ok im stumped. please help

[Groundhawger]

my dad has a 98 gmc 4x4 with a 350 vortec. we just put this engine in the truck about a month ago. we bought it from a guy that took it apart and checked it out and cleaned it up. We put a new stock oil pump on it, then got it running. when cold has about 50 lbs oil pressure, when warn, oil psi goes down to about 10 lbs and engine starts knocking. so we pulled the pan and put a high volume on it, its doing the same exact thing. any idea what it is?? we are lost. warm down the road at about 70 its 18 psi and idle its about 0-10lbs. please help.

[Captn. J]

my dad has a 98 gmc 4x4 with a 350 vortec. we just put this engine in the truck about a month ago. we bought it from a guy that took it apart and checked it out and cleaned it up. We put a new stock oil pump on it, then got it running. when cold has about 50 lbs oil pressure, when warn, oil psi goes down to about 10 lbs and engine starts knocking. so we pulled the pan and put a high volume on it, its doing the same exact thing. any idea what it is?? we are lost. warm down the road at about 70 its 18 psi and idle its about 0-10lbs. please help.

bearings ? or is it obviously u guys killed it? besides putting new oil pump is not gonna save it

[Crazymays77]

yup sounds like bearings to me too.

[old school truck dude]

Bearings are probably gone in it..  

[2trackr]

Cam bearings

[dirtydog]

main  bearing

[J.C.]

If you got a fram filter, change it to an stp and try that. If not, must be bearings. Are you getting fuel in the oil? That will thin out the oil also

[ToughBowtieTruck]

Mine did that. Was a rod bearing. I drove my tbi 350 like that for 50,000 miles. Then when I was doing a hard acceleration the rod started knocking full-time. 20w50 oil got me by another few thousand miles. 

[Strapless]

If she is knocking its too late..

[72 Bogger]

main  bearing

[Jjay78]

probly a rod berring.... ya could try a better filter and a lil heavier oil.. but thats kinda like sticking your finger in a leaky dam to stop the leak...your gonna have to fix it the right way soon either way