When optimizing or repairing your aircraft’s exhaust system, many details must fall into place for an efficient and precise exhaust system set up. Learn how to deviate from the STC installation instructions and the importance of precision for the engine’s heat shroud replacement, alternator belt and bracket assembly. 

Explore this guide for meticulous insights into optimizing your aircraft’s exhaust system with the Knisley Piper Aztec STC Exhaust System. 

Knisley Piper Aztec STC Exhaust System Requirements

When preparing to overhaul or repair your aircraft’s exhaust system with replacement parts, check the following: 

• What is the aircraft Serial Number? 
•  The aircraft’s serial number must be either:
  • serial number 27-2505 through 27-3836, 
  • Serial number 27-3838 through 27-3943
    
    

• Additionally,  the aircraft must be equipped with dual 70 amp, 12 volt Delco-Remy Alternators.

• NOTE:  If the aircraft has the dual Prestolite alternators, no deviations from the STC approved data is required.

How to Deviate STC Exhaust Systems 

1. The swing arm called for in the STC instructions is the one used on the Delco alternator installation, therefore, purchasing a new one is not required.
   
   
2. The Lycoming bracket P/N 77756 is still required.  When using this alternator bracket a spacer, approximately 1″ in length, will need to be fabricated.  You will also need to purchase a longer bolt (AN6-36A).
   
   
3. You may need to fabricate a support bracket between the starter and alternator to replace the one that is currently installed.  This bracket is approximately 3 x .75 x .24 and is made out of a suitable steel.
   
   
4. The placement of the heat shroud is moved slightly to allow more clearance between the shroud and alternator.  One of the Knisley clamps (CS051) is shimmed to the cross-over to facilitate the relocating of the heat shroud.
   
   
5. The alternator belts should be P/N 37A19773-367.
   
   

NOTE:  These alterations from the STC installation instructions are not approved. Knisley Welding did not preform an installation conformity on Aztec’s with the early model Delco-Remy alternators. While the deviations are minor, the deviations need to be addressed on the FAA Form 337.  A field approval of these deviations may be required.

QAA: Your Resource to Knisley Piper Aztec STC Exhaust Systems

Quality Aircraft Accessories stands as a premier destination for top-notch solutions in aircraft exhaust system overhauling and replacements. With our commitment to excellence for our partners and clients, we deliver the highest quality products and services to aviation enthusiasts and professionals alike. 

Whether it’s overhauling existing systems or providing replacements, Quality Aircraft Accessories has earned a reputation for providing reliable, top-tier solutions that prioritize safety and performance in every flight. Explore our Customer Resources for unmatched expertise and contact a representative for more information today.

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