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Discussion Starter #1
All,

First post! I've got an '06 that I've had for about a year and a half now. 35K miles and pretty strong-until yesterday during normal driving. The exhaust immediately sounds different to me and there is a much noisier (than usual) tick coming from the engine. Feels like less power but I'm not about to attempt a full power pull when I suspect something is up. Oil pressure gauge says that I've got usual pressure. At a cursory look, I do not see exhaust leaks from engine-back. I did see what I'm guessing was a fair amount of fuel (unusual) being thrown out the exhaust. For these reasons, I feel like something is up at the valvetrain and the heads will need to be pulled for proper diagnosis. Or perhaps I've destroyed one of the cats but not sure that explains the louder tick or liquid noticed.

Here are a couple of other facts about the car that may or may not be helpful:
-Tuned on hptuners
-No CEL displayed
-BTR stage 2 cam. Uncertain about springs, rocker, etc as the car was purchased this way
-Kooks 1 7/8" headers, Corsa cats-back
-FAST102 intake/tb

I should be able to drain the oil tonight to look for metallic shavings. In the meantime, any other ideas? I am curious if pulling some data from hptuners might shed some light on the issue.

I am very new to the scene, so I don't doubt that shortly I will be hunting around for a good service manual. I may have to become familiar with hptuners as well.

Thanks
 

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Try idling the car in your garage or something, and try to find the source of the noise. Like you said, change the oil, and cut the filter open to see if there are shavings in there. If you have good pressure after the engine is hot (20+ at idle, and 10 more per 1000RPM after that), then i doubt it's a bearing issue.
 

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Discussion Starter #4
Sure, I guess my biggest concern lies with the idea of continuing to run the engine if it sounds like it may be struggling and therefore potentially causing more damage. Perhaps that is a mistaken thought though.
 

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If it's minor and you run it, then yoi're good. If it's Major and your run it, then it's gonna need a rebuild regardless. So with #1 at least ya have a shot at not tearing down engine.
 

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Discussion Starter #7
Thanks for the replies, I will report back after doing some digging. Where can I find a good repair manual for this vehicle, whether online or book?
 

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I purchased a GM factory service manual from emanualonline.com. Very in-depth searchable PDFs that cover 04-06, manual and auto. It cost me 20 bucks and has been very helpful. However, now that I post that, I'm sure someone will point you where to find one for free lol
 

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When I was still on Facebook there was a pinned post in one of the (many) GTO groups that had PDFs of a lot of the sections of the manual, but not all, hopefully this link still works:

Uploads
 

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Discussion Starter #10
Secrets revealed...

500145


Anyone dealt with this before? Pushrod all the way against its opening, but I'm not seeing scoring, metal, etc. I do still need to drop the oil to take a look:
500146


What's protocol here? Thanks for the help.
 

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I would guess that your lifter is toast. But check out your rocker and the pedestall that it sits on to make sure they're not damaged.
 

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Discussion Starter #13
Just came loose. Will pull off the rocker valve and probably replace it. Check underneath where it sits for visible signs of damage, pull the rod and verify trueness.
 

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i would look at the rocker arm bolt hole and the boss, as well, make sure the boss didn't crack or break or the rocker bolt didn't pull out of the hole leaving trashed threads, too.
 

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Discussion Starter #18
I am guessing that a failed lifter would have produced a much more noticeable effect on driving and potentially led to loss of oil pressure though I am not able to verify without tearing down the motor a good bit.

After a good bit of running around trying to find a 12pt 8mm socket, I've been able to survey for some more damage:

Scoring at the valve cover and on the rocker arm support stand:
500180


Pushrod seems true and shows signs only of minor scuffing:
500181


Rocker arm shows some signs of wear:
500182


The end of the valve and the keeper look so-so, picture below doesn't show well:
500183


I think that my plan for now is to only replace:
valve spring rocker arm #10214664
valve spring rocker arm support stand #12552203

I'll have to take off all intake and exhaust rocker valves to replace the support stand. Question for you all-in order to do so I'll need to make sure engine is rotated to TDC. Right now (right bank), cyl #2 exhaust valve is what's being worked on-without the timing cover off, how do I verify cam/crank position? I looked at the harmonic balancer and see that it's got 4 sets of dots around the circumference in a pattern like o oooo oooo o but I'm not sure what these marks refer to.

500184


Instead of looking at dots I may be able to rotate the crank and follow the movement of one of the pushrods.

Thanks
 

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Put a dummy pushrod in the holes. Crank it over until you feel the exhaust pushrod start pushing out. Then you will have 0 lash on the intake valve. Put a dummy pushrod in the intake side and crank it over until you feel the intake valve start closing. You now have 0 lash on tje exhaust side. You want to tighten rockers at 0 lash. I am wary of the lifter tho man. I would also replace that pushrod. You can buy single pushrods from BTR for 6 buck.
 

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Discussion Starter #20
Can I inspect for a bad lifter without pulling the head by replacing support, rocker arm, pushrod and checking to see if the rocker arm then has play i.e. it looks like I can substantially vary the lash?

Thanks!
 
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