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Source for a Replacement Alternator Belt?

Canadian_JOY

Well Known Member
At 10 years of age I'm thinking our alternator belt might be ready for replacement as preventative maintenance. After looking the Lycoming part listed in the Aircraft Spruce catalog I have to believe there is a source of belts that are at least as good as those and perhaps not quite as "gold plated" in the price department.

Our current belt is a Gates product. Are most folks going to their local automotive parts supplier for replacement belts? I've also looked at the segmented belt however I'm not sure I've heard very many positive reviews of their use over the long term in an aircraft alternator application.

Thanks in advance for sharing suggestions based on your operational experience.
 
Take the numbers off your old Gates belt (or the whole belt itself) to any auto parts store & they can match it up. No different from a common car V-belt.
 
At 10 years of age I'm thinking our alternator belt might be ready for replacement as preventative maintenance. After looking the Lycoming part listed in the Aircraft Spruce catalog I have to believe there is a source of belts that are at least as good as those and perhaps not quite as "gold plated" in the price department.

Our current belt is a Gates product. Are most folks going to their local automotive parts supplier for replacement belts? I've also looked at the segmented belt however I'm not sure I've heard very many positive reviews of their use over the long term in an aircraft alternator application.

Thanks in advance for sharing suggestions based on your operational experience.


I use a Gates Automotive belt that I purchased from Amazon. The Gates Automotive belts are listed as NOT For Use On Aircraft but mine is working fine. (2nd Gates belt in 19-years) Typically I do not replace the belt till the prop is off then install a new one.

I prefer the Gates belt as I believe they are the highest quality available. Local auto parts did not have Gates belts but could have furnished a belt from another manufacturer.
 
...

If you have one belt that is good, but just makes you nervous, you can keep them both on. I've never tired it with the RV. A lot of guys I know keep two on. You band one out of the way. If one breaks, you don't have to pull the prop to mount the other one. Very handle of it breaks while traveling.
 
I have been happy with the Dayco Top Cog V-belts. Available at local auto parts store and high performance racing shops.
 
Thanks for confirming the local auto parts store as a good source of supply for these belts. Much appreciated!

I've seen the second belt installed on a couple of airplanes. No way do I want to take the constant speed prop off to have to change a belt. The only reason I'm looking at changing ours now is because the prop is off for other reasons and I thought I should take advantage of this opportunity. Believe it or not, the lack of an alternator drive belt is one of the reasons why I really like Continental engines...
 
Dayco belt available in Stittsville

Hey Mark,

I just replaced my PP alternator belt a couple of months ago as a precautionary measure after 700 hrs / 7 years. I obtained mine from Prime Choice Autoparts in Stittsville. Gave them a call and they ordered it since they don't have stock, but got it in a day. I asked for a Gates or Dayco, and they were able to get Dayco.

I too thought of a spare belt, however I would rather replace the belt at regular intervals and not have the spare belt sitting in a hot engine environment baking away. Then again I have a fixed pitch prop.
 
When I worked at Conti - the engineers said that the belts are exactly the same. They are tracked differently for traceability.

I got a dayco "cog belt" with my PP alternator.
 
"Not for Aircraft use" disclaimers are very common. They're just put in by lawyers who know an airplane lawsuit can cost 1000 times more than a car lawsuit. I have an engine hoist that says the same thing.
 
Lets not get off track.

The Dayco "Top Cog" vee belt is a marketing name, not a physical description.

I know it is confusing, marketing is supposed to be. They want you to LIKE it not think about it.
 
Resurrecting.... I'm looking for a part number on a Gates belt. My old belt is just a smidge too long, and a NAPA belt I purchased to replace it is riding high in the flywheel and alternator pulleys. The NAPA belt is 10mm wide - not sure if anyone has found a company that makes a narrower belt that would ride flush in the pulleys.
 
There's no way for us to know your flywheel pulley size, alt pulley size, etc, so,

https://www.google.com/search?q=gates+v+belt+size+chart&oq=gates+v+be&aqs=chrome.3.69i57j0j5j0.16214j1j7&client=ms-android-google&sourceid=chrome-mobile&ie=UTF-8

Does that give you a starting point?

Edit: Don't forget, riding on the bottom of the v is worse.

Lycoming O-360, Plane Power 60A alternator. The NAPA 7350 belt is the proper length at 904mm / 35 5/8", but the 10mm / 13/32" width seems to be too wide because it is riding a little high in the pulleys (according to the A&P who is "supervising" my condition inspection.) FWIW, the old belt that was slightly too long, was also 10mm wide, and rode high in the pulleys.

Naturally, the first Gates / v-belt table I clicked following the above link was flagged as a site with viral content by Chrome.

I suppose the real question is about the belt riding high in the pulley, and is that really an issue?
 
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I'm going to assume here that the new one has a "B" in the part# get the same length or the next shorter length in an "A" width
 
Resurrecting.... I'm looking for a part number on a Gates belt. My old belt is just a smidge too long, and a NAPA belt I purchased to replace it is riding high in the flywheel and alternator pulleys. The NAPA belt is 10mm wide - not sure if anyone has found a company that makes a narrower belt that would ride flush in the pulleys.

Mine on my RV-8 O-360 with B&C 40 amp alternator is a NAPA 7360 (note that the 7365 supplied by B&C was too long by about a half- inch). The 7360 also worked well with my original Nippon Densu alternator.


Chris
 
Link to actual belt specs:
https://www.napaonline.com/en/p/NBG257350

Did you take a look at the Gates .pdf I linked? There are belts spec'd in both metric and English. Within each group, there are multiple belt *angles* (of the 'V') available. Any chance you need an English spec belt with a sharper angled profile?

Gates video on determining proper belt fit:
https://www.youtube.com/watch?v=87MtHNzOq3g

I'd be a little surprised if a 50+ year old Lyc designed pulley had metric specs.

:)
 
Keep in mind that there are more than one "widths" of the ring gear carrier pulley. My neighbors Rocket has a wider pulley and the belt sits deep - just flush. I thought mine was wrong because the belt sits proud by 1/8. So I went out and bought "his" belt PN and sure enough, it also sits proud. Same on a variety of ring gear carriers I have laying around.
 
Segmented Belt

Dave Anders is using a the segmented belt, mentioned in this thread, on his RV after a friend had used them for 10 years on his boat. Allows you to change the belt without removing the prop.

Will see what his feedback is on this over time...

Cool idea.
 
Segmented belt

I’m interested in seeing how a segmented belt holds up. Replacing it at a set interval would be possible. 5 years instead of waiting until 500 hrs when the C/S prop comes off for reseal?

This would prevent the belt from aging the typical 10 years between prop removal for 500 hr mx.
 
I?m interested in seeing how a segmented belt holds up. Replacing it at a set interval would be possible. 5 years instead of waiting until 500 hrs when the C/S prop comes off for reseal?

This would prevent the belt from aging the typical 10 years between prop removal for 500 hr mx.

Not sure how it will hold up in an aircraft alternator installation but I can say that over the last 10+ years I have cut many thousands of board feet of both soft and hard wood on my table saw and am still running the same linked belt from Lee Valley. Still smooth and no slip. Have one for an emergency spare in my kit for the 7.
 
Yeah, a Spare is Good

I like to keep a spare belt tied out of the way. Those things are hard to replace, especially with a three blade propeller. It?s a real bear having to pull that thing over the third blade.
 
Great idea!

I like to keep a spare belt tied out of the way. Those things are hard to replace, especially with a three blade propeller. It?s a real bear having to pull that thing over the third blade.


That?s a great idea! I never thought of that. I wish I had. I just changed my belt a few weeks ago.
 
I like to keep a spare belt tied out of the way. Those things are hard to replace, especially with a three blade propeller. It’s a real bear having to pull that thing over the third blade.

This is not a bad idea for an emergency (to get you home), but history has shown that when a belt is replaced with one that has been tied in place the new belt does not last long.

The heat cycling causes a dormant belt to take a "set" and does not last long after set into active use.
 
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Take the numbers off your old Gates belt (or the whole belt itself) to any auto parts store & they can match it up. No different from a common car V-belt.

Rush, it's 10 years old. Do you really think even Gates is going to have a p/n still visible after 10 years?
 
True!

Mel, you?re right, that belt tied back out of the way gets thermal cycled same as the belt in use (maybe worse, in fact) and it suffers. But even that short life should be plenty to get you home where it?s much easier to install a new, good belt. It can be pretty tough to change a belt on an engine with a constant speed prop when you?re on a ramp far from home. And just for the record, I forgot to get a back-up belt last time I had the (fixed pitch) prop off. My buddy has an RV-6 with a Hartzell and he?s running a segmented belt from, um, I think he said Grainger. I?ll find out.
 
Ross..... Did Dave install a belt driven alternator after he went EFI?

In the past, Dave machined off the pulley and ran a vac mounted alternator.

Grainger also carries a quality link belt. I have carried one for 15 years. If you decide to try one,keep in mind that they are directional.
 
I am with Mel. Talking with my IA with 40 years experience all he has noticed about the spare belt concept is the spare is usually in worse shape than the running belt after a couple of hundred hours. Those of you with a tied-off spare take a close look at it next oil change, especially on the narrow (bottom) side. Chances are it's weather checked along with being very stiff and reluctant to go back into it's proper shape. Kinda like a dead cat on the side of the road.
 
At 500 hrs, I found that the Dayco Top-Cog belt was missing a few segments (cogs?) and had significant cracking in-between the segments. The belt is available through Amazon or at most auto part stores. The fine print says its made in the PRC (China)?..For the sake of alternator reliability to supply power for both of my electronic ignitions and avionics, a PP alternator with 500 hrs on it, coupled with a automotive belt from the PRC isn't inspiring.....did I mention that I installed a B&C standby alternator...
 
I am with Mel. Talking with my IA with 40 years experience all he has noticed about the spare belt concept is the spare is usually in worse shape than the running belt after a couple of hundred hours. Those of you with a tied-off spare take a close look at it next oil change, especially on the narrow (bottom) side. Chances are it's weather checked along with being very stiff and reluctant to go back into it's proper shape. Kinda like a dead cat on the side of the road.

I would expect this. Rubber tends to age better when it is exercised regularly. Regular movement tends to slow down the hardening of most rubber.

Larry
 


Yes, Dave now has a lightweight flywheel and front mount alternator.

I'd stick with the US made one from McMaster rather than Harbor Freight stuff. Support US industry.
 
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Yes, Dave now has a lightweight flywheel and front mount alternator.

I'd stick with the US made one from McMaster rather than Harbor Freight stuff. Support US industry.

Looks like he is also running your ignition.
 
I carry one of those linked belts (forget the brand at the moment) in my emergency kit. I figure it'd be good enough to get home in the event of a broken belt.

I suppose in a real pinch you could do what we did back in our student poverty-stricken days...use a nylon stocking :)
 
I like to keep a spare belt tied out of the way. Those things are hard to replace, especially with a three blade propeller. It?s a real bear having to pull that thing over the third blade.

I'd suggest removing the prop every so often, say 5 or 6 years, clean the sludge out of the crank and install a new belt, forget tying up a spare.
 
I'd suggest removing the prop every so often, say 5 or 6 years, clean the sludge out of the crank and install a new belt, forget tying up a spare.

agreed. my original belt has been on 7 yrs and looks new. I have a B&C alternator.
 
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