What Would You Do - Timing Nightmare

Discussion in 'General Motoring' started by Tom Hawley, Jan 25, 2007.

  1. Tom Hawley

    Tom Hawley Guest

    Evening All,

    For anybody that remembers i've posted a few times about ongoing noises
    from the timing belt region of my Peugeot 306 HDi after a nightmare
    scenario 10,000 miles ago when I tried to get the belt and kit done
    along with crank pulley.

    That scenario - on undoing, the crank bolt snapped and it became
    necessary to have it drilled out. After this the only possible
    replacement involved chemical metal around a narrower bolt - original
    thread obviously shot. Crank pulley held tight with a separate nut. No
    signs of this botch having caused any problems according to (new) mechanic.

    The (old) job complete, I took the car away but have always been
    concerned by some noise from that general area, chirping/ticking at idle
    and scraping under load. Yesterday a wapping sound from the belt cover
    kicked in so I took it to the garage (different one, won't get into that
    again).

    The situation i'm now in - stripped down so far to the crank pulley held
    in by this chemical metal, i'm told it could take some serious time to
    get the crank pulley off, which is required to get the lower casing off
    to even figure out what was causing the timing related problem - there
    was clearly a problem - this belt looks 70,000 miles worn after 10,000.

    I ask them to continue and could be looking at 10 hours labour (best
    guess), another timing kit and possibly a water pump. The crank setup
    would have to be replaced in exactly the same way again.

    I can ask them to reassemble it to working for total of 3 hours labour
    but looking at the belt its going to wear to snapping sooner rather than
    later and then its no good to anybody. I'm not a guy that would pass the
    problem on to an unsuspecting ebay bidder, attractive a solution as it
    sounds.

    This car cost me £2800 in late 2005 and is about to hit 90k. Its seen
    around £800 quids work in the 1.5 years since bought. This is looking
    like around £500 more. They seem fairly confident they can do it, but
    not hour many hours it will take - removing old chemical metal being one
    hard to predict activity, and putting in more being the other.

    So, what would you do? My thoughts are its not saleable unfixed, I need
    a car, its been very reliable generally but i'd imagine 90k is about the
    threshold for other issues to start occuring - clutch works fine but
    bites past half way - thats another 3-400 quid job if it went.

    One plus point - i've probably stretched this problem out to about its
    limits without making things any worse - if i'd had it checked 6 months
    ago i'd be in exactly the same position.

    Any input or similar experiences welcome and appreciated.

    Cheers,
    Tom.
     
    Tom Hawley, Jan 25, 2007
    #1
  2. Tom Hawley

    Duncan Wood Guest

    Heat it with the oxy torch & the chemical metal will fail, then helicoil
    the end of the crank
     
    Duncan Wood, Jan 25, 2007
    #2
  3. Tom Hawley

    Coyoteboy Guest

    I, personally, would have replaced the crank with a half-decent second hand
    unit or at least removed it and had it worked on where the repair could be
    done and balanced correctly. Also did you know that your crank pulley is
    often dynamically balanced with the crank and altering it can cause
    problems? I'd only expect that to make difference on a high-revving
    lightweight engine though I must admit.
     
    Coyoteboy, Jan 25, 2007
    #3
  4. Tom Hawley

    Dave Baker Guest

    So you mean there is a stud in the crank now rather than a bolt.
    Clearly it has. The crank thread should have been fine if the bolt had been
    drilled out accurately and the thread cleaned up with the correct tap.
    Trying to do it in situ and by hand the trained chimp involved probably
    drilled through the side of the bolt into the crank and so wrecked it. Even
    so it should then have been possible to helicoil it back to the correct
    size.
    There should be no chemical metal anywhere near the pulley unless this is a
    strange design. All the chemical metal should be doing is holding the stud
    into the crank and the pulley should fit over the crank nose. You're being
    told a load of bollocks here basically. It sounds like the crank nose is
    also buggered and the pulley is running off centre because it isn't located
    properly. Probably the stud in the crank holding the pulley is off centre.
    That's what causing rubbing noises and it will also be stretching the belt
    every revolution as well as stressing the tensioner.

    You're heading for a broken belt and a written off engine. All the valves
    will be destroyed if that happens, quite probably the cam too on a diesel
    and if you're really lucky it'll punch a hole into a piston.

    Get the engine stripped down by someone who actually knows what they're
    doing and fit a decent s/h crank or at least repair the one you have
    properly.
     
    Dave Baker, Jan 25, 2007
    #4
  5. Tom Hawley

    Duncan Wood Guest


    Modifying the centre of it will make practically no difference, the 4th
    moment of inertia thing works to your advantage for once.
     
    Duncan Wood, Jan 25, 2007
    #5
  6. Tom Hawley

    Mike G Guest

    I'm with you. When the bolt broke he had a perfect crankshaft, with the
    remains of the bolt stuck in it. IME providing care is taken, it is usually
    possible to remove broken studs, bolts etc without damage to the thread.
    If the broken bolt couldn't be removed with the crankshaft in situ, it
    should have been removed, and the broken bolt drilled and bored out to
    thread core size with the c/s in a lathe. At least that way the OP would
    have finished up with an undamaged c/s, rather than the bodge he has at
    present.
    Even if the old thread in the c/s is damaged, maybe it can be bored in the
    lathe and a 'Helicoil' fitted to bring it back to std. If not it can
    probably be bored o/s and Helicoiled to accept a larger diameter bolt.
    Either way is a perfectly acceptable repair.
    Mike.
     
    Mike G, Jan 26, 2007
    #6
  7. Tom Hawley

    PC Paul Guest

    I would think the extra wear on the belt is due to the bodged pulley being
    slightly off alignment. Taking the engine out or stripping it to get the
    crank on it's own seems like the best way forward. Or take the easy but
    risky route and replace the belt every 5,000 miles?

    Doesn't seem like the sort of job you could do with the engine in the car to
    me, to get it all rebored/helicoiled dead straight.
     
    PC Paul, Jan 26, 2007
    #7
  8. Tom Hawley

    Duncan Wood Guest

    It's not that bad, the bolt isn't what locates the pulley.
     
    Duncan Wood, Jan 26, 2007
    #8
  9. We were somewhere around Barstow, on the edge of the desert, when the
    drugs began to take hold. I remember Tom Hawley
    Personally, I'd strip the engine and have the crank properly repaired.
    If you have to rely on a garage to do it, the cost might be a bit high
    though - look seriously at fitting a known good engine from a breaker
    and get what you can back for the old one by flogging it on ebay.
     
    Grimly Curmudgeon, Jan 27, 2007
    #9
  10. Tom Hawley

    MrCheerful Guest

    the pulley is aligned by the exterior surfaces of the crank, not the bolt.
    I would look for other faults first.
     
    MrCheerful, Jan 27, 2007
    #10
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