Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

Timing Belt Wear Question UPDATED 2-4-07

 
Old 02-02-2007, 10:45 AM
  #61  
Schocki
Addict
Rennlist Member
 
Schocki's Avatar
 
Join Date: Sep 2002
Location: Bucharest, Romania
Posts: 1,664
Default

Hi Gang,
First: I agree this TB is not new, no way. If a TB shows that much wear after 1500 miles, it would have produced some sort of noise and would have failed 5 miles later.

Second: I had a lot of fun in my old job at Sheppard AFB. One of my duties was to proof read USAF officer performance reports. The look on some faces after I rejected reports due to grammar: PRICELESS
Schocki is online now  
Old 02-02-2007, 02:22 PM
  #62  
marton
Super User
 
marton's Avatar
 
Join Date: Nov 2001
Location: zürich, switzerland
Posts: 2,233
Default

Hi Schocki

HTML Code:
Second: I had a lot of fun in my old job at Sheppard AFB. One of my duties was to proof read USAF officer performance reports. The look on some faces after I rejected reports due to grammar: PRICELESS

Reminds me some years ago I did a project for the British RAF with a big technical team.
The last deliverable to a tight time schedule was a user manual. None of the team could write so the content of the manual was awful.
I delivered it to the Project owner who handed it over to Quality man. His report was,
Font Correct
Font size Correct
Line spacing Correct
Paper size correct
Grammar Correct
Manual is 100% OK.

Marton
marton is offline  
Old 02-02-2007, 02:22 PM
  #63  
marton
Super User
 
marton's Avatar
 
Join Date: Nov 2001
Location: zürich, switzerland
Posts: 2,233
Default

Hi Schocki

HTML Code:
Second: I had a lot of fun in my old job at Sheppard AFB. 
One of my duties was to proof read USAF officer performance reports. 
The look on some faces after I rejected reports due to grammar: 
PRICELESS

Reminds me some years ago I did a project for the British RAF with a big technical team.
The last deliverable to a tight time schedule was a user manual. None of the team could write so the content of the manual was awful.
I delivered it to the Project owner who handed it over to his Quality man. His report was,
Font Correct
Font size Correct
Line spacing Correct
Paper size correct
Grammar Correct
Manual is 100% OK.

Marton
marton is offline  
Old 02-02-2007, 05:20 PM
  #64  
tdelarm
928 Addict
Rennlist Member
 
tdelarm's Avatar
 
Join Date: Nov 2001
Location: IN BETWEEN A FROZEN CONCOCTION AND INDECISION
Posts: 1,741
Default

Ahhh...did you just double post

10 YARD PENILE-ITY FOR IMPROPER RENNLIST etiquette!
tdelarm is offline  
Old 02-02-2007, 05:46 PM
  #65  
heinrich
928 Collector
Rennlist Member

 
heinrich's Avatar
 
Join Date: Jan 2003
Location: Seattle
Posts: 17,264
Default

no no
heinrich is offline  
Old 02-02-2007, 06:17 PM
  #66  
marton
Super User
 
marton's Avatar
 
Join Date: Nov 2001
Location: zürich, switzerland
Posts: 2,233
Default

HTML Code:
Ahhh...did you just double post
Only 10 yards penalty? Thank you thank you I am not worthy

Marton
marton is offline  
Old 02-04-2007, 12:48 PM
  #67  
ROG100
Addict
Rennlist Member


Rennlist
Site Sponsor

Thread Starter
 
ROG100's Avatar
 
Join Date: Jan 2003
Location: Double Oak, TX
Posts: 15,605
Default Timing Belt Removed - New Pictures

I removed the TB covers on Friday and took some interesting pictures.

It is possible that only the WP & TB were changed and nothing else and I mean nothing else!

The WP looks new, however if the TB was new it certainly experienced some serious wear in a few miles.

At 45 BTDC the timing marks were lined up perfectly. Prior to removing the TB the tension was spot on.

The belt is tracking forward on the right side cam gear and rubbing against the roller arm.
Both the idler and tensioner pulleys show uneven wear.
The pivot bolt looks straight to the eye.
All the bolts & washers seem to be in the right place.

What is causing the belt to track forward or at least be positioned forward and the uneven wear on the rollers?

Looking forward to hearing your thoughts.

Car is an 86,5 with 60k miles.
Attached Images          
__________________


Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014

928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
ROG100 is offline  
Old 02-04-2007, 01:01 PM
  #68  
AO
Supercharged
Rennlist Member
 
AO's Avatar
 
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,899
Default

My bet is a bent tensioner pulley bolt. At least I think that's the bolt - it's the one that BigDave found as the cluprit for his TB failure as well as a few others.
AO is offline  
Old 02-04-2007, 01:05 PM
  #69  
Garth S
Addict
Rennlist Member
 
Garth S's Avatar
 
Join Date: Oct 2003
Location: Nova Scotia
Posts: 7,203
Default

I would first evaluate the carrier arm bushings: does the arm have any play in the radial plane?
Garth S is offline  
Old 02-04-2007, 01:10 PM
  #70  
ROG100
Addict
Rennlist Member


Rennlist
Site Sponsor

Thread Starter
 
ROG100's Avatar
 
Join Date: Jan 2003
Location: Double Oak, TX
Posts: 15,605
Default

Andrew,
The bolt looks perfectly straight with a steel rule - how bent are we talking?

Garth,
No play on the tensioner roller in either plane.
There is some slight wear in the two non metallic bearing inserts where the pivot bolt passes through.
Maybe .015" total. They will be changed.
Attached Images  
__________________


Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014

928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
ROG100 is offline  
Old 02-04-2007, 01:33 PM
  #71  
928drvr86.5
Addict
Rennlist Member
 
928drvr86.5's Avatar
 
Join Date: Jan 2005
Location: Dubuque, Iowa.
Posts: 1,658
Default

Check the plastic bushings in the Tensioner arm where the shoulder bolt pictured passes thru. If the shoulder bolt is straight it is probably worn bushings. It Could also be that the tensioner arm is bent but i doubt it.
928drvr86.5 is offline  
Old 02-04-2007, 01:35 PM
  #72  
ROG100
Addict
Rennlist Member


Rennlist
Site Sponsor

Thread Starter
 
ROG100's Avatar
 
Join Date: Jan 2003
Location: Double Oak, TX
Posts: 15,605
Default

Sterling,
Everything is being replaced - just trying to understand what happened in the first place.
The idler bearing has a small amount of play - maybe .025" total. Definitely on its way out.
Whats amazing is that IF the WP is new they took the idler pulley of the old one and put it on this one with the wear in the bearing - negligent in the first degree!
Roger
__________________


Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014

928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
ROG100 is offline  
Old 02-04-2007, 01:36 PM
  #73  
ROG100
Addict
Rennlist Member


Rennlist
Site Sponsor

Thread Starter
 
ROG100's Avatar
 
Join Date: Jan 2003
Location: Double Oak, TX
Posts: 15,605
Default

Ben,
See post #70.
Roger
__________________


Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014

928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
ROG100 is offline  
Old 02-04-2007, 01:44 PM
  #74  
Rick Carter
Contributor of Nothing Worthy
Rennlist Member

 
Rick Carter's Avatar
 
Join Date: Apr 2004
Location: Central Ohio
Posts: 9,773
Default

Originally Posted by ROG100
Ben,
See post #70.
Roger
This was my experience:

Here are some pictures of the bushing in the tensioner arm that failed causing all the damage. The pictures arent the best, basically the bushing cracked and ovaled out which alloud the tensioner to rock in relation to the rest of the pulleys pushing the timing belt forward into the tensioner bracket (thats what the shiny silver grooves in the arm are, the belt cut them in)

http://www.lasotaracing.com/carter/broke/ten1.jpg
http://www.lasotaracing.com/carter/broke/ten2.jpg
http://www.lasotaracing.com/carter/broke/ten3.jpg
http://www.lasotaracing.com/carter/broke/ten4.jpg
http://www.lasotaracing.com/carter/broke/ten5.jpg

Here are pictures of what it looked like with the belt still on it, you can see how the pulley is cocked at an angle to the crank pulley...

http://www.lasotaracing.com/carter/broke/al1.jpg
http://www.lasotaracing.com/carter/broke/al2.jpg
http://www.lasotaracing.com/carter/broke/al3.jpg
http://www.lasotaracing.com/carter/broke/al4.jpg
http://www.lasotaracing.com/carter/broke/al5.jpg


And this is the end result

http://www.lasotaracing.com/carter/broke/result1.jpg
http://www.lasotaracing.com/carter/broke/result2.jpg
http://www.lasotaracing.com/carter/broke/result3.jpg

The driver side head has all the exhaust valves bent severely, the passenger side isn't as bad, but they still need all new exhaust valves and guides...

bunch of Porsche valvetrain parts... http://www.lasotaracing.com/carter/broke/parts.jpg
Rick Carter is offline  
Old 02-04-2007, 01:44 PM
  #75  
928drvr86.5
Addict
Rennlist Member
 
928drvr86.5's Avatar
 
Join Date: Jan 2005
Location: Dubuque, Iowa.
Posts: 1,658
Default

Rock on, i just did a quick cursory check of the thread.
928drvr86.5 is offline  

Thread Tools
Search this Thread
Quick Reply: Timing Belt Wear Question UPDATED 2-4-07


Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: