2001 XJ 4.0L with about 148,000 on it
Rebuilt the engine due to an oil pressure issue. Below is all the parts and work that went into it

1. Decked Block
2. Resurfaced Head
3. Bored Cylinders (the paper work I have doesn't specify the specs)
4. Cam Bearings
5. Core Plugs
6. Reconditioned Connecting Rods & resized (again no specs)
7. Polished Crankshaft
8. Pistons (Speed-Pro H802CP-030)
9. Piston Rings (Hastings 4815-030)
10. Main Bearings (F/M 7211M)
11. Rod Bearings (F/M 6-3310CPA)
12. Rocker Arms (Enginetech)
13. Oil Pump & Pick-up Tube (Ultrapower M81A & Sealed Power 22414270)
14. Timing Chain Kit (Enginetech TS385B)
15. Camshaft and bearings (Both Enginetech)
16. Valve Lifters (Enginetech)
17. Remanufactured Camshaft Synchronizer (Cardone)
18. Push rods

As far as engine parts, pretty sure that is everything

After I was done, long story short, I put off this project almost 2 years due to personal reasons

When I finally got around to see if the engine would start it DID. I drove it a few months ago for literally no more than 10 mins, while driving I hear this kind of tapping sound, it was coming on the back of the block near cylinder 6. After starting the Jeep up again it stopped, but then started again when I turned it on and off.

I plan on very soon taking it apart to figure out the problem. With not much more information I can provide, any ideas on what that sound could be or what could cause it? When I rebuilt it, I followed ALL torque specs and spent countless hours watching videos to make sure I was doing it correctly.

Also since it has been sitting for so long, I will also be doing ALL fluid and oil changes, getting rid of gas (probably shouldn't have driven it tbh) and anything else I see that needs changing. Anything else I should inspect since it has been sitting for so long?

Sorry for this long post, I just want to drive my jeep again

 

Are you sure youre not hearing the evap solenoid on the passenger side firewall? Those damn things are annoying and will make you feel like the engine is making noise.
Did you do a proper cam breakin before you drove it? Worst case if no break in and crappy oil, could have wiped a cam lobe or killed a lifter. Or it could be tons of other things....