Caterpillar 318bl burning oil

Hi everyone, I'm new to the forum but could sure use some suggestions on a problem. I purchased a cat 318bl with the engine knocking. We took everything apart & found the number 6 rod bearing destroyed, so we replaced the crank & rod, had the head gone thru, rebuilt the turbo & had the block checked & honed. We reassembled with new bearings, rings & gaskets, the engine started right up & sounds great but was smoking, we were told the rings need to seat. So we have ran it for about 20 hours now & the problem is not any better, in fact it seems to be getting worse because now when we put the machine under load the low oil pressure light comes on & off & the throttle is surging. I have now been able to track the machines history a little bit & found that it was sold at an auction to the guy that I purchased it from. The auction listed the machine as having blow by, the guy I got it from only ran the machine about 3 hours & I guess that was when it ate the bearing. I have talked with the engine shop about the issues since I think something was over looked now knowing the blow by issue, they don't really have any idea what could be causing the problem & before I tear everything back down I would appreciate any in put. I would like to add that we completely removed the turbo & exhaust manifold & ran the engine & it appears to be smoking from every cylinder. Sorry for such a long post but I'm stumped. Thanks in advance for any in put. Steve

Caterpillar 318bl burning oil