stephenspann27 said:
THe only scary thing is if it has a reground crank in it or "reconditioned" rods that require .20 over bearing or somthing.. I think it's usually stamped in the crank though... and I could use "plastigauge" to check the clearance.
I replaced my rod bearings about a year ago. I was fighting a low pressure condition and some rod noise.
Like 5-90 said, this can be done with the motor and tranny in the vehicle.
Since my crank didn't have any obvious damage and looked and felt smooth, I didn't get it ground. I started with a set of standard size bearings and did them one at a time. I plastiguaged each bearing to verify the size. I was fully prepared to source over sized bearings but it wasn't necessary in my case as each bearing was within spec.
Make sure as you are disassembling each rod end that you protect the crank by slipping a piece of rubber hose over the threads on the rod. Also after you've checked the sizing make sure to use assembly lube during your final assembly. Your motor will be starved of oil for a few seconds during initial startup, especially if you've replaced the oil pump like I did. It's cheap insurance, might as well do it while you've got everything apart.
Now that thats been said. Are you sure you have bad rod bearings? There a lot of noises that the 4.0 can make that sound like bad rod bearings but are not.
When does the noise show up? Is it consistent throughout the rpm range or does it go away?
First things first, try and get a mechanical gauge to check the oil pressure. Extremely low oil pressure is usually indicative of bad bearings but it's not a guarantee.
If you do decide to do the bearings I would do everything you mentioned at once. You've got it all apart might as well do it then.
With 260+ I'd replace-
-Harmonic Damper
-Timing Chain and gears ( you should get a seal and gasket with the install kit)
-Oil Pump
-Bearings
-RMS
-And I would definitely vote on the one piece oil pan gasket. It makes things a lot easier.
