aaz engine problem??

[fairport11]

i am presently replacing the 1.6td in my vanagon with a 1.9td aaz engine. i have read and read all kinds of scary stuff about the cam pulley failing. other than taking the crankshaft from a fully running engine for machine work, what should i do to cure the problem? how do you do the dowel pin thing on the engine?? other ideas?? i was planning on a new timing belt and tensioner.

[Quantum-man]

i am presently replacing the 1.6td in my vanagon with a 1.9td aaz engine. i have read and read all kinds of scary stuff about the cam pulley failing. other than taking the crankshaft from a fully running engine for machine work, what should i do to cure the problem? how do you do the dowel pin thing on the engine?? other ideas?? i was planning on a new timing belt and tensioner.

If there is an issue, you won't cure it by dowelling the cam pulley

Try key word searching for crank pulley mod

[Quantum-man]

i am presently replacing the 1.6td in my vanagon with a 1.9td aaz engine. i have read and read all kinds of scary stuff about the cam pulley failing. other than taking the crankshaft from a fully running engine for machine work, what should i do to cure the problem? how do you do the dowel pin thing on the engine?? other ideas?? i was planning on a new timing belt and tensioner.

If there is an issue, you won't cure it by dowelling the cam pulley

Try key word searching for crank pulley mod

Further to this, I'd like to say that I'm a little if not significantly pessimistic about machining the nose of the crank to prevent pulley slip.
Why?
Well...
Assuming the crank bolt has been correctly tightened, the slip can only take place if the stress is great enough. This great leverage on the pulley will come via the timing belt. But it will only come down the belt from cam turning resistance, or indeed a tremendous change in momentum of the cam. I believe that turning resistance in the cam is well within the remit of the 1.9 pulley.
The change in momentum part from normal driving, probably peaks with that funny trait of gasser drivers of revving, then switching off
If someone has altered/reset the cam timing and not properly cleaned and fastened the cam pulley, then slippage there can be catastrophic.

Properly set the cam pulley grips like a vice.
Sorry I'm rambling on with no direction.
Basically although the crank pulley is a weak point, I don't think it shows up until human error somewhere, or spontaneous problems involving either piston to valve clash, down to fatigue, or timing issue; or even belt failure due to a picked up stone or bolt wedging, when belt cover left off.
I think that it is rare for the crank pulley to slip with no issues elsewhere, and so risking messing up the crank nose, when the primary cause is still waiting to happen, is something to weigh up.

I'd like to see statistics on failure despite the pre-emptive pulley mod.

[rdezsofi]

The 'scary issue' you refer to involved the crankshaft pulley, not the camshaft.
.....I believe the issue was not caused by the timing belt at all, but rather by the alternator belt if I recall correctly. Apparently there was something about sudden deceleration that put tremendous torque on the crank pulley.....and a little woodruff key just wasn't enough over time. Also, if I recall correctly....a factory 'fix' was to use an alternator with a clutch system, so the alternator basically freewheeled during rapid deceleration of the engine. As a machinist, I wouldn't hesitate to do the crankshaft nose modification...it's a much more solid/bulletproof design. But I would also probably go with the alternator clutch setup simply to relieve that particular stress. Someone correct me if I'm wrong, but that's the history of the issue as I remember it a few years back.....

[Fatmobile]

I remember someone posting that a sepentine belt had a much more solid grip on pullys.
Whereas a v-belt might not let the alternator drive the crank, but a sepentine would.
I had 2 1.6TDs with the crank nose messed up and pistons had hit the valves, one died that way

and the other had it happen in a former life followed by an attempt to recusitate;
which left me with a fresh topline head and used NA pistons with squirter grooves cut in them.

So I'm not so sure it's a serpentine belt thing, or a 1.9 thing, could still be a ratcheting alternator pully thing.

I think the stock keyway is a bad design, always seems like a little play in it.
All my rebuilds get the D-sprocket, it's easy to machine them with less play, less likely for the bolt to get loosened by the back-and-forth motion.

[fairport11]

In order to do the "d" machine cut to the crankshaft, does the crankshaft have to be out of engine or can it be done while still in engine?

[Fatmobile]

A couple people have found ways to do it with it still in the car.
I had a tool made that bolts to the end of the crank but haven't tried it out yet.

[fairport11]

Great , what does it look like . Ir would be helpful to see it , pretty tough to picture it .

[Fatmobile]

http://www.vwdiesel.net/forum/index.php?topic=29230.0

[fairport11]

does anyone know if the harmonic balancer for a tdi will fit and can be used on a AAZ? would think they are the same but not sure and the VW dealer has no idea, dunces.

[fairport11]

got the crank pulley off and surprise, no damage at all, looks like new. the harmonic balancer rubber is toast though. that would have been a big "wobble" issue in short time. also, where does one get the alternator clutch for a retrofit??part number ??does a tdi harmonic balancer fit a AAZ? BTW--you guys have been great, thanks

[the man 53]

Clutched alternator pulley upgrade on AAZ
« on: February 10, 2010, 02:01:04 AM » Quote

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I recently upgraded the stock alternator pulley on my AAZ to the “clutched” or “freewheeling” type, and thought that some of the information I learned may be useful to others. I know this has been covered in other posts, but there are some details not previously covered that I learned along the way.

First of all, according to my research, there are two sizes (diameters) of pulleys.

Part # 038 903 119A, or it’s superceded part# 022 903 119C, or various other #’s, is for A4 and later vehicles (1999+). Size is 61.5 mm. O.D. It is too big for the AAZ.

Part# 028 903 119AA is for A3 TDI’s. Size is 55.5 mm. O.D. This is the one that can be swapped onto an AAZ alternator. Brand I bought was edit vendors name was there here in Vancouver.