Notes From Changing the V-Belts
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Quick Update
After 100 miles, the A/C belt stretched a bit and the cold measurement
dropped from 30 Kg to 18 Kg. I retensioned it this morning to 30 Kg and
now is quiet. This is normal as the belts get settled in. Will check in again
after a week of driving.
After 100 miles, the A/C belt stretched a bit and the cold measurement
dropped from 30 Kg to 18 Kg. I retensioned it this morning to 30 Kg and
now is quiet. This is normal as the belts get settled in. Will check in again
after a week of driving.
Last edited by bruce7; Sep 29, 2012 at 03:37 PM. Reason: edited for accuracy
Rennlist Member
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From: Canada & the Alps
Bruce, since you didn't mention it, are you using a stock sized AC belt (13 x 1085) or did you go with a slightly longer 13 x 1100 belt.
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Banned
Joined: May 1998
Posts: 10,005
Likes: 60
From: Somewhere....
This thread is now in the 993 DIY section here:
https://rennlist.com/forums/993-1995...e-v-belts.html
Best to all!
John D.
https://rennlist.com/forums/993-1995...e-v-belts.html
Best to all!
John D.
Rennlist Member
Joined: Sep 2009
Posts: 8,679
Likes: 785
From: Canada & the Alps
And you had to tighten the belt by using the tensioner bolt?
I guess there are manufacturing variances in the AC compressor mount. Mine is tight without having to use the adjuster at all. I'll measure the tension.
A couple of days ago I noticed a Conti-Tech 13 x 1100 AC belt (a non-Porsche branded belt) on another 993. It seems some have been using this sized belt.
I guess there are manufacturing variances in the AC compressor mount. Mine is tight without having to use the adjuster at all. I'll measure the tension.
A couple of days ago I noticed a Conti-Tech 13 x 1100 AC belt (a non-Porsche branded belt) on another 993. It seems some have been using this sized belt.
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Clarification on V-Belt Tensioning
Clarification on V-Belt Tensioning
Various documents that describe the v-belt tensioning procedure are not very
clear or are wrong and confuse what should be a simple affair.
Adrian Streather's book "Porsche 993 The Essential Companion" on page 481
provides misinformation that is so wrong it's hard to fathom what he was thinking
or what source he derived his information. (See "Belt Tensioner.pdf" file.)
First, the aftermarket version of the tensioning tool shown is designed for belts
with much higher tensions than used on the 993. He should have shown a
photo of the Gates KriKit Gauge 91107 with scales matching those of the Porsche
tool 9574 shown in the drawing.
In fact, the Porsche Special Tool 9574 (PN 000-721-957-40) is actually the
Gates KriKit Gauge with Porsche packaging. (See photo.)
Far more misleading though is his note regarding the need to convert Porsche
scale increments to Kg. This is completely false and should be disregarded.
Porsche confused things in the shop manual by stating the tension specifications
in terms of "scale increments". They should have said simply "Kg". They say in the
checking and adjusting procedure to read off the measurement from the top scale
which is Kg, so that is how the tension specifications should have been stated.
Again, in the the TSB for the V-Belt Tension Tester Special Tool 9574, Porsche
refers to "tester scale units" when they have already stated Kg. It's unusual since
the TSB is typically terse and adding the extra wording is completely unnecessary.
(See "TSB V-Belt Tension Tester Special Tool 9574.pdf" file.)
So, stick with Kg and forget about "scale increments" and "tester scale units"
and you'll be OK.
-bruce
Various documents that describe the v-belt tensioning procedure are not very
clear or are wrong and confuse what should be a simple affair.
Adrian Streather's book "Porsche 993 The Essential Companion" on page 481
provides misinformation that is so wrong it's hard to fathom what he was thinking
or what source he derived his information. (See "Belt Tensioner.pdf" file.)
First, the aftermarket version of the tensioning tool shown is designed for belts
with much higher tensions than used on the 993. He should have shown a
photo of the Gates KriKit Gauge 91107 with scales matching those of the Porsche
tool 9574 shown in the drawing.
In fact, the Porsche Special Tool 9574 (PN 000-721-957-40) is actually the
Gates KriKit Gauge with Porsche packaging. (See photo.)
Far more misleading though is his note regarding the need to convert Porsche
scale increments to Kg. This is completely false and should be disregarded.
Porsche confused things in the shop manual by stating the tension specifications
in terms of "scale increments". They should have said simply "Kg". They say in the
checking and adjusting procedure to read off the measurement from the top scale
which is Kg, so that is how the tension specifications should have been stated.
Again, in the the TSB for the V-Belt Tension Tester Special Tool 9574, Porsche
refers to "tester scale units" when they have already stated Kg. It's unusual since
the TSB is typically terse and adding the extra wording is completely unnecessary.
(See "TSB V-Belt Tension Tester Special Tool 9574.pdf" file.)
So, stick with Kg and forget about "scale increments" and "tester scale units"
and you'll be OK.
-bruce
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Another use for the Porsche Polygon Wrench
This week I did the Alternator Pulley Update and discovered another use
for the Porsche polygon wrench. I don't use the Porsche polygon wrench
to counterhold the alternator shaft. For that I use the Snap-On triple-square
socket. But the other end of the polygon wrench I discovered must have
been designed to enable you to pop off the outer pulley half from the alternator
shaft. I couldn't take a picture to show it in action because it would have required
3 hands. But what you do is come in underneath the pulley with the
pointy end and twist the wrench to pop off the pulley. I would continue to
include this in the list of required tools.
The new pulley half is thicker due to the fact that the spacer is now machined
in as part of the pulley. As a result it can be harder to pull off the shaft.
See photos below.
for the Porsche polygon wrench. I don't use the Porsche polygon wrench
to counterhold the alternator shaft. For that I use the Snap-On triple-square
socket. But the other end of the polygon wrench I discovered must have
been designed to enable you to pop off the outer pulley half from the alternator
shaft. I couldn't take a picture to show it in action because it would have required
3 hands. But what you do is come in underneath the pulley with the
pointy end and twist the wrench to pop off the pulley. I would continue to
include this in the list of required tools.
The new pulley half is thicker due to the fact that the spacer is now machined
in as part of the pulley. As a result it can be harder to pull off the shaft.
See photos below.
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Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Update on Changing the V-Belts
Wanted to do an update to this thread concerning the belt tension sensor
and tools. Recently my fan belt sensor broke and I decided to remove it
from the system. This thread covers that:
https://rennlist.com/forums/993-foru...lt-sensor.html
As a result, I had to change all the belts. I change them yearly anyhow just
before July 4th when I take a driving vacation. When I did I took some notes
and a couple pictures that follow.
The PDF file is a checklist useful for someone who has done it before and just
needs a refresher of the steps. I should point out that this is tailored to my
car and situation, yours may be different.
The first photo shows the parts that are removed during disassembly from left
to right. Then when you put it all back together, you go right to left and you
shouldn't get things out of order.
The next photo shows the tools used to disassemble and remove the belts.
The last photo shows the tools used to refit and adjust the belts.
-bruce
and tools. Recently my fan belt sensor broke and I decided to remove it
from the system. This thread covers that:
https://rennlist.com/forums/993-foru...lt-sensor.html
As a result, I had to change all the belts. I change them yearly anyhow just
before July 4th when I take a driving vacation. When I did I took some notes
and a couple pictures that follow.
The PDF file is a checklist useful for someone who has done it before and just
needs a refresher of the steps. I should point out that this is tailored to my
car and situation, yours may be different.
The first photo shows the parts that are removed during disassembly from left
to right. Then when you put it all back together, you go right to left and you
shouldn't get things out of order.
The next photo shows the tools used to disassemble and remove the belts.
The last photo shows the tools used to refit and adjust the belts.
-bruce
Pro
Joined: Nov 2013
Posts: 558
Likes: 11
From: Ventura
Resurrection for an incredibly helpful thread.
Great tips in this thread, I really wish I had seen it before replacing my belts.
I would like to add that the KriKit can still be purchased from any Napa auto parts store. My local store had it the next morning. The tool itself comes in a Napa branded box and has a Napa sticker on it. There are two versions of the same part number (Gates 91107), the V.1 and the V.2. The V.2 or "KriKit II" is a higher cost ($17 vs. $12) and a higher measuring range(50-150kg) than the V.1, however it states that it is for ribbed belts while the V.1 doesn't. I didn't exactly know what that meant but felt it couldn't hurt to have that capability. This lead me to purchase the V.2 (not knowing it's range) but now that I understand the scale I think the V.1 is necessary for Porsche's specs. I will be returning the V.2 to my Napa tomorrow and will get a V.1.
Also, the tool kit that came with my car did not include a 12 point wrench like in post #23 but it did have a tool like the one to separate the pulley on the other end of the 12 point wrench in aforementioned post.
Great tips in this thread, I really wish I had seen it before replacing my belts.
I would like to add that the KriKit can still be purchased from any Napa auto parts store. My local store had it the next morning. The tool itself comes in a Napa branded box and has a Napa sticker on it. There are two versions of the same part number (Gates 91107), the V.1 and the V.2. The V.2 or "KriKit II" is a higher cost ($17 vs. $12) and a higher measuring range(50-150kg) than the V.1, however it states that it is for ribbed belts while the V.1 doesn't. I didn't exactly know what that meant but felt it couldn't hurt to have that capability. This lead me to purchase the V.2 (not knowing it's range) but now that I understand the scale I think the V.1 is necessary for Porsche's specs. I will be returning the V.2 to my Napa tomorrow and will get a V.1.
Also, the tool kit that came with my car did not include a 12 point wrench like in post #23 but it did have a tool like the one to separate the pulley on the other end of the 12 point wrench in aforementioned post.
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Updated checklist
Getting ready for a road trip and changed the belts today.
Updated the abbreviated checklist with a couple of notes
resulting from todays install.
1 - Had to use the polygon wrench and the long flat-blade
screwdriver to slowly walk the alternator inner pulley half
off the alternator shaft.
2 - Had to use the Dremel to cut/grind off one fan belt pulley
screw that rounded out. Wouldn't start the job without one.
-bruce
Updated the abbreviated checklist with a couple of notes
resulting from todays install.
1 - Had to use the polygon wrench and the long flat-blade
screwdriver to slowly walk the alternator inner pulley half
off the alternator shaft.
2 - Had to use the Dremel to cut/grind off one fan belt pulley
screw that rounded out. Wouldn't start the job without one.
-bruce
Rennlist Member
Joined: Mar 2005
Posts: 2,963
Likes: 1,000
From: Colorado
I would also add to buy some of the Allen pulley bolts (if you haven't done the RS pulley, I haven't) and have them ready. After adjusting my fan pulley 3 times now to get it just right, I fear my pulley bolts are on their last leg. Does anyone have the torque specs for those? Thanks!!
Rennlist Member
Joined: Feb 2008
Posts: 978
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From: Earth
I keep my belts at much lower tensions than what Porsche recommends. Never had an issue. No noise.
I find the Porsche recommended values very excessive, and causing premature wear.
Same with rear tire pressures...
I find the Porsche recommended values very excessive, and causing premature wear.
Same with rear tire pressures...
Thread Starter
Racer
Joined: Aug 2008
Posts: 476
Likes: 34
From: Los Angeles
Fan pulley screw torque values
I looked in the copy of the workshop manual I have and didn't find a
specified torque value for the fan pulley screws. But in the book
"Porsche 993, The Essential Companion" by Adrian Streather, he quotes
on page 483 10Nm (7.5 lb ft).
And on the pcarworkshop site they quote 9.7Nm (7 lb ft):
http://www.pcarworkshop.com/index.ph...Specifications
The metal is very soft and when hot I think it rounds out easily. Probably
better to work on a cold engine but not always possible.
I used 10Nm and this time I used by 1/4 torque wrench which gives a better
feel for such a low torque than the the 3/8 torque wrench.
-bruce
specified torque value for the fan pulley screws. But in the book
"Porsche 993, The Essential Companion" by Adrian Streather, he quotes
on page 483 10Nm (7.5 lb ft).
And on the pcarworkshop site they quote 9.7Nm (7 lb ft):
http://www.pcarworkshop.com/index.ph...Specifications
The metal is very soft and when hot I think it rounds out easily. Probably
better to work on a cold engine but not always possible.
I used 10Nm and this time I used by 1/4 torque wrench which gives a better
feel for such a low torque than the the 3/8 torque wrench.
-bruce