Well it’s a sad day guys. After weeks of work on my Camaro, we finally put it back together and it had 0 oil pressure. We even attached a mechanical gauge with the ict billet adapter and confirmed it. We tore it down because it had a lifter stuck. Decided to hone the lifter bore to try and salvage it and put all new lifters in (should’ve have it machined but on a strict budget at the time) Now to give you a run down. It held 20 lbs of oil pressure at idle before the rebuild. However it used to hold 40lbs constantly, about a month before the rebuild. Once the oil pressure dropped to 20lbs I noticed it started to wobble a little bit (thought it was just the gauge). Now to fast forward after the rebuild we added a Melling 10296 oil pump. But after we started it, it had 0. We didn’t actually think it was zero considering just before the tear down it always heal at least 20lbs. We just assumed it was the OPS or the gauge (we did replace the OPS). I should add when we started it, it first was 0 then went to about 15. Then later dropped to 0. Once it dropped to 0 and stayed and we would rev it (I know we shouldn’t have done that but like I said, we really thought it was just the gauge or OPS) it went up a little; only about 15lbs at 3k rpm. My auto teacher is not the brightest, I prefilled the oil filter but I reminded him we didn’t prime the oil pump and he said we could just crank the engine a bit before hand. We crank it for about 10-15 seconds before he said to start it so I did, (should also mention he started to rev it up and down a few seconds after it first started) and now we’re here. I’m not trying to shift the blame to him but want to see if that could be a potential problem. Also the same lifter that got stuck sounds to be knocking again, not for sure if it’s the lifter but appears to be that, I think it’s not getting oil. I am replacing the short block anyway because it ran with no oil pressure for that long I just want to know if I should get a knew oil pump or not because there is no way I am putting a bad oil pump in my new engine.

 

Oil pumps rarely go bad. Not saying they don't, can't, won't, never have, never will, or ANY SUCH THING; only, it's pretty rare. Sure they wear out, and old ones with lotsa miles are fornicated; but in a new build, ... not so much.

I'd be more inclined to think you have the wrong pickup tube O-ring on it. In these motors, the straight pickup tube version gets the thin O-ring; the "necked down" or "flared out" or "crimped" looking version (hard to describe... but DEFINITELY not "straight") gets the thick one. I know of no year, L designation, vehicle model, or ANY OTHER WAY to know which O-ring to use, other than, straight vs the other. You just gotta LOOK AT IT and choose the right one.

Sounds to me like you used the wrong pickup tube O-ring. VERY EEEEEEZY to do, especially if you take out a "green" one and put another "green" one back in or the like.

The most likely oil pump failure that could cause this would be a stuck pressure relief valve. Usually a result of debris hanging it up. Again, not saying "it's not that" or whatever, just, it's not the FIRST go-to explanation for this situation. Maybe the 2nd or 3rd but not the 1st.

 

Im about 90% sure we put the black o-ring back on the pick up tube as that what was on it before we replaced it. I still have the box so I can see which one I didn’t use, to find out for sure. But wouldn’t it still hold some oil pressure at idle? I mean considering that the green o-ring is bigger. Also I should mention it wasn’t our first though of what it could be, we thought it could be cam bearing as that would explain why the lifter is supposedly not getting oil again. However I just wanted another opinion as when we put in the new 5.3 I am not putting in a defective oil pump so I wanted to see if anyone else thought it could’ve been the oil pump.

 

Can't say about "black" or "green". That's precisely THE POINT I was making about using the "green" one or whatever. You can't use color as the guiding principle.

Straight pickup tube end, you need the thinner O-ring. Not straight, you need the thicker one. I've seen black, green, blue, and red ones come in kits. Some were thick, some were thin. Can't say I remember which were which although I'm QUITE SURE I've seen both thickness of at least black and green.

No if you use the wrong O-ring it will NOT build pressure like it's supposed to. If there's a leak on the suction side of the pump, the pump will draw in AIR instead of OIL. It doesn't do a good job of pressurizing AIR, and even if it did, it wouldn't lubricate worth a crap. A leeeeeeeeeky pickup O-ring is DEATH to these motors.

Most likely your problem isn't the pump. Yes it could be; but not likely that it's "defective", as in made wrong, or broken, or such as that; rather, FOREIGN MATTER got hung up in the relief valve. But that's REALLY uncommon even though it DEFINTELY DOES happen.

Most likely, your problem is that you used the wrong O-ring. Either you used the thin one where it needed the thick, in which case you have a gap in there; or, you used the thick where you needed the thin, in which case it didn't go down into the bore like it was supposed to and is now leaving a gap where the whole assembly didn't quite go together right.

Please notice my repeated and emphasized use of the word "likely". Understand what that means. Use it wisely.

Pickup tube O-ring. Check that first. THEN AND ONLY THEN move on to other potential "explanations".

 

Oh. My bad. I get what you are saying now. I am pretty sure my pickup tube was the straight end in which case I would use the smaller o-ring. However it is possible it was the tapered end in which case I needed the larger o-ring which I did not. However what still doesn’t add up is that we used the same size o-ring that was previously on the pick up tube, which I know was good as it held oil pressure.

 

Check it carefully. You might also have this problem. https://www.saccitycorvette.com/OilTubeHoldDown.html

 

The oring is usually culprit after a new pump install. My mind keeps going back to that stuck lifter in the lifter bore. I'd pull the covers and rotate the crank to see if that rocker is moving on that same suspect lifter. If it's stuck in the bore again it could effect oil pressure by blocking that oil galley and starving the other lifters down the line.

 

Or be stuck high enough to let the oil just puke out the hole and there be no oil pressure.

Either way I say check the lifter out


And revving it a little after the oil pump install is okay. It's a good idea to at least pour some oil into the pump before installing it. The gerotors seal on a thin film of oil, if they are dry they may not seal enough to pull oil up and into the pump. New pumps can sometimes be finicky about picking up oil, I have had it happen with other pumps too and sometimes all it takes is a quick rev to get them to move fluid.

If you really want to prime it first, pour some oil into the oil galley hole on the driver side of the block at the front
https://www.melling.com/videos/how-t...mp-by-melling/

 

I was going to add that you want to pour oil in your new pump which is what I did for my rebuilt SBC 350 and the new oil pump I installed on my LS1. You want to avoid a dry start and you do that with assembly lube and/or oil depending on the part. Bearings and such assembly lube is good and an oil pump adding oil will work. And I was thinking it could be your o-ring causing your problem.

 

I just had a realization. Like I said I did have a bit of oil pressure. Afterwards I decided to add a ICT billet oil port adapter. Once I did this I had 0 oil pressure afterwards. I have heard these can reduce oil pressure as they block oil passage.

 

You have a fitting inserted in the adaptor? I’ve seen fittings get threaded in too far there and completely block oil flow to the engine...

 

Yeah I it's a 1/8 NPT fitting. It is attached to a mechanical oil pressure gauge.

 

Id pull the plate off it were mine and measure the fitting depth on the backside. Do not unscrew the oil filter fitting. Just remove the plate and observe. Fingers crossed for you...