N14 Top End Knock

Hey everyone,
Trucks been OTR for about three days now and my drivers telling me there's a top-end knock on cylinders 1-2, he can't really figure out which it is. I had him use his phone as a stethoscope to narrow down where it was but I get an error when I try uploading that file here, its an audio file and that seems to be not allowed. In essence, sounds like someone is tapping the head with a small hammer on the passenger side of the engine, its normal noise down by the rocker boxes and cam. The number one cylinder had its injector replaced not two weeks ago from a truck that was running well and that fixed smokiness on startup. As per the old thread, there was a hefty amount of algae in the tanks that was not discovered until after the truck had stalled several times from the filter getting clogged up, I'm wondering if that could have damaged the injectors or allowed some of the algae to get through the filter and clog the injector mesh filter. I'm not sure if this is a bad overhead or a dead injector, the driver says it's not down on power at all, but the knocking has him concerned.

 

If the injector is over fueling at a idle they will knock like that. It's called fuel knock. It's a possibility.
I find those n14s sound like a bag marbles at idle anyway. Some sound like there comin apart.

 

It started off like that, you could throttle it up and it would disappear but now it knocks continuously, it quiets down with throttle but doesn't disappear like it used to.

 

I'd say a bad injector. I always go for a six pack
Makes for a smooth running engine

 

That's what I was thinking, I read on here a while back that Cummins stopped making these injectors and the quality of remans was really lacking, does that have any merit or just some hearsay?

 

Yeah, except it seems like there is at least one failing per year and it would be pretty expensive to replace the whole pack each time one fails

 

If you do go for injector(s) make sure to get the PX style instead of RX. PX has a higher rebuild overall quality, more parts of the injector are overhauled. From what I understand

 

The ones failing, is it the same injector everytime???
This is another reason to replace all six. If one fails the others are sure to follow.

 

I'm not sure. Never owned a Cummins but I do know they have a subpar injector on those n14s in general.

Just get a quality set from a reputable builder with a good warrenty. Do all six . It will run smoother and shouldn't have to go back in there for long time

 

I have the same issue, just did cylinder cut off test yesterday trying to find the bad injector, all seem to be working, but I know one is not working right. Just gotta wait until it fails I guess