engine running poorly

here is the story.i am buying this high comp ka24de with a compression of 11:1.the pistons and rings are OEM and the rings are new.i was told befor the motor was pulled out it was running but poorly.it had a rough idle and spit out clean oil from the exshaust.what could be the problem? thanks

how long has this motor been run since the rebuild?

what was the break in procedure?

if its spitting oil out of the exhaust, thnen its either poorly seated piston rings, bad valve seals, or least on the list head gasket.

whatever the case a leak down test will tell you whats going on in there.

but if its oem pistons then to lower compression the block must have been shaved, and if that was done poorly then the head gasket will not seal well, whatever the case its too much repair work.

sasha i am not sure about those.not my engine but i plan on buying it