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Timing Belt Wear Question UPDATED 2-4-07

 
Old 02-05-2007, 05:33 PM
  #121  
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Originally Posted by ROG100
Bill,
Heres a pic of the left hand cam gear with the TB in place.
Slightly off center but no where near the front as on the right side.
Ah, yes, a much better shot. Looks fine.

John Kelly's post with pics illuminates this as well. The rust inside the plastic bushing signifies a lot of corrosion that shouldn't be there. Perhaps poor sealing of the pivot bolt. Whatever the cause, rust is very abrasive.
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Old 02-05-2007, 06:00 PM
  #122  
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To clarify my decision about upgrading to the later style bracket between the WP and Tensioner roller carrier.
To me this will greatly decrease the possibility of this situation happening again.
Does the group agree that this is a positive upgrade?
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Old 02-05-2007, 06:03 PM
  #123  
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The center TB cover is different but can be changed to accept
 the extra bracket very easily.
Forgot about that point.
Whoever (PO) put the new style WP pump in, they also modified the center TB cover.

I think they did it with a lumberjack axe; does not really matter as it is only cosmetic.

I will try to tidy it up when I put it all back together.

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Old 02-05-2007, 06:06 PM
  #124  
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Does the group agree that this is a positive upgrade?
In my case, the water pump roller bearing seized but I assume this was in no way related to the later WP version installed.

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Old 02-05-2007, 06:34 PM
  #125  
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Originally Posted by ROG100
Is the tensioner carrier the same?
87 is 928 105 489 02 the one we have here is 928 105 489 0R (yes R )
"R" indicates a casting number AFAIK.

PET shows 928 105 540 05 as the carrier part number for an 86.

Calling Mr. Bailey....
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Old 02-05-2007, 06:41 PM
  #126  
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Rog I went through this with my '85 Euro. The tensioner sits farther forward, so the tbelt cover in the centre must be replaced with an S4 one. You may have to mod the driver's cover shorter to fit it. The tensioner arm and tensioner must be upgraded as well. The new pump will spin against the old centre cover as well so double reasons to change it ALL.
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Old 02-05-2007, 06:58 PM
  #127  
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Interesting - when I did this to my early 87 it was just a case of cutting away a small piece of the cover to accommodate the new bracket.
I would have thought that an 86.5 and an early 87 would be practically the same.

Calling Mr Bailey please!
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Old 02-05-2007, 07:06 PM
  #128  
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Roger, an 86.5 might in fact have a lot of S4 parts. Lord knows its true for the electrical bits.

Yo! Jim?!
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Old 02-05-2007, 07:18 PM
  #129  
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According to PET the 86.5 and the early 87 had the same center cover.
As this mod worked on my early 87 my gut tells me it will be OK on the 86.5.

Oh Jim are you out there
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Old 02-05-2007, 07:36 PM
  #130  
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The attached pics illustrate in one case, the 'S4' carrier arm and stud array on the left used from '87 - '95 compared to the late 32v arm assembly as used through '86.5 with the pivot bolt .... on the right.
The second image shows the 7.4mm ( ~8mm) differential offset observed in the piston rod dimple of the arm for pivot bolt applications from mid run 16v motors through to end of the early non-S4 32v motors ( both have the tapped hole for the tensioner alarm, beginning ~'83). The arm on the right is the same in both pics - sort of a 'mid generation step.
The forward offset was to center the line of force acting on the TB so as to minimize any residual torque forcing the tensioner roller and carrier arm to twist sideways ..... causing the obvious mistracking.The major change was a thicker mounting flange for the tensioner body .... which brought everything 'in-line'.
The S4 pivot stud not only added more robust M10 threads into the pump body, but increased the span between the pivot bushings - further stabilizing the arm: the last evolution was the cross brace from the arm tip to the pump body.

The vertical plane through the center of the cam, crank, oil pump and water pump pulley drives was unchanged from '78 - '95: that is why it is a breeze to update easily.
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Old 02-05-2007, 07:40 PM
  #131  
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Garth's post should be stuck in the newbie thread. I don't know how many times I've gone looking for those pics.
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Old 02-05-2007, 07:51 PM
  #132  
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Hi Garth,
Great info my friend and thanks for taking the time to post.
My carrier arm is the same as the one on the left in the top picture and the one on the right in the lower picture.

So I should be good to make the change - Yes?
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Old 02-05-2007, 08:05 PM
  #133  
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Originally Posted by ROG100
Hi Garth,
Great info my friend and thanks for taking the time to post.
My carrier arm is the same as the one on the left in the top picture and the one on the right in the lower picture.

So I should be good to make the change - Yes?
Y'all have me confused mon ami ... the top pic left arm is the S4 type, and has the machined boss on the upper left to mount the idler roller directly: the arms to the right in both pics are identical, and are late 'pivot bolt' generation - the main difference re. the S4 is that the idler roller presses on to the pump boss ... which is absent on the S4 pump.

Before typing more, which change are you referring to? .....doing the S4 arm/pump/stud to replace the later gen pivot bolt type?
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Old 02-05-2007, 08:51 PM
  #134  
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Hi Garth,
"doing the S4 arm/pump/stud to replace the later gen pivot bolt type?"

I did this on my early 87 which already had the later style WP.
Just added the bracket that goes from the pivot point to the WP.
Apart from the bracket the only other change was the slight mod to the center cover to accommodate the bracket.

I am assuming that I can do the same with the 86.5. Except in this case would have to use the later style WP and Pivot pin, the updated idler roller and screw that holds the bracket to the pivot point.

Am I making the right assumption or do I need a different roller arm?
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Old 02-05-2007, 09:00 PM
  #135  
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Start with 86.5
Update brace
needs pump update
ok
update pump
needs idler arm update
ok
update idler arm
needs updated tensioner
ok
update tensioner
needs centre cover update
ok
update centre cover
needs updated driver's cover
ok
update driver's cover


Simple isn't it
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