Now a new timing issue

[wadem]

Hi again guys, so after my last advanced timing post and been so pleased with how my AAZ is running, I now have a new problem.
For the third time, thats right 3 times in a row, my timing is going out all by itself. I could tell the first time that  it was not running as well as it had been since the advanced timing thread. Harder starting and different sound. So, pulled it all apart again and saw that it was out! At TDC on the crank the cam was just a smidge off as well as the pump had become more retarded. Set it all up again and it drove fine for another day or 2 then it happened again. Same routine, found it out again, fixed, and back together this morning. Running awesome again, but i'm thinking it won't last.
  The car runs just fine going down the road, lots of power and no smoke, but again you could tell it was just a little out from the optimum setup that i locked it into. I dont think its out enough to blame it on a skipped belt cog. Its like something is coming loose just enough to upset the balance slightly. My cam sprocket is torqued to 33 foot lbs, the IP sprocket (adjustable) has the 3 bolts and they are very tight. I have read some info that this could be the nasty crank bolt issue! But mine has the newer multi point bolt in it and its so tight i cant budge it even with a 4 foot snipe.....what am i missing here?
  My sequence to  tighten and adjust has been, TDC on the flywheel, lock cam, loosen cam bolt, line up cam and lock it in, torque cam bolt, recheck that nothing has moved, adjust the IP to same setting as before, torque those up...thats it.  The last 2 times I spun the crank over via the crank nut about 100 times and all was still lined up.
  So wuz up!!!

Wade

[R.O.R-2.0]

Hi again guys, so after my last advanced timing post and been so pleased with how my AAZ is running, I now have a new problem.
For the third time, thats right 3 times in a row, my timing is going out all by itself. I could tell the first time that  it was not running as well as it had been since the advanced timing thread. Harder starting and different sound. So, pulled it all apart again and saw that it was out! At TDC on the crank the cam was just a smidge off as well as the pump had become more retarded. Set it all up again and it drove fine for another day or 2 then it happened again. Same routine, found it out again, fixed, and back together this morning. Running awesome again, but i'm thinking it won't last.
  The car runs just fine going down the road, lots of power and no smoke, but again you could tell it was just a little out from the optimum setup that i locked it into. I dont think its out enough to blame it on a skipped belt cog. Its like something is coming loose just enough to upset the balance slightly. My cam sprocket is torqued to 33 foot lbs, the IP sprocket (adjustable) has the 3 bolts and they are very tight. I have read some info that this could be the nasty crank bolt issue! But mine has the newer multi point bolt in it and its so tight i cant budge it even with a 4 foot snipe.....what am i missing here?
  My sequence to  tighten and adjust has been, TDC on the flywheel, lock cam, loosen cam bolt, line up cam and lock it in, torque cam bolt, recheck that nothing has moved, adjust the IP to same setting as before, torque those up...thats it.  The last 2 times I spun the crank over via the crank nut about 100 times and all was still lined up.
  So wuz up!!!

Wade

i would bet that your crank sprocket keyway is just about dead..

does your crank pulley wobble at all?

the only way your timing can change on its own, is when the crank sprocket key, and crank keyway are worn out..

[ORCoaster]

Key shearing?  Tensionor not tight or have the right washer under the nut?

[R.O.R-2.0]

Key shearing?  Tensionor not tight or have the right washer under the nut?

usually when they jump teeth, the valves get wrecked..

i doubt the belt is jumping time.. i imagine the keyway is trashed, and the timing is changing because the crank sprocket cant stay located in one spot..

[bbob203]

time for a tdi crank sprocket upgrade id say.

[tyb525]

So anyone know why VW switched to the keyway design, instead of keeping the old style taper fit?

[wadem]

 All the info i have read says that the last IDI's (1996)were not susceptible to the loosening crank bolt/sprocket! If the bolt s so tight that you cant budge it with a 4 foot snipe, how could the sprocket be loose?
  Also, is there a work around or a home made tool that i can make/use to lock the crank while i attempt to remove the bolt? Or is it imperative that you use the proper VW locking tool?.......not really looking forward to this .
I guess it is my hobby car but I think i have had this thing ripped apart about 5 times in 1 week!
Any tips on how to do this job would be great......

Thanks guys

Wade

[TylerDurden]

Before you rip it apart, you might consider marking each sprocket and determining exactly what is moving/changing.

[TylerDurden]

PS: I'd use a scratch-awl to make fine marks.

[wdkingery]

Impact guns get bolts out of spinny locations

[tyb525]

I thought the AAZ had a keyway cam sprocket also?

[R.O.R-2.0]

So anyone know why VW switched to the keyway design, instead of keeping the old style taper fit?

they never had a tapered fit on the crank sprocket.. its always been a ghetto design since the water cooled inline 4 cylinder came out in the early 70s..

they changed from the original style, to the TDI D-shaped crank snout and friction fit sprocket just because of soo many crank nose failures..

and as for the cam, no diesels EVER came with a key in the keyway on the cam.. they are a taper fit, and never were intended to use a key to locate the pulley, like on a gasser..

and if your belt is tight, then the only thing that is changing your timing, is a slipping crank sprocket..

[tyb525]

sorry, I though I read that AAZs had a keyed cam sprocket. I also thought we were talking about the cam sprocket not the crank sprocket

[R.O.R-2.0]

sorry, I though I read that AAZs had a keyed cam sprocket. I also thought we were talking about the cam sprocket not the crank sprocket

nope, no diesel ever had a key in the keyway on the cam..

CRANK sprocket.. the one on the bottom of the engine.. the one that the pulley bolts to..

start your engine, and look at your crank pulley as the engine is running.. does it have ANY run-out? does it wobble AT ALL? you should barely be able to tell that the crank pulley is spinning, because it runs soo true..

if your crank pulley has any wobble to it AT ALL, then i would remove the crank bolt, and inspect the crank nose, and the crank sprocket..

[wadem]

Good info, thanks guys. I looked at the crank pully while running and it was almost perfect....almost. So i guess as you say it should come apart. I think that the only thing that could be doing this is the crank sprocket.......so stay tuned and i will forward the results.
  So just to give me more thoughts so i dont sleep tonight, if the crank keyway is damaged or smashed up, is there an in car fix for this? I love my old Jetta, but i bought the car for 600 dollars 2 years agao and it has been a love of labour ever since. I have learned a ton about the IDI's, mostly from you guys. But i think before I rip a crank and engine out of her, i would probably just let it go. Kinda of too bad because it runs great, air con and cruise actually work, its a great hobby car!
  Anyway, if i can get away with just replacing the crank sprocket and bolt, wonderful. If there is a in car repair for a worn crank nose, might consider that. Anything more invasive and its bye bye