Oil pressure issue

At the first week of idle the oil was at about 3 or 4 bars, which is roughly around 40 psi.

After letting it run for its usual 30 mins for a few times over a week, I decided it was time to drive it. Seemed to be fine. After 3 weeks into the startup I took it to town the other day and after 5 mins into the drive I realized my oil pressure is dropping down past 1 bar, about 14 psi or less. The chevy mech man here told me the engine only need 4 psi per thousand to run.

It has a brand new oil pump and brand new everything. I am running royal purple break in oil. I took the pressure sender off and tried to hook my manual gauge up but it only reads 25psi or above. So no go, I unhooked the oil sender and cranked the engine and the oil came out. So I have oil traveling my engine.

There is no over heating problems, oil level is good and there are no leaks or unexplained smoking like a bad seal some where, also checked the gauge and have full sweep when grounded. I am not sure what to do next. Please help.

You might check to see that you didn't install the lines backwards to the oil filter. I did that once

If that was the case would it not have had pressure at all to begin with? I will double check everything on the bottom too just to be safe.

Get rid of the royal blue "break in oil" , Brake in oil is not meant to be driven much. Also I would not break in a motor on a synthetic oil.

I also wondered about that. The oil gets really thin when at temp

Unhooked both lines and had my wife turn the ignition over, oil comes out of both lines. This sounds like the pump or the gasket to the pan is messed up. I will have to pull it apart to find out.

Hmm, that's pretty weird.
I have a RH pan and i had to drill/tap a hole between the two lines and put in a bolt to really hold the pan down in that area.

I'm in the process of dropping the cross-member to pull the pan to see if the o-ring is pinched or something. Other than that the LS1 guys are saying the pressure regulator valve in the pump could be stuck. Not sure. I just bought this one new from Chevy, and have two old ones that I can run to see if that helps.

I will double check the gasket seal between the in and out ports on the pan once I get it off. I am hoping the pump is bad since it worked and now it doesn't, it would make sense that the valve would be stuck then. But nothing else right now is clicking in my head.

Regarding dropping the cross-member, has anyone designed a brace to hold the engine up without the cross-member in place. I have seen them on some cars for working on the lower end with a setup like ours. I would be able to work under there without my cherry picker in the way.

Lay piece of pipe across the strut towers and just loop some small chains down around the second tube on the headers. It'll hang fine.

Harbor freight also sells a bar. I don't think it's much better than a piece of pipe though...

I have been using a piece of pipe for years. I just drilled a couple of holes in it and use 2 "J" bolts. I hook small pieces of chain on to those to hold the motor and they give me some adjust ability.

Here's what could be your problem. Especially on a new re-build....

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I have no idea. I will have to look at that. It sucks if I have to pull this thing completely out again. I did find my pickup tube debris screen was clogged with what seems to be chunks of gasket maker, but that doesnt explain the back feeding. The plug that your thread list might be an issue. I will let you know.

Where did the gasket maker glob come from? there is no reason to use sealer on nearly any part of these motors. 90% of the gaskets are "O: ring based gaskets.

In the tutorial they also mention a stronger oil pump spring for bigger cam, higher Oil pressure....
but here's what I'm talking about can be overlooked on the back of the block under the cover....

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Eric, I may have messed up when installing all my parts. I saw that the oil pump went against the block and connected to a galley there, but I had no gasket, I used a small amount of gasket maker there to make sure it had a good connection to the galley. I mostly likely did something wrong, I saw everything else had a gasket of some kind and figured it needed it too.

Well I am pulling everything apart to make sure its ok. I did drive it some with the pressure issue after the GM mech here told me it should be ok. I did not have any bad noises or overheating, or unexplained white smoke so I am hoping the engine is still good.

I have the engine out and back on the stand. I pulled apart the valve covers, oil pan, and rear block seal. So far nothing out of the ordinary, except some gunk inside the oil passage when I took the Allen bolt out by the in and out ports on the bottom of the block. I dont think I had this block dipped when I got it since it was already rebuilt and assembled. That is probably my problem.

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Still need to pull the crank pulley and front cover off to check the oil pump completely. But everything on the engine is still looking good.

Great news, I broke my crank pulley tab trying to get it off earlier. I dont have any type of heat source to loosen the thing up with, so I am going to have to take it back to the machine shop that did the balancing and have them finish the rest of the tear down and dip the block then. I am hoping by February to be back up and running.

Aww man, that sucks. After you had this all in and ready to go. Well at least its during the winter when you wont drive it much anyway. Hope all goes well at the machine shop.

well found a big enough 3 jaw puller to pull the pulley off at home and tore the engine down the the bottom end for the night.

I made a couple of discoveries I will add up to a first time mistake. The first thing I noticed is when I removed the rockers arms, the 7th cylinder intake rocker had came unload and allowed the pushrod to bounce around and chew the rocker up alittle. I dont think it is to devastating but will be calling comp cams to find out for sure. That cylinder did not look like it had been fired once.

The second thing I found out is that I dont believe it was the gasket maker I put on the oil pump that was the cause of the pressure issue. I know now it is not right but the gasket seal was still in one piece and no tears. I did however find in the valley area that there is a layer of silver paint coming off the interior of the engine. That would explain the floating particles that clogged my pickup tube and oil pump.

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I am finishing the tear down and going to take the block to get dipped. I will also have them check the bearings to ensure they are still good.

Who painted the inside of the block?

The previous owner did or where he got it from.

sometimes it takes alot of tries to get it right.sorry for your bad luck .i myself went through a simular situation except my motor had sat for a couple of years .and when i installed it and got it running i had an oil presure issue you would never believe the culprit could be some wasp nests that were constructed while the motor sat.trashed a 600 dollar crankshaft.one thing about it you will be able to put the car to gether blinfolded i bet.this your second one youve built so far if i remember right.its looking good though my compliments keep up the good work friend