I have the 05 5.4L Lariot. 96K on the Clock and ESW expired in June. Has always made the VCT noise, dealer always said was normal, but 2 wks ago the power went way down during hard acceleration, which was the knock sensors kicking in. So.....to restore some temporary power I have disconnected the knock sensors and started researching the cause of the knock. Ticking/light knock is most noticeable in passenger side front wheel well and through the exhaust manifold when listened with a stethiscope probe. I suspect a roller/rocker is deteriorating, but still am suspicious of the VCT/Phasers. Since I'm gonna pull the valve cover on left side I have 3 questions.

1. Any advice on what to look out for on that side of engine, passenger, to ease the access to valve cover?

2. Is there anything specific to look for or measure on the VCT that would indicate impending failure, any visual clues to a bad one over a good one? Can you look at one still connected to cam and determine it's good or bad?

3. Anybody run a compression check with an old school hand held compression tester, or do I need a thread in tester for the spark plug hole?

Colin

 

Sounds like you may have the timing chain tensioner problem, too. Research it on here. You are probably hearing spark knock due to the cam being retarded under low oil pressure, which is due to a leaking timing chain tensioner.

 

Alright, so I dove in and this is what I found.

Passenger side 3rd piston back, the intake vavle rocker bearing failed. Upon removing the valve cover and rolling the cam lobe off the rocker, the rocker arm had WAY more side to side slop than the rest. So I marked off the phaser/cam sprocket/cam position to keep everything in line just in case. Then I backed off the cam caps until I had enough room to slip the bad rocker out, as well as one right next to it. The roller in the bad one had at least a 1/8th slop up and down, obviously a failed bearing. The good rocker/roller had no noticeable slop.

I have to point out, this was done without a spring comressing tool, just back the cam caps off enough to clear the rocker past the lifter.

This being a Sunday, and not knowing what parts were needed until dismanlting, I'm stuck till tomorow to get a new rocker.

$24 from the parts store.

So far so good!

 

Yep that will work. Retorque cap bolts to 8-12 Nm. How does the lash adjuster and cam lobe look?

 

Cam looks just fine, the only way I could tell was by rolling the cam lobes off the rocker and shaking it. The valve lifter slides up and down, smooth.

 

Actually the tip of the lash adjuster should not move at all. It should be pumped up and relatively hard. A VERY small amount of movement if you press on it would be ok but if the tip is down and you can move it up and down freely then it is broken. Maybe I'm just misinterpreting your discription when you say it slides up and down and is smooth.

 

I had the exact same problem on my '05 but I waited a few days longer to take a look at it. By then, the rocker had worn a groove in the cam lobe. Sounds like you caught it just in time.

While I was at it, I had replaced my phaser. The engine purrs as quiet as a kitten now with only the injectors making any noise.