[massey478]

I just happened to view these old posts. I wanted to say how it is most important to use high pressure air to blow out crud around spark plugs before removing them, especially on the V-6 engines we are using. I blow the cavity around the plugs out twice around the engine because stuff from around one plug can fly over to settle around one just blown out. I then loosen the plugs about one turn and repeat the blow-out procedure before completely removing them. It is so easy for crud to settle around the plugs and then if not blown out goes down into the cylinder when the plug is removed. The least it will do is score your cylinder wall. The worst is if it is a piece of some kind of crud that settles on the piston top, maybe sticking there, it causes a knock. It may eventually come loose and it may not. Worst case it might dent or break down the top ring land on the piston then you have a major problem, broken ring, scored cylinder wall. Also check the plug sealing ring seating area in the head for crud. You do not want crud getting between the plug sealing ring and the head, causing it to not seal properly. To clean them I put a bit of grease on the end of a flat blade screwdriver and go around the machined seat carefully with the screwdriver end, the grease captures the bits and keeps them from going down into the cylinder. I-6 engines were bad about inhaling a carb air cleaner mount retaining screw on the carb top that vibrated loose or other trash that might get unnoticed into the air cleaner when changing it. Instant knock! I have seen the screws pressed into the piston top virtually permanently. Head off, new piston, hopefully no cracked head or scored cylinder.