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GM 3.6 VVT

is there any way to manually actuate the VVT solenoids with the top end open and timing covers off to see just how much the chain and gears move in and out of time? I don't know much about them but have heard all kinds of horror stories on the various engines that have this variable timing. GM 5.3 and 6.0l are notorious for issues on compression loss when they "turn off" cylinders for their so called hyper-miling. what exactly does it do internally when it "turns" a cylinder off?

I'm only asking because I can assume it holds the valves slightly open venting compression when running. could it have opened the valves further that it was supposed to?
 
one other thought and I'm sure you already accounted for this... did you have the head surface milled? could this effect the clearances on an already by design tight tolerance engine. when the VVT actuated the damage occurred. if I'm not mistaken the vvt will only actuate under very light cruising at highway speeds.
 
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So I'm pretty sure this engine doesn't have the cylinder deactivation. The vvt is activated hydraulically via engine oil pressure and the PCM. This engine is only 217 CI and puts out 275 HP. And gets decent gas mileage. I'm pretty sure the vvt gives it more performance.
And no the head wasn't milled.
 
  • Variable Valve Timing (VVT): variable valve timing, or cam phasing, helps the 3.6L V6 deliver optimal performance and efficiency, and reduced emissions. It allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or driveability.
 
The VVTs cant move the cams enough to bend valves. Ive have the solenoids stick and max them out and all it does is run rough and set codes. The only way to bend valves is to jump time, float valves, or the valve to piston clearance is too small.

This had been a head scratcher thats for sure.
 
I did a search last night and it seems that this is a common issue for these engines due to a loose timing chain or faulty tensioners. it's possible that ether like you said the tensioner had failed or the chain stretched after the install. if it stretched, I would claim Chinese steel!
 
Bummer. I wonder if you can prompt them for some further info as to what they think caused it, or if they're staying close-lipped because the answer is a defect on their part.
 
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