I recently removed the head and heat exchanger on my Volvo md2030 / Perkins perama engine replaced head gasket had a small hole in the heat exchanger aluminum welded and reassembled. Upon attempting to restart engine it acts as if there is no compression. While the head was removed I had turned the crankshaft over in order to clean the top of the Pistons and get debris out. Any ideas? The engine ran normally before disassembly but I could tell there was water getting into the cylinders due to the color of the exhaust.