How-to: Replace the Cam Phaser (aka: VVT Actuator)

Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
I have seen the inside of this engine waaaaaaaaay too many times.

Because of a P1345 code and poor fuel economy, I am forced to replace the cam phaser again. This time, I will be using a Dorman as per this thread:
Dorman now has VVT cam phaser

This time, I documented the install for anybody that wants to replace theirs.

Difficulty (out of 5): 3.5
Tools required: Assortment of wrenches, ratchets, extensions, screw drivers. Socket sizes: 7mm, 10mm, 15mm, Allen socket, Kent-Moore chain holding tools J 44217
Time required (removal and install): 4 to 6 hours

1. Remove intake manifold and valve cover
2. Remove the spark plugs (this will make it easier to turn the engine)
3. Remove the top chain guide (two bolts)
4. Turn the engine until both marks on the gears line up with the dark links on the chain and the word "Delphi" is parallel with the cylinder head.

DSC_0004_1.JPG

5. Using either a wrench (maybe 1") or an adjustable wrench (like me), hold the camshaft at the hex part while you loosen the camshaft phaser bolt. Only Loosen.

6. Install the Spent-Moore J-44217 chain holding tools. The tools look like this:

j-44217.jpeg

They go like this:
Chain holders.jpg

Make sure they are hooked to the chain link as close to the shoes as possible, secure and moderately tight. Don't go crazy. The important thing is that they are securely holding the chain on each side. If they come off while the gear is off, you're in for a world of extra work when the chain tensioner extends fully and locks.
7. Remove and discard the cam phaser bolt.
8. Wiggle the cam phaser forward to disengage it from the camshaft and remove it from the chain.
9. Install the new phaser, aligning the mark on the gear with the dark link. It should slide right on the camshaft. If not, the old phaser may have been a little loose and the camshaft may be out of alignment. Turn the camshaft ever so slightly back and forth using the wrench while pushing on the phaser, it should eventually slide in. I had to do this as my old one was loose and allowed movement internally.
10. Install the new bolt snug.
11. Remove the chain holding tools.
12. While holding the wrench on the camshaft, torque the bolt to 18 ft-lbs. Then, while still holding the camshaft, turn the bolt another 135 degrees (I just guesstimated it).
13. The rest is the reverse of removal.

A few notes:
- Since the battery was disconnected, you will have to clean the throttle body before reinstalling it.
- Now is a good time if you need new plugs. (ACDelco 41-103)
- If your CPAS is old, it wouldn't be a bad idea to replace it or at the very least, clean it if there is no oil in the plug.
- You should change your oil before starting this job just so the new phaser doesn't have to deal with dirty oil while breaking in.
 

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mrrsm

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Great Write Up!

But to prevent either Accidental Injury to the Mechanic's Hands and Fingers or Damage to the Tiny Valves or Pistons Tops...if the camshafts should suddenly rotate under the influence of 24 Valve Springs Under Compression ...AFTER the restraining Timing Chain is removed from the Sprockets on the two camshafts... then this tool should be installed over the Flat Ends of the Intake and Exhaust Camshafts at the back of the head... AFTER achieving Top Dead Center on the #1 Cylinder and the word DELPHI is level with the top from of the head. The use of the 1" Wrench on the Hex Portion near the Front of the Exhaust & Intake Camshafts must still be used as suggested above.

http://www.etoolcart.com/camshaft-holding-tool.aspx
536172.jpg


I don't know why they photographed this tool in this odd position... as it will only be in the correct position if placed on the ends of the two camshafts with the two Flats facing UP... Horizontal and Level... and then the tool should slide on over the camshaft ends from the BACK side of the engine head easily.

Also... The New VVT Actuator must be PRE-LOADED by slightly turning the unit Clockwise and NOT FURTHER or past the Internal Stop... as it can be damaged. If this PRE-LOAD is not done prior to installing the Black Link on the Timing Chain Exhaust VVT Gear... then the Valve Timing will NEVER be correct.... and the engine will not run properly and will throw DTCs. It is very easy to damage the Internals of the VVT Unit... so do not use too much torque when rotating the mechanism BY HAND prior to installing the Timing Chain.

In some cases... the above listed tool must be removed in order for this to be accomplished. DON'T FORCE ANYTHING and remember that as soon as the Timing Chain is finally on the sprockets and the New Bolts (cannot re-use the old sprocket bolts) have been "Torqued to Yield" with the Torque Angle Meter... then the above tool should be removed before you forget it is attached at the back of the camashafts
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Also... The New VVT Actuator must be PRE-LOADED by slightly turning the unit Clockwise and NOT FURTHER or past the Internal Stop... as it can be damaged. If this PRE-LOAD is not done prior to installing the Black Link on the Timing Chain Exhaust VVT Gear... then the Valve Timing will NEVER be correct.... and the engine will not run properly and will throw DTCs. It is very easy to damage the Internals of the VVT Unit... so do not use too much torque when rotating the mechanism BY HAND prior to installing the Timing Chain.

Ah yes, something I forgot to mention but having replaced this part two times and replacing the timing chain, I have yet to find the cam phaser, new or used, to be in any other position than the proper fully advanced. I have tried to move it by hand and found it to be impossible to turn either way. Seeing the spring on the Dorman phaser leads me to believe that it returns to this position automatically.
As indicated in the manual, new/rebuilt ones come pre-loaded in the correct position.

For the cam holding tool, yeah, I didn't have it and didn't feel like giving more money to Spent-Moore. Again, having opened this engine three times, the camshaft has never spun on its own.
 
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Jan 13, 2024
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Ah yes, something I forgot to mention but having replaced this part two times and replacing the timing chain, I have yet to find the cam phaser, new or used, to be in any other position than the proper fully advanced. I have tried to move it by hand and found it to be impossible to turn either way. Seeing the spring on the Dorman phaser leads me to believe that it returns to this position automatically.
As indicated in the manual, new/rebuilt ones come pre-loaded in the correct position.

For the cam holding tool, yeah, I didn't have it and didn't feel like giving more money to Spent-Moore. Again, having opened this engine three times, the camshaft has never spun on its own.
Which are the two top chain guide bolts you’re talking about? The ones behind the two round screw plugs?
 

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mrrsm

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LL8TOPTIMINGCHAINGUIDEBOLTS.jpg43430248272_89674fc65f_c.jpg29607409338_1c8fdba7d3_c.jpg
 
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mrrsm

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Yeah... Quite a lot of differences ...with the loss of that One Cylinder...comes the issue of the Motor being so 'imbalanced'. You will appreciate observing Rick DeBoss up in Canada working away on this Motor on a Timing Chain(s) Swap:


And some More Help from Eric "O" at SMA (South Main Auto) up in Avoca, NY with THIS Five Part, On Topic Series:


Some Excellent Views of a 3.7L "Blown" Vortec 3700 Tear-Down worth downloading and referring to:


And Finally, Calvin (NIVLAC57) gives us a Tour of the 4, 5 & 6 Cylinder Vortec Engines:

 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
And also later years with the aluminum valve cover didn't have the chain guide.
 
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