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TR2/3/3A Alternator failure Latest

TexasKnucklehead

Jedi Knight
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Alternator failure up-date

As you may recall, my 35amp Kubota/Denso alternator had a front bearing seize and sort of stranded me in Ohio. After replacing the bearing (which is the exact same bearing as is used in the front of the original generator) and looking more closely at the failure, I am convinced the pulley spun on the shaft. The pulley nut tightens with the same rotation as the belt is driving it, and will automatically re-tighten itself. The pulley material is softer than the nut, shaft, bearing or washer and ground material away until the back side of the pulley dug into the housing, finally causing enough heat to seize the front bearing. The rear bearing was fine. The attached picture shows how much the nut receded into the face of the pulley. It took over 5,000 miles before the pulley dug into the alternator case and I really didn't see it coming. I am amazed I was able to make it back to Houston with a pulley (on a new alternator) that fit poorly -loose on the shaft and held from spinning by the tension on the nut and a lot of blue lock-tight.

To keep this from happening again, I used my Dremel and small cut-off wheel to grind a crescent into the shaft much like the one on the generator and water pump. With the key installed, there is no way for the pulley to spin on the shaft. I also drilled and tapped a set screw into the center of the pulley, but I'm sure that's just me being overly cautious. Since I had to disassemble the case to remove the bearing, I painted the case black so it looks less like an alternator. And since it was apart anyway, I opted to rotate the field so when reassembled, the voltage regulator would not be as close to the exhaust manifold and the wire connections are on the outboard side, instead of inboard.

During this whole ordeal, I discovered the alternator really needs a different belt. The relative location of the tension bolt of the alternator is different from the generator. The alternator is at 12oclock, while the generator is at 10oclock compared to the pivot bolt. Apparently when I first installed the alternator, the belt was stretched enough to work. When I tried to install a new belt (because the old one broke upon bearing seizure) it was too short. The interim 'fix' (in Ohio) was to drill a hole in the tension arm. That probably would have been OK, but I should have realized that in this position the belt could vibrate enough to rub against the pivot bolt -since I installed it with the exposed threads forward, instead of rearward... So by the time I got to Houston, the belt had a groove dug away and the tension arm had broken at the bolt by the water pump. -Now the pivot bolt is installed with the exposed threads rearward, the nut no longer interferes with the regulator cover, and I'm using a narrower belt so a stock non-drilled arm can be used.

Original Generator Belt Gates Truck green stripe TR28386 7/8"x39-1/8". New Alternator Belt Gates Truck green stripe TR24379 21/32"x38-1/2". Note how odd it seems to have a shorter belt that yields more 'length' due to thickness. The new belt does not bottom out on the pulleys. It no longer rides higher than the top edge of the pulleys.

If you are running an alternator with the original wide pulley, and without a key installed, I suggest you install a key. I am hoping for more than 5,000 worry free miles from my latest repairs.
 

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TR3driver

Great Pumpkin - R.I.P
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Re: Alternator failure up-date

Maybe I missed it. How do you know the bearing didn't fail first and cause the pulley to spin on the shaft?
 
D

Deleted member 8987

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Re: Alternator failure up-date

Yeah...and now you have removed the "safety" of the pulley spinning when the alternator locks up. Break a belt and pitch it into the rad at 60+ might not be the best thing to happen to you.
 
D

Deleted member 8987

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Re: Alternator failure up-date

so....maybe part of the issue...but every time the word "alternator" shows up in any post, it is on a yellow background with blue letters? Sort of like advertising sites hyperlinks...but it's not.
 
D

Deleted member 8987

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Re: Alternator failure up-date

and in quotes it doesn't...and if you copy a post an paste it, the highlight is not there.
 
D

Deleted member 8987

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Re: Alternator failure up-date

so does the word failure. Did the original poster set those highlights, and that's what's triggering the forbidden page?
 

CJD

Yoda
Country flag
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Re: Alternator failure up-date

Cool...I can post through the copied link, but can't get here directly.
 

SASSAMON

Senior Member
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Re: Alternator failure up-date

The highlighted words alternator and failure are probably due to this page being a results of a search using those words.

Quite a clever way to get around the forbidden blockage. I will have to remember this technique.

Roger
 

CJD

Yoda
Country flag
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Re: Alternator failure up-date

But...
...how can you search if you don't know what to search for?


Wait.

Wait.

Wait.


I got it!
 

Basil

Administrator
Boss
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Re: Alternator failure up-date

Hello all, I notice someone (SASSAMON) above mention a "forbidden" blockage. Well, thanks to TexasKnucklehead I think I have discovered (and hopefully fixed) a very odd issue. He contacted me that he was unable to access the site at all and I discovered that his IP address had been added to my firewall and blocked. (I have since removed the block). But after researching his issue, I discover the reason he was blocked.

If some of you had tried to get to this specific thread and were told "Forbidden, you don't have access," it is because of a particulate security rule on my server that I never realized until now was there.

Seems if you try to go to a thread that has certain words in it (like the word "update" that is in the title of this thread), my security rules sees that word in the browser URL and thinks it is an attempt to do what is called an SQL inject attack (like a hacker trying to inject unwanted "stuff" into my database). As a result, my firewall blocks that IP address. If, after 5 such failed attempts, the IP will be blocked completely from the server (and thus you would not be able to access the site at all until I remove your IP address from the firewall).

Anyway, I have modified that rule so that it "should" not be activated when simply trying to "get" to a thread (after all if you are doing a "get" operation it isn't likely you are trying to put anything into the database). Let me know if this has helped. Thanks to TexasKnucklehead for bringing this to me attention.

Basil

PS: I'm going to post a global note about this in case others are having similar issues in other forums/threads.
 

Basil

Administrator
Boss
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Re: Alternator failure up-date

so....maybe part of the issue...but every time the word "alternator" shows up in any post, it is on a yellow background with blue letters? Sort of like advertising sites hyperlinks...but it's not.

If you follow a link that was based on a search that had the word alternator in the search, then, yes, you will the the word that was searched highlighted in yellow. If you just come to the forum, and click on the thread title in the Triumph forum, then you will not see that. For example, this URL was the result of a search:

https://www.britishcarforum.com/bcf...or-failure-update&highlight=Alternator+update

But this was just from clicking on the thread in the forum:

https://www.britishcarforum.com/bcf/showthread.php?109661-Alternator-failure-update

Click on the two and you will see the difference.
 
OP
T

TexasKnucklehead

Jedi Knight
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Re: Alternator failure up-date

Sorry I haven't responded sooner, but I was sort of locked out... and unsure why or how or even if I was.

Maybe I missed it. How do you know the bearing didn't fail first and cause the pulley to spin on the shaft?

I don't "know" that didn't happen. I assume the pulley had been spinning on the shaft for some time, eventually causing enough heat to seize the bearing. I assume this because the bearing on the other end of the shaft is fine. It's only a few inches away and is the exact same bearing. It bothered me that only one bearing heated up and I assume it heated because of the heat from the pulley. I've seen bearings come apart, and I've seen them melt or get chewed up, but this one got really hot, melted the seal and discolored the balls. -But I really don't know what happened first. Why would a bearing fail without something to cause it? How could I figure out what happened first?

As far as the belt breaking if/when the pulley seizes, that already happened. The broken belt was a little wrapped around the fan, but I don't think having a key in the alternator would make the situation any worse. Plus the original generator uses the same key as I installed, so there is no "safety" being removed by adding one to the alternator.

Thanks Basil for getting me back on -I had no idea alternator, failure, or update could be so problematic.
 

TR3driver

Great Pumpkin - R.I.P
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Re: Alternator failure up-date

The front bearing takes a lot more load, and heat, than the back bearing does. That's why on the original generator, the front bearing is a relatively large ball bearing, while the back bearing is just a little plain bushing. On most Ford & GM alternators, the back bearing is a little bitty thing, too.

There's also the possibility that someone tapped the pulley into place, driving against the bearing. Ball bearings really hate that, it can start a failure that takes a long time to show up. Using an impact wrench can sometimes cause problems too.

I don't know how you could tell which came first, it's kind of a chicken and egg sort of thing. I only asked because you seemed fairly certain in your original post.

There seems to be an awful lot of those alternators running around without a key (neither of mine had a groove in the shaft), and the pulley I took off was not a particularly snug fit (about the same as the generator pulley, both moved with just finger pressure). I'm not saying you're wrong, or that your advice isn't good; I'm just a skeptic.
 
OP
T

TexasKnucklehead

Jedi Knight
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Re: Alternator failure up-date

I appreciate your skepticism. Skeptical is a good place to be. I was a little skeptical before I left for my trip because I was too confident in the TR3. Or maybe too confident in my ability to modify it for the better. Perhaps I didn't tighten the pulley enough in the first place. Perhaps the bearing was abused during assembly. Perhaps this alternator is not rugged enough for 12 hours of uninterrupted driving in a TR3. Perhaps my specific pulley was softer than normal. Who knows?

I do know that I added a key in hopes that some of the issues with the last pulley will not be repeated. Perhaps it comes down to where I put my faith. After the incident in Ohio, I lost a lot of faith in my TR3. Adding the key and re-installing the 'failed' alternator has renewed my faith. -Not that I won't remain skeptical for a while.

Thanks for all your thoughts.
 

CJD

Yoda
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Re: Alternator failure up-date

Don't loose faith! I look forward to reading about your TR3 roadtrips!
 
D

Deleted member 8987

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Re: Alternator failure up-date

I appreciate your skepticism. Skeptical is a good place to be. I was a little skeptical before I left for my trip because I was too confident in the TR3. Or maybe too confident in my ability to modify it for the better. Perhaps I didn't tighten the pulley enough in the first place. Perhaps the bearing was abused during assembly. Perhaps this alternator is not rugged enough for 12 hours of uninterrupted driving in a TR3. Perhaps my specific pulley was softer than normal. Who knows?

I do know that I added a key in hopes that some of the issues with the last pulley will not be repeated. Perhaps it comes down to where I put my faith. After the incident in Ohio, I lost a lot of faith in my TR3. Adding the key and re-installing the 'failed' alternator has renewed my faith. -Not that I won't remain skeptical for a while.

Thanks for all your thoughts.

It isn't the TR you need to lose faith in. It was the alternator. If you have had this issue once, maybe you need to add another alternator with pulley (and new belt) to the boot storage location for trips.
 

poolboy

Yoda
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Re: Alternator failure up-date

I remember suggesting that perhaps the Kabota tractor alternator may not have been built for sustained high speeds in a automobile.
TexasKnucklehead said he exchanged the Kabota pulley with one off the generator to compensate...still I wonder if that was enough for that bearing ..and now after reading Randall if the pulley was tapped into place during the exchange, did it damage the bearing as Randall says possible.
Seems like a real automobile application for a replacement shouldn't be that hard to find.
 

TFB

Jedi Knight
Country flag
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Re: Alternator failure up-date

I also had concerns about alternator rpm with the smaller than stock alt.pulley on my 40A Kubota nippendenso type$70 ebay gray market unit.
It came with a smaller thin belt pulley that matched the Moss fan eliminator set up,which luckily has a smaller than stock crank pulley.
I think when I did the math the alt. would be close to its max 11k at engine 5k.
8k miles and still feels smooth.
Excessive belt tension would be my first guess for failure of subject alt.
Tom
 
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