I did something very unbelievably stupid, and I am hoping one of you or more could help me with advice!

I bought this cool little tool that was supposed to help lock the engine by stopping a piston through a sparkplug hole. I was using that so that I can unscrew the crank bolt off without the crankshaft moving.

Big mistake: The tool was not perpendicular to the cylinder wall, so when I was trying to unscrew the crank bolt, the piston pushed up and broke off the brass tip of the tool. I ended up having to remove the head so that I can remove the brass tip out of the cylinder! Talk about every mechanic's nightmare.

After taking off the brass tip, I noticed that the piston, after breaking off the brass tip, had continued moving up and pressed against the steel end of the tool. It resulted in a small, half-moon dent on the piston crown.

The half-circumference of the dent is slightly bigger than the eraser end of a pencil, and the depth at the curved notch is less than 1 mm.

Would this dent in any way affect the compression of the cylinder? Or what? I kept hearing advice to always be careful not to scratch the pistons. I need to know if the piston needs to be replaced or not. Nothing else in and around the cylinders has been touched or scratched.

Many many thanks in advance for your advice and help!

-DS

1993 Volvo Wagon 155k, 5 speed
1993 Volvo Sedan 95k
1989 Volvo Sedan 120k