How in the world did he get it up to 4K????????? That one's supposed to be governed at about 2150! With the weight of the rods and pistons, I'm surprised there's anything left of the crankshaft! The fit of the sleeve in the block is critical, as any wobble allows coolant leakage into the crankcase, and promotes sleeve breakage about the middle, resulting in exactly the symptoms you're describing. If it's a fresh rebuild, the sleeve projection above the block might have been set wrong on assembly, or the lower ring in the block where the coolant seal ring fits might be oversized, letting the sleeve wobble in the block. The fix there is to bore out the lower sealing ring, and install a short piece of cylinder sleeve in it. That's an out-of-the-frame overhaul procedure, which can get VERY expensive!
Jerry
