So, I got the engine back in the truck and fired it up. I expected some rattles as everything had to wear the lifters had to fully pressurize and then things would quiet down.

Ehhh, not so much. After the engine comes up to temp, the oil pressure drops to around 2-4 psi at idle and it sounds as though no oil is getting to the valve train at all.

This is after new "matched" cam bearings, cam and lifters, new main and rod bearings, and an oil pump, timing chain and gears that had less than 100 miles in them.

The timing cover was in good shape with minimal scoring, and my 30+ yrs of automotive work told me I could reuse it.

Funny thing is, when I replaced the timing set and oil pump back in the late summer, the engine sounded a lot better. Granted I didn't have a manual gauge at the time to check pressure, but based on the sound of the engine, it ran better with a worn out bottom end, wiped cam lobes and a walked cam bearing!

Looks like I'll be tearing it back down today for another look see.

Frustrated to say the least

 

O-ring on pick-up tube?

Thought maybe cam bearings were installed wrong, holes not lined up, causing upper end racket, but you have no oil pressure...so, oil pump, pick-up tube...maybe? Did you have the oil pump apart again or just reinstall front cover complete?

This sucks, period. Good luck.

Brian.

 

Could be the wear on the cover was to much or the oil pressure relief valve. No idea how to test that one but I'm sure a smarter person will have the info. Assuming if course the pump was primed and moving oil.

 

Pick up tube o-ring was in place. I thought about that right off.

So, I tore it down again and didn’t find anything obvious. I also dropped the #7 & #8 rod bearings as they are farthest away from the pump. They looked good with no wear and plenty wet with oil.

Here are some pics of the pump backing plate and the pump housing. To me, this looks passable. All the wear marks pass the finger nail test, and the pressure relief spring was not stuck. Pump housing was clean. The only thing that’s different on the set up is an oil filter adapter so I could install a pressure sending unit.

Anyone have a spec on the clearance between the pump gears, housing and backing plate? I looked in the RAVE and couldn’t find anything.

Before I drop $500 for a new cover and pump, it’d be nice to know if this is the issue.

 

Can see machining marks even in that deepest groove (which leads away from v-wedge). In my mind...that doesn't look that bad...but pictures are not seeing, feeling. However, you say it passes the fingernail test...so...this is one of those moments...the I don't know for sure kind. Granted, I'd surely believe this pump should create more than 2/4 pounds pressure. I'd expect a pump that looks like that to be in the 20/30 range.

Maybe this pump built pressure before...because there was excessive voids/gaps in bearings and such? Maybe, I'm just not seeing something? How did you prime the pump. Maybe remove the adapter you added for the mechanical guage? Just grasping at straws here.

Brian.

 

Two things come to my mind.
1. Accuracy of gauge/sensor as oil light not reported on. Many are not very accurate at the lower end of scale.
2. You may be ultra sensitive to noises after recent reassembly.
.....

 

When you put it all together did you pack the oil pump full of Vaseline? Maybe it wasn't primed?

 

The oil pump was already full and I put nearly a quart of oil in the filter prior to installation. The light went off within seconds of start up and as I was continuing to top off the cooling system I noticed that the upper valve train wasn’t quietening down.

So, I killed the engine and hooked up some jumper wires to see what the gauge reading was. The gauge is an electric Autometer gauge so I feel pretty confident in its reading. As I suspected, about 6-8 psi at idle at full operating temp. No oil light and I believe the OE sending unit opens at 4 psi. to shut off the light.
Perhaps I should have let it run a little longer but I didn’t care to wipe out a set of bearings and a new camshaft.

That was early on Friday. Later in the day I went back out to finish topping off the coolant and fired it up. Still rattling but the autometer gauge showed about 25 psi after coming off fast idle. As I was filling the coolant and the engine was heating up, i could see the pressure was dropping. At 180 degrees, the oil pressure was back down to less than 10 psi.

 

Check the rocker shaft/rocker placement. If somehow you got the rockers 180 degrees out (oil hole at the top instead of bottom) it will do that.

You could also consider seeing how much pressure you can get using a priming system. It's not the same as with the engine spinning, but it is close. Google LS1 engine priming and there will be some good options. During my last rebuild I almost made one out of PVC pipe but did not. You could prime through the cooler lines and get a sense if the problem is pump or clearances. You could even do it with the pan off but that would get messy in a hurry and not sure you would be able to observe significant differences between the flow from the bearings.

Good luck.

 

Here was my cover and gears that were producing 7-8 psi at idle and 25 psi at 2000 rpm. If you only have 100 miles on the cover and pump, I would suspect other problems. I share your frustration. Have dealt with similar problem and more since buying in July