Yer pistons are fine......maybe smoothen the ridge just a bit. There's no good excuse for a low mileage engine to do that, I doubt the belt broke or all your pistons would look like that. Check the valves real close and see if there bent, it could've been out of time just a bit and/or got revved too high and floated the valve. Good luck
PS. Welcome to the forum

Read lots and you'll learn tons.
Since misery loves company, here's mine:

As per Rabbitman... smooth out the ridge and away you go. Engine's been running fine for months now.
Any recommendations on smoothing out the ridge? BTW Thanks for the welcome!
yours isnt bad at all.. I'd just wire wheel it smooth and get on with it. I've seen far larger impressions in pistons on motors that ran great.
PARTY TIME!!!!!! ;-)
Welcome!
As most have said, it should be fine, but if you're worried you can check the protrusion above the deck with a straight edge and some feeler gauges so you know the rod isn't bent.
Yeah, the mushrooming is pretty impressive don't cha think ??
The PO replaced the head but left the pistons as pictured so I never got to see what the valves and head looked like... :cry: