As well as I can recall, TB's wear neither a manufacturing date nor a 'best before' date ..... so unless the belt were stored over a hot running electric motor spewing ozone to rot the elastomer, and delivered covered in cobwebs and mold - the Continental belt used should be fine. Having stored a fresh belt for a year is a non issue.
By hand turning the motor, you can verify how well the belt tracks on the cam gears and tensioner roller: if it tracks correctly, the good news is that it is unlikely you have anything less than a perfect job done ..... save for the last issue. I then rest my case, your Honour , that the as delivered tension was too low - just hovering over the minimum tension to keep the tensioner nose spring from breaking continuity in the alarm circuit. A few miles on the belt would then be adequate to trigger the alarm, as the belt beds into the cogs and loses some of the static tension.
Crap happens to even the best, but appears that no damage suffered - a good catch was made! BTW, was the tension set with an official 9201 tool? If so, that can be a trick to use correctly.

 

Trying to get to the best solution here. Thank you for all your thoughts on this.

 

Hi Steve,

I have a four car garage, with my race car apart, my M3 apart and an M3 parts car in it. My wife insists on keeping the remaining bay (not unreasonable consider the northeast climate ).

I had the money to get the work done AND ensure it would not be take apart with so many "while I am at it" projects that it turns into another jack stand queen (like the M3 and race car). Unfortunately this type of work is most difficult on my back as well, which seems to be aging ahead of me. So, with a shop I could trust, I thought the decision was appropriate for me.

Live and learn, nothing easy for me...

 

The problem is, if Stan tightens the belt, he has nothing to show the shop and he is on his own. Also, doing so presumes there is nothing else wrong. If you assume the shop set the belt tension THAT low, the warning should have tripped immediately. It's just too far below the window for me to be that facile about it. Sure, on my car I might look over the belt and tighten it and be done with it, but only if it were a bit low, not this much. Something doesn't add up.

 

I have emailed photos of everything to the shop, cam sprocket marks, dampner mark, tensioner gauge while on belt and tensioner bolt.

I emailed David Roberts about the belt, as I bought it from him. He said he hasn't seen or heard of any issues with a timing belt that sat on the shelf. David Roberts did notice that the tensioner bolt was out further than it was with the last one.

My leaning is that , for whatever reason, it was not properly tensioned to start with.

 

Hi Stan,

I just took a second look at your picture of the tensioner adjusting bolt. It appears to me to adjusting bolt is in the housing quite far for such a low timing belt tension reading.

Was the tensioner rebuilt as part of the TB job? If so, this might be another avenue to investigate further. Would the TB tension be affected if the 35 belleville washers were installed incorrectly (all in the same direction)?
Adam

 

Yes, the tensioner was rebuilt. Interesting another comment I got was that the tesnioner bolt had plenty of adjustment left...

 

I would remove the belt and check all of the belt run, also to suspect is the water pump pulley , when this happens its not unusal to see the belt this loose.
The tensioner looks normal as far as the remaining bolt length( you can still some of the factory blue thread sealant)

 

We intend to review it on Friday.

The blue thread sealer is loctite used by the shop that did the work.

Thank you again for the thoughts!

 

Hi Stan,

I stand corrected on the tensioner bolt length.

I just got home and checked the bolt length on my pair of '86.5's. On the gold one, there's 8 threads showing between the bolt head and the nut; on the green one there's 7.

I used the Porsche 9201 tool to set the TB tension on both. Last year, Mike (njsharkfan) did a side-by-side compare of the Kempf tool vs. 9201 on the green car. 5.3 on the 9201 tool was equal to a high-side reading on the Kempf tool.

Adam

 

Thank you, good information.

Hard to see with mine, but from the photo I would speculate mine could be 6 or 7.

I wonder if the range is really wide and/or changes from year to year. Musings for another day perhaps