So I know LS engines have valve train noise but what I am hearing on my 02 seems louder than I recall being normal.

This is new territory for me and I’ve been doing a lot of reading/sleuthing to figure out if my valvetrain is fine or if I need to replace either the springs, rockers, and/or lifters. As far as I know, everything is OEM spec. Until I figure out if there is an issue, or if it is just in my head, I haven’t been driving the car.

So to get a move on things, I took off my valve covers today to see if any of the rocker arms could freely push down the pushrod (and to see if my z still has the yellow springs). Luckily, no yellow springs and no vertical movement when pushing on the rocker arm where it meets the pushrod- just a bit of lateral movement on most arms (which I’ve read is normal). Rocker arms were all torqued to 22ft lbs.

With all this, I had a couple questions for those with way more experience:

1) From my video below, does the valve train sound excessively noisy? The video was taken on a cold January night and the car had been sitting for a couple weeks at this point. The oil temp at the time of the video was in the 40s if I recall. Fast forward to April, I still hear this sound at start up and after the engine warms though it is much fainter.

2) Three of the springs on the passenger bank are notably more compressed than others. When examining the driver side, I could couldn’t visually distinguish a height difference across the springs. Do the pictures below show problematic springs that should be replaced?



Just to show the height difference, looking from the top of the passenger bank

Passenger side springs facing firewall

Pass side springs, pix 2

 

The springs should have various levels of compression they are all in varying degrees of opening and closing based on the cam/crank.

It sounds a little loud but its tough to tell from a video. If you do decide to replace anything just do everything at once and save yourself the aggravation.

 

I'm not going to make any claims based on an audio clip, but it does not sound like death noises.

Agreed with above. The rockers will depress various valves / springs based on the four stroke combustion cycle of Intake, Compression, Power, and Exhaust.

 

Thanks Tusc and PaulWall! I’m going to do a but more probing to see if anything obvious is amiss- pushrods that freely twist/ let it idle with the valve covers off to see if anything is frozen. If they check out, I’ll need to think about what is done next.

I did use a mechanics stethoscope on the head but nothing obvious jumped out to me. The #4 sounded a bit rougher but it wasn’t much different than the others. If you use a stethoscope to identify a lifter issue, does the bad lifter very clearly sound different than others (I’m guesing that may depend on how bad the lifter is?)

 

There is another thread on the forum last night with same concern. That one was more audibly metallic impact. Again, I can't guarantee anything from a phone recording. Also - notably - I am not a mechanic and my cars break a lot. So consider who you're listening to!

 

I think you are chasing a ghost. If you are looking for an excuse to add a cam I say do it. Otherwise I think you are fine.

 

I appreciate the advice! I also think there’s a good chance I’m chasing a ghost. I listened to the video from that post last night and it did sound louder/more metallic-like than what I heard on mine back in winter. I’ll likely check the pushrods for excessive movement and see what it looks like at idle with the covers off. If that looks ok, I’ll start driving it and just keep an ear out for any noticeable difference.

I do plan on keeping the cam stock so as much as I want to tackle a project like this for the sale of learning-by-doing, I only want to do it if I really need to.

 

Just saying if your going to leave it go redline it and that will show something or not. If your not comfortable with the noise take it apart its your engine. If i heard that in my engine i would of parked the car and tear it apart at first chance. No way i would leave that. Yes these engines make valvetrain noise but not like that. Or i could be wrong and ignore me.