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Cam gear and chain installation

Discussion in '2nd Gen. Tacomas (2005-2015)' started by foampile, Aug 12, 2015.

  1. Aug 12, 2015 at 11:57 AM
    #1
    foampile

    foampile [OP] Well-Known Member

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    Last night I did a preliminary "rehearsal" of installing cam gears and chain following the not so very detailed instructions in Haynes and here, as well as fiddling around myself. The reason I say "not so very detailed instructions" is because neither specify the exact manual steps of mounting the chain on the cam gears and (when I finally got it right) I realized it is critical to do it in the only one way possible.

    Here is what I did on my engine's left side:

    1. Before setting the camshafts in the head, start with the intake camshaft that has a VVT actuator on it. Note that the VVT actuator smaller sprocket (on which the small chain connecting the two camshafts goes, vs the big one where the main chain goes) has two marks: one single dot and one double dot. I think when you face the yellow marker links on the small chain forward (facing the radiator), the left yellow link straddles the tooth that is directly above the single dot marker on the sprocket. Since it is hard to see the sprocket dot marker from above, I also drew a line on the actuator with a sharpie so that it can be seen more easily from above.
    2. With step 1 completed (left yellow link over the single dot sprocket marker), set the exhaust cam sprocket into the small chain so that the dot marker (this sprocket doesn't have a double marker like the intake one) is straddled by the right yellow link when the yellow links are facing forward (towards the radiator). Make sure the sprocket is off the camshaft.
    3. With step 2 completed, your intake camshaft has the small chain on it and the chain also wraps around the exhaust sprocket, only then are you ready to set the assembly into the head. I tried setting the intake camshaft into place before setting the chain, fitting the chain over but then I was unable to fit the exhaust sprocket in. The only way I was able to do it was to assemble it outside. Make sure that the yellow marker links on the chain are facing up. Then you set the whole assembly in the head journals loosely (we will set it tight in the next step) while pressing the plunger on the tensioner that is in between the two sprockets.
    4. The next step is to You will need to kinda wiggle the whole assembly when setting it in place to make sure both camshafts sit snug into the journals AND that both are in the rotational position when no cams are actually pushing their respective lifters (this is critical in order to sit snug in the journals).
    5. If both shafts are sitting snug in the journals (which, as explained in step 4 means no cams are pushing their lifters in that position), you can set the two front bearing caps that hold each shaft in the front journals. Each of those caps has a notch in the middle that is used as a guide to align it against the little chain's yellow markers. The not-so-great instructions I was following merely say that the clamp markers need to align with the yellow links, however, it doesn't specify whether they should align the middles of each link or either end. In my case, I was unable to align them with the middles of the yellow markers but was able to align them to (I think) the left side of each link respectively when looking from above while the shafts were sitting in the journals all the way in.
    6. Proceed with torquing the rest of bearing caps to spec. Each bearing cap bolt (including the front caps) should be at 11 ft/lbs

    Those would be the instructions that I sortof amalgamated between external references and my own trials and errors. The only question, other than the general inquiry whether the rest of it is right or am I wrong somewhere, was to confirm what I have bolded in step 5, regarding the alignment of notch markers on the front bearing caps and the yellow marker links on the chain.
     
    Last edited: Aug 12, 2015
  2. Aug 12, 2015 at 1:53 PM
    #2
    Wishbone Runner

    Wishbone Runner Because 4R

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    King/Dirt King
    Here is what mine looked like during disassembly. The zip tied gears are exactly in the position they were in when they came off, with the yellows not lined up, and I put them back in just like this, 7K on them with no issues.

    DSC01736_zpsdcab1f5c_989addaf7c99647e9890064e5d160eae63194646.jpg

    DSC01737_zps88f901ec_8ced598c8c926e806614840e9f57d8b6297664b5.jpg

    DSC01739_zps6ce6d3ab_815fde78ab6f462a028d9ba4f3e084deb11bd930.jpg

    DSC01740_zpse613a3e0_5a6fc6649a1ece063ea51c90eed82b3434c25f34.jpg
     
    foampile[OP] likes this.
  3. Aug 12, 2015 at 2:07 PM
    #3
    foampile

    foampile [OP] Well-Known Member

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    do you know if it matters whether the yellow links on the little chains are facing towards the front (radiator) or the back (inside the heads) ?

    also, i didn't take the VVT actuators off, just left them on the intake camshafts.
     
  4. Aug 12, 2015 at 2:37 PM
    #4
    Wishbone Runner

    Wishbone Runner Because 4R

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    Based on my pics, they point to the rear.
     
    foampile[QUOTED][OP] likes this.
  5. Aug 12, 2015 at 3:26 PM
    #5
    foampile

    foampile [OP] Well-Known Member

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    I noticed that your VVT drums look different than mine, I'm guessing yours are older.

    timing_chain.jpg
     
  6. Aug 14, 2015 at 8:39 AM
    #6
    foampile

    foampile [OP] Well-Known Member

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    On the left side, I was able to align the yellow links with the marks on the sprockets AND align the notches on cam bearings with the sprocket marks (which also means the centers of yellow links) AND make sure the camshafts sit in the journals all the way. Please note that there are two marks on the intake (VVT) sprocket, one with a single and one with a double dot. The one that I aligned the left side was the double mark in order to fit it in the puzzle.

    On the right side, I had to straddle a yellow link over the SINGLE dot mark on the intake camshaft (which also has a double dot mark) in order to be able to sit both camshafts in the journals (when I say "sit in the journals" I mean that the shaft is completely lodged in the journals without any cams propping against a lifter to raise it) but the marks/yellow links were not aligned with the notches on the cam bearings when the shafts were both in a sitting position. In order for them to be aligned on the right side, they cam bearings must be in place and the camshafts must turn approximately 30-45 degrees, for which crankshaft turning with the whole timing chain assembly is necessary.
     

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