Very Weird , When The Engine Is Noisy You Take Large Needle Nose Pliers And Squeeze The Hose Shut Across It As You Can Access It Somewhat Easy And Hold It Closed For About 30 Seconds Or So The Noise Stops
Release The Pliers And Noise Comes Back
You Will Create A Vacuum With In The Engine From The Hose Not Being Able To Circulate Gases / Blowby But How Does It Stop The Noise ?
CAM ( Valve ) COVER TO AIR CLEANER
Hose Location Viewed From Front of Engine ,Behind And Just To The Right of The Oil Fill Cap
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I'm gonna chime in here because you seem to be running in circles, hearing zebras where there are only hoofbeats.
That said --- I cannot fathom WHY pinching a CV hose causes any difference in your noise.
Come with me as we take a little journey inside your engine .......
That hose you're pinching should be under at least a slight vacuum at all times, drawing back into the valve cover - never flowing into the sound chamber.
The vacuum is ultimately controlled by the vacuum value in the plenum AFTER to throttle plate, by allowing more or less throttle opening as controlled by the computer.
The nipple end on the valve cover has a small metering (fixed) hole of 'X'-diameter that is supposed to draw
clean air from the zone between the air filter and the throttle plate.
That clean air is supposed to be drawn into that nipple and air flows into the valve cover to wash the crankcase of fumes from cylinder blowby and the after-byproducts of internal combustion - including water also from the humidity in the air.
If it does NOT purge the crankcase --- being drawn into the vacuum side of the PCV system --- it will keep collecting condensate (water) in the pan.
Every time you shut the engine off, then that water partially falls out of suspension and gets to reconsolidate and create rust and corrosion to the parts inside the engine.
OK --- so what does this diatribe by me info do for you?
If you haven't rusted the mechanism of the VVT - there's something else to consider.
When water collects in the lowest part of the crankcase (the pan) and gets drawn up by the oil pump where it gets mixed with the lube oil, it gets to eat your noble parts like aluminum and iron.
One of the things that suffers the most from water contamination is the camshaft and followers which are in critical need of fully slippery oil for it to live.
The bearings, piston rings and chains can take a lot of water abuse but the CAM is under serious loads that require very clean, non-contaminated oil at all times.
It is not impossible to grind the cam flat or weld a follower to the lobe for lack of decent oil - and that won't necessarily show up on a compression test; so a compression testy will usually only find things that are really wrong.
A tossed follower or flat cam lobe WILL make a difference in performance at higher than cranking or idling RPM because you have 2 intakes and 2 exhaust valves per cylinder and I've seen these Atlas engine toss a single follower from time to time.
So - now I've given you another place to check out.
PART 2 --- I had a partially collapsed piston from the joker who bored my block and pressed the piston pins and rods.
........... because he crushed one of the pistons - not enough to be measurable - but enough to make a slapping noise until the piston got warmed up and the noise went away.
I detested that little red-headed twerp for lying to me like he did - even to this day - as he cost me a stroker 350-383 build that I got to do a second time on MY dime!
You MAY have a broken piston. It gets quiet as it warms up --- that's a big hint.
I'm done slaughtering zebras for you ..... I also brought some of my own.
