I have a bit of a mystery here and am working my way through solving it. Thought it would be a good idea to post here to gather some collective wisdom.

The noise is a louder-than-normal ticking coming from underneath the valve cover. It's not there for the first 10-15 seconds of a cold start but starts getting loud and reaches maximum volume right about when the air pump turns off. This is not a super loud tick but not normal either.

The car in question is a bone-stock '04 with ~103k miles. I've have it since 66k and have put approximately 13 track days on it. The day before my most recent track day (mid-June) I installed a freshly powdercoated valve cover and did a valve adjustment. Only minor adjustments were needed and nothing was out of spec. The valve cover was sandblasted before the powdercoating so I made sure to clean it using brake cleaner and paper towels prior to install. I was about to go out on my third track session when I started up the car and it seemed the valvetrain was ticking louder than before. The car drove fine and I finished up the track day, set a PB time at Sonoma. The extra noise was still there when driving home from the track and it seemed like the low/mid-range was not as crisp but this is coming from my butt dyno and we all know how accurate that can be.

Not liking the noise, I changed the oil, removed the valve cover, thoroughly washed it out with water, and set my valve lash. One valve was a little loose but the noise still persists.

What I've done is...
- Redid valve lash adjustment
- Disconnected fuel injectors one by one: noise doesn't go away
- Checked compression: 215-230psi across the board

I did a ton of reading as far as others who've had similar issues. Some have solved it and others haven't. Based on my testing, it is assuredly not the TCT, not a rod, not the injectors, and not out-of-spec valve clearances. There have been suggestions in other threads that the lost motion assemblies may be to blame but I haven't seem a success story yet.

Today, I removed the cams and performed a visual inspection on the valvetrain. Wear patterns on lobes and bearings look ok, no scoring. Retainers look ok at a glance but I've not put a mirror to them yet. I've over-revved it on multiple occasions but not in a long time, plus it's an AP2. I've scoured the FSM for a spec for the LMAs but found nothing. I thought there would be at least a free length spec or something. I'm thinking of just tossing in some new LMAs and seeing what happens. Curious to measure mine vs new ones.

I'm planning on doing another track day next month.

Sorry for the text wall, any ideas guys?

 

Do you have a sound clip, you can post?

Thanks!

 

Unfortunately, I did not have the foresight! The cams are currently out and I'll probably order some new LMAs considering they're not very pricey.

 

+1 on this.

 

I happen to have two brand new ones you can have if you ever come to south bay

 

Thank you for the offer! What part of the South Bay? I work in Menlo Park and find my way down there once in a while.

I'll get a clip up as soon as I can!

 

Thank you for the offer! What part of the South Bay? I work in Menlo Park and find my way down there once in a while.

I'll get a clip up as soon as I can!
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I'm in San Jose, could possibly meet at the milpitas meet?

 

Thank you for the offer! What part of the South Bay? I work in Menlo Park and find my way down there once in a while.

I'll get a clip up as soon as I can!
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I'm in San Jose, could possibly meet at the milpitas meet?
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I'll send you a PM

 

Are you sure your spark plugs are sealing? I chased a hot engine tick like you describe on my J35 (Ridgeline). It was loose spark plus but I would swear it was a valve tick.

I know you pulled them for a compression check, but check the gaskets.

 

Good suggestion! I considered that but didn't see excessive carbon blow-by on the plugs and they were tight when I removed them. I made sure to get them nice and tight before I ran it last as well.

I did get new plugs to put in once it's back together. Planning to do one more careful inspection of the valvetrain tonight and then make a parts order tomorrow.