Changed plugs-Motor tapping

[joenow22]

Changed sprk plugs 93 Camry 4 cyl and the plug wires, the wires were very brittle and broke in pieces when removing the long rubber stem part that fits to the plug and part of the old ceramic on the plugs. Vacuumed out as best could and removed plugs with possibly some of the rubber boot/ceramic falling thru the plug opening and on top of the piston.

After startup had a tapping noise that soundedlike it was valves tapping. Then it quit and started back. They tapped 15 seconds or so off and on.

Next day the sound appeared to be in the lower engine ....

Removed the valve cover and did not see anything unusual. Drove car for about 40 miles and no noise anywhere
Question is:
#1) Is it possible that if any spark plug boot/ceramic did fall on top of piston if any damage could be done
#2) If it did fall on top of piston is it possible to work its way down into the oil pan

Was told by a mechanic that if anything like boot/ceramic landed on top of piston no damage could be done that it would basically disentegrate.

Any suggestions appreciated... Thanks

[frenum49]

Your mechanic is generally correct. The chance of a bit of ceramic that fell through the spark plug hole actually causing damage to the piston or bending a valve is pretty slim. This is not to say that it couldnt happen. It is not possible for a large piece of ceramic to find its way into the oil pan unless you have a hole in one of your pistons. Not likely. If one of your pistons was that badly damaged you would know. Your engine would not run even remotely well. There is not much you can do to get the piece out of there short of pulling the head. If you thought you had dropped a nut or bolt down in there I would recommend pulling the head. Even if you had, after starting and driving the car, the damage would already be done. However, if the bottom end is still knocking you will at the very least need to install new bearings and hope that the crank journals have not been harmed. Again, I highly doubt that the ceramic bits would cause this. So the bottom line is, dont worry about the ceramic pieces. They are probably already dust by now.