And another AAZ engine bites the dust

[AadmanZ]

Are you sure that anything is damaged internally? Would you be able to drive with the symptoms of only a 'slight rattle' if timing was off and valves hitting or even stuck open due to being bent?
I feel very optimistic... makes a change  :roll:
Sure it won't start now but that's another issue

No I don't, that was the main reason for this topic

I think the rattle was the pulley coming loose, then, when I started it up (after sitting for a few days) it wouldn't fire up properly, bucked and that's when it came loose.

Ok, well anyway, pics are in:




My first comment: what a sh!+ construction..
The big question: is this crank done for?

Taking the whole engine apart and welding the crank is not an option, the man hours involved would be much more than just swapping over a running engine. First quote (reliable breaker) was 500 euros> 720 CAD> 336 sterling.

[Doug]

Re: M&M post previous: Am I missing something here? Or have aliens just landed.

[Doug]

AZ, you are right! It is a pretty poor effort on the part of VW to turn out stuff like that. 500 euros is not a bad price for a guaranteed running engine supposing that it is in fair shape. But what if it is not and needs more work as well. Besides the crank nose on that one may be in worse condition. Most wreckers only give guarantee against total failure. Sometimes the devil you know is better than the devil you don't know. I am no expert on the AAZ motor but from your pictures the crank nose looks okay. Maybe just a new sprocket, bolt, and some locktight will do the job. Top end parts like valves are cheap to replace. If you are there you may as well do it right.

[AadmanZ]

AZ, you are right! It is a pretty poor effort on the part of VW to turn out stuff like that. 500 euros is not a bad price for a guaranteed running engine supposing that it is in fair shape. But what if it is not and needs more work as well. Besides the crank nose on that one may be in worse condition. Most wreckers only give guarantee against total failure. Sometimes the devil you know is better than the devil you don't know. I am no expert on the AAZ motor but from your pictures the crank nose looks okay. Maybe just a new sprocket, bolt, and some locktight will do the job. Top end parts like valves are cheap to replace. If you are there you may as well do it right.

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Yeah, I know, let's wait for some more comments... Cuz it does look like quite a bit of it is worn off, and fixing the head without properly fixing the (known) weakest part of the engine seems a bit stupid.

[burn_your_money]

I'm also not an expert on AAZs but looking at the crank I think you need to get it fixed.

You might be able to find someone that can machine the crank to fit the TDI crank pulley with everything installed the way it is now, you'd need to remove the cam though

[AadmanZ]

Well, just discussed it with my local (bike) mechanic..  engines are engines right? (This is a guy I know and trust, he would be my first choice when doing any machining/welding on anything.)

Weld a (new) pulley (straight) onto the crank..
Time everything
Crank it over, see if it fires up..

(So, basically, yes I do hope the valve fixin' fairies have been doing their thing in my engine bay )

If it does, great.. if it sounds rough, there might still be a bent valve, but that can then be replaced.

If it doesn't fire up, we can still pull the head off for inspection.. If all the valves are stuffed, I can always get another engine...

Saw some really nice completely overhauled ones on Ebay.. Lots of €€€ but very Naissss, me like..

[Doug]

I am not sure what sort of a mechanic would recommend a fix like that! The heat will destroy the seal immediately behind the sprocket (major oil leak will follow) as well as probably destroy the bearing behind the seal. Then you really do have a mess on your hands. There is no easy way to fix things right. Don't let some knob who thinks he is a mechanic try a stunt like that.

[AadmanZ]

I am not sure what sort of a mechanic would recommend a fix like that! The heat will destroy the seal immediately behind the sprocket (major oil leak will follow) as well as probably destroy the bearing behind the seal. Then you really do have a mess on your hands. There is no easy way to fix things right. Don't let some knob who thinks he is a mechanic try a stunt like that.

Never mind that, the guy knows his business, he hasn't seen the setup though. His theory is that the crank should soak up a lot of the heat. which sort of makes sense.

I know there is no such thing as a cheap fix, but it p!$$es :evil: me off that a few mil of material (and not a broken conrod or something that dramatic) should mean damage this dramatic.

[Doug]

"His theory is that the crank should soak up a lot of the heat. which sort of makes sense."

WTF

[AadmanZ]

Never mind, I don't even think you can get in there without disassembling most of the engine anyway..

Is there anyone who knows his stuff and can say whether or not this can still work with a new pulley?

[Doug]

Judging by the pictures. I would say that the keyway looks serviceable. You may only have to dress off the raised edge on the end of the keyway with a file. Do not file the tapered portion. Then try a new sprocket with a new bolt. If the fit has no slop then remove and apply Locktight sleeve retainer as per instructions. Then assemble it to time it and see if your valves are still intact.

[AadmanZ]

Keyway is indeed serviceable, new pulley fits like a glove.

Put everything back together, retimed it, fired it up, it kept running on three cylinders, but with quite some mechanical noise. Removed the head and found that most valves had hit pistons (as they would) and that there were quite a number of cracks in the head itself. Pictures will follow, but head will most likely have to be rebuilt/replaced.

[Doug]

I am surprised that you were able to get it started. There must be a couple of good sets of valves. If the cracks are between the intake and exhaust valves on each cylinder, just ignore them. All VW diesels have these cracks and some head rebuilders will try to sell you a new head but it is a scam. The cracks rarely cause any problems. Don't let some wizard with a TIG torch mess with them either. That will cause more problems than not.

[AadmanZ]

Pics are in.. (crappy phone pics, but still) I marked the cracks.. They are mainly between the valve and the glowplug chamber. (or whatever the hell that is)




I counted about 7, will have to take some better images, but it does not look nice. Anyone have any images of the "normal" cracks as they are "supposed" to be in these heads?

Valve marks on all the pistons.

[Doug]

If the cracks have not penetrated into the coolant jacket, I would not worry about them. What you are seeing is not unusual. The only way to check the valves properly now is to disassemble the head checking the valve head run out with a V block and a dial guage. or just eyeball them by rolling the stem on a flat surface looking for the head of the valve to wobble. If your head has a couple of hundred thousand Kms then replace valves and guides for optimum sealing and oil consumption control. The pistons will be fine but you may want to drop a new set of rings in it as you have it all apart.