Cat MXS C15 ticking

Hey guys. Bought an old TMC 2007 Pete with a cat mxs. Probably not my best purchase ‍♂️ Anyway, the truck had issues I was finding which is normal for a million mile rig. But here’s what happened, truck ran like #### and surged. Took to the dealer they told me the problem was a 625hp tune. They changed it to a cat 550hp tune. Then they ran the overhead and found broken Iva housing. Replaced that. Finished overhead and surge was gone. I obviously noticed a lack of power now. So I bought a temporary fix. The fixed fuel harness. Tried it and it made this ticking noise when driving. So I decided to pull it off. Ran ok after. Then as time went on maybe 3 or 4 week later I noticed this tick get louder and louder and louder. It sounded like the back of the block loudest at the passenger side down by the oil pan most likely resonating through the block right? Well I took it to a shop. Was told my head might be going bad since it was a gold package overhaul TMC did meaning head was original. I know this is long but here’s where it gets interesting. Took it to Pete... found a broken injector spring. Replaced it. Noise still there. Took it to cat in Des Moines iowa and it was there over a week. Night and day they looked at this truck. They tore this truck clear down to the block inspected every component found zero issues besides a bad head. Replaced the head. Did new overhead. They claim noise was gone. I can still hear it plain as day. But they told me the truck ran low on hp on the dyno. So I said replace the transfer pump. They did. Brought the hp up a little. But they had this truck over a week. They tried new ecm, new injectors, they tried the new head, they pulled my pistons and checked every last part including my cam. They tried new wiring harnesses. Still idles rough and has a ticking/soft knocking. It sounds worse when the fuel harness is on but no matter what it’s there cold or warm. Runs fine down the road and the noise goes away if you’re under a load going uphill but otherwise it’s there. It’s pissing me off and I’m tired of throwing money to find dead ends. The engine was torn clear apart and no issues were found. Every tech touched it, multiple shops, they called other car dealers, still there. What am I missing??! Looks like my exhaust bellow could be bad... but they wouldn’t make an internal sound. So what’s going on here?

 

ill give that a whirl. But what baffles me is how the entire thing has been gone through or has been rebuilt
Or replaced and STILL does it. The only components in that engine that might be original is the cam, timing set Etc etc. But according to CAT that all was in good shape. They even said it looked like someone replaced the Cam at one time. I don’t understand how I can hear this plain as day across a parking lot but every technician or mechanic that stands next to it can’t hear and claims they hear a normal CAT engine. I know for a fact that sound wasn’t there when I bought it. So I can’t be going crazy. Couldn’t be the clutch somehow making noise could it??

 

One thing also not stated above.... they pulled the head and found cylinder 4 exhaust valves were hitting the piston. After the new head it still (in my opinion) has the noise. They claim they don’t hear it but to me it’s loud so idk how they don’t. But after the new head cylinders 3 and 4 are low on hp and are low on fuel rate. They tried new injectors wondering if maybe the aftermarket injectors were starving out after cylinder 2. But that did nothing. Still ran and sounded the same. They literally spent a week on this engine scratching their heads and called me up on a Friday and said they were beat. Had no idea. Said they’re chocking this truck up to officially kicked their ### because they have no leads to go on. So I ended up picking it up. I asked if the cam needed replaced because it ran that way before the new head as well and the cam was from the old head. They swore up and down that cam was perfect.

 

Reman head from CAT