Well about a year ago,I was driving my car around town and just before going back home I decided to give it a quick run though the gears and everything was fine up untill i i shifted to third and saw my oil pressure drop to 0. I coasted down in neutral into a parking lot, only took about 30 seconds to get to the parking lot and shut it down. Pulled it home and threw it in the garage and just getting around to it right now.

I pulled the oilpan and discovered that my oil pump had gone bad, replaced it then just to be sure, I checked the main and rod bearings and all looked in very good condition (engine has about 1000 miles on the rebuild). I went ahead and put it together and started the engine only to find out that its knocking, oil pressure is right at 50ish cold and 25ish hot idle.... knock is coming from the top pass. side and sounds like its coming from the very front of the motor so I took the valve cover off and I notice my pushrods aren't squirting oil. here are the things Ive tried so far.....

With a stethescope on all of the rocker nuts, I hear no major difference between them.

I decided to readjust the rockers(engine running), I noticed that on #2 when I tighten the exhaust side adjuster nut down the sound almost disapears but only for about 2-3 seconds. Note that this only happens when I turn the nut past 1/4 turn(almost a full turn).

I decided to pull the first two pushrods out and start it like that thinking that if the knock went away that meant the lifter was bad, but the knock was still there....

are there any reliable ways to check if a lifter is bad?
any suggestions you guys might have are very welcome. Thanks

 

When you pulled the pushrods, did you pull those lifters out too? Was there any trash plugging the pushrods? If the sound went away for a few seconds after adjusting, and no oil is coming out of those pushrods, it would lead me to suspect you might have a damaged cam bearing. If you haven't already, take a close look at those lifters too. Knocks and taps and strange sounds can sometimes be subjective.

Edit: Just wanted to add my reasoning to this. You still have oil pressure, but the pushrods there aren't getting oil through. The front cam bearings are furthest from the pump and may have been starved while you were coasting in. It doesn't take much sometimes for it to happen. When you adjust those lifters, the sound goes away for a few seconds, but then the lifter, being hydraulic, compensates and the noise comes back. This may not be the cause but it's what I would suspect happened.

 

I only pulled the pass. side valvecover and pulled the pushrods through there, so no I didnt take out the lifters. I do have some comp cams lifters laying around that I took out to install the ls7 lifters on there now, I could take the intake off and swap them out but do you think I'd be wasting my time?

There was no trash plugging the pushrods btw.

Also, Just throwing ideas out there.....I kinda though different when the sound goes away while tightening that rocker arm, kinda made me think that I was taking slack from inside the lifter in a way quieting it down then it would bleed off a few seconds later but I dont really know too much about that.

I'm really hoping its not the bearings...makes me want to sell the car if it is, just dont want to mess with it anymore. how hard is it to replace the cam bearings while the engine is in the car? I MIGHT decide to replace them but only if I find a good price cam to replace my cc306

 

Not possible to replace them all.

With a new pump, you might experience the same thing people do on a fresh rebuild-it takes several minutes to get flow from the pushrods (especially, if you did not prime the pump).

 

OOPS! I'm pretty sure I forgot to prime the oil pump....
I remember when I rebuilt the engine I filled the oil pump with assembly lube before I installed it, then before putting the intake back on, primed the pump with a drill............all of which I didn't do this time around lol

I'm scared to let the car run longer because I dont want to cause more damage, I've only ran it for about a total of 5minutes all together.

does the fact that the knock goes away while tightening the rocker meke anyone else think that its the lifter making the noise? or the bearing?

 

It's a possibility but since it was described as a knock rather than a tap noise that lifters make, that's what made me lean away from it.

 

ok heres a quick vid of the noise..click
now that I think about it it fits more under tap than knock.....my mistake.

edit:
Also, most of the oil you see on there is from me pouring some on top of the rockers and pushrods before taking the video

 

Have you looked closely at the springs to be sure none is broken?

I have to say that I find it curious that you found your oil pump had "gone bad". That's like something that never happens.

 

I havent had a chance to look at the springs yet, its freezing out so maybe tomorrow.

I didnt want to make my first post too long with all the backstory and wanted to focus more on the present problem....
I dont really know what happend to the pump but when I took it apart, I found the gears had chipped off edges and the pump would not spin anymore. I ended up replacing the pump, shaft, and the oil pump drive (had teeth chipped off).