pp000830

I recently replaced the outer pulley (alternator shaft) belt that to my surprise failed over a short period. I have come to realize that if the belt is even just slightly over tensioned its service life is shortened from years to a few months. Also, it seems the Continental belt runs a smidgeon tighter than the OE Porsche belts of the past so if anyone is contemplating a belt change be sure to have one or two 0.05 shims on hand to fit the Alternator belt into the proper tensioning range. It also makes me wonder if some of the complaints concerning belt failure have to do with over-tensioning at replacement.

Also, I have been looking for a workaround to the compressor being detached from its base to replace its belt as this is the biggest pain and time-consuming aspect of a belt change.

• I was thinking that the base has quite a bit of unused travel in its belt tensioning range.
• I also observed that the specified belt just bearly misses being able to slip over the compressor pully without unbolting the compressor.
• So, I ordered a belt that is 10mm longer than specified and it may just have the needed slack to slip over the pulley and still be tensioned w/o needing to unbolt things.

Wish me luck!
Andy

993pbug

So what was the outcome of the “test” with the longer A/C belt?

I had to do a quick alternator belt change a week ago and didn’t have time to replace the A/C belt. Since I was planning on finally installing it tomorrow, the result of your effort has peaked my interest.

Brett - 1996 C4

I was breaking a few alternator belts way back when I first got my 993 (around 2000). Turns out there was a TSB for the alternator pulley: replaced with the 993 turbo version and haven't broken a belt since. You might want to check if you still are running the original pulley. I think the turbo version has a dichromate finish (looks kind of yellow).

levtron

yes... whats the outcome on the longer belt... I have to install a new one...and like the idea of not having to remove the compressor....

Churchill

Here's the easy way to have a long and happy life with your v-belts: adjust them as loose as possible. Not so loose they get thrown off the pulleys or squeal. But you don't need to make them any tighter than that. I'm continually amazed at how many people overtighten their belts without stopping to think about how they work and what they're designed to do.

IainM

I can confirm that a 43" belt is the way to go. I got a Gates 43" from O'Reilleys and with the tightening bolt fully released, I was able to slip the belt over the crank and then over the compressor pulley, just like on a Honda or a Ford. I tightened the side bolt to about 3/4" wiggle in the belt and bolted it down. Went for a run, turned on AC and there was cool air and no screeching from behind.
The 43" belt really makes this job as simple as is should be. Good call Andy!

boomboomthump

I may give this a go as well. I noticed the other day that my belts appear to be on the verge of breaking. The do seem rather tight.


This will be my first belt change since picking up the 993. Is there a nice how-to somewhere?

IainM

Remove old belt with bolt cutters, blade or other quick removal.
Loosen 4X 13mm bolts top side compressors (front left as you look at it is not captive, needs a wrench underneath)
Loosen tightening bolt on underside of compressor right side (passenger for US)
easily slip on 43" belt.
tighten side bolt
tighten 4 13mm clamp bolts
crack a cold one and celebrate a job well done.

PFDGSB

Paste a link to the belt you used?

IainM

I just went to Oreilleys and had them cross reference the Dayton 4L430 that Andy posted above. I got a Gates equivalent, no inter web needed

boomboomthump

I was meaning all the belts. I did find this one: https://rennlist.com/how-tos/a/porsc...v-belts-377004
I sometimes forget there is more to explore around here than just the 993 sub-forum.


That said, can you clarify...

In your first post you said that with the 43" belt, all you needed to do was loosen the tensioning bolt and then you were able to slip the longer belt on while still being able to properly tension it.


But in your next post you said you still need to loosen the (4) 13MM bolts that hold down the compressor, which I thought was what we were trying to avoid by going with a longer belt?


Which is it?

IainM

You just need to loosen them so the compressor will slide. Before you had to remove the compressor then tension the belt while trying to get the 4 bolts back in.
Absolute nightmare. with the 43” belt you loosen, put the belt on and tighten with the adjuster and then clamp down with 4 bolts. Literally a 5min job. It’ll take you longer to find the 13mm socket

boomboomthump

Gotcha, thanks.

Didn't realize you normally had to remove the compressor. The how-to I linked to doesn't state or show that. It just says the same, that you had to loosen and slide over, so I was assuming the longer belt was to avoid all of that and get by with just loosening the tensioning bolt.