Few months ago I put in a 130k mile 98 ZJ engine in my XJ.
New timing chain, sprockets, and gaskets.
No slack in the rods from what I could tell when I had the pan off.

All has been fine for a few thousand miles.
Over the last week it has been slowly getting noisier and noisier.
At first was so little that I was even questioning myself if I really heard anything out of the ordinary. Now, it's crazy noisy.
It otherwise runs just fine. Doesnt seem down on power or anything.

Please try to ignore the fan running in the first video. It was nowhere near as loud as the engine noise.
Second video is showing the lag in building oil pressure. I should have waited as after it sits, it takes much longer to build pressure, but gives you an idea that it is not normal operation.

https://www.youtube.com/watch?v=-3Vg...ature=youtu.be
https://www.youtube.com/watch?v=fq9n...ature=youtu.be

What could this noise be? Main or crank bearings?

 

It sounds awful from the video . How old is the oil/filter ?

 

About 4 days. Noise and oil pressure issue started before.

 

My suggestion is stop running it and start looking to find the source of the sound . Pull valve cover , then oil pan if you must . Hard to diagnose any further over the Internet without more info .

 

Is the oil level good?

 

an oil analysis cost ~$40..if its high in metal, you know for sure a strip down is needed, which is better than a rod thru the block

( I didnt listen your vid, but wont drive something with radical internal engine noise)

 

Although it would not affect oil pressure... a possible source of the noise is the harmonic balancer coming apart. Happened to mine.

 

Youre on the right path. Turns out it was water pump.
First time I removed the belt and checked it it was fine so far as I could tell.
Removed belt again and was very clear what the issue was.

Now onto the slow to rise oil pressure.

 

Glad the noise wasn't something serious. Keep us posted on the oil pressure. I am not so sure (fingers crossed) that you even have an issue. Sometimes we worry too much. LOL

 

Thanks, me too.
Im going to get a mechanical gauge tomorrow jut to confirm.
May also just change the filter yet again. Maybe draining back. Ill test with a quick of and start to see.

New vids
https://www.youtube.com/watch?v=oHfy...ature=youtu.be
https://www.youtube.com/watch?v=2Qaj...ature=youtu.be