Got an 06 e450. 150,000 miles. Has no high pressure oil. I can get that but the question is took the exhaust crossover off back of turbo, so manifolds are open now. While I crank on engine there is a popping sound and white smoke comes out of manifold. Is this a sign of valve train problems or something with egr?

 

That sounds a lot like the 08 shuttle bus I just put a long block in. It ate a lifter.