Alternator belt question

[bradp]

Curious.  I had to troubleshoot a dead battery for my wife's jeep today and went through alternator testing.  Got to thinking... what the process for alternator belt replacement is on our Lycomings ... does the prop need to come off to get the belt on?   

Apparently I don't stop thinking about airplanes...?

[tony]

yes

[dlthig]

I knew a guy who said that he kept a spare on his Cherokee. Apparently he had it safely wired and out of the way. I doubt the FAA would approve, but it made him feel better.

[Guest]

Yes the prop does need to be removed in order to replace the alternator drive belt.  Outright belt failure is very rare, with little value in keeping a spare on the engine.  By the time it would be needed it would be just as old and rotten at the one in use.

Clarence

[carusoam]

Decades ago belts didn't last very long. It was normal to see a spare belt tied in place.  Polymer science has come along way since 1965...

Best regards,

-a-

[carqwik]

Just replaced both belts on my plane.  The prop came off...  I think one of the belts was 15 years old.

Edit: I should note the prop came off due to looseness in one of the prop blades (required minor shim to fix)...so made sense to replace the belts.  Otherwise, it probably wouldn't have happened.

Edited October 5, 2016 by carqwik

[bonal]

3 hours ago, M20Doc said:

Yes the prop does need to be removed in order to replace the alternator drive belt.  Outright belt failure is very rare, with little value in keeping a spare on the engine.  By the time it would be needed it would be just as old and rotten at the one in use.

Clarence

Quite true but if I do break a belt and make it to a safe landing on battery but the field has no mech support on site and I have a spare belt pulled back I can install it with simple tools on board and most likely be able to make it back home on the spare where a new replacement can be installed 

[ArtVandelay]

Anybody have experience with open ended belts, like this:
http://www.optibelt.com/en/power-transmission/products/other-belts/optimat.html?cid=3647

[Guest]

Never seen that one, but I have heard of using panty hose to make a fan belt.

Clarence

[wrench]

6 minutes ago, M20Doc said:

Never seen that one, but I have heard of using panty hose to make a fan belt.

Clarence

I tried using those as a Christmas gift for the wife many years ago but I don't recommend that anymore.

[1964-M20E]

I have heard o these belts before but have never used them.  In the case of a broken belt this may be a very good way to get home especially if there is no mechanic on the field.

[jetdriven]

You can also still go by charging the battery then turning off anything non-essential. You can fly all day this way if you turn the master off 

[mooniac15u]

10 hours ago, bonal said:

Quite true but if I do break a belt and make it to a safe landing on battery but the field has no mech support on site and I have a spare belt pulled back I can install it with simple tools on board and most likely be able to make it back home on the spare where a new replacement can be installed 

Without an A&P to sign off that belt replacement it would not be a legal repair.

[Andy95W]

Just now, mooniac15u said:

Without an A&P to sign off that belt replacement it would not be a legal repair.

I thought it meant that it never broke in the first place.

[bradp]

.... But it does suggest that alternator belt may be one of those timely things to replace if the prop is off for another reason.  

[Guest]

7 hours ago, N1395W said:

I thought it meant that it never broke in the first place.

Installed by ramp Elves, close relative of the hangar Fairy.

Clarence