intake cam valves bent twice now...

[AWDTalonDE]

After just turning the car off the intake cam valves have bent. First before the motor was touched the car randomly didn't start up and we found out the valves bent. After a full rebuild replacing nearly everything and running it strong, the problem happened again. The timing isn't off yet there is 0 compression across. What could cause this to happen, maybe a bad CAS?

 

[somdturbo]

Are you using a new timing belt? If not old one might be strectched making it easy to jump teeth.
Is it tentioned correctly? If not might be skipping teeth when it cranks.
Bad CAS will not effect it. The physical timing determines the interference of the motor.
I would guess that either the timing jumped or your timing marks are not clear/correct.

 

[brute]

The 0 compression means your valves are open when you try to do the test. This means your timing is off. And if your timing is off, you'll probably bend valves. You need to recheck how your timing is. Make sure everything is lined up. It's just about rechecking everything at this point.

 

[AWDTalonDE]

yes brand new belt on, however what I don't understand about if the timing is off or if we mis timed a mark is that this problem orginally started without any change to it. Nothing was touched and it was running fine then we turned it off and it wouldn't turn on again, and the valves were bent. It seems as if there is something else wrong that is causing this, but I will re-check the timing on everything.

 

[4g63mightymax]

I would have to guess that your timing belt tensioner is probably not keeping correct tension on the belt, and allowing your cam to slip teeth. Did you replace it when you did the timing belt the first time? Take the tensioner off and try and compress it. If you can do it by hand, it is total junk, nobody is that strong. It should take some serious pressure to push the pin down (like a vise with several minutes of constant pressure). I have replaced a few of these on my own cars, so I know it is a commonly broken part.
Good luck and be sure to post what you find, so that you can help the next guy with this same problem.
-Jeremy

 

[AWDTalonDE]

hmm I don't understand how this thing could've messed up again though, we just checked the timing marks and they are normal.

So now twice the intake cam only side of the valves are bent with all the belts and timing in tact, wtf???

 

[perley03]

Are you sure you checked them correctly? The two marks on the cam gears should face each other and they have to be dead on, but those marks also have to be parallel with the top of the head. That is why you need to use a straight edge to check this. Also check your crankshaft marks, as those could have been off as well, throwing your base timing off as well.

 

[AWDTalonDE]

was just thinking, we just replaced the balance shaft belt but is there any chance that that's the cause for the problem?

 

[dieseltech]

This is a long shot. Has the head been planed? There can only be .008in of material removed and then you will run into problems

Overall height of the head is: 132.0 mm or 5.197in with no more than 0.2mm removed or .008in removed

 

[AWDTalonDE]

never got it planed, anyone else have any clue before i just take this to a shop to let them figure it out? THe main thing to look at is this problem happened first with no real sign of failure before I just try to turn it on and the valves were bent.After the rebuild and running strong i try to turn it on again after having ran it throughout the 2 days turning it on and off when needed and it happens again. Bent intake cam side of valves.