Author Topic: 1.9 TD AAZ engine crankshaft pulley wobble, will pinning be sufficient?  (Read 861 times)

April 19, 2020, 03:47:38 pm

bencuri

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My car has the usual problem of AAZ engines: the crankshaft pulley bolt broke out, now a new one is put back and fixed, but the pulley is wobbling. I have read that pinning is done to avoid issues like this, but I am not sure if pinning is only good to prevent the issue, or it is also useful after the wobble has developed? I would prefer pinning to  welding, due to the fact that in my car there is enough space not to remove the crankshaft when pinning, so I could save money.




Reply #1April 19, 2020, 06:03:04 pm

fatmobile

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 Not sure why the pully would wobble,.. unless the nose of the crank isn't flat/square.
 How much damage did the key do to the crank nose?
Where are you located?
 The best fix is to make a flat spot and use the TDI "D" sprocket.
I made a tool to do that on the car and it works great.
Haven't lent it to anyone yet.
 The deposit would have to be pretty high.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #2April 20, 2020, 06:15:27 am

bencuri

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I am located in Hungary. Actually it is the serpentine belt pulley (the name is harmonic balancer maybe) that I can see is wobbling. The nose of the crank might not be totally flat. The repairman tried to make it flat, but I think he couldn't make it dead flat. The keyway was damaged in a way that a corner of the keyway protruded outwards, I guess that is what the repairman tried to flatten.

The symptom is exactly the same like in this video:
https://m.youtube.com/watch?v=uAl_8GwCLXw
« Last Edit: April 20, 2020, 06:21:24 am by bencuri »

Reply #3April 20, 2020, 10:40:07 pm

fatmobile

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The serpentine belt pully is bolted to the timing belt sprocket.
 There is a bump on the timing belt sprocket that fits in a hole on the pully.
Maybe he put the pully on wrong, didn't line the hole up with the bump.
4 ways you can put it on.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #4April 21, 2020, 04:47:26 am

bencuri

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Well maybe, that can also be the case. Unfortunately I cannot check it myself as the serpentine belt tightener system is not the stock one and I am unable to remove the fixing screw of the tensioner having been screwed in too tight. But will ask a technician to check. However I am not sure at all that the repairman flattened the nose correctly, as he did not remove the crank or engine from the car when repairing, so it can easily be the case that he could not make it perfectly flat. We'll see.

So in case the crankshaft needs to be repaired, you say pinning is not enough in this case, but I should go for the D shape mod? I was hoping I could avoid that to spare money. :/

By the way, can you take a photo of that crank modifier tool, maybe I could ask a machine shop to make it for me.


« Last Edit: April 21, 2020, 06:30:13 am by bencuri »

Reply #5April 21, 2020, 11:56:11 pm

fatmobile

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Andrew showed me how to make this.
 So maybe a machine shop can make one for you.



The little key holder doesn't need to be there at all,..
 bolting it to the crank holds it fine.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #6April 27, 2020, 09:46:26 am

bencuri

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I have researched how much money and time would it cost to make such a tool, and I concluded it wouldn't worth. Machinists here did not really like the idea when I told them about what I want. They are quite passive here when it comes to do unusual jobs. Very likely I will try pinning instead, as for that process I can have the needed parts prepared for a very low price, and I will do the drilling myself. If it fails I will have the crank replaced in a shop.

Reply #7April 27, 2020, 11:22:16 am

libbydiesel

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If it fails, you'll need to replace more than just the crank.  The pistons will hit the valves.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #8April 27, 2020, 03:52:02 pm

bencuri

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The thing is maybe it already happened when the center bolt broke and the pulley fell off a few months ago. The mechanic did not check, but there is a chance the engine is wrecked already. It is difficult to start up the car since then, and there are skipped beats when running. Spending 400$ on a suspiciously bad engine (and an exhausted car) is just too much for me. If this was a case about doing prevention for an engine that represents value, I would go the sure way. The car concerned is only kept for the purpose of using on bad roads, no need to worry about it's future.