It's got 1000 miles and the noise does not get louder at higher revs.

 

Wow only 1000 miles, that's no good. I recently purchased a Cherokee with what I think is piston slap on a recently rebuilt engine. I haven't taken it apart yet to check, but from my research and listening to the engine I think it is at least piston slap or I'm hearing.
I found this thread to be extremely useful. https://forums.4wdmechanix.com/topic...vetrain-noise/
I also used a small pipe to help pinpoint the noise. In my case I hear the knock most on the driver's side of the block when putting the pipe against a the freeze plugs around cylinder 4, 5, and 6.
Maybe try uploading the video to YouTube or something similar. Good luck!

 

Did you beild the engine or did you have a shop put it together ? and did change the head or exhaust ?

 

I had an engine shop do the short block. I provided the RA from SCAT. Got the head from Clearwater and reused the exhaust manifold to pass smog...

 

Sounds valve train related to me. Like either a lifter got stuck closed or you are losing a lobe on the cam.

 

Did you use a tube or a long screwdriver or something to try and locate the noise? What I believe is piston slap on my engine cannot be heard any more with a pipe anyway except on the driver's side freeze plugs. Valve cover, timing cover, oil pan, and anyway else I tried, didn't sound any louder with the pipe to my ear than without.

 

Thanks. I just did the 500 mile oil change and no metal was present. Used zinc oil and zing additive, so I'm fairly confident that it's not a lobe. Lifters all pumped oil, but I will check again as soon as I can get to it.

 

It does sound like a lifter to me allso . have you checked the rocker arms to see if any are loose ? and maybe you can run it with out the valve cover on and check to see if it is a lifter or loose rocker arm .

 

There's a couple things that I forgot to mention. This sound started from the very first start, post build, and though you can't hear it on the video, there is like a sucking/suction cup/plunger type sound to this. Not sure if this means anything, maybe it'll ring a bell...

 

What kind of lifter preload are you running? If you got one super loose, that would make sense.

 

I clocked the preload from zero lash, with help from member 97grand4.0, and all were safely within the range. I'll be rechecking all of this soon.

 

 

Clocked from preload?

 

Is it your purpose to be a smart ***?

 

Very cute man. I have one of each, but I'm trying to get some differing opinions here so try to resist your urge to be superior...