My Box had high cam deviation on bank 2, (2001, 3.2L, 53k miles) and then suddenly earlier this year I noticed what I believe is chain noise. (more on that in this thread:
Engine noise diagnose assistance - Possible vario cam actuator/pad/chain issue?)
Here is a video of
the noise.
I stopped driving it, removed the motor and tranny and started by opening up the bank 2 side as it had the large deviation. Interestingly, while one of the 2 pads (the top one) was worn significantly, it was not "broken" just worn. I also found it interesting just how unworn the other (lower, towards the head) pad was. Any one seen this type of variation before?
My (first) big question now is how safe is it to rotate the crank with the cam sprocket hanging like it is? I have new actuator rail guides ordered with pelican, but it will be a bit before they get to me. I would like to rotate around to get bank 1 at TDC so I can open up that side (I believed that is where I heard the noise). Is it better to wait for the guides so I can put bank 2 back together first, or can I just guide the loose chain with my hand? I have all the tappits out, bagged and labeled and no cams pushing down, so I would assume the values would all be clear of the pistons? I am making an assumption that the specific links on the long chain between the IMS and the exhaust cam sprocket do not matter as long as the crank is at TDC (and the correct one over the whole 720 degrees) and the cams are in time with each other and lined up correctly to TDC (intake slot facing directly towards block for bank 2) which i will deal with putting them back in.
Another thing I wanted to note was that the colored links of the cam chains were not set on the dots on the cams. There were however to to my understanding the correct number of links between the dots (15 and 6). I am guessing experienced techs may not care much about the colored links being right so long as the amount of links is correct but was curious to see if others encountered it, is it a clue that someone has been in there before, or perhaps the opposite as the original manufacturing process of the engine only needed to verify the amount of links, not color?
Another reason I want to turn the crank is to better see piston 4. I stuck a scope in the spark plug holes and noticed that the top of that piston looks really dirty.. however it is currently at TDC so I don't know if it is just because it is so close to the camera. I wish I had done a leak down test before opening it up.
Here is an image of piston 4:
And here is another (i think it was 5) for comparison:
Definitely getting to know this engine, hoping that I can find the root cause of the noise!