The timing belt of my accent 2010 cut and bend 8 out of the 16 valves, after replacing the valves it does not shock for it to start

The belt is worn out and is disintegrating. It has probably jumped time. The reason the engine won't start. Depending on your car, Some engines are no tolerance. Meaning if you keep cranking it and the belt breaks, the pistons can slap the valves, bending or breaking them. Replace the belt.

if you have damaged rods or valves in your engine, there would be almost no chance that the engine would run or even start. it is quite possible that you did not get your timing right when changing the belt. in most cases, getting the pulley to piston 1 TDC does not always guarantee that the engine timing is correct.
my advice is to recheck the timing of the engine, as well as Ignition timing (which is also controlled by the positioning of the crank pulley) before condemning any internal mechanical failure.
to answer your question, there is no written way of knowing whether your rods or valves are damaged without taking apart the engine and inspecting for damage. however, damaged internal components will always leave a trail.
you can try draining the engine oil and checking the oil for any metal filings. you can also take out the oil sump to check for any pieces of broken metal in the sump.
hope that helps

usually the timing belt or chain wears and causes the piston to bend the valves

this is an interference engine meaning if engine turns out of time due to a broken timing belt the pistons can contact and bend...in this case the intake valves.if belt is on properly perform compression and leakdown tests to confirm damage to valves..sorry for bad news.

Timing belt on this vehicle. Replace at 120K miles. You may bend a valve if the belt breaks on you. Very expensive then.

if the timing belt breaks it will bend the valves

1st you may want make sure that's not an interference engine. if it is then chances are the valves are bend in the head. changing the timing belt probably won't help then. If its not an interference head, then you would need a timing mark diagram which can be found online. be very careful that all marks are aligned. when finshed installing the timing belt, rotate engine by hand twice and re-align marks before putting the rest back together! hyundai should be able to tell u if the engine runs interference or not.

hi from uk the cambelt timing marks for accent 1.3/1.5 petrol are as follows= the cam cog has a hole drilling between the outer toothed and the central securing bolt this hole at TDC number 1 cyl is at top central and lines up with a V cut in the cyl head at rear of cog ? the crank cog at TDC number 1 cyl is a pop mark on both the cog and on thefront face of engine quite noticable ! these line up and are at approx 12 -30 pm when viewed fit new belt from crankcog in anticlockwise ie crank then cam then tensioner HOWEVER! if you are considering just replacing belt and tensioner ? be warned this engine is an interferance engine that is to say if belt fails whilst driving there may/will most probably be damage to the valves (bent) due to contact with pistons so would advise caution and suggest compression test all cyls after fitting new belt and tensioner and before rebuild completely once valves have bent they will not contact pistons again but you will have serious missfire/s and probably back fire up inlet manifold coupled with failing to start if engine is high milage ? consider removal of cyl head and check? de coke and replace damaged or best all valves then engine will have improved performance and more milesin future hope this helps

Timing belt replacement is NOT easy and not for the average do it yourselfer. Installing the belt incorrectly can cause severe engine damage by bending the valves, breaking pistons etc. Take this one to a professional.

first thing i need to know is did the timing belt break?
second is are you sure you aligned the timing marks and after the belt tensioner was tight you rechecked to make sure the timing stayed where you had it.
next step would be a compression check to if a valve was bent whenchanging the belt
i have seen this happen and this engine is an interferance engine.
later paul