Hey all new to this forum. I did a timing chain DIY with a friend's honda accord euro 2010 LX with the K24Z3 engine (we did it together) and the valves were damaged after he cranked the motor a couple times. We made absolutely sure the timing chain was timed with the timing marks on both cams and the crankshaft at TDC positions on the gold links while using cam locking pins. And the chain tensioner was set about 3-5 clicks after we let the pin out. We spun the crank a couple times clockwise with little resistance. And we also made sure we put everything back together as it were before like the belt, pulleys, rocker cover etc. The diagnosis of the bent valve was determined by my friend's local mechanic which I would assume he did a compression test of all 4 cylinders.

What could have caused the valves to be bent?
Did the valves hit the pistons? If so did we miss a crucial step when doing the timing chain?
Did we need to have done a valve lash adjustment after doing a timing chain?
Is there more potential damage than just the heads?
Does the lower block need to be pulled apart and inspected as well?

Any help would be greatly appreciated and if someone could shed some light on where we went wrong with this DIY. Thanks!

 

Why did you replace the timing chain in the first place? Was it broke or just replaced it for stretch/general maintenance? If it was already broke then that's what bent the valves if it wasn't broke then we have other problems. When I do a timing job I always turn the crank pully 2 rotations and check to see if all the timing marks line up, if not I rotate it again another 2 times because some motors are different and im not completely familiar with that specific engine but 90% are 2 rotations of crank for 1 rotation of camshaft once I do that I line everything back up and check my timing marks again, if one is off I take it back apart and do everything again clocking the camshaft back or forth a tooth until I get everything lined up prefect. Remember this isn't a race and it somewhere you really want to take your time and pay attention since there is alot going on. Next once I have everything back at TDC I will check my chain/belt tension and make sure that it feels good and snug. Once the belt/chain tension is tight and everything is lined up prefect I still rotate the engine over quite a few times and check everything one last time before buttoning everything back up. Then when its time to start the engine I bump the key a few times to make sure i don't hear anything interfering, its easier to fix it now than it is with bent valves. Another good idea is if its your first timing job and your unsure about your work you can pull the fuel pump fuse so that the engine wont fire up and just spin it over with the starter paying close attention to anything that sounds like its hitting.

Now if the valves are bent then further inspection would be to pull the head (valves don't come out without pulling the head) and inspect the pistons for damage. If you got lucky then the pistons are fine and chances are at your experiecne level it would be better to but a head, rather than to pull valves and replace the valve guide and valve and take it to a shop so they can install the new head and install the timing chain correctly. I wouldn't take it to a shop before pulling the head in my personal opinion because if the pisotns are destroyed you will be charged for the head to be removed and inspected and then charged for a replacement motor and the labor to do that.

Sorry about your luck man it seems you had done your research but sometimes its better to have someone with you that has done a timing job so that way they can give you pointers and guide you through the process of it. I would be glad to help and answer more questions