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Cam belt noise?

Discussion in '308/328' started by AZDoug, Oct 7, 2009.

  1. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
    1,437
    Along the Verde , AZ
    Full Name:
    Doug
    It has been so long since I drove my car, I don't remember what is normal.

    Do the cam belt make a gear meshing/whirring type of sound? It is louder with the motor cold on startup.

    Can't be much else making a noise from that part of the motor except the cam drive cog bearings,as water pump and alternator are both newly overhauled, and AC is not installed.

    Thanks,
    Doug
     
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  3. tomoshea

    tomoshea Formula Junior

    Dec 29, 2003
    541
    Ireland
    Full Name:
    Tom O'Shea
    #2 tomoshea, Oct 7, 2009
    Last edited: Oct 7, 2009
    The answer I think is it really depends on the car........

    Mine makes no noise on start up from cold and is very quiet, but as the engine gets warm it makes the kind of sounds you mention as tolerances change, is it the belts... I don't think so, more likely the gear lash between the crank shaft drive and the cam belt drive gears..

    My belts however do "sing" i.e make a low whine type noise, which is not unusual for 308 engines when tensioned, especially with newish belts.

    I don't think there really is a normal for cars of this age?
     
  4. Jbryant

    Jbryant Karting

    Sep 23, 2006
    220
    California City
    Full Name:
    Jeff Bryant
    Well mine has always made a sound like you said. Sounds like a turbo running back there....

    Kind of cool to me. I have simi-new belts and bearings so it gives a sound like
    I am running either a turbo or blower back there. Keeps the young kids from wanting to show off there Honda Junk at red lights.....
     
  5. Neonzapper

    Neonzapper F1 Rookie

    Oct 19, 2008
    2,531
    MD/FL/Philippines
    Full Name:
    Mykol
    Mine makes a noise (high pitch whirring/singing/whistle, but not too loud).

    Another thread awhile back said it is normal, and a non-scientific way to know your belts are fresh, good, and tight. I never doubted it, because my belts were brand new at the time.
     
  6. bill brooks

    bill brooks F1 Rookie
    Silver Subscribed

    Jul 30, 2007
    3,577
    waynesburg,pa
    Full Name:
    bill brooks
    i have a similar sort of "whine" which i had been enlisting the help of several f'chat
    contributors to get their opinions as to the probable source. my car is an '87 328.

    at first thought it was the alternator (still possible) was making the noise. however, the
    whine is only apparent from 2000-3000rpm and peaking at 3000 and then falling off as
    the other engine noises mask it.

    some suggested the t.o.and pilot ass'y. there is really no change with the clutch depresssed
    or engaged, or with any particular gear.

    revving the engine to 3000rpm with the gearbox in neutral elicits the whine as does placing
    the gearbox in neutral, pressing the clutch in/out and keeping the revs at 3000. i will admit
    that i cannot elicit this whine by placing the car on jackstands and running in gear. it only
    seems to show up on the road. left turns sound the same as right turns. it is apparent
    driving straight as well. slow sweepers seem to be the easiest to hear the whine. it does
    seem to be coming from my side, as the co-pilot (who does not have a hearing deficit)
    claims it cannot be heard from her side.

    thinking maybe the ring gear might be rusty, i added an additional 8oz. of redline mtl to
    provide a little more immersion. that didn't help either. after the first drive of this season,
    when the whine 1st became audible, i thought it was the gearbox oil. so i changed to
    redline mtl from redline 75w-90es, which i had used without event the 2 previous years.

    what's odd was the whine was not present last fall after the driving season ended.

    the only things changed over the winter pm was installing new alternator and water pump
    belts. they were properly tensioned with a gates belt tensioner.

    just to rule out the alternator once and for all, i'm going to remove its belt and go for a
    short spin. if the whine persists, then i need to look elsewhere.

    the whine sounds like a turbo spooling up/down. it is not particularly worrisome except
    it was not apparent in previous years. it has not changed in intensity in 3000miles this
    year, and does not sound as if something is getting ready to fail. it's just there.......
     
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  8. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
    1,437
    Along the Verde , AZ
    Full Name:
    Doug
    My noise isn't motion or clutch related, it is engine related, I think is is just new belts,as it almost sounds like the belt teeth meshing in the cogs.

    It has just been so long since I last drove the car prior to installed new belts and tensioner bearings, I can't remember what is normal.

    Doug
     
  9. Mike Florio

    Mike Florio Formula Junior

    Jun 19, 2003
    575
    NW Rural Nevada
    Full Name:
    Mike Florio
    I had a whining sound on cold startup that I eventually tracked to spun cam belt tensioner bearings. I found it during a belt change when I decided to change the tensioner bearings as well (they spun freely, but I changed them anyway). It was pretty clear what was happening once I removed the inner race.
     
  10. eurogt4

    eurogt4 Karting

    Apr 15, 2006
    243
    Sacramento, CA
    Full Name:
    Mike
    I would suspect cam belt tensioner bearings also. Find a long screwdriver, put the tip on the locknut or stud that holds the tensioner bearing adjustment, put the end of the handle against your ear. Check both banks. Does that sound like your noise?
     
  11. hardtop

    hardtop F1 World Champ

    Jan 31, 2002
    11,253
    Colorado
    Full Name:
    Dave
    Oil pumps tend to whine when cold with the pitch rising and falling with revs.

    Dave
     
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  13. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
    1,437
    Along the Verde , AZ
    Full Name:
    Doug
    Tensioner bearings are brand new along with belts.

    Doug
     
  14. eurogt4

    eurogt4 Karting

    Apr 15, 2006
    243
    Sacramento, CA
    Full Name:
    Mike
    I have had new tensioner bearings that were noisy, but assuming that is not the problem, "hardtop" may be on the right track. When it is making the noise, put your hand on the oil cooler and feel if it is vibrating along with the noise. I had one a few years ago that made a whining noise, especially when cold, and you could definetly feel it in the oil cooler. Was told that this happens a lot. Replaced the cooler and it was much better. Somewhat normal noise as long as it isn't too loud ?
     

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