Alternator pulley help!!

[fused]

Well now my mechanic has taken a proper look rather than me guessing  :embarassed: the alternator pulley looks original and worn. The problem with the VW software is I need the original alternator part number to identify the pulley! unless anyone else has an original '90 gti alternator, with the same pulley setup?? I can't post picks but if someone could host for me that would be great. in the mean time here are the dimensions.

                 
                 | V |                       The depth of pulley and spacer is 50mm, with the spacer being 30mm long
                 |    |                       with a diameter of 25mm. the Pulley is 70mm diameter with the securing
                 |    |________          nut on the outer edge, indicated in RED.
                 |    |
                 |    |             
                 |    |
                 |    |
                 | ^ |


If anyone has the original alternator with this pulley or any bright spark remembers the correct code if they can get back to me. Maybe we can set up a sticky thread for other lost pulleys?! :embarassed:

Steve

[krankenshafter]

I'm not an expert but as I understand it cranks have a natural vibration frequency This is a tortional vibration and it results in the crank winding up and unwinding along its length.Take any piece of metal and twist it back and forward like this and it will eventually break, commonly where a journal joins a web. The damper does exactly as its name implies and counteracts this vibration by absorbing the forces. There is a lot more to it than that but the main thing is don't lob your damper away and replace it with a solid pulley.  Check out your belt tensioner - take the whole lot off and make sure it is all free. I used to loosen all the bolts to a light nip before tensioning the belt and re-tightening them.

[fused]

^^Updated ^^

thanks for looking

[dadrathers]

I had a similar problem recently. The belt that drives the alternator was vibrating at about 2000 rpm and above. I checked the pulley for play in the bearing and sure enough there was some. So I replaced the alternator - came with a pulley - but the problem did not go away i.e. the belt still vibrates.

Talk of dampers and wrecking the crankshaft has got me very worried. Mine has two pulleys cos it has power steering. What would the damper look like? If it has two pulleys does it not have the damper? In the Haynes  Figure 9.2 shows two pulleys and the pointer to them says "damper or pulley". So if you don't have power steering and therefore only one pulley is there a damper but if you have two pulleys there is no damper???

[fused]

From what I have peiced together, there is a ruber damper built into the pulley itself so you probably can't see it, I think you tell if it is fubared by rocking it either front to back as you look head on or rotating left to right and cheking for excess movement, what ever that would be? Anyone know the correct way to test this??

[hexomire]

every crank pulley haves a damper, if you have the double one for the power steering its actually not double but there are two pulleys. the standard single with a damper and inside this one there is a metal smaller pulley with no damper. only diesel engines have a double allu pulley with a damper.

i never had no problem with pulleys wearing out.

[fused]

Please Please don't let this thread die before someone posts a part number!!!   

or I'll have to go to VW and ask them to order all pulley combinations for a 90 golf!!  then choose one!