What Would You Do - Timing Nightmare

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.

 

Heat it with the oxy torch & the chemical metal will fail, then helicoil
the end of the crank

 

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.

 

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.

 

Modifying the centre of it will make practically no difference, the 4th
moment of inertia thing works to your advantage for once.

 

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.

 

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.

 

It's not that bad, the bolt isn't what locates the pulley.

 

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.

 

the pulley is aligned by the exterior surfaces of the crank, not the bolt.
I would look for other faults first.