TheSamba.com :: View topic

Wed Oct 25, 2006 8:54 pm

Guess I goofed. Fan Belt that my mechanic put on seemed to work. The bolt on generator pulley was too tight for my Carple Tunnel wrists to loosen. While checking oil, etc... last weekend there was lots of rubber dust around the engine and belt slipped off the generator pulley. Not like this a week ago. I put the belt on; motor runs fine and there is much more air movement noise (whistle) than before. What does everyone recommend for proper size belt? I have a bone stock '65 with 1200. What size do I need? Guess it is time to start working on it myself. Thanks, Jeff

Thu Oct 26, 2006 2:47 am

Stock size is 9.5x900

Thu Oct 26, 2006 7:23 am

Have fun learning the shimming system. I used to hate that when I first started.

Thu Oct 26, 2006 8:51 pm

Thanks for the help. Will get one plus a few spares this weekend. Jeff

Thu Oct 26, 2006 9:05 pm

kdfjeff wrote: Thanks for the help. Will get one plus a few spares this weekend. Jeff

Good idea, you never know! :wink:

Fri Oct 27, 2006 5:36 am

an alternator fan belt will work better.

Fri Oct 27, 2006 6:42 am

[quote="Bruce"]Stock size is 9.5x900[/quote]

Sorry Bruce, but the correct size for the generator equiped cars is 905 x 9.5mm.

The commonly available 900mm belt results in all shims being needed between the pulley halves and often the 900mm belt is still too tight.

The Alternator equiped cars use a wider (for increased strength) and longer (because the wider belt rides higher in the engine pulley groove) belt - 912mm x 10.2mm

Regards

Fri Oct 27, 2006 1:42 pm

Aussiebug wrote: Bruce wrote: Stock size is 9.5x900
Sorry Bruce, but the correct size for the generator equiped cars is 905 x 9.5mm.

No it isn't. The 905 belt is the size that all the suppliers substitute because they don't have the correct one. Use the 905 belt and it will ride too high in the pulley, slowing your fan, causing your engine to run hotter than intended.

It was very common in the past for people to carry a spare fan belt. Many would buy a spare belt when they bought the car new. Then that belt never got used. I have seen many of those 40+ year old belts in car's trunks. 9.5 x 900 with a VW logo on it.

Some suppliers list the 905 belt for use with 12V generator equipped cars. This topic is about a fan belt for a 65. A 65 has a 6V generator.

Fri Oct 27, 2006 2:06 pm

Im using a 10X900, my old one was too loose, thanks to bugformance sunnyvale (who also installed after 12volt conversion). 10X900 runs smoother, nice and snug, NOT tight.

Fri Oct 27, 2006 2:27 pm

make sure its not too tight. as your engine warms, it shrinks and gets tighter.

Fri Oct 27, 2006 5:28 pm

Bruce is correct. at least for german beetles.

Fri Oct 27, 2006 10:19 pm

Hmm, looks like different things for different cars. Yes this is a stock 6v with generator and stock pulleys. I stopped buy Unique in Mission Viejo today and was advised a 9.5x905. I work in millimeters for the paycheck so am familiar with the 5mm difference proposed here. By adjusting the shims will this accomidate the slack between the two?

The belt on the car is pretty wide and actually slipped off the pulley. Also rubs to the point of creating a layer of belt dust around the engine. Looks like the correct width is 9.5mm. By adjusting the shims can I accomidate for a 5mm increase with belt size? Muir advised to have 1/2 inch flex in the belt. Is this total or per side? I want to make sure I don't over tight and create too much wear on the bearings.