setting timing

  • Kingman
    Kingman
    Senior Member
    • 1294

    #16
    Way too tight! Do a 90* twist test or put a ruler behind the belt and put 22lbs of force on it and the belt should deflect 1/2". There's tons of thins around the house a guy can compile to work. Being able to only push it down 1/4" is asking for a snapped camshaft. When you can twist the belt 90* without an insane amount of effort, you've got it about right.


    As long as the tooth count is correct the timing is set and really if everything isn't lined up absolutely perfectly, and belt tension being correct, it can look a bit off. Tooth count is the most important.
  • xanmanz31
    xanmanz31
    Senior Member
    • 218

    #17
    Kingman;349334 wrote: Way too tight! Do a 90* twist test or put a ruler behind the belt and put 22lbs of force on it and the belt should deflect 1/2". There's tons of thins around the house a guy can compile to work. Being able to only push it down 1/4" is asking for a snapped camshaft. When you can twist the belt 90* without an insane amount of effort, you've got it about right.


    As long as the tooth count is correct the timing is set and really if everything isn't lined up absolutely perfectly, and belt tension being correct, it can look a bit off. Tooth count is the most important.
    so with the 90* rule of thumb with the belt horizontal i should be able to turn it perpendicular without too much force? with a ruler i should be able to push down 1/2 inch? should i be able to do this with all spans of the belt? cam to cam cam to crank tensioner to cam?
  • Twisted`Z
    Twisted`Z
    Senior Member
    • 3213

    #18
    xanmanz31;349221 wrote: my issue is that its pulling only the LH cam clockwise when i put belt on with tensioner loose. then when i tighten tension it will pull counterclockwise slightly but not enough to bring back to mark.

    http://youtu.be/kbXqMh_ij84[/video]]
    From what I could see in the part of your video that my computer loaded (internet hasn't been fond of youtube lately, only got about half of it). You do know that there is a timing mark on the gear that is on the crank shaft that lines up with a corresponding mark on the oil pump? Properly time the motor with the timing covers and crank pulley off the motor. Make sure that your crankshaft mark lines up. From the video (could've been camera angle) of crank timing gauge, it looks that your crankshaft could go clockwise just a hair. Though those markings on the crankshaft pulley are supposed to be for checking timing on a running engine with a timing light.

    Did you pull the intake plenum and remove the driver side valve cover, along with passenger side and loosen the rocker shafts on both heads? It can be done with just passenger side really, but so much easier to get properly timed if both heads have their rockers loosened and cams can free spin.

    If it's not quite lining up at proper belt tension, try again. Whatever amount you are off by is how much you need to add/subtract from your cam positions before installing and tightening down the belt, and if your crankshaft timing is really off by a hair or so, adjusting there might also help a bit.
  • les_joey_paul
    les_joey_paul
    Senior Member
    • 743

    #19
    I didn't loosen them at all when I timed my car, it was hard to turn the pass side cam into place because of the spring tension, but it did stay there when i installed and tensioned the belt.
    http://z31performance.com/showthread…2-2-(-now-NA2T
    My build thread (:
  • visco
    visco
    Member
    • 63

    #20
    Ive done about 8 t belt changes over the past 10 years and I never loosen the cams. If the dimples on the crank and cams( not the marking on the back cover) are at the proper tooth count, that's what you need. I've had several instances where the right or left or both cams rolled. I used a wrench to turn them back to proper position/tooth count to line them all up. Most times I have to hold the wrench while another set of hands slides the belt onto the sprockets. I just did 3 timing belts within the last 4 months. Two times I was able to get the belt on with the correct tooth count without the tensioner installed and then slide the tensioner onto the stud , while keeping the tooth spacing at the proper count. An extra set of hands helps with all of this stuff.
    I use a motorcycle drive belt tensioner gauge to apply the 22 lbs of pressure. I also mark the T belt back cover to the 1/2" deflection so I can line it up when I'm pushing on the belt. Never had an issue.
  • xanmanz31
    xanmanz31
    Senior Member
    • 218

    #21
    Twisted`Z;349345 wrote: From what I could see in the part of your video that my computer loaded (internet hasn't been fond of youtube lately, only got about half of it). You do know that there is a timing mark on the gear that is on the crank shaft that lines up with a corresponding mark on the oil pump? Properly time the motor with the timing covers and crank pulley off the motor. Make sure that your crankshaft mark lines up. From the video (could've been camera angle) of crank timing gauge, it looks that your crankshaft could go clockwise just a hair. Though those markings on the crankshaft pulley are supposed to be for checking timing on a running engine with a timing light.

    Did you pull the intake plenum and remove the driver side valve cover, along with passenger side and loosen the rocker shafts on both heads? It can be done with just passenger side really, but so much easier to get properly timed if both heads have their rockers loosened and cams can free spin.

    If it's not quite lining up at proper belt tension, try again. Whatever amount you are off by is how much you need to add/subtract from your cam positions before installing and tightening down the belt, and if your crankshaft timing is really off by a hair or so, adjusting there might also help a bit.
    originally i had to pull the LH head to replace valve seals. yes cams were loose & everything was off. i do know the crank sprocket has the punch mark that lines up with notch on oil pump. i tried to get the crank marks lined first & run the belt from there. in the video i just didnt want to take the pulley off again (lazy). on all three punch marks i have marked them with white paint pen so they stand out more. the crank is the hardest to set since the angle is so poor. i set it by eyeball first then put timing cover and pulley on and adjusted then belt. however when installing belt the crank was able to move just enough to be a pain.