DS21 & DS21M / DS19A & DS19MA Repair Manual — Page 86

37, Drill a hole 11.5 mm diameter in the of the core plug and tap it 14 by 200, 38. With a bronze drift, tap the plug into the hole a few mm to free it from the three punch marks (a). With a scraper remove the metal turned down by these 3 punch marks (a) to lock the core plug. 39, Withdraw the core plug with extractor (B) MR.1540-170. 40, Clean the core plug hole in the cylinder head.