[s-cars] welcome to my nitemare

[Paul Heneghan]

I'm not sure I follow the "locking tool will sheer the cast keyway" bit.
The locking tool holds the crank pulley stationary, so if you try and
undo the crank bolt, there should be no transfer of torque through the
crank pulley to the crank shaft and therefore no stress to the key.

However, I'm amazed at how many of you have suffered from this problem.
I had thought I was the only one!  It happened to me years ago as a
result of the one and only time I got a shop to do the timing belt
change.  A few months later the car lost all power - I traced it to a
timing problem and assumed the belt had jumped a tooth.  It happened
again a few days later and then I realised that the crank pulley had to
be turning with respect to the crank.  Luckily I got to it before the
pistons got to the valves.  There was no eveidence of any key when I
dismantled it.  It had been ground to dust.  I reckon the shop either
didn't use loctite, or didn't use the correct torque, or quite possibly
both!

In my opinion (which isn't worth much as I've only ever done 4 TB
changes), this problem is either due to poor rebuilding techniques such
as omitting loctite or using the wrong torque on the crank bolt, or
using some fiendish way of removing the bolt involving putting a
ludicrous torque on the key either by the use of an impact driver or by
jamming the flywheel while simultaneously jumping up and down at the end
of an 6' extension bar on the crank bolt (reluctant wives are usually
involved in this procedure).

Paul

p.s. Thanks for the warning about replacing the bolt - I thought it was
a typically massively over-engineered German bolt capable of infinite
reuse.  I'm surprised that it's not mentioned in most reviews of the TB
change.

p.p.s Just out of interest, could all of you who have come across a
crank pulley failure send me a 'me too' email - I'll report back to the
list on the numbers involved.

p.p.p.s. If there's enough of us, maybe we should set up a support group
and hold meetings - "Hello, my name is Paul, and I'm a keyless crank
pulley owner..."

> Message: 4
> From: QSHIPQ at aol.com
> Date: Tue, 7 Oct 2003 08:40:12 EDT
> Subject: Re: [s-cars] welcome to my nitemare
> To: strangconst at rogers.com, beernuts at online.no,
> 	s-car-list at audifans.com
>
> This is pretty common in S cars, actually in 5000/200's
> before them...  The problem appears to be the locking
> compound on those threads really makes the bolt stubborn
> coming out.  So much so that many times the locking tool will
> sheer the cast keyway.  A close inspection of the keyway is
> in order when t= he timing belt service is done.  I'm not
> sure this is a replace every time par= t if it's inspected.
> If you want to go that route, I'd suggest changing the 4 a= llen
> bolts and torquing them to spec as well.   The problem
> appears to be looking
> at the back of the pully.  From what I read below, I'd guess
> that the last = TB already sheered or deformed that key, and
> that the installer just lined up = the hash mark on the front
> cover without inspection.  This usually manifests itself with
> a spin sometime down the road, especially if the crank bolt
> was=  reused and stretched a bit...  BTST.
>
> The part that I WOULD routinely replace is the crank bolt.
> Audi specifies this, and for good reason, it definitely
> stretches on install.  I have one = in my shop that failed,
> luckily I felt it getting weak and when it let go, it sti= ll
> had enough attached to the sheer to back it out.  The bolt is
> 12USD and is available at the parts counter.
>
> HTH
>
> Scott Justusson
> QSHIPQ Performance Tuning
>
>
> Paul Heneghan,
> Lecturer (Computers and Networks)
> BBC Training & Development
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>
>

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