N14 Top End Knock

Replaced 1 and 2 before I called it quits, the knock is way dimmer but still there. I still haven't set the valves as it got pretty late, tommorow I'm planning on doing all of them and doing the full overhead. I'm guessing since the knock dimmed out but stayed local cylinder 3 is also going to have a bad injector. I'm wondering if it's also going to be a mash of PX and RX injectors the rest of the way.

Take it with a grain if salt, the injector that failed was an RX reman, number 1 was a PX and seemed to be brand new, the connector was still gray and not that grayish brown from sitting in oil, I reached out to premco and they said they'd test them so I'll be sending them their way. They claim to get better results because they manufacture their own injector parts instead of relying on Cummins.

PS. Harbor Freight has a set of brushes that fit the injector cups super well if you're in a pinch and need them.

 

Final update, trucks up and running and sounds darn near perfect. Valves were all pretty close, that's what I'd assume since it had an overhead two weeks ago. Thanks for the help everyone.

 

Here I was thinking I had it fixed. Drivers been OTR and said the knock came back today. I took every precaution and changed all the injectors, photographed and compared every piston crown and all was nominal. I'm having him pull the fuel filter just in case it got clogged with alage again (previous problem in a different thread). All the injector cups were cleaned and inspected, no cracks or coolant leakage.
Engines power according to him isn't reduced at all. I had the engine running with the Jake's off and all the valves and injectors have the same amount lift so I don't think it's the cam which leaves the head, either a burnt valve or cracked head, but theres no coolant system pressure and the exhaust has no sweet smell, no misfire either. The knock sounds just like someone has a hammer and is hitting the rocker housing with said hammer every cycle. I'm at a loss because the truck runs like a raped ape, no reduction in power just a very loud obnoxious knock.

 

The overhead wasn't touched this time around, I checked it just to be sure. I mark all my bolts with nail polish as a visual reference for if anything's backed off, all was set, a bit tighter then, but still could get the feelers in and out with some persuasion.
That second part almost sounds like the Jake's warped because of improper tightening or loosening and bowed up. It ran fine with the Jake's on and off and came back after 50 miles, driver says it's been slowly getting louder and louder up to thr previous volume of the video above. The thing I dont get is it disappears the second the injector gets unplugged.

I used the stethoscope and checked each of the rocker boxes for a ticking or scraping noise to rule out a cam and followers but ther was just the normal whirring. I've got an audio recording but cant figure out how to post it.

 

Could it be a bad harness with a weak connection that's allowing the injector to open partially and under fuel?

 

Driver just reran the overhead and the knock didn't change. If it is the cam follower, can I R&R with the same shims to keep timing?
The thing I don't get is how it could be the valvetrain if replacing the injectors made it go away for a bit.