How to remove lower cover?

Discussion in 'General Motoring' started by Bill, May 1, 2010.

  1. Bill

    Bill Guest

    I'm changing the timing belt in my 97 Civic and have a question I'd
    like to ask you experts:

    How do you get the "lower cover" off?

    I have the manual, and it just says "Remove the lower cover and
    dipstick tube." It doesn't give any instructions on how to do this,
    how many bolts there are, etc.

    I've removed 4 bolts from the cover. Does anyone know if there are
    more? Do I just take a screwdriver and pry the plastic lower cover
    out? Or does it slide down?

    How about the dipstick tube? How does it come out? There is a bolt at
    the bottom. Do I need to take it off? Do I just pull it up to take it

    Thanks for any help you can give,
    Bill, May 1, 2010
  2. Bill

    Tegger Guest

    The dipstick tube is held on by a clip about half-way up, then it pulls up,
    and out of the block. You should use a new O-ring. Re-use of the old one
    can cause leaks.

    The lower cover sometimes sticks and requires a bit of a tug. It does pull
    straight off, though. Wiggle the wiggle-able areas with your hand, and
    study the parts that won't move, in case you've left a bolt in place. Use a
    strong light to help you see, since there's little room to see or work.

    Tension the new belt BEFORE you put the covers back on. The tensioner needs
    a bit of manual help to pull the belt to the proper tightness; the spring
    won't do it all. Take CAREFUL note of the tension on the current belt;
    duplicate that tension with your new belt.
    Tegger, May 1, 2010
  3. Bill

    Bill Guest

    I think why you're telling me to:
    Is because the MANUAL IS WRONG!!!

    Is that possible, that a company as good as Honda could make a mistake
    in the manual? Maybe it was outsourced?

    The mistake is: Tension Adjustment (p 6-18, in my manual)
    It says to remove the upper cover, and loosen the adjusting bolt.
    The problem is that the adjusting bolt is under the LOWER COVER, so
    you would have to remove the bolt, pulley and lower cover, to be able
    to adjust the tension of the timing belt.
    Same mistake in the re-installation instructions, to tension the belt.
    It says to put back on both covers, rotate the crankshaft, then remove
    the upper cover and adjust, but you can't just remove the upper cover
    and adjust.

    Has anyone else noticed this? Or could I be mistaken? I'm using the
    Civic 1996-2000 Service Manual, for 97 Civic.

    Also, do you have a good way to put added manual pressure on the
    tensioner? I'm trying to just pull up with my hand, then tightening
    the bolt while holding it, but it's hard to tell if it's working.

    Bill, May 2, 2010
  4. Bill

    Tegger Guest

    It's not "wrong", really. It's just that (most?) manufacturers seem to
    think their tensioners will always apply correct tension unsing only the
    spring that's provided for that purpose. I have personally found that
    the spring alone usually leaves too much slack in the belt, so I "help"
    the tensioner with one hand, and then tighten the bolt with the other.

    There is a big, flat plug in the lower cover, about the size of a
    quarter. You remove this to get a thin-wall socket on the adjusting bolt
    for the tensioner. The problem is that the tensioner's spring alone is
    never enough to tension the belt properly.

    You don't need to put the upper cover back on if it's already off.

    There is a removable plug, in the lower cover, for the adjusting nut.

    That's why you needed to take note of the tension of the existing belt
    before releasing it.

    As for properly tensioning the new belt... Temporarily put the crank
    bolt back with both covers off, then use that to put all the slack on
    the tensioner side. Make sure there is about 1/4" of slack in the belt-
    run between the cam and the water pump. Push on the belt until all the
    slack is where you are pushing, to make sure you've accounted for all
    the slack.

    If you don't want to put the crank bolt back for fear of not being able
    to remove it again, just tension the belt the specified way. If more
    tension is needed to ensure the 1/4" slack, tap the (loosened) tensioner
    bolt with your ratchet. This may be sufficient to shock the tensioner
    into tighter engagement. I'm assuming you have turned the engine so all
    the slack is on the tensioner side, as specified in the manual.

    When you start the engine for the first time, listen for an unusual
    humming or whining noise that wasn't there before. If you hear that, the
    belt may be too tight.
    Tegger, May 2, 2010
  5. Bill

    jim beam Guest

    need to be VERY careful with this advice dude. if the spring tensioner
    mechanism is used correctly, and it's checked for smooth operation
    before hand, and the procedure is followed per the book, you will get
    correct tension. over-tension is something to be avoided at all costs.
    the cam "bearing" is the bare aluminum block. if the tension is too
    high, the oil film that's supposed to separate the two moving parts is
    too thin and the head wears. the resulting catastrophe is something you
    can go to almost any junkyard and see for yourself.

    again, i respectfully think this could be misinterpreted and excess
    tension result. belts do not need "tension" to run - they need
    engagement [this is a toothed belt, not a friction belt]. the honda
    service manual procedure, if followed to the letter, gives precisely the
    right result.
    jim beam, May 2, 2010
  6. Bill

    Tegger Guest

    I generally agree, but I disagree that the tensioner will apply correct
    tension when used as per the shop manual.

    Now that I've done enough timing belts to be familiar with the correct
    level of tension, I've found that spring-loaded tensioners (even brand-
    new, and even across different makes) usually don't apply quite enough
    force unless "helped" a bit.

    Your caution about overtension is a good one. I've found that
    overtension is often accompanied by a humming or whining noise that
    changes with RPM.

    The primary thing is that there should be SOME slack in the belt. Even a
    just little slack is sufficient to prevent engine damage.

    I'm not so sure. Even when brand-new, those tensioners tend to have just
    enough "stick" to cause excess slack. The slack isn't fatal, mind you,
    but it's more than the belt should have. Excess slack is most likely to
    cause the belt to contact the cam cover or the timing cover, and result
    in rubber dust, but is unlikely to have any other deleterious effects.

    Whatever method of tensioning is used, aiming for about 1/4" of
    deflection between cam and water pump is just about right. And you're
    pushing on the belt with your thumb/finger with maybe a pound of force,
    once you've used the crank pulley bolt to put all the slack on the
    tensioner side.

    Again: the key is SOME slack. The belt ought to have some very obvious
    looseness; as you say, it ought /not/ to be snug.
    Tegger, May 2, 2010
  7. Bill

    jim beam Guest

    well, there's a knack to it, agreed, but the tension does work as

    1. take the tensioner off and clean everything up.

    2. reassemble, and tighten bolt so that the tensioner moves, but can't
    tilt, even by the slightest bit. /that/ is what stops the thing from

    3. follow the manual for belt tension, esp belt rotations.

    4. before finally tightening the tensioner bolt, jiggle the ratchet
    laterally. it loosens any final stiction. from then on, the belt
    tension will be exactly perfect.

    only if the tensioner bolt is too loose. people tend to go "i'll
    slacken this thing right off, just to be sure", but that, unfortunately,
    is the wrong thing to do.

    that's a touch tight. again, it's a toothed belt, not friction -
    different rules apply. that would be too tight for a motorcycle chain.
    same thing here.

    jim beam, May 3, 2010
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