AlexPeterson
Well Known Member
I began the annual conditional inspection yesterday knowing that I would need to replace the hinge on the alternate air door, as it has been getting pretty sloppy the last few years. Here are some pictures of the parts.
Big picture, so to speak:
Note below how thin the edge had worn, over 3/4's the .032" thickness is gone:
The hinge is also quite worn laterally:
There are also cracks on the relatively weak portion of the airbox top (the part riveted to the fiberglass) onto which the hinge was riveted. Will need to think of how to best repair that. I will use a SS hinge, and may try to have the door close against rubber in some way.
In general, the whole airbox design has been problematic with regards to maintenance. I've replaced the top plate which fastens to the induction system twice, and I've strengthened the fiberglass bottom once. The fiberglass was wearing almost through where the filter contacts it (and yes, it clamps firmly on the filter). There is a tremendous amount of acoustic vibration in induction systems, that could be a large portion of the problem. Additionally, the prop pulses are hammering away at it. I'd suspect the latter is the main culprit.
This wear I have on the alternate air door (which is outside the filter) should be carefully contemplated by those with similar moving parts inside the filter. My opinion is that doors, sliders, etc., are best not put in a position where parts could be inhaled by the engine in the event of a cracked part coming loose.
Big picture, so to speak:
Note below how thin the edge had worn, over 3/4's the .032" thickness is gone:
The hinge is also quite worn laterally:
There are also cracks on the relatively weak portion of the airbox top (the part riveted to the fiberglass) onto which the hinge was riveted. Will need to think of how to best repair that. I will use a SS hinge, and may try to have the door close against rubber in some way.
In general, the whole airbox design has been problematic with regards to maintenance. I've replaced the top plate which fastens to the induction system twice, and I've strengthened the fiberglass bottom once. The fiberglass was wearing almost through where the filter contacts it (and yes, it clamps firmly on the filter). There is a tremendous amount of acoustic vibration in induction systems, that could be a large portion of the problem. Additionally, the prop pulses are hammering away at it. I'd suspect the latter is the main culprit.
This wear I have on the alternate air door (which is outside the filter) should be carefully contemplated by those with similar moving parts inside the filter. My opinion is that doors, sliders, etc., are best not put in a position where parts could be inhaled by the engine in the event of a cracked part coming loose.
