oil compressing them at the recommended load. There is a spec for lifter bleed down in the fsm. Load/time and bleed down distance are all critical to the test. I do not have the specs here so maybe some one can offer the data.

Go through the 7 suspect ones and see if they will pump on while submerged in oil. They should be solid as a rock under hand pressure not yielding at all. If you have a drill press, you can put a good amount of load on them and if they are bad they will compress in short order.