Chrysler, VARMA, and NAPA

Jim K

Jim K

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Yet another alternator failure. This one was probably my fault.

At annual, slightly before we determined the engine had to come apart, we found one of the mounting ears had broken off my last one. I had held on to its predecessor which has a good case but a bad slip ring, so I swapped out that case half. Based on the fact it only lasted 40 hours before the rear bearing failed, seems likely I got dirt in it or something. Better that than the engine, I suppose.

Anyway, I went ahead and ordered an overhauled unit for $750 +core :vomit:. Which is a bargain compared to the Hartzell at $1500.

This, and the knowledge that this is quite literally a Chrysler "Squareback" alternator from the early 70's led me to find that automotive versions can be had for under $100. It also seems to me that under the guidance of AC 23-27, such a part could be used and signed off as a minor modification.

Here's the rub... automotive alternators run CW, but aircraft run CCW. The alternator doesn't care which way it spins.... but the alternator fan does. So I looked at my two old certified 4111810's:

IMG_20250607_191721654.jpg

Oops. I guess it doesn't matter which way the fan spins. Or at least, not much.

At a minimum, I'm going to order an automotive unit to disassemble and see if I can find any differences. Then I'll have it on hand when my next CerTIf1Ed alternator craps out.

As always, I ask.... what am I missing?
 
Racerx said:
You're missing a Tig welder to fix that broken ear.
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Oh, I have one. That was the plan until the bearing went out. And by went out, I mean went out and chowdered the shaft too. It was moving so much that one of the brushes fell out. What I don't have anymore is a lathe to clean up the shaft after welding it. At $750 a pop for these stupid alternators, a guy could justify one pretty fast. I think the $99 COTS solution makes more sense though.
 
Jim K said:
It also seems to me that under the guidance of AC 23-27, such a part could be used and signed off as a minor modification.
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You don't need AC 23-27 to install it as a minor, only a willing mechanic. However, you'll find even though each alternator may have a common ancestor the internals are a bit different quality wise. If it wasn't, someone would have developed an STC to install NAPA ones decades ago. Regardless, have seen a number of vehicle alternators on TC'd aircraft but they usually tend to fail a lot sooner than their aircraft cousins do.
 
Years ago, a high school friend worked for Chrysler. He explained to me why M Marine, and A Aircraft alternators were priced so differently, and worth the difference.

Quality control went to the production line and removed a random alternator from the production line, and gave it a full function test, If it failed, corrective action was done to bring production up to standard.

If it passed, it had a marine part number attached, and shipped out as a marine part.

Periodically, a potential M was transferred to the full function and maximum output for an extended period, while monitoring for radio freq. noise. If it passed that test, it received an aircraft part number, and shipped as an a certified aircraft part.

Obviously, that fully tested part cost more to produce, and test, and was more valuable to the customer.

When we use a regular Chrysler or Ford alternator, we are making a very small gamble that this individual item is not fully functional.

The odds are probably more than a thousand to one in your favor.
 
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geezer said:
Years ago, a high school friend worked for Chrysler. He explained to me why M Marine, and A Aircraft alternators were priced so differently, and worth the difference.

Quality control went to the production line and removed a random alternator from the production line, and gave it a full function test, If it failed, corrective action was done to bring production up to standard.

If it passed, it had a marine part number attached, and shipped out as a marine part.

Periodically, a potential M was transferred to the full function and maximum output for an extended period, while monitoring for radio freq. noise. If it passed that test, it received an aircraft part number, and shipped as an a certified aircraft part.

Obviously, that fully tested part cost more to produce, and test, and was more valuable to the customer.

When we use a regular Chrysler or Ford alternator, we are making a very small gamble that this individual item is not fully functional.

The odds are probably more than a thousand to one in your favor.
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That covers a $100 price boost, not a $1400 price boost.
 
I ordered an AC-Delco reman from Rockauto this morning. $39. Which is an order of magnitude (literally) less than Hartzell wants for a pair of brushes. It will be interesting to compare it to the certified unit I have. At a minimum, I'll have a new set of cases. Anybody know where to get a rotor dynamically balanced?
 
Not knocking your Rockauto alternator.

A rebuilt of the highest quality will need brushes replaced sooner than a new one.

The rebuilld machines the slip rings smooth, and un avoidably further from the ends of the brush holders. This gives more leverage to the extended brush, and requires a longer piece of brush in the holder to prevent leaning from straight in. In addition, a re machining is never as smooth as the original, so friction wear is faster.

Simply inspect the brushers more often, and replace while still half remaining. Brushes are cheap.
 
I assume the regulator is external? Replacing that as well?
 
WDD said:
I assume the regulator is external? Replacing that as well?
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Yes, external regulator. It seems to be fine, so no, not replacing it. Surprisingly Chrysler used external regulated alternators on cars well into the 80's and maybe later.
 
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"I'll take 'Things I Should've Seen Coming' for $100, Alex"

The $39 alternator arrived. It was sold as "overhauled". I didn't expect much, thinking at least the cases, rotor, and stator would be good and I could put in quality bearings myself. What I got was a new "made in China" POS. The cases are newly "manufactured". They appear to have been cast in a mold made in the dirt patterned off an original. Probably made of melted down soda cans. Thankfully (?) the cooling fan hits the case, so I have a solid reason to return it, and Rockauto is willing to issue a refund and cover the return shipping, so I'm only out $15. This is an "AC Delco Gold" branded unit, BTW. Guess that name doesn't mean anything anymore. I went ahead and ordered a NAPA Reman for $100. We'll see how that looks. At least I'm learning.

IMG_20250613_081211719.jpgIMG_20250613_081216335.jpgIMG_20250613_081058611_HDR.jpgIMG_20250613_081134811_HDR.jpgIMG_20250613_081104766_HDR.jpg
 
Jim K said:
They appear to have been cast in a mold made in the dirt patterned off an original. Probably made of melted down soda cans.
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Dang. I had thought better of RockAuto. And that is indeed some downright offensive ugly casting.
 
I’ve seen castings like that coming from Pakistan.
 
So, to continue beating this dead horse...
The $100 NAPA alternator showed up...3? weeks ago. It looks better than the $40, but not much. It also drags on the case. So it's going back, too. Now I have to decided if I want to try the $250 one that Summit sells. Surely it's as good as OEM....right? RIGHT?
 
Quit abusing yourself and let Hartzell abuse you instead. It’ll cost you $1,500, but you get a free alternator with it. Unfortunately that’s less fun and educational for us. Apologies to the audience…
 
455 Bravo Uniform said:
Quit abusing yourself and let Hartzell abuse you instead. It’ll cost you $1,500, but you get a free alternator with it. Unfortunately that’s less fun and educational for us. Apologies to the audience…
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Hartzell can eat a fat ****.

I've kind of decided that instead of sending a core back to Falcon, I'm going to keep them. It's costing me $200, but between the two I have i can make one good one. I really want to see the Summit racing one, but i think I've hit my limit of buying parts i don't actually need.
 
My engine driven fuel pump in one of my past planes once went out. That same “aviation certified” pump was around $200. My mechanic said it’s the same pump old Chevys had and we found a new “automotive” pump for $20. We bought that one, used the case of my failed pump, used the parts of the “automotive” one and he called it an overhauled fuel pump. Took him about 30 minutes at a $75 per hour shop rate.
 
Is there a rebuilder of starters, generators, and alternators, nearby? We have one about the same distance from me as NAPA is. They do good work, and reasonable price.
 
bluerooster said:
Is there a rebuilder of starters, generators, and alternators, nearby? We have one about the same distance from me as NAPA is. They do good work, and reasonable price.
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AFAIK, the last one local to me closed a couple years ago. IIRC, they also had a sign stating they wouldn't work on airplane parts. Of course, the alternator off my '75 Dodge pickup OTOH ;)
 
The only starter/alternator re-builder I know about in my area is a retired guy who does it out of his garage as a sort of keeping busy thing. And last time I called him he wasn't currently doing it because he'd broken his hip.
 
Jim K said:
IIRC, they also had a sign stating they wouldn't work on airplane parts. Of course, the alternator off my '75 Dodge pickup OTOH ;)
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Many moons ago when flying QCU Challengers we learned that when ordering a Gates belt for the prop redrive to use the term "off road vehicle" ... and in reality it is! :biggrin:
 
Jim K said:
Hartzell can eat a fat ****.

I've kind of decided that instead of sending a core back to Falcon, I'm going to keep them. It's costing me $200, but between the two I have i can make one good one. I really want to see the Summit racing one, but i think I've hit my limit of buying parts i don't actually need.
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would you be ahead to hit the junkyard and pull 2-3 of the right ones off chrysler vehicles? Then you can see that you're getting good cases
 
MIFlyer said:
would you be ahead to hit the junkyard and pull 2-3 of the right ones off chrysler vehicles? Then you can see that you're getting good cases
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Not a bad idea. Around here though all the junkyards scrap everything older than 20 years, at which point the old squareback was long gone. You'd have to find a vintage car scrapyard. We're also talking nearly 50 year old parts. Possible some classic car yard might have a pile of them though, they used them in everything for like 20 years.

Now....an automatic ebay search might be worth setting up...
 
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