I had zero compression on cylinder 1.
Took the head apart and turns out that i have a bent intake valve on cylinder one. spark plugs were in one piece and car gets spark/fuel.
Timing is all good and other three cylinders have full compression.
oil and coolant level/ color look good.
cylinder walls look healthy.

Damage can be seen as attached.

my question is.
- i will obviously be redoing the valves but is piston replacement necessary?
- what risks would i be running into by keeping the same piston?

any comments would be appreciated!!

 

So what was bouncing around in the cylinder to create all the surface damage???

 

Any damage to the bore?

 

I would replace that. The piston has taken a beating. Also, all those little pits can hotspots on the piston surface, which can cause knock/detonation..

 

it looks like it was caused by detonation

no damage to the bore

hmm thanks for your input

 

all the indents on the head don't look like det. i wonder if the damage on the piston face can be minimized by polishing.

 

Its definitely not detonation, something got in there. That something probably also bent the valve when the valve tried to close on it, the valve did not hit the piston. Detonation creates a lot more, much smaller pits, and its generally around the outside of the crown piston