I’ve an old Shuttle that I use today for audio CD ripping and backup. Nothing special but it sits in my office next to my hi-fi and just does the job. It’s got a bit noisy so I decided to buy a new silent fan. I selected an 80mm x 80 mm case fan. (Note the standard fans are 25 mm in depth.) Here’s the reference to the one I bought http://goo.gl/S7jaE

I should have checked first! On removing the heat pipe assembly I realized that Shuttle have used a 15 mm to keep space to a maximum. Rather than abandon or look for a silent 15mm fan (not so easy). I decided to proceed and fit the 25mm fan. I did it by simply bending the fan lugs on the heatsink assembly parallel to the main structure. Instead of holding the fan with the screws I simply used four tie wraps. OK, it’s not so elegant but it works. I took the precaution of measusing the temps before and after using the little speedfan app. http://www.almico.com/speedfan.php

Well the job is done, and the machine is much quieter. Take care with this sort of modification as it’s quiet easy to damage the computer. Good luck with your upgrade.

(The photos depict the Shuttle PC with the removed fan)