valve? - Performance Forum

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valve?
Monday, April 16, 2012 2:57 PM
My girlfriend gt popped a chain tensioner and skipped timing A LOT. I replaced the tensioner and went to turn it back to TDC and it wouldn't go. It'd stop millimeters away from lining up. I thought maybe the cams were off but i turned them and still no TDC. No mater what valves are open it still hits something at TDC. I thinking a bent valve from skipping on timing. Correct?

Re: valve?
Monday, April 16, 2012 4:13 PM
possible... i'd drop the oil pan and look for carnage.



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Re: valve?
Monday, April 16, 2012 7:14 PM
You would drop the oil pan before taking the head off?
Re: valve?
Monday, April 16, 2012 7:46 PM
no question. you don't have to play with the timing set to drop the oil pan. nor head bolts that can't be re-used.



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Re: valve?
Monday, April 16, 2012 8:06 PM
If I do find stuff in the oil pan what would be the culprit? It's like no matter what I set the cams too I can't get the crank too or pass tdc. Any scenarios?
Re: valve?
Monday, April 16, 2012 9:12 PM
If the bent are valves enough to stop the piston from going all the way to top dead center, you'll never get it to rotate past TDC. If you find metal in the oil pan, look up at your pistons from underneath too see if the valves went trough the pistons. Another way to check would be if you could measure your valve spring height under the compression stroke at TDC and compare them to a stock height to see if they are compressed. If they are, the valves are probably bent.
Re: valve?
Monday, April 16, 2012 10:13 PM
Either way the head is coming off correct? I never took off the oil pan to a automatic. Not only that but both motor mounts are off with a jackstand holding the motor via piece of wood and oil pan. I have a complete head from my last ld9 that i can throw on her gt. So if all signs point to valves...
Re: valve?
Monday, April 16, 2012 11:22 PM
I'd drop the oil pan as well... if there is any carnage, you'll need to get that out of there... you can, however, determine if you have a bent valve by pulling the cam towers and looking at the valves prior to pulling the head. at the point you are at now, you should be able to get the cam towers off pretty quickly... Make sure you don't have any exploded lifters



Re: valve?
Tuesday, April 17, 2012 7:10 AM
Takin off the oil pan on an auto any harder then a manual?
Re: valve?
Tuesday, April 17, 2012 11:59 AM
So i went down to the cams and noticed that the first lifter on the exhaust side is sticking up about 4 millimeters. What would cause that? Still no tdc with both cams out...
Re: valve?
Tuesday, April 17, 2012 5:25 PM
Pull the plugs out see if any one of the pistons looks badly chewed up. Or just pull the head. You're already that far it's not too much more work.




Re: valve?
Tuesday, April 17, 2012 6:48 PM
Pulling the head tomorrow morning. Is there such a thing as used valves? Or once there mated with the head its a done deal? I have a full head valves and all and was wondering if i could steal a valve from it just to get it running again..
Re: valve?
Tuesday, April 17, 2012 7:06 PM
Are you sure the timing is not 180 out of sync?



Re: valve?
Tuesday, April 17, 2012 7:30 PM
I thought the timing was just effed so i pulled the cams and even with none of the lifters being pressed it still wouldn't go to top dead center.
Re: valve?
Wednesday, April 18, 2012 7:55 PM
jason norwood wrote:Are you sure the timing is not 180 out of sync?


Wouldn't it still be able to make two complete revolutions but be out of sync with the ignition timing?
Re: valve?
Wednesday, April 18, 2012 10:10 PM
Two broken intake valves in cylinder one along with a punched piston.
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