My son was helping me set engine to TDC, had a thin plastic stick down the #1 cylinder hole to gauge when TDC was reached. Its an '88 Camry 4 cyl....so there are tubes on each cylinder, with the spark plug at bottom of each tube. Valve cover is still on. It is a pebble about half the size of a standard round air gun BB. He had just got up off the driveway, his hand was sweaty, and the pebble stuck to his palm unknowingly. It made an audible CLINK when it came to rest right on the edge of the spark hole. I tried to get it out with a piece of sticky tape on the end of a stick, but I only succeeded in knocking it down into the cylinder. So it is somewhere completely unreachable, on top of the piston. So when I start the car up that pebble is going to bounce around inside the cylinder, and I guess eventually it would go out the exhaust valve if it opens that wide. Then there is a chance it might be trying to go through the exhaust valve just as the valve is nearing closed position, and then the valve might be damaged so that the compression of the cylinder is decreased. How can I get it out short of a major tear-down of the block? I don't have a vacuum pump, so I can't vacuum it out. I do have an air compressor and spray wand. Maybe if I connect a thin tube up to the compressor and force high-pressure air down the spark hole, it would come shooting up? And then the odds of being completely sure it is out are slim, unless I see it come out, as I sure don't have a borescope lying around.
So I don't know....maybe there is a chance it will just break up...but maybe it will damage the cylinder. I don't want to take a chance. Ideas?