# 2005 GTO LS2 valve adjustment?



## rnoswal (Dec 2, 2007)

I am hearing what sounds like lifter clicking while idling. I haven't driven another LS2 engine, but I raced a 350 chevy in a dirt track class and the LS2 seems to feel a little rought under power. Say from 2500 rpms on up. Like a miss, but hard to isolate. I replaced the plugs and that didn't seem to make a difference. Next was to pull the valve covers and check the rockers for a possible loose adjustment. I haven't had the covers off, and I have heard there is no adjustment, but that doesn't seem right. I know hydraulic lifters are self adjusting, but they can be out. So I was wondering what the initial setting was. 

Lifters pumped up, loosen them till the pushrod turns then turn the adjuster a certain amout, like a turn, more or less. There must me some initial adjustment from the factory! I just wanted to be able to try something when I had the covers off, but I can't find any info on this.

Let me know and thanks.

Russ


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## B-ville Goat (Oct 5, 2008)

When they say "non adjustable" it's because there isn't a stud with a nut on it that you can loosen or tighten to adjust, there is a bolt through it that just gets torqued down, therefore no adjustment. If you have a miss you would have a check engine light for sure. These engines do make a good bit of noise that is considered normal.


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## GM4life (Mar 18, 2007)

He is correct, our valvetrain has no adjustment. It is normal for them to sound like a sewing machine, if you have a missfire your check engine light will also light up, they also run alittle rough with some rocking.


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## 6QTS11OZ (Mar 27, 2005)

If the sound you hear isn't extremely loud or obnoxious then it is more than likely okay. It's just the nature of the LSx engines. What you may be hearing is piston slap. There is virtually no skirt on our pistons therefore they're going to make noise as they move up and down the cylinder. It is more noticeable when you first start the engine. After warm-up it pretty much go away. If it's ONLY during idling then you're okay. You will also hear a little injector noise too. And get used to the engine shaking at idle. I haven't seen one that didn't shake yet. It's perfectly normal unless it feels like you're going to get thrown out the driver's seat. Like the other's have said, if you haven't thrown a check engine light then you're fine. Trust me, if there's a missfire, the ECM will catch it.


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## vxssls1 (Sep 9, 2006)

try changing to a different oil LSx engines are very sensitive to oil brands/viscosity's 
you may have to try a few different ones to get one that makes your motor quiet
excessive engine noise is not expectable 

maybe you may have a small exhaust leak that will sound like a tapping noise


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## rnoswal (Dec 2, 2007)

Thanks guys. The noise isn't offensive, just there and wondering if it was adjustable. There are no engine codes and vxssls1, you may be right about the exhaust leak. I have noticed some there and I mean to get a set of headers eventually. The noise is internal and apparently nothing to concern myself about. I am using Mobil1 that has been in the car since I have owned it. 5-30wt. 40K miles, should I go for a little thicker oil maybe?

Thanks for the replies.

Russ


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## vxssls1 (Sep 9, 2006)

rnoswal said:


> Thanks guys. The noise isn't offensive, just there and wondering if it was adjustable. There are no engine codes and vxssls1, you may be right about the exhaust leak. I have noticed some there and I mean to get a set of headers eventually. The noise is internal and apparently nothing to concern myself about. I am using Mobil1 that has been in the car since I have owned it. 5-30wt. 40K miles, should I go for a little thicker oil maybe?
> 
> Thanks for the replies.
> 
> Russ


I use castrol edge 25/50 in my Ls1 and it is quiet as a mouse hot or cold
and allot of guys here use castrol edge 10/60
but I dont think use get it over in the US

what is the weather conditions like where you are
if it is cold thicker oil may not be the best 
but IMHO 5/30 is to thin
if you do your own services have a look at the oil next time you drain it it will be as thin as water 

I know most guys over there will disagree but I have had great success with it
I use to use thinner oil and it made my motor sound like a sowing machine 
and on the advice of my machanic I switched to thicker oil


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## rnoswal (Dec 2, 2007)

Thanks again. I live in Louisiana and it does get hot for 6 months, 90 plus and 95 to 100 during July and August. I will try the thicker oil during the next change. The winters are mild and only occasionally get in the 30's during january and february.
I was more concerned with the closer tolerances in the bearings as to the viscosity of oil and not needing the thicker oil to make up for old school larger tolerances. But maybe the thinner oil was more for cooler climates and even more for gas mileage. Synthetics don't thicken up nearly as much as petroleum oils during winters or even just starting up cold. 

Thanks again.


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## ArmyGTO (Mar 5, 2009)

i'm having a ton of problems with my 06, check eng light came on read the codes, having a cylinder missfire, load tapping that everyone says is a lifter but no one can find it when they take it apart, also my check oil light flashis from time to time, bank 1 too lean, have exhaust smells bad, i had a comp cam installed the hole kit spring, push rod, so on. and had no noise till about a few days ago. i'm thinking a 02 sensor is throghing everything off, but i'm no mech, if anyone has anything to help send me a message, i'm new to the forum thing, and not sure on how to use this site yet, thanks again


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