What is this ticking noise?

Discussion in 'General Motoring' started by brett, Dec 23, 2005.

  1. brett

    brett Guest

    I have a '92 Honda Civic EX with 156k miles. It runs fine and doesn't
    give me any problems. The oil was changed about 500 miles back.

    I hear this very fast ticking noise on about the first five blocks in
    the morning. Then it stops. It's coming from the motor and some one
    else probably wouldn't notice unless I pointed it out.

    When I start the car, it idles at about 1500 RPMs. About three or so
    minutes later, it is at around 1100 or 1000 around five minutes. Now
    if I take off, I don't hear this noise. I imagine the noise is the
    engine turning at higher RPMs because the oil has not heated up yet and
    it takes more effort to turn the cam. Once the motor heats up,
    everything is well lubricated, hot and so it runs very smooth. But
    what could this noise be?

    Also, do I actually need to wait until the car idles down to 1100 RPMs
    each morning? I've read that about 30 seconds of warm up time is just
    fine. My car is just below 1500 RPMs at 30 seconds. To me, that
    doesn't show it has warmed up at all. What's the general concensus on
    this?

    Thanks,
    Brett
     
    brett, Dec 23, 2005
    #1
  2. brett

    Elle Guest

    Sounds like the valve lash (distance between rocker arms and
    valve stems) is set a bit on the high end of the spec. This
    is very common. It's better to be on the high end of the
    spec than the low end--too small a clearance can cause valve
    damage, IIRC. Googling will yield some discussion of this.

    You hear it first thing because the valve parts are not
    warmed up and so are relatively contracted. As they warm,
    they expand, and that clearance reduces.

    Check your manual's maintenance schedule for how often the
    valve lash is supposed to be checked (and so possibly
    adjusted). Though I ignored my 91 Civic's for 150k miles
    (out of ignorance), then checked it. All was fine. But don't
    do as I did. It is risky. Valve damage is expensive. I got
    lucky.
    I think that's because, when accelerating quickly while the
    engine is still pretty cold, the higher RPM makes the
    ticking harder to detect. The rate of valve opening and
    closing will depend on RPM, after all.
    I've read the same. Only in the rare times the temperature
    has been below 10 degrees F have I ran out and warmed up my
    91 Civic for five-to-ten minutes. I don't know if that's
    necessary, even in really cold weather.

    My Civic is doing fine after 14 years and 172k miles, over
    half of which were driven in the Northern U.S., with its
    abysmally cold winters.
     
    Elle, Dec 23, 2005
    #2
  3. brett

    brett Guest

    So how long do you usually let your car warm-up during the various
    seasons?

    I guess the conclusion is that it is much better to allow the engine to
    idle down. This way, you elimate all valve lash and probably a few
    other things you weren't aware of. Do you agree?

    Thanks,
    Brett
     
    brett, Dec 23, 2005
    #3
  4. brett

    Elle Guest

    I live out west in a much milder climate now. Lows in winter
    during the day are, at the very worst, around 25 F. And
    that's rare. Also, I have a garage. So these days I never
    purposely let my Civic sit and warm up upon leaving my
    house.

    When I go into the mountains to ski, and the car is exposed
    to the elements and extreme cold (teens or worse, degrees
    F), sometimes I'll give it a minute or so, tops. I don't
    know if that's really necessary. (If there's a sheet of ice
    built up on my car, that's different, but that's of course a
    special situation and not really your main concern, I
    think.)
    No, I don't think that's necessary at all. The engine
    control system senses several parameters (air temp, coolant
    temp, etc.) and deals with the car being cool. The engine is
    tough enough to take it, IMO. I don't think one will squeeze
    more life out of one's car by letting it sit a few minutes,
    idling in the driveway, before leaving. Engine oils are
    better than they were a few decades ago, as well. (Certainly
    synthetic is a vast improvement! I don't use synthetic, but
    I would if my car were new or just had its oil lube system
    thoroughly cleaned. Not that anyone bothers with the
    latter.)

    At most, by warming up the car first, I figure one's muffler
    might last longer. They rust prematurely when one goes on
    only short trips, as you probably know, not allowing
    sufficient heating to evaporate away accumulated
    condensation in the exhaust system.
    One is more likely to eliminate all tapping, perhaps. But
    again, I don't think a little tapping is going to affect the
    valves' life by much at all. I base this on reading about it
    on the web. People generally say get it in spec, and better
    to tap a little than not at all.

    Off the top of my head, I don't know whether eliminating
    /all/ the valve stem-rocker arm clearance at normal engine
    operating temperatures is desirable or by design.
    No. The engine control system (and thermostat) senses yada
    yada (see above) and adjusts fuel flow, coolant flow, and
    RPM etc. so as to achieve ideal conditions in a reasonable
    amount of time.

    Also, I think the engine valve design is plenty tough enough
    to deal with a bit of tapping, as long as the lash is still
    in spec. (Else the spec for the lash would be more
    exacting.)

    Keep checking back. Many of the regulars are busy during the
    day and do not get to the group until later.
     
    Elle, Dec 23, 2005
    #4
  5. brett

    Elle Guest

    At normal op temps, it does idle lower, like 750 RPM,
    doesn't it?

    The normal operating idle RPM will vary by car model and
    year, but I would think your 92 Civic EX normal operating
    idle RPM was closer to my 91 Civic's (about 750 RPM, for a
    1.5 L engine).
     
    Elle, Dec 23, 2005
    #5
  6. brett

    brett Guest

    It drops below 1000 when I put it in gear. Yes, probably 750 perhaps a
    little lower.

    Thanks,
    Brett
     
    brett, Dec 23, 2005
    #6
  7. brett

    SoCalMike Guest

    valves ever been adjusted? thats a start. another possibility is "piston
    slap" which is not harmful, just an annoyance.
     
    SoCalMike, Dec 24, 2005
    #7
  8. brett

    brett Guest

    I haven't had the valves adjusted but it sounds as though I can go
    until the car is sold (200k?) without any problems. They'll want an
    arm and leg to check any of this so I'll keep avoiding it.

    Thanks,
    Brett
     
    brett, Dec 24, 2005
    #8
  9. brett

    SoCalMike Guest

    its really not too difficult, if you have a set of 1/2" sockets (or at
    least one to turn the crank pulley) and a few metric wrenches to get the
    valve cover off and do the job. oh- and a feeler gauge and spark plug
    wrench:) i think a flathead screwdriver is also used on the valve adjust
    bolt.
     
    SoCalMike, Dec 24, 2005
    #9
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