What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

PP Alternator to Denso - Another Alternator discussion...

L

litgourley22

Member
All - apologies for yet another alternator discussion but I'm having trouble piecing together all the knowledge on the other threads to fit my specific situation and I have a few questions. I'm hoping this can turn into a Plane Power to Denso "conversion" thread to for anyone as electrically dumb as me. I've tried to summarize all I've learned on the previous threads here, so please correct any errors you see.

I have a Plane Power AL12-EI60/B Alternator that failed. I've only partially taken it apart, but it makes a grinding noise so I suspect the bearings are toast. When looking at the prices of a "plug and play" Plane Power alternator, I was hard pressed to play $1300-1500 for a replacement when lots of you are running a Denso alternator that costs less than $200.

So I ordered a Denso-type alternator (WIlson 55 Amp alternator) from O'Reillys down the road. It's US made and came recommended from a buddy of mine. I do know there are other options like the ND Alternator for about $103 w/o shipping, in hindsight I could've saved some cash on that one. Anyway...

After careful examination of the differences I noted a few things
1) The Denso alternator has 2 prongs, and the alternator wire attached to my airplane is a 3 prong. See picture below with the regulator removed.
2) It's "upside down" - the alternator must be flipped 180* to be mounted on the existing mounts.
3) The old regulator has an extra wire (makes sense since it's got 3 prong connection)

Once I took the old and new regulators off, they're an exact match besides the additonal wire. and it SEEMS like i could just take the old PP regulator and attach it to the Denso alternator, but I'm not sure that's smart based on it being a used part with used brushes on a new alternator. This would alleviate my problem of having to change out the alternator wire which would be nice.

I'm tracking that if you need to switch to the 2 prong alternator wire, you may need the B&C Field Wire Kit. For the mounting you may need a B&C mounting kit. I saw some links in the other threads so I'll include them here so you don't have to go back and forth.

B&C Field Wire
B&C Boss Mounting Kit w/ Belt
B&C Case Mounting Kit w/ Belt

I have a few questions for you guys to hopefully clear up any confusion.

1) Can I and SHOULD I just take the PP Internal Regulator and put it on the new Denso Alternator, or would a better option be to buy the B&C Field Wire kit which will plug directly into the new alternator and regulator. I bought a pigtail connector from amazon that looks like it would work. See picture.
2) I've given no thought to doing an external regulator, I understand the internal regulator is plenty good enough but still hear that some of you have gone to the external regulator.
3) I'm concerned the pulley won't line up where the old alternator was mounted and that the new mounting may require a new longer belt (obviously not a big deal) and taking the old pulley off the PP alternator. Is that accurate?
4) What else am I missing for this conversion?

I attached a few photos for reference.

Again, I'm self-admittedly not smart on electrical stuff, especially when it comes to alternators, but I'm hoping to learn a little from this so any help, links or comments are greatly appreciated. Let me know what you guys think.
 

Attachments

  • IMG_2352.jpg
    IMG_2352.jpg
    1.6 MB · Views: 92
  • IMG_2353.jpg
    IMG_2353.jpg
    1.8 MB · Views: 78
  • IMG_2354.jpg
    IMG_2354.jpg
    1.9 MB · Views: 82
  • IMG_2355.jpg
    IMG_2355.jpg
    2.1 MB · Views: 95
Last edited:
litgourley22 said:
All - apologies for yet another alternator discussion but I'm having trouble piecing together all the knowledge on the other threads to fit my specific situation and I have a few questions. I'm hoping this can turn into a Plane Power to Denso "conversion" thread to for anyone as electrically dumb as me. I've tried to summarize all I've learned on the previous threads here, so please correct any errors you see.

I have a Plane Power AL12-EI60/B Alternator that failed. I've only partially taken it apart, but it makes a grinding noise so I suspect the bearings are toast. When looking at the prices of a "plug and play" Plane Power alternator, I was hard pressed to play $1300-1500 for a replacement when lots of you are running a Denso alternator that costs less than $200.

So I ordered a Denso-type alternator (WIlson 55 Amp alternator) from O'Reillys down the road. It's US made and came recommended from a buddy of mine. I do know there are other options like the ND Alternator for about $103 w/o shipping, in hindsight I could've saved some cash on that one. Anyway...

After careful examination of the differences I noted a few things
1) The Denso alternator has 2 prongs, and the alternator wire attached to my airplane is a 3 prong. See picture below with the regulator removed.
2) It's "upside down" - the alternator must be flipped 180* to be mounted on the existing mounts.
3) The old regulator has an extra wire (makes sense since it's got 3 prong connection)

Once I took the old and new regulators off, they're an exact match besides the additonal wire. and it SEEMS like i could just take the old PP regulator and attach it to the Denso alternator, but I'm not sure that's smart based on it being a used part with used brushes on a new alternator. This would alleviate my problem of having to change out the alternator wire which would be nice.

I'm tracking that if you need to switch to the 2 prong alternator wire, you may need the B&C Field Wire Kit. For the mounting you may need a B&C mounting kit. I saw some links in the other threads so I'll include them here so you don't have to go back and forth.

B&C Field Wire
B&C Boss Mounting Kit w/ Belt
B&C Case Mounting Kit w/ Belt

I have a few questions for you guys to hopefully clear up any confusion.

1) Can I and SHOULD I just take the PP Internal Regulator and put it on the new Denso Alternator, or would a better option be to buy the B&C Field Wire kit which will plug directly into the new alternator and regulator. I bought a pigtail connector from amazon that looks like it would work. See picture.
2) I've given no thought to doing an external regulator, I understand the internal regulator is plenty good enough but still hear that some of you have gone to the external regulator.
3) I'm concerned the pulley won't line up where the old alternator was mounted and that the new mounting may require a new longer belt (obviously not a big deal) and taking the old pulley off the PP alternator. Is that accurate?
4) What else am I missing for this conversion?

I attached a few photos for reference.

Again, I'm self-admittedly not smart on electrical stuff, especially when it comes to alternators, but I'm hoping to learn a little from this so any help, links or comments are greatly appreciated. Let me know what you guys think.
Click to expand...


Here is a great article that gives some background on alternators and explains which plug terminal does what in the internally regulated alternator. Just do a Google search for the different type plug wiring- two terminal or three. I see no reason to use your old regulator on a new alternator.
 

Attachments

  • Alternators 101.pdf
    1.6 MB · Views: 66
Last edited:
www.maniacelectricmotors.com

Alternator Rebuild Parts List for 1993-1995 Toyota 4Runner T-100 PICKUP 3.0L - 13496

**Availability on complete units may vary. You will be notified if your order can not ship immediately and/or you can contact us to verify availability if needed - Thank you! <h3>Quality Aftermarket Alternator - 1 Year Warranty</h3>Alternator with Denso Design Specifications, 60 Amp/12 Volt, CW...
www.maniacelectricmotors.com

Check out this site for alternator repair parts and videos on how to repair them.

Your pp alternator includes an over voltage crow bar circuit for protection. If you stay with the internal regulator you may want maintain this.

I have purchased the repair parts and performed the repair on my plane power alternator.
 
Last edited:
Thanks for asking the question. I was similarly confused on the subject. Just an aside I had a 2 1/2 year old PP alternator with a similar rear bearing issue. Hartzell replaced the alternator free of charge. Sounds like it is a bit of a known issue.
 
Jetmart said:
Thanks for asking the question. I was similarly confused on the subject. Just an aside I had a 2 1/2 year old PP alternator with a similar rear bearing issue. Hartzell replaced the alternator free of charge. Sounds like it is a bit of a known issue.
Click to expand...
Well, that would be convenient. Mine is almost 20 years old from what I can tell in the logs. Never hurts to try though.
 
Last edited:
jmra72a said:
www.maniacelectricmotors.com

Alternator Rebuild Parts List for 1993-1995 Toyota 4Runner T-100 PICKUP 3.0L - 13496

**Availability on complete units may vary. You will be notified if your order can not ship immediately and/or you can contact us to verify availability if needed - Thank you! <h3>Quality Aftermarket Alternator - 1 Year Warranty</h3>Alternator with Denso Design Specifications, 60 Amp/12 Volt, CW...
www.maniacelectricmotors.com

Check out this site for alternator repair parts and videos on how to repair them.

Your pp alternator includes an over voltage crow bar circuit for protection. If you stay with the internal regulator you may want maintain this.

I have purchased the repair parts and performed the repair on my plane power alternator.
Click to expand...
Great find. I'm wondering if its worth it to open up the case and replace the bearings.
 
DanH said:
Unfortunately, the usual failure mode is enlargement of the bearing bore in the rear case. The bearing itself is probably fine.
Click to expand...
Very interesting - any thoughts on if this is due to extra vibration, weak casing, pulley too tight, or something else? I wonder if this failure mode the same in the auto world.
 
rv8ch said:
Very interesting - any thoughts on if this is due to extra vibration, weak casing, pulley too tight, or something else? I wonder if this failure mode the same in the auto world.
Click to expand...

My belt was tightened according to specs. My understanding, unconfirmed, is that there was an issues with the PP alternators themselves.
 
Last edited:
rv8ch said:
Very interesting - any thoughts on if this is due to extra vibration, weak casing, pulley too tight, or something else? I wonder if this failure mode the same in the auto world.
Click to expand...
Some of us have been kicking around the idea of cooling the rear case with a modified rear shroud, the idea being to reduce the expansion difference between the aluminum bore and the steel bearing shell. However, it's not worth doing without measuring before/after temperature at the bearing cavity. Evidence matters. At the moment it's a guess.
 
Update on this journey: called Plane Power they’re going to inspect my alternator to see if it qualifies under warranty. Would be a huge win, but I think we all know how this will go.

I went out to the airplane for a bit and found a few things to consider.
1) the Denso alternator has a smaller mounting hole on the non-threaded side. Will need to be machined out to fit the AN5 bolt currently on the mount.
2) the 3 prong connector has the same “jump” wire (I don’t know what it’s called) as the B&C connector kit. See pic below.
3) My tension arm definitely is too short (so to speak) and will need to find the standalone tension arm that comes in the B&C kit.

Anyone know where to buy only the tension arm? I’ve searched the part number and can’t seem to find just the arm for purchase.
 

Attachments

  • IMG_2360.jpeg
    IMG_2360.jpeg
    1.4 MB · Views: 45
  • IMG_2355.jpeg
    IMG_2355.jpeg
    2.1 MB · Views: 45
Reviving this thread because I need an electrical guru to help me out.

I need some guidance on how to make sure I don’t re-wire the new connector to the wrong leads. The wires aren’t labeled on the current connector or into the alternator, copy red is hot and white is not, but when I looked at a wiring diagram the wires seem to be incorrect.

Anyone done this piece before?
 
The internal regulator works perfect, people say it has no voltage protection only to make you buy their junk, research the internal vr has protection. And I would never use a clone of a Denso, take a Denso and a clone apart you will see why. The Denso is bulletproof works great lasts long time, thats why damn near every new car you buy has a real Denso.
 
Yeah I'll be keeping the internal regulator set up. I'm gonna try the alternator I bought since it's made in the USA and it seems to be pretty good quality. I just need to figure out the wiring situation.
 
Ruready said:
The internal regulator works perfect, people say it has no voltage protection only to make you buy their junk, research the internal vr has protection.
Click to expand...
I'd love to see some documentation regarding that internal overvoltage protection. What ya' got?
 
litgourley22 said:
Update: Plane Power is replacing my faulty alternator and sending out a new one this week. Crisis averted.
Click to expand...

That’s great. That’s what they should do and is what they did for me. They may have some issues but they do seem to be standing behind them.
 
I do not want to rock the boat. IMHO the B and C 60 amp alternator paired with their Linear external regulator is the best most reliable option.
 
Years ago I had a noisy PP alternator. Saw the cost of replacing with another PP. Decided to take it down to our local auto electric shop & see what he could do with it. I told him about the special PP regulator & to test & reuse if it checked out.
Later that afternoon I got it back, with premium bearings & brushes, machined armature & changed out rear housing that he had laying around.
$45 normal rebuild, because I mentioned it was in my home built, $65.
That alternator is coming up on 1k hrs.
 
You must log in or register to reply here.
Back
Top