Chirp sound from alt. belt area

At back side of the crank pulley, there is a tin that has " tabs" at the 3 and 9 o'clock positions. In the warmer ambient air temps the tin or crank pulley may be expanding few thousands and just enough for the tin to touch the back side of the pulley. The fix is  to wiggle a screw driver between the two surfaces creating gap. If that doesn't resolve the issue then you are on track to remove the belt to locate the source which may be the fan lightly touching the shroud that involves a light shale and twist of the fan shroud and that may resolve it , but the correct way is to add or delete one or more of the round fan shim washers which I don't think you want to get involved with while you are in Fl.

Alan Merklin posted:

At back side of the crank pulley, there is a tin that has " tabs" at the 3 and 9 o'clock positions. In the warmer ambient air temps the tin or crank pulley may be expanding few thousands and just enough for the tin to touch the back side of the pulley. The fix is  to wiggle a screw driver between the two surfaces creating gap. If that doesn't resolve the issue then you are on track to remove the belt to locate the source which may be the fan lightly touching the shroud that involves a light shale and twist of the fan shroud and that may resolve it , but the correct way is to add or delete one or more of the round fan shim washers which I don't think you want to get involved with while you are in Fl.

Thanks, Alan. We just got home tonight and I'm looking to get this fixed in prep for Carlisle. I'll give it a look on the weekend. BTW, we stayed one night at the Courtyard in Shippensburg on the way down. Nice as always. 

Trailering the Roadster on the trip was uneventful and convenient but way less fun than driving. 

Years back, I was hearing a chirping sound after I did a tune up. I thought it was maybe  the generator going out so I flip the belt off and it still had the noise. I mess around with this for days trying to find the source of the sound. I asked my friend at a Porsche repair shop if he had any ideas what it might be causing the sound. He said to make sure the rub block in the distributer was greased or it would get hot and chirp. Sure enough, I forgot to lube the cam block for the points. A dab of Bosch grease on the block and the chirp was gone.

Butcher Boy posted:

Years back, I was hearing a chirping sound after I did a tune up. I thought it was maybe  the generator going out so I flip the belt off and it still had the noise. I mess around with this for days trying to find the source of the sound. I asked my friend at a Porsche repair shop if he had any ideas what it might be causing the sound. He said to make sure the rub block in the distributer was greased or it would get hot and chirp. Sure enough, I forgot to lube the cam block for the points. A dab of Bosch grease on the block and the chirp was gone.

Thanks for that but I have no points and the chrip is much louder than a points cam could be. 

David Stroud IM Roadster D posted:

Alan Merklin posted:

At back side of the crank pulley, there is a tin that has " tabs" at the 3 and 9 o'clock positions. In the warmer ambient air temps the tin or crank pulley may be expanding few thousands and just enough for the tin to touch the back side of the pulley. The fix is  to wiggle a screw driver between the two surfaces creating gap. If that doesn't resolve the issue then you are on track to remove the belt to locate the source which may be the fan lightly touching the shroud that involves a light shale and twist of the fan shroud and that may resolve it , but the correct way is to add or delete one or more of the round fan shim washers which I don't think you want to get involved with while you are in Fl.

 

Alan, I took a look behind the crank pulley and there's no sign of any scraping against any tin. Further research shows that there may be a chance that the cooling fan may be rubbing against the cooling housing and my test there will be to drive the car in hot conditions till the chirping starts, stop the engine, remove the fan belt as quickly as possible and turn the alt / fan by hand listening for any scraping. I probably should check that big nut at the back first to see if it has loosened in any way allowing a minor wobble. 

If I do find chirping by turning by hand, info shows that the fan can be shimmed back a bit which looks like a simple but tedious task. Any idea where to get such a shim ? Would they be a common hardware store item or a dedicated VW part? 

Again, there is no chirping when the engine runs on startup. Just very pronounced when the engine is completely warmed up in warm to hot ambient temps. Thanks. 

your chirp is your alternator pulley. the pulley's half against the alternator is moving. replace it with a CB billet one and your noise goes away. a little white grease on the belt also helps

David Stroud IM Roadster D posted

If I do find chirping by turning by hand, info shows that the fan can be shimmed back a bit which looks like a simple but tedious task. Any idea where to get such a shim ? Would they be a common hardware store item or a dedicated VW part?

David, I picked up a couple of these Gene Berg fan spacers when I ordered my new fan.  http://www.geneberg.com/produc....php?products_id=808

Did you consider there might be a Cricket hiding somewhere in the engine compartment. 

mppickett posted:

David Stroud IM Roadster D posted

If I do find chirping by turning by hand, info shows that the fan can be shimmed back a bit which looks like a simple but tedious task. Any idea where to get such a shim ? Would they be a common hardware store item or a dedicated VW part?

David, I picked up a couple of these Gene Berg fan spacers when I ordered my new fan.  http://www.geneberg.com/produc....php?products_id=808

That helps with pulley alignment but I don't think it's going to help David's problem.

I agree Al,  the Berg ones are more for the alt pulley. But, seems like the last time I looked at the diagram, there were a few spacers inside that allowed a small amount of front to back adjustment on the fan. 

mppickett posted:

I agree Al,  the Berg ones are more for the alt pulley. But, seems like the last time I looked at the diagram, there were a few spacers inside that allowed a small amount of front to back adjustment on the fan. 

 

Aren't they more like the shims that go under the gen/alt. pulley nut? And they go under the big nut at the fan end?

Don't know. I need to pull apart the remains of my fan assembly anyway. I'll let you know what I see and if it looks like it might allow any shifting of the fan front to rear. I've been putting it off because of that big a** nut that has to come off.

The only thing I found in my old one was a 2mm slotted wavey spacer right behind the 36mm nut. 

Looks like all of the front to back adjustment happens at the pulley end of the alternator.

@Michael Pickett wrote- "The only thing I found in my old one was a 2mm slotted wavey spacer right behind the 36mm nut. "

I have heard of people having to space the fan away from the gen/alt side of the fan shroud- usually just 1 or 2 shims so it doesn't rub. Could you check for me if the big pulley shims will fit over the hub? I don't think I have 1 handy to take apart to check. Thanks in advance! Al

I totally agree with Anthony.  Back when VW ran generators, the bearing closest to the fan pulley would dry out and chirp under acceleration.  It was pretty common.  Install a new bearing and it was cured for a few years.  Rinse and repeat.
I have not seen the same thing with the newer alternators (better/bigger sealed bearings?) and totally believe that the back half of the pulley is at fault.  Try the rear spacer trick behind the pulley.  It’s cheap and easy to do.  It’s just a flat washer.

ALB posted:

@Michael Pickett wrote- "The only thing I found in my old one was a 2mm slotted wavey spacer right behind the 36mm nut. "

I have heard of people having to space the fan away from the gen/alt side of the fan shroud- usually just 1 or 2 shims so it doesn't rub. Could you check for me if the big pulley shims will fit over the hub? I don't think I have 1 handy to take apart to check. Thanks in advance! Al

Yes,. Pulley shims fit (tightly) over the hub.

Anthony posted:

your chirp is your alternator pulley. the pulley's half against the alternator is moving. replace it with a CB billet one and your noise goes away. a little white grease on the belt also helps

Thanks for that, Anthony. You seem pretty certain. If the front ( fan belt side ) pulley nut is on as tight as it should be, are you saying the back half of the pulley is " wobbling" causing the chirp noise with the belt or are you suggesting it is loose or what, please ? 

Further, how much deflection should be in the belt when all is warmed up ? Thanks.

the problem is using replacement parts that are not built like the OEM parts. either the rear half of the pulley is loose on the hub or the front half is loose on the hub. either one will cause the same noise. I have tried several new ones available from PPI, IMC, wolfsburg and so on. the best is using a CB billet stock pulley.

Gordon Nichols posted:

I totally agree with Anthony.  Back when VW ran generators, the bearing closest to the fan pulley would dry out and chirp under acceleration.  It was pretty common.  Install a new bearing and it was cured for a few years.  Rinse and repeat.
I have not seen the same thing with the newer alternators (better/bigger sealed bearings?) and totally believe that the back half of the pulley is at fault.  Try the rear spacer trick behind the pulley.  It’s cheap and easy to do.  It’s just a flat washer.

Ok...I haven't had time to get the front pulley apart and Anthony did not answer my question about the possibility of pulley wobble, so Gordon, I'll ask you. What is at fault with the back half of the pulley ? Crooked and wobbles causing belt / pulley chirp ? What would adding a spacer behind the pulley achieve ? Thanks.