Finding TDC on 1.5l wagon

nwoodsman04nwoodsman04 Band Wagon
in Engine & Drivetrain
Hi there. I just picked up a '86 RT4WD with a blown head gasket and am about to pull the head. I have aligned the TDC mark on the crankshaft pulley with the timing cover mark but am unsure about the camshaft pulley marks. There is no arrow or "up" indicated on my cam pulley. Only one of the two stamped lines (the slightly longer, less faint one) can be seen in the photo, but they are both sitting parallel to the top of the head. Is it at TDC now or do I have to rotate it another 360 degrees?
Thanks,

Luke

Comments

  • JakerJaker familEE
    There are 3 lines on the camshaft pulley. The 2 lines that are diametrically opposed (180 degrees apart) are to be lined up with the surface of the cylinder head where the valve cover gasket sits. The 3rd line is meant to be "up". Not necessarily straight up, but pointing in the upwards direction as opposed to down.
  • nwoodsman04nwoodsman04 Band Wagon
    Hmm, there are only two stamped lines on the face of this cam pulley that I can find.
  • udubrx7udubrx7 Senior Wagonist
    I'm assuming the timing belt is already off... Are the two lines 180 degrees from each other? If so, look really really closely 90 degrees away from either side of one of the marks, there definitely should be some other kind of marking to signify which side is up.
  • nwoodsman04nwoodsman04 Band Wagon
    The belt is still on. I'll take another look.
    Thanks
  • nwoodsman04nwoodsman04 Band Wagon
    I just checked the pulley looking for a third mark. The only other stamped marking I found was a faint "4". If it came out in the photo it would be where the arrow indicates. Could this possibly indicate TDC?
  • udubrx7udubrx7 Senior Wagonist
    I dunno what to tell you... that looks different from the service manual.

    177.jpg
  • bam-bambam-bam Council Member
    I just noticed you're working on an '86...maybe the marks are different? Either way, it doesn't matter.

    If you have the crankshaft mark lined up, you ARE at TDC, the only question is whether you're on compression stroke or exhaust stroke. Are both intake and exhaust valves closed? (compression) Or is the exhaust valve(s) open? (exhaust stroke).


    I suspect that you're at TDC, compression stroke. It just sounds like the marks are lined up from your description. BUT even if you're not, it wouldn't matter- as long as you put it back the same way you took it apart!

    Do this before you take the belt off, just to ease your mind: Turn the crank a full turn, then see if any of the camshaft markings line up. I suspect they won't, and the exhaust will be open. Watch the valves as you continue turning the engine in its normal direction...you should see the intake open as the piston travels downward, then close as the piston comes up on compression stroke.
  • nwoodsman04nwoodsman04 Band Wagon
    Thanks to everyone for your help. I hope to have the head off today so I can get it running before all the snow is gone here in north central Minnesota!
  • udubrx7udubrx7 Senior Wagonist
    Good luck!
  • JakerJaker familEE
    If you're happy with the cam timing before you take it apart, I've seen people of a more anal nature mark the timing belt and the pulleys before removing the belt. Just run a mark of "white out" for example across the timing belt edge and onto the pulley to show exactly where the belt was on the pulley before removing it. Do this at the cam pulley as well as the crank timing belt pulley. There's usually a small line cast into the crank pulley for TDC, in additon to the ones on the cam pulley and the crank pulley for alternator/AC/power steering.

    Then if you're changing to a new belt, just accurately transfer those marks onto the new belt, and line up your marks when you put it back together.
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