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-   -   Timing Belt Wear Question UPDATED 2-4-07 (https://rennlist.com/forums/928-forum/327991-timing-belt-wear-question-updated-2-4-07-a.html)

Schocki 02-02-2007 10:45 AM

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 :)

marton 02-02-2007 02:22 PM

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
:_otopic:
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 02-02-2007 02:22 PM

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

:_otopic:
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

tdelarm 02-02-2007 05:20 PM

Ahhh...did you just double post :icon107:

10 YARD PENILE-ITY FOR IMPROPER RENNLIST etiquette! :D

heinrich 02-02-2007 05:46 PM

no no :D

marton 02-02-2007 06:17 PM

HTML Code:

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

Marton

ROG100 02-04-2007 12:48 PM

Timing Belt Removed - New Pictures
 
9 Attachment(s)
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.
:bigbye:

AO 02-04-2007 01:01 PM

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.

Garth S 02-04-2007 01:05 PM

I would first evaluate the carrier arm bushings: does the arm have any play in the radial plane?

ROG100 02-04-2007 01:10 PM

1 Attachment(s)
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.

928drvr86.5 02-04-2007 01:33 PM

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.

ROG100 02-04-2007 01:35 PM

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

ROG100 02-04-2007 01:36 PM

Ben,
See post #70.
Roger

Rick Carter 02-04-2007 01:44 PM


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

928drvr86.5 02-04-2007 01:44 PM

Rock on, i just did a quick cursory check of the thread.


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