Hi all. New to the forms and I wanted to get your opinions on just what might be happening with my timing chain slack issue. First, i've got a 2010 F150 SuperCrew Lariat with the 5.4 3v engine. I've learned to love FordTechMakuloco on Youtube and i've followed his videos to the letter. I also have the factory ford manuals and a subscription to Chilton online.

Over the winter, I took the engine out and completely rebuilt it for longevity reasons; I like the truck and I want it to last (150k miles) Here are the specs:
Block honed and decked with Cylinder heads being reworked with new guides, seals, and valve job
Stock Pistons and Rods with new Hastings Piston Rings
Clevite Mains and Rod Journal bearings
Melling M360HV Oil Pump
Cloyes Timing Chain Guides
Ford Motorcraft OEM Chain Tensioners (updated gasket design)
Ford Motorcraft Timing Chain(s)
Ford Motorcraft Crank Trigger Wheel
Ford Motorcraft Crank Sprocket
Ford Motorcraft Camshaft Phasers
Ford Motorcraft Camshafts
Michigan Motorsports Hydraulic lifters and roller rockers
Mahle Head Gaskets
Dorman VCT Solenoids
Felpro Gaskets
Pennzoil Platinum Synthetic 5W-30 oil (heavier weight than 5W-20)
Ford Motorcraft Oil Filter
Continental Belt and Hoses
SKF Exhaust Headers (cheap)
Stainless Steel exhaust studs and nuts
Dayco Harmonic Balancer
Ford Motorcraft Spark Plugs
New Sparkplug Boots and springs
Original Fuel Injectors sent out for cleaning and blueprinting

Truck has been running just fine after reinstallation. About 100 miles in I started to hear a loud ticking noise at idle that would increase or decrease with the engine RPM, or all together go away when cruising.

I took the valve covers and front cover off and found that the right hand (passenger) timing chain is going slack then re-tensioning again and slapping the top chain guide when turning it over by hand. You can watch the hydraulic chain tensioner loose pressure and retract when the chain goes slack. Ok, replaced the tensioner thinking bad luck and turned it over by hand again... same problem; new tensioner retracts and the chain goes slack by about two fingers width.

Has anyone ever seen this before? i'm quite confused as to why its doing this. Left hand (drivers side) is fine.