2003 Kia Rio Broken exhaust valves

NED J

MEMBER
2003 KIA RIO
4 CYL
FWD
MANUAL
60,000 MILES

01) I am faced with a 2003 KIA 1.6 ltr DOHC motor with all 8 exhaust valves broken off & subsequent piston & cyl wall damage.

02)The timing belt appears good, teeth are sharp with no deterioration seen.

03) No sludge, heat discoloration or LOL evidence & no cooling system failures.

04) Each pair of exhaust valves in each cylinder broke off about ¼" above the valve head. The stems are still in the guides in the head & keepers are in place.

05) There is no damage to any intake valves.

06) The vehicle operator said the motor was running and just cut off!

07) Has anyone seen this before and is there a known cause for this failure? I am stumped fpr a COF.

08) I never saw a failure like this where only the exhaust valves are broken & the untake undamaged. And both cams are driven by the same belt.

2 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

WOW. That is odd. I have never seen one do that before, especially with the timing belt good. Was the motor in time when you took it apart? Was there a failure of the key in the crank by chance? All I could think of would be excessive advance of the crank. Since the piston "chases" the exhaust valve if the crank were advanced too far it could hit them. Im not real sure, that is weird. Time for a yard motor and try again. Lol