RhinoSS

When I had my LQ4 apart during my swap I noticed a bad cam bearing and journal. I did a full set of bearings and threw in a low mile pull out cam from a 2002 LS1. I just happened to have it sitting around and it shared the same P/N as the original.
Once I got the motor back together and in the truck I've noticed a little valve train noise. Not extremely bad, but enough to make me worry about it's long term reliability. I think it sounds like 1 or 2 lifters that are loose or not pumping up properly.
Since I've been having noise issues I started searching and found most people run .050 to .080 preload on their lifters. I measured the preload from 0 lash and found I had about .60 preload at 1 1/4 turns, however I had much less than the required 22 ft/lbs of torque stated in GM manuals. I have a feeling that going to the full 22 ft/lbs will yield a preload higher than .1. Does this indicate my pushrod length is incorrect? I have a hard time believing that two Gen III cams with the same part number have a different base circle.
Pushrod length appears to be the same between the LQ4 and the LS1 that this cam came from. This is a very basic stock part rebuild, can anyone see what I'm possibly doing wrong?

There's always the chance of having a bad lifter, but I'm trying to rule out all other possibilities before yanking the heads. This motor was a take out from a 1500HD and set idle for about 18 months to a year prior to being installed in my truck. To my knowledge, the top end had never been broken open prior to me.

smokeshow

iTrader: (16)

Can you get a video? Sometimes valve train noise is just...well, noisy. And theres not a lot you can do about it. I went semi crazy trying to quiet mine down, and just settled on the fact that it's going to be loud.
Now if you can hear it from more than like 15 feet away, then you may have a problem. Does it go away after a few minutes of warmup? Also, whats your oil pressure look like?

RhinoSS

At the moment I have the coil packs and covers off. I can probably get it back together tomorrow. This LQ4 is much noisier than my LM7 that it replaced. If the noise was uniform I wouldn't be nearly as concerned, however it sounds like 1, maybe 2, lifters that are loose. I can easily hear it in the cab with windows up. At startup one could definately hear it from over 15 feet. It does quiet as it warms, but never fully goes away. There are some times I drive the truck and can barely hear it, others it's very obvious. It may be my imagination, but I feel that it is getting slightly worse with time. I've driven it roughly 200 miles since the swap was completed.
One additional thing I neglected to mention was that I did add a set of edelbrock shorties at the same time. I say this for full disclosure of changes, but don't feel it is the cause since the noise sounds like it runs at valve train speed, and uneven from bank to bank. The pass side seems louder than the drivers.

Oil pressure is a solid 45 lbs at hot idle, moving up to 65 when pushing above 3.5k.

Bumpers

iTrader: (10)

I just swapped my rockers out on mine cuz my pass side lq4 rockers were noisy as heck.. I put the ones out of my 5.3 on the pass side and it quiet'd down a good bit and both sides sound about the same now.. But the top end on these engines are loud anyway

RhinoSS

I did pull the rockers and checked the roller play, thinking it could be a potential issue. I'm far from an expert, but I think they seem ok. Just to check I guess I could always swap the left bank for the right to see if the noise follows suit. Unfortunately my 5.3 left the garage yesterday, destined for another swap.

Something else I may mention is that it makes quite a ruckus at initial start up, but quiets down in around 5 seconds as the lifters pump. It's a very similar noise to what I'm hearing, however seems like multiple cylinders at start up, then one the remaining time.

Since my preload range doesn't seem to coincide with my 22 ft/lbs, should I trust one measurement over the other? My worry is that I'm overtightening the lifter which has caused this issue.

smokeshow

iTrader: (16)

From how you explain it, it sounds fine. My clicky lifters have been in for something like 6000 miles now, and not a hint of a problem. Just noisy

AKlowriderZ71

iTrader: (22)

Are you using stock rocker arms, or have you installed an adjustable setup?

supercharged680

iTrader: (1)

not trying to hijack ur thread.. but do u usually loose HP if u have lifters in there that arnt adjusted *preload*

RhinoSS

The rockers are 100% bone stock. In fact, the only valvetrain component that isn't reused was the cam. However, it was from the exact same year of motor, with the same P/N.

Yes, you can lose horsepower when your valves are not properly adjusted.

smokeshow

iTrader: (16)

That could be part of the problem. Lifters are a wear in place item, so when you replace the cam regardless if its the same part number you should replace the lifters as well.