thats the first thing i thought of when it got louder that it could be a piston slap.... but the sound is so intense right next to the cat on driver side. it does get quieter when it comes to operating temp, but at certain throttle positions it goes away completely then comes back when letting off gas or steppin on it. could the cat be defective? i know what it sounds like when piston slap/bent rod/lifters are ***'d and this sound is very different. its almost like the exhaust is bouncing in the cat but now its so loud the sound is coming from everywhere it seems like. it drives fine, feels fine power wise but the sound is so damn annoying. but like i said if it was internal problems wouldnt the check engine light come on?

 

Lifter x3. I had that prob a while back.

 

Have you guys noticed that the "tick" noise was more evident after you put LT headers on your trucks? Every GenIII engine vehicle I've ever owned, I have put LT headers on, and always after the header install, it sounds like you got lifters pecking.

What happens is, these Gen III engines have an amount of valvetrain noise anyway. When you put the LT headers on them, they act as a noise conduit and amplify the valvetrain noise heard as a "tick" or a "peck". If you listen closely, the noise has it's own timing to it....it has rythym to it. It's basically a noise you'll have to deal with if you run long tubes. Nothing to be troubled about.

 

I'm going to listen a little closer this morning on my drive to work and see if I can hear the noise all the time or just at idle. I'm thinking it's the lifter but don't want to change out lifters and have the same noise after going through the effort. I currently use Mobile 1 10w40 but the weather hasn't changed too drastically in the last few day.

 

in my opinion mobile 1 is your problem mine was making that weird knock noise. when i changed my oil last time it was pitch black at 1500 miles(mobile 1). The knock is gone for now but i can hear it coming back. i would switch to royal purple and i bet it will be gone.

 

How's your oil pressure? The lifters on cyl #7 are the last to get oil in direction of oil flow. If you have a bad cam retainer plate gasket, bad pickup tube o ring or a weak oil pump, it'll tick around cyl #7.


Happy reading:

Engine Knock or Lifter Noise (Replace O-Ring) #02-06-01-038 - (12/02/2002)
Engine Knock or Lifter Noise (Replace O-Ring)
2001-2002 Chevrolet Camaro

2001-2003 Chevrolet Corvette

2001-2002 Pontiac Firebird

2002-2003 Cadillac Escalade, Escalade EXT

2000-2003 Chevrolet Suburban, Tahoe

2001-2003 Chevrolet Silverado

2002-2003 Chevrolet Avalanche

2000-2003 GMC Yukon, Yukon XL

2001-2003 GMC Sierra

with 4.8L, 5.3L, 5.7L or 6.0L V8 Engine (VINs V, T, Z, G, S, N, U -- RPOs LR4, LM7, L59, LS1, LS6, LQ9, LQ4)

Condition
Some customers may comment on an engine tick noise. The distinguishing characteristic of this condition is that it likely will have been present since new, and is typically noticed within the first 161-322 km (100-200 mi). The noise may often be diagnosed as a collapsed lifter. Additionally, the noise may be present at cold start and appear to diminish and then return as the engine warms to operating temperature. This noise is different from other noises that may begin to occur at 3219-4828 km (2000-3000 mi).

Cause
The O-ring seal between the oil pump screen and the oil pump may be cut, causing aeration of the oil.

Correction
Inspect the O-ring seal and replace as necessary. Use the applicable part number listed below. Refer to the Engine Mechanical sub-section of the appropriate Service Manual.

Parts Information
Part Number
Description
Qty

12557752
Seal-O/Pmp (O-ring)

(F and Y Cars)
1

12563963
Seal-O/Pmp (O-ring)

(C/K Trucks)
1


Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Usage
Labor Time

J1060
Pickup Tube and Screen - Replace
F Car
3.7 hrs

Y Car
4.3 hrs

C Truck
1.3 hrs

K Truck
2.1 hrs

 

Oil pressure is good (40-44psi)and the noise seems to be distinctly lifter at this point. I originally wanted to believe the injector could make that noise since the change out is relatively painless but I have verified my lifters are the culprit. Alas it is time to put in the LPE GT-7 cam but I now need to find out what performance lifters are available? The LS7s seem to be a popular choice right now. Does anyone have any experience with these or other lifters worth considering?

 

I am running the LS7 lifters. What can I say? They are lifters. They tend to bleed down on me after sitting overnight but I can live with 5 seconds of ticking until the lifters get oil pressure. This may be partially due to the fact I am running patriot dual gold valve springs with my combo. More spring pressure is probably pushing the oil out of the plunger during hours at rest.

 

Post a vid or audio clip of your "tick" so we can listen

 

I don't expect anything magic as far as hydraulic lifters go, I just don't want to pick the wrong lifters since it means pulling my heads to replace them. I can pick up the LS7s for about $110 but I haven't checked out any other brands to compare. Here's what I have as far as a replacement part list. LS7 lifters, Comp 7.4 pushrods, LS6 valve springs, and all required gaskets. Is there anything else I should consider at this time?