Audi RS2 timing or belt question

[minim]

Oh I just contacted the previous owner and asked him about the problem on WOT. He said that this was something that came now recently (this summer) just after the fuel pump was replaced on the car. He didn't think it was related to the sprocket as the rebuild was done in 2011 and the car was working fine until recently this summer. This makes me even more scared of changing to the original sprocket with a 10 degrees change in case I put something out 10 degrees.

[twoqu]

My theory is that mechanically everything is in the right place unless there is a difference in the key position of the two different pullies. We know there is a different rotor position but that is to put it back to the correct position so that the ecu see it when it expects to.
Might be worthwhile to wait for the cable and see if there are any hall sender fault codes stored. If there is I think that adds weight to our incorrect pulley theory.
If it was my vehicle I would replace the camshaft belt and the crank pulley if changing the pulley. You might even consider using a stronger version of the crank pulley that are available as that also is a known weak spot. There is no danger in it being out if you are using all the correct components. It just looks from the pictures that the pulley is incorrect and this may be confusing the ecu hence the performance is degraded.
By the way I hope you understood what I meant about the water pump. It looks as though the exchange version uses the TDi casting. Presumably there are no original casting left to exchange.

[minim]

Correct me if I'm wrong now as English is not my first language but when they key position is different how can everything be mechanically in the right place? If the key is in a different position won't the cam change it's position to the crank then?

I checked the package tracing of my cable now and It's expected on Tuesday so I will check for hall faults then. However I don't get to delete fault codes, start the engine and then check if the hall fault came back as the car is dissembled now during these checks.

The belt and crank pulley was changed for about 8-9000km ago but I will order new parts if you think it is smart to change belt and crank pulley at the same time as changing the upper sprocket. I just hope the crank sprocket is possible to get trough Audi :X I guess I will know tomorrow when I call my dealer.

Yes I understand the part about the water pump. It all made more sense now that I got to know that the crank sprocket should be about half a tooth off the mark

Thanks for all the superb info guys! This knowledge saved me from hours of research if I ever would have found it out by myself!

[twoqu]

Without a direct comparsion its all theory on my behalf I am afraid.
Personally I think that the cam pulleys are identical with just the hall sender rotor repositioned. Thats why the mark does not line up. Had they made a dedicated pulley surely they would have made the mark in the correct place to prevent confusion. In fact they could even have got someone to scribe a line on it.
I think the RS2 exhaust cam is a completely different grind taking into account that Porsche also wanted to alter the inlet by the advertised 10 degrees. Rather than grind new inlets they used the cam pulley position to alter the installed position of the inlet in conjunction with the waterpump and the 150 tooth cambelt. Thats why the inlets are the same p/n but differ in the advertised (installed) timing. So its the relative position of the cam pulley that accounts for the installed timing change. If the hall sensor rotor was not then repositioned the ecu would see it in the wrong position. So Audi or Porsche redesigned/repositioned the rotor onto existing cam pulley blanks to save a few Deutschmarks. The cam pulley position altered the installed inlet timing of the otherwise stock inlet and the repositioned hall sensor rotor satisfied the Motronic that the position relative to the firing stroke was correct. The only downside was the incorrect timing mark. Thats my theory but without a direct pulley comparsion its just that - a theory!
All we can say is that that the correct RS2 pulley appears to have the B on the rotor. If you accept my theory it also accounts for the fact that both pulleys have the same part number stamped on them. It is evident that Porsche or Audi raided the parts bins and either used off the shelf Porsche components of uncertain origin, like the injectors, MAF, FPR even the turbo perhaps which I think has exotic origins (968 Turbo?) and on things like the brake discs (and cam pulley/water pump) modified existing parts.
I don't want you to buy unecessary and undoubtedly expensive replacements parts but it does appear the pulley is incorrect. We have established the head is at least the ADU one and the exhaust cam appears to have the right lift. As the inlets cams are all the same, the cambelt has the correct number of teeth and the water pump is correct in terms of its teeth, the only suspect item is the pulley. If we accept that the physical relationship is the same with both pulleys and we know the rotor position is not, we can theorise that that is the issue. If its backed up with an historic hall sensor fault code (00515 I think) then I would argue that not a coincidence. It will only ever be right with all the correct components fitted in the correct position in my opinion. Let see what Vagcom says.

[minim]

Ok. It does sound like a good theory. Will check for fault codes from the the sensor once I get vagcom.

I called my local Audi dealer today to check if the sprocket was available and it still is if ordered from Germany. The only bad thing is that they want $400 for one. That's a a lot for just testing if my sprocket is not the correct one. Won't order this until I've checked with vagcom atleast.

[UrS4boy]

Here are a couple of photos that might or might not help.

The first is of an RS2 ADU showing the way the cams line up and also how even the "B" can be seen from the back side of the G40 Hall sender shutter wheel.



The second is a photo of a G40 Hall sender shutter wheel showing the general arrangement of the shutter opening in the wheel (I think this is from an AAN (or ABY). Looks like the shutter opening is centered directly across from the "key" for the camshaft keyway. Presumably, the ADU opening would be the same size but shifted 10 degrees) (a photo of an ADU shutter wheel would be helpful - but I don't have one).

[minim]

I'll go out and remove my sprocket from the cam so I can try to take a picture from the same angle. It should then be possible to see if the opening is 10 degrees off or if it's at the same place as the one in picture.

[minim]

Now I have removed my cam sprocket and tried to take some pictures of it. It's hard to get the exact angle to compare but I made a short video of the first attempt here. It does look like I have a offset on the housing but the key and the mark on the wheel looks like it's at the same spot. Will work on a better picture for it.

Edit: Sorry for not asking to use your picture first UrS4boy, I just came to think of it now. Please let me know if you want me to remove the movie from youtube again.

Not sure if I can get the youtube window to work but here is the link also. http://youtu.be/ntrjPm9nOO0

[twoqu]

Indeed but the high cost also adds weight to the theory that somebody broke it, perhaps without the owners knowledge if they do not do their own maintenance, found out the cost of the correct replacement and bodged it up with a considerably cheaper and easy to source used AAN/ABY pulley. To be honest I have a used ABY pulley that looks in better condition than that one!
Apart from hurting my eyes and giving me a headache it does appear from your video that as suspected the rotor is repositioned but the pulleys are the same. We could really do with a static pic of the RS2 pulley from behind.
Its a long shot but perhaps you put a wanted advert up for an RS2 pulley. Somebody might have one. Alternatively a cost effective measure may be to use an aftermarket adjustable cam pulley with the provision to adjust the rotor position. It will be a bit of trial and error though but should be mucher cheaper than the OE RS2 replacement!
If you are not familar with the Audi I5 the key in the cam pulley is a known weakpoint as well as the crank belt pulley due to the keys breaking. Thats why at the very least its recommended to replace the crank pulley at every cambelt change. Both were a poor material choice and design really and do a lot of damage when either fail.

[minim]

It sure would be a lot easier to determine if my pulley is correct if I could get my hands on a picture from a RS2 pulley from behind to match those up and see if mine is correct. From what I saw when I compared the picture UrS4boy posted with the one I took of mine it looks like mine has a offset on the rotor. Sorry for the headache but this was the best way to show the difference I think

I did make such a thread on a Norwegian Audi forum so I hope I can manage to find a used one.

If my pulley indeed is 10 degrees off and making my engine not go as it should those $400 on a original new one is well spent in my opinion. The only thing putting me off atm is that by the looks of those photos my pulley isn't like the ones used on AAN/ABY. I do not want to go the route of an adjustable one as I think it's, for me, just saving some bucks and getting into a lot of trouble. I do not have enough knowledge to adjust one properly and I do want to keep my engine stock.

I am not so this is good information. I managed to find the reinforced version of the crank pulley from a parts dealer here in Norway so that one I will get. Is the reinforced version something my Audi dealer could sell also or is it just aftermarket dealers? Will be fun to see what the readout from vagcom says tomorrow.

[twoqu]

This is not a recommendation just an illustration of a cheaper, arguably beter quality replacement than the OE. It states the hallsender rotor is adjustable.
I think you are probably spoilt for choice in your location for alternative parts.

http://npsheads.omaverkkokauppa.fi/Adjustable-cam-gear-with-hall-window-for-Audi-5cyl-20v

[twoqu]

I still think that you are getting hung up on this 10 degree issue. If we accept the pulley key is in the same position then even with the incorrect pulley the camshafts are installed in the correct position for the RS2 when aligned one tooth out. The issue is the rotor position I think which is confusing the ecu. The inlet cam is the same as the ABY/AAN but its installed spec is different due to the one tooth out position. That what I understand. Otherwise the inlet would have been a completely different grind which could with a bit of thought been installed with a pulley which had a correct time mark. Audi or Porsche saved 0000 of Marks by using standard components and adapting them rather than tooling up for what would have been a very small production run. Again thats my theory!

[minim]

Yeah I found one looking exactly like that one but as I don't know how to set the hall window I won't get it right anyways that's just why I said that I think it's better to spend the little extra in getting a OEM part rather then spending the extra money of having a professional setting the hall window. It would maybe be possible to set it if I had some good pictures of a ADU pulley but again it would be only "approx" set and not as accurate as a OEM one wouldn't it?

[minim]

I still think that you are getting hung up on this 10 degree issue. If we accept the pulley key is in the same position then even with the incorrect pulley the camshafts are installed in the correct position for the RS2 when aligned one tooth out. The issue is the rotor position I think which is confusing the ecu. The inlet cam is the same as the ABY/AAN but its installed spec is different due to the one tooth out position. That what I understand. Otherwise the inlet would have been a completely different grind which could with a bit of thought been installed with a pulley which had a correct time mark. Audi or Porsche saved 0000 of Marks by using standard components and adapting then rather than tooling up for what would have been a very small production run. Again thats my theory!

We might be talking past each other due to language problems I think (my lousy english..) If I understand correctly the pulley with the key and mark in the outer ring is at the same place for ABY/AAN/ADU right? But the inner ring/disk is placed different. If you look at the video at 1:33 and pause it there I've drew some red lines where the hall window is at. Those 4 marks are for the edges on my pulleys end points and on the picture that was given here (AAN/ABY). There is a little bit of opacity in that still picture at 1:33 so you can spot the AAN/ABY pulley behind my pulley. I can't measure the offset but it's about 1/3 of the hall window's size to the left. The AAN/ABY pulley picture is the one in the front.

Since there is a offset on the hall window on the pulley that is installed in my car and the original AAN/ABY pulley I just get confused around the whole thing :X

http://www.youtube.com/watch?feature=player_detailpage&v=ntrjPm9nOO0&t=92

[twoqu]

Obviously if you want it to look stock than an original one is the only way to go. I was just suggesting a cost effective solution if it turns out what we suspect is the case. Of course if we knew the exact position that would solve your problem and answer something I have wondered about every since I found out the difference on the RS2 - Why did they do that!
At least you are getting your hands dirty which is more than most RS2 owners do!