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What is this part called?

rotoiti

Well Known Member
... and where can I buy it?

https://goo.gl/photos/KGL1bUPtxfL6HHVF7

Is it a belt tensioner? Pulley?

The story:
On approach to Sedona, AZ my alternator light started blinking. When I landed I saw that this part was broken and the alternator belt was completely loose. See the (out of focus) video for an idea: https://www.youtube.com/watch?v=kpSlpxwovIw

With a help of a local mechanic I was able to swap in another one from the air conditioner belt but now I need to replace the missing one. I call it a pulley but I don't know whether that's what I am looking for.

Thanks for any suggestions.
 
Idler Pulley

It's called an Idler Pulley.

The Aviation Department at your local auto parts store or Amazon will have it.
 
So after more than a month of searching, purchasing wrong parts over the internet and visiting literally 7 auto shops who couldn't help me find a replacement (when shown the broken part) I am back to ask the forum for help.

Can anyone suggest where can I purchase an idler pulley that would work with an IO-540 for an alternator belt? A link to a parts supplier would be great :)
 
So after more than a month of searching, purchasing wrong parts over the internet and visiting literally 7 auto shops who couldn't help me find a replacement (when shown the broken part) I am back to ask the forum for help.

Can anyone suggest where can I purchase an idler pulley that would work with an IO-540 for an alternator belt? A link to a parts supplier would be great :)

Why is there one there in the first place? I have never seen one on any Lycoming engine I have looked at.
 
Pulley

Some Lycomings use idler pulleys. I would start with a Lycoming parts manual for your engine model. If no luck there try a parts manual for a aircraft that uses that model Lycoming engine as this engine part may be airframe specific. For Example: A Piper PA32R-301 (Saratoga) with Lyc IO-540-K1G5 uses a idler pulley/tensioner setup like the one in your video.

Don Broussard

RV 9 Rebuild in progress
 
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Well, since you are in deep already, press the bearing out and take dimensions, then, get a replacement bearing and press it back in.

EDIT: Observing that it is a v groove pulley, most definitely press the bearing and get a new one. You can run a weld bead around the ID of the outer race and shrink it for removal if there is nothing left to press. This should be a quick easy job. Finding the bearing is the hard part. Get a good name brand. Find a bearing house near you, there should be several good ones. They might do the replacement for you if you say it is for an off road specialty vehicle.

Or try a VW Diesel idler - http://www.partsplaceinc.com/products/product-detail.aspx?sku=16610
 
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I believe pulleys are there because of the clearance issues. The aircraft is equipped with A/C. The builder chose to put the A/C compressor on the right side, and moved the alternator to the left side. Both belts run pulleys, see the picture below:
pulleys.jpg
 
I had an Aha! moment while searching the web for the pulleys.

The system is part of Flightline A/C. This is one of their early systems, they dropped the pulleys in their later iterations.

I sent John from Flighline A/C an email about the pulleys, hopefully he will have some pointers.
 
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