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-   -   4.2L Exhaust Camshaft Actuator installation question (https://chevroletforum.com/forum/trailblazer-27/4-2l-exhaust-camshaft-actuator-installation-question-94556/)

donnieb March 10th, 2019 6:09 PM

4.2L Exhaust Camshaft Actuator installation question
 
I'm installing my camshaft sprockets and the Haynes and Chilton Manual say the same thing: "Rotate the exhaust camshaft actuator clockwise until it stops." Here's the problem: which part of the sprocket assembly is the "camshaft actuator?" Is it the (back) half with the sprocket on it, or is it the front disk shaped part?
The back end with the sprocket on it wants to go all the way clockwise when the engine is rotated clockwise by hand from the crankshaft nut. So that seems to be how it should be when the bolt is finally torqued down.

Does anyone know? I've looked at a bunch of posts and videos and every one of them skips over this critical step. It says in the manuals that if it's not rotated all the way clockwise, it will cause engine damage.

Note: I just finished replacing a broken valve spring. I had to remove the cam sprockets. It looked like the cams were timed correctly with with the crank at TDC when I buttoned everything up but that actuator gave me heartburn. I just ran the engine and code P0017 came up. Engine seemed to run fine.

Added this: I found an illustration showing that the front disk needs to be rotated all the way CW, soooo, somethings wrong. Back to tearing apart the valve cover...OK, I see that my actuator is not rotating at all, just a small amount. It's supposed to rotate something like 25-degrees. OK, gotta figure this one out...

More: the VVT Sprocket is damaged and I ordered a new one from Rock Auto. Will install tomorrow. I noticed on a Gibson Garage video that the normal position for the VVT actuator is all the way CW, so that's why no one mentioned it before in any posts or videos.

oilcanhenry March 14th, 2019 1:19 AM


Originally Posted by donnieb (Post 386763)
I'm installing my camshaft sprockets and the Haynes and Chilton Manual say the same thing: "Rotate the exhaust camshaft actuator clockwise until it stops." Here's the problem: which part of the sprocket assembly is the "camshaft actuator?" Is it the (back) half with the sprocket on it, or is it the front disk shaped part?
The back end with the sprocket on it wants to go all the way clockwise when the engine is rotated clockwise by hand from the crankshaft nut. So that seems to be how it should be when the bolt is finally torqued down.

Does anyone know? I've looked at a bunch of posts and videos and every one of them skips over this critical step. It says in the manuals that if it's not rotated all the way clockwise, it will cause engine damage.

Note: I just finished replacing a broken valve spring. I had to remove the cam sprockets. It looked like the cams were timed correctly with with the crank at TDC when I buttoned everything up but that actuator gave me heartburn. I just ran the engine and code P0017 came up. Engine seemed to run fine.

Added this: I found an illustration showing that the front disk needs to be rotated all the way CW, soooo, somethings wrong. Back to tearing apart the valve cover...OK, I see that my actuator is not rotating at all, just a small amount. It's supposed to rotate something like 25-degrees. OK, gotta figure this one out...

More: the VVT Sprocket is damaged and I ordered a new one from Rock Auto. Will install tomorrow. I noticed on a Gibson Garage video that the normal position for the VVT actuator is all the way CW, so that's why no one mentioned it before in any posts or videos.

The camshaft actuator must be fully advanced during installation. Engine damage may occur if the camshaft actuator is not fully advanced CLOCKWISE.

donnieb March 14th, 2019 3:21 PM

My actuator is not working. It's jammed in the fully CW position. So I'm replacing it (parts here tomorrow). By the way, what kind of engine damage? Anyone know?


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