Setting timing belt tension

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  • #1

    Setting timing belt tension

    So, maybe I'm a little rusty, but the tensioning instructions from the 96 Pathfinder FSM make little sense to me. It's something like this:
    1. Loosen tensioner and turn 'all the way loose'
    2. Put new belt on
    3. Turn tensioner 70-80 degrees
    4. Tighten tensioner
    5. Spin motor
    6. Loosen but hold steady tensioner while pulling the timing belt
    7. Tighten the tensioner
    8. Put 1/2" wide 0.35mm feeler gauge on tensioner for no apparent reason


    Those are from memory so they might be slightly off. Still, this makes zero sense to me. Turn the tensioner 70-80 degrees from what starting angle? How taught is the spring supposed to be? Why is there even a spring there? All the videos and some photos from install guides show people turning it 70-80 degrees counter-clockwise instead of the clockwise the FSM specifies.

    So far I've just turned it roughly 80 degrees clockwise from where it sits loose when the new belt is on. Seems tight to me.

    I know the 84-86 or so FSM specifies loosening the rocker arms and a using a spring scale to measure the tension, but that was superseded. This procedure seems like it should make more sense. Or I am on crack.
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
  • #2
    fyi timing belt change videos :

    http://www.youtube.com/watch?v=CvMaBZXgSkA
    Nissan 3.0 V6 timing belt, Water pump And thermostat p1

    http://www.youtube.com/watch?v=meYzjmpgUtc
    Part 2. Nissan 3.0 V6 timing belt, Water pump And thermostat

    http://www.youtube.com/watch?v=MMQo3a7krfI
    Part 3. Nissan 3.0 V6 timing belt, Water pump And thermostat

    this is good too:

    http://www.youtube.com/watch?v=n6tT1TNMWvw
    1987 Nissan 300zx: Episode 18: Timing Belt Install
  • #3
    Yeah I've seen that. As best as I can tell from the video, he turns the tensioner the opposite way the FSM specifies. He turns it counter-clockwise, when the FSM specifies clockwise.

    Link to time I'm talking about

    However, it likely doesn't matter which way as long as the tension is still correct.
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
  • #4
    So… anyone?

    What is 70-80 degrees starting from?
    What's the point of the feeler gauge?
    What's the point of loosening the tensioner-but holding it, and pulling on the belt? To make sure it's not too tight? How can this be accurate at all?
    BLOZ UP.com
    It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.
  • #5
    I set it by feel…I sometimes verify with my spring scale. But I know how it should feel.
    Cha iro

    enjoy building it yourself.
    if it fails, fuck it.
    at least you gave it a whirl.
  • #6
    Originally posted by BLOZ UP View Post
    So… anyone?

    What is 70-80 degrees starting from?
    What's the point of the feeler gauge?
    What's the point of loosening the tensioner-but holding it, and pulling on the belt? To make sure it's not too tight? How can this be accurate at all?
    Whew. I'm going through this now and have all the same questions as you. My thinking with the feeler gauge is it is a check to verify the belt is tensioned enough as it says as you do it, it will turn 2.5 teeth. I'm thinking as the gauge is rolling in, the cam gears will roll back a couple of teeth.

    I'm still trying to understand the reference as well. 70 to 80 from where.

    Did you ever figure this out?
    Jeff
    71 240z

    80 280zx 10th Anniversary

    88 300zx Turbo, 89 300zx Turbo

    Datsun Jeff
  • #7
    I am following this. I too am about to do my timing belt and cam seals for the first time
  • #8
    "I'm still trying to understand the reference as well. 70 to 80 from where."
    You put the allen wrench in and turn it 70-80 degrees to tighten per the 96 Pathfinder FSM.

    You can look how the tensioner is clocked before you loosen it with the old belt on. You can even feel the tension on the old belt if you want.
    Nissan didn't specify a belt tension in the Z FSM, so I've always just tightened it up like it was. You'll know if you get it too tight, it'll whine.

    And I don't loosen the rocker arms.
  • #9
    So far with removing mine and receiving my new tensioner and spring, it appears you wind it about 1 revolution because that is all the spring will allow, slide the belt on and adjust tensioner. From reading some other post, folks have ditched the spring altogether.

    Remember, before removing your plugs, blow the ever living daylights around your spark plugs to get all the junk out. I also broke them loose about 1/2 way and blew again. Got even more crap out.

    The other reference which I confirmed with my old belt, is between the cam gears you should only be able to twist the belt to 60 degrees. If you can't, it's to tight, if you can get to 90, it's to loose.

    Last reference I saw was between the cam gears, with 22lbs of force it should deflect about 1/2" and 1mm of sag with a straight edge between cam gears.
    Last edited by JSM; 11-22-2017, 12:48 PM.
    Jeff
    71 240z

    80 280zx 10th Anniversary

    88 300zx Turbo, 89 300zx Turbo

    Datsun Jeff
  • #10
    Found this. In my Hanes manual.
    1 Photo
  • #11
    Hard part is 22lbs of force.
    Last edited by JSM; 11-22-2017, 01:48 PM.
    Jeff
    71 240z

    80 280zx 10th Anniversary

    88 300zx Turbo, 89 300zx Turbo

    Datsun Jeff
  • #12
    Well I’ve been looking at different belt tension gauges and can’t find one I like that is affordable.
  • #13
    Originally posted by JoeV11 View Post
    Well I’ve been looking at different belt tension gauges and can’t find one I like that is affordable.
    Where's the link?

    Is a fish scale accurate?
    Last edited by JSM; 11-22-2017, 02:50 PM.
    Jeff
    71 240z

    80 280zx 10th Anniversary

    88 300zx Turbo, 89 300zx Turbo

    Datsun Jeff
  • #14
    You can use a push tensioner, that's what I use on my Harley to adjust the drive belt tension. You push it down and measure the deflection. I see one that go to 30lbs on Amazon. Reviews say the sticker peels off.

    https://www.amazon.com/Gates-7401-00…;psc=1&ref
    $35
  • #15
    Anyone recall if the tensioner nut had a lock washer? Mine did not. Did anyone use loctite on the nut? I wonder why they give a range for the torque on the nut?
    Jeff
    71 240z

    80 280zx 10th Anniversary

    88 300zx Turbo, 89 300zx Turbo

    Datsun Jeff

    Comment

    • Dunkine
      #15.1
      Dunkine commented
      11-26-2017, 07:14 PM
      Nut - Conical Washer - Flat Washer - Tensioner - Spring.

      Guessing it's an acceptable range. The whole + or - thing. I usually go a little shy of the top range depending on which torque wrench I'm using (cheap, or super cheap one). So if I can get it in that range, I'm good.
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