I just put me ls1 back together again. And the oil press. is only 20 pounds, and will go down after it warm. All i did was mill the heads,polish the crank, and add new bearings,rings,new timing chain.

 

mine did the same thing i hope thats not your problem. Mine spun a rod bearing, you might want to check that blue o ring on the pickup tube good.

 

Did you check your bearing clearances?

 

It has only been running for 45 min. or so. we did check the o ring, when we first started it. it had 45- 60 psi. it has gone down. it will go to zero, and if wait about 5 min. it will go back to 25 psi. and then go back down after awhile

 

Yes every bearing was in the middle of it

 

4 times out of 5, oil pressure problems are a result of a bad sending unit. Test it with a real gauge and not the dummy gauge inside the car.

 

I have a mech. tide into that deal in the side of the oil pan. It reads the same

 

Any other ideas?