Tell me what this is...
Here is the setup...

Stock 5.3L
* 214-.600'' cam
* stock push rods
* stock rockers
* stock lifters
* 918s

Since the cam install, I've heard a slight tapping sound that seems to come from the drivers side. I have yet to take things apart and see what is going on. Two nights ago, the tapping got very loud... and then fell back down to its normal knocking pitch...

To give you an idea, it's 'normal' tapping sound as far as loudness goes is only audible when the windows are up and the AC is off.

A few notes.
* Increases with RPM
* Oil is good
* Oil pressure is good (40-60)

On the way to the track tonight, the tapping got very loud again and I drove it home.... Still fades in and out. Sometimes your sitting there thinking hte motors coming apart and then later on down the road it goes away...

What exactly is this? Any damage?

 

Start with the simple things, get yourself a wooden broom handle or a mechanics stethescope and start poking around. Listen to your fuel injector rails to see if the noise is coming from there, if it's quiet then touch the cyl head around each exhaust port, if nothing move down to the block. It should be obvious where the problem is once you start listening.

 

stock pushrods flexing/bending?
That's a lot of cam and spring pressure for the stock pushrods.

 

Moddoo, that's a definet possibility and changing out the push rods will probably be the first order of business.
... pretty quick lobes for stock push rods

 

Check out this thread:

https://www.performancetrucks.net/fo...gurgling+noise

 

I dont think thats what they are referring to..


I have the same problem on mine..
starts off barely audible and then it sounds like a gremlin trying to hammer his way out, and then fades away..
I can make it stop if I run the RPMS up..

I too was leaning towards the push rods not be long enough..
this is the first time I have heard of someone else having the same problem.

 

I ordered some 7.5s... Should be long enough. Coming in today or tomorrow... I need to check the tracking #.... But I will be putting them in soon because we got a TS or Hurricane headed our way. I wanna know if this is the culprit. By the way, I used a pushrod length checker and 7.4 was dead on with 0 preload so we added .1 for 100 preload... I kept reading inbetween .050 - .120 is what you want with the stock lifters so we'll see.

By the way, I have .030'' milled heads, and 1.43'' base circles (stock is 1.553'').

One last thing... Read some of this : Pushrod info

Forgot one thing... I'm using 7.4s at the moment which would be 0 preload... When the lifter is riding on the base circle, my pushrods are so short that I can wobble the rocker from left/right, right/left on the valve stem.

 

I cant believee your running a .600" lift cam with stock pushrods.... you have probably bent them.....

they could be too long also...what might be "tapping" is the pushrods pushing to much against the lifters and the lifters being fully compressed all the time!! you need a pushrod checker tool to be sure you get the right length pushrods...

 

I have a stock LQ4 with a stock valvetrain, and mine sounds like that. I logged it last night and there was ZERO knock, so I know it wasn't detonation. I'm thinking mine is air in the cooling system/heater core....and I'll try to address it this weekend. Maybe my problem is diffent...but it sounds the same.

 

I had a similar sound and was told that it might be a collapsed lifter. It would come and go, and finally went one day and never came back.