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The Uppity 12v Admin
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Discussion Starter #1 (Edited)
By popular demand, this is the story of how d89 put a big boy alternator on his 12v Cummins:


Not really. But that is pretty daggum sweet.

After an electric fan swap, the stock 130-amp Denso unit was quick to show it's limitations. Both fans on high speed (roughly a 60 amp draw) was enough to discharge the batteries at idle. The Leece-Neville 110-555 JHO I selected to replace it uses the J180 Long Hinge mounting configuration. This is one of several alternator mounting standards in the heavy equipment industry, and as such is very common. Most J180L alternators can be attached to the Dodge 6BT using the bracket and spacer dimensions in this writeup, however, some minor installation details will likely vary if you use another J180L alternator.

I chose the Leece unit (brochure, tech specs) because it was featured in a writeup that I followed for installing a Leece-Neville on a 6BT in a 1st Gen. This is a good writeup, but the pulley size information is useless for us with 2nd Gen trucks, due to outdated part numbers and a different crank pulley size. While I assumed most J180 alternators would fit, I wasn't interested at the time in taking a chance with something that I hadn't seen work. Remanufactured units can be bought online for $100 all day long. Any alternator shop worth their salt will have shelves full parts to rebuild one, and any truck shop with a parts department will have complete units in stock. The Leece is a good choice, but if I were to do this swap again, I would choose the Delco 28si (brochure). They are a newer and better design, are available with a 200-amp peak output, dual internal fans, a stronger low-rpm output curve, and remote battery voltage sensing. Reman units are available online for $150 and all the same stuff holds true about parts availability.

There are two ways to install the alternator. Each has benefits and drawbacks. The first "stock replacement method" adapts the alternator to the stock mounting location and orientation. The other "JoeDirtPNW method" installs the alternator upside down. I will cover both methods as I've ran both.


Stock Replacement Method

Pros:

  • Minimal fabrication. Most of the sleeves and spacers can be bought at a hardware store.
  • No permanent modification. It allows for a stock alternator to be reinstalled if necessary.
Cons:

  • Requires a light clearance grind to the belt tensioner.
  • The nut on the back of the lower mount is difficult to access.
  • Heater outlet tube must be repositioned, resulting in very little clearance to oil filter mount.

JoeDirtPNW Method

Pros:

  • Cleaner looking install.
  • Leaves more room on top of the alternator for *ahem* other stuff.
  • All mounting bolts/nuts are in plain sight and easy to access.
  • No clearance grinding required on belt tensioner.
Cons:

  • Requires more fabrication that the Stock Replacement Method.
  • Requires permanent modification to the thermostat housing.
  • Little clearance between the positive output stud and the oil filter. Use extreme caution when changing the filter.
  • Little clearance between negative output stud and turbo air inlet tube.

Stock Replacement Method Installation

I initially mounted it with the Stock Replacement Method as I was following the aforementioned writeup for installing a Leece-Neville on a 1st-gen truck. I have some reservations about the hardware that was chosen in that install. The SAE hardware (3/8" instead of M10, etc) hardware that was used left the alternator very sloppy on the bottom mount. Don't get me wrong. It tightened up fine and I ran it like that for probably 15k without any problems. But, the .030" diameter difference between the M10 clearance hole on the mount and the 3/8" bolt, and the .015" diameter difference between the existing mount holes on the alternator and the 1/2" OD of the store-bought bushings add up. A guy would be better off using the metric hardware I have outlined below. This better hardware does not match what I have in my pictures, but the "what" and "where" is all the same.

Stock Replacement Method hardware (non-critical dimensions are in green):

Top Bracket mount:

  • 1/2-13 x 3/4 flange bolt (need 1)
  • 1/2" washer (need 1)
Bottom mount:

  • .400" ID, 1" OD, 2" long spacer (need 1)
  • .400" ID, .516" OD, .560" long bushings, or store-bought 10mm to 13mm bushings 16mm long (need 2)
  • M10x145mm flange bolt (need 1)
  • M10 flange nut (need 1)
No modifications need to be made to the lower mount. All the dimensional changes are dealt with by the bushings and spacers on the bolt. One of the smaller spacers goes inside each of the feet. The front one is slid back so you can see it:







The stock upper mount needs a small tab added to it to accommodate the Leece's larger size. This could be made to bolt on to the stock mount, if a person chose. I decided to leave the existing hole open so that I could reinstall a stock unit if I had to.



On mine, I had to put a washer between the tab and the alternator to preserve the alignment.



Installed:




Lower mount:


Clearance around lower mount nut:


JoeDirtPNW Method Installation

I decided to re-mount my alternator like @JoeDirtPNW did in his build thread. My primary motivation for this was to eliminate the upper bracket used by the Stock Replacement Method to make more room for an engine-driven OBA compressor. Though, I would advocate this method in general because it's much easier to get to all the bolts when you need to take the alternator off, and it doesn't force the water pipe into the oil filter mount.

JoeDirtPNW Method hardware (non-critical dimensions are in green):

Top mount

  • .313" ID, 1" OD, .940" long spacer (need 1)
  • .313" ID, .516" OD, .560" long bushings (need 2)
  • M8x150 flange bolt (need 1)
  • M8 flange locknut (need 1)
Side mount

  • .500" ID, 1" OD, 2" long spacer (need 1)
  • 1/2-13 x 3 flange bolt (need 1)
Bottom mount

  • M10x60 flange bolt (need 1)
  • M10 flange nut (need 1)
  • Custom bracket (print attached)
I removed 1/2" from the front of the top mount.


This is the top mount hardware:


Upper mount:


Here's the lower mount hardware:


Here is the print for the lower mount. There is a higher quality PDF attached to this post.


I decided to weld the M10 flange nut to the bracket. Easier that way.

Side mount:


Lower mount, from rear:


Lower mount, from front:


These show the tight clearance against the positive terminal and the oil filter:





Install complete:




 

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The Uppity 12v Admin
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Discussion Starter #2 (Edited)
Pulley Sizing

I found three suitable sizes of pulleys that are readily available for this alternator. 60mm, 70mm, and 76mm. As I mentioned before, the part numbers in the other writeup are no longer good through any of the half-dozen sources I contacted. The supplier that was finally able to help me out was an alternator shop in Spokane, WA called Battery Systems. They appear to be a semi-national chain, with many stores west of the Mississippi. It took several trips down to the local branch, which has a very patient parts guy who was willing to thumb through several books to come up with what I was looking for:



I have ran the 76mm and 70mm pulleys. I have not ran the 60mm and don't plan to. Both pulleys I ran had slightly different modification requirements for them to fit on this alternator.



Both pulleys have a step on the back that needs to be machined off.



If you don't have access to a lathe, a machine shop shouldn't charge but a few dollars for this, as it's an extraordinarily simple operation. In addition to the removal of the step, the total width of the pulley should be taken down to 1.400" to 1.420".



This dimension has a fairly forgiving tolerance, as there is a long belt distance between grooved pulleys on either side of the alternator. This means the belt isn't going to be significantly affected by this amount of misalignment. The water pump pulley is close, but has a smooth back so the belt can track wherever on it. When I initially installed the alternator with the 76mm pulley, I faced it down to a thickness of 1.420". The belt tracked about .100" forward from it's previous wear mark on the water pump pulley. I was somewhat concerned and kept an eye on it for a time, but 12k or 15k later (however many miles it's been), the belt is still in tip-top shape, so I'm not worried about it. When I switched to the 70mm pulley, I cut it down to 1.400" and that, combined with changing the mounting, moved it most of the way back to the stock location.

Fitment specific to the 76mm pulley:

This pulley has a deep counterbore (.395") where the nut sits when tightened. The alternator shaft is 7/8" where the pulley sits, but the nut thread diameter is smaller.



The counterbore prevented the nut from securing the pulley against the step in the shaft below the fan. To get around this, I made a washer. The dimensions are .895" ID x 1.646" OD with a thickness of .150".



This pulley has the correct keyway for the key that came with the alternator shaft.

Fitment specific to the 70mm pulley:

This pulley's counterbore was shallower (.319"), so the washer I made for the other one wasn't required:



Other than that, the 70mm pulley doesn't have a keyway. There are two options. Have a machine shop broach a .150" keyway in it, or remove the key from the alternator shaft. I chose to remove the key when I installed it because the nut, properly torqued, will hold the pulley in place just fine.

Electrical

Wiring is simple for this particular unit as it has a self-exciting voltage regulator. Just hook up the battery connections. I had cables made from 2 gauge welding cable with crimped and heat-shrunk ends sized for the terminals. They are 30" long, but could easily be 6" shorter. I deleted the factory alternator wiring. This caused the CEL to illuminate, which I chose to deal with by removing the bulb, as the CEL is pretty much useless on a 12v anyway.

Belt Sizing

Unfortunately, I can't simply give you the proper belt size at this time. The reason for this is that I have deleted my fan pulley as part of my e-fan conversion. It should only be a couple inches longer than stock, but there are enough variables that it should be determined on a case-by-case basis.

Here is how to determine proper belt length:


  1. With the belt completely off the engine, stick a socket wrench in the tensioner and pull it back until the pulley is where it normally sits with a belt on it. Move the handle of the wrench so that it rests against the frame rail, and let the tensioner spring holds it against the frame.
  2. Run a tape measure around all the pulleys in the same routing the belt follows. Have the end of the tape somewhere you can easily see it. I found it easiest to have it on the bottom of the crank pulley. Pull the tape tight and record the measurement. You will probably need to round up or down. Either way is fine, the tensioner's range of motion actually gives you quite a bit of wiggle room.
  3. Go down to your favorite parts house and tell them you need an 8-groove serpentine belt in whatever length you came up with.
  4. Put the belt on the engine to confirm the length is correct.
  5. PM d89 so he can edit that length into this post. Also be sure to tell him whether or not you have A/C, what alternator, what install method, and what pulley diameter you used. His hope is to create a chart that can account for all the variables so people can just know what they need ahead of time.
  6. Enjoy your awesome new alternator.
 

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Great writeup, as always! :thumbsup:

I believe this should make its way into the Tech Articles...
 
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Problem with these mods is clearance under the hood. I removed my very reliable belt driven plow pump for clearance issues while working on my truck.

I wonder what it would take to run dual smaller alternators instead.
 

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D89
I was just thinking about replacing our batteries, cables and alternator. I feel like you just give me the last push!
Thank for documenting everything so well, a lot of time and effort placed to freely share your knowledge.
Keep up the good work!
 
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Here is a good way to lookup belt part numbers, I found one close to the size I needed and made sure that its a standard size that all auto parts stores carry. If yours is not a common size it might be a good idea to have a extra in you tool box.

http://www.daycoproducts.com/online-catalog-1?part_type=20
 

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Here is the print for the lower mount. There is a higher quality PDF attached to this post.
A side not I dont think that lower mount will work on the larger output alternators, looks like it will tuck the smaller ones on there really tight!
 

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Discussion Starter #11 (Edited)
It won't fit on the larger ones like the Lestek like you're running, but it snugs the JHO right up to the belt tensioner. An even shorter bracket could be used on a 28si since they are physically smaller and don't have the giant fan which is more of a fitment problem than the case of the alternator.
 

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Discussion Starter #12
A short demonstration of the alternator running the grid heaters on the post-start cycle:

 

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Discussion Starter #14 (Edited)
So...



...I ordered a 28si.

Due to the 10,000 rpm continuous / 12,000 intermittent rating on this alternator, I'll be using the 60mm pulley. That will give me about 150 amps at idle (essentially max output on my current Leece), the rated 200 amps by 1400 rpm, and about 215 amps at 2250 rpm. Max continuous engine rpm with this pulley is 3425 and max intermittent is 4100.

I will note any necessary changes to the mounting hardware. Wiring wise, all I should have to do is add a wire for the remote sense.

In the mean time, here's some more alternator porn. Stay tuned.

http://www.delcoremy.com/getmedia/90520e29-6966-4656-a04e-9053e59b5929/Delco-28SI-Single-Page-Brochure-12-14.pdf.aspx
 

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So...



...I ordered a 28si.

Due to the 10,000 rpm continuous / 12,000 intermittent rating on this alternator, I'll be using the 60mm pulley. That will give me about 150 amps at idle (essentially max output on my current Leece), the rated 200 amps by 1400 rpm, and about 215 amps at 2250 rpm. Max continuous engine rpm with this pulley is 3425 and max intermittent is 4100.

I will note any necessary changes to the mounting hardware. Wiring wise, all I should have to do is add a wire for the remote sense.

In the mean time, here's some more alternator porn. Stay tuned.

http://www.delcoremy.com/getmedia/90520e29-6966-4656-a04e-9053e59b5929/Delco-28SI-Single-Page-Brochure-12-14.pdf.aspx
I could have tracked you down a large case Leece. Im pretty sure I have a 200 amp leece i would have damn near gave you......

On a side note there is going to be a dyno day in my neck of the woods, thinking i might try to get a set of injectors and doing a pull.....
 

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Discussion Starter #16
I wanted to stay away from the large-case stuff because of my OBA, part of the reason for swapping is that the 28si is a little bit physically smaller than the JHO.
 

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Discussion Starter #17 (Edited)
Mounting of the 28si using the JoeDirtPNW method was basically the same as it was for the Leece.



There is one caveat though, the 28si can be tucked WAY down towards the tensioner compared to the Leece. I wasn't interested in re-working that mount and buying a shorter serpentine belt, so I re-used all my old mounting.

Here's the Leece and the 28si side by side:





The only thing I did differently was I cut down the factory rear sleeve to the same width as the casting:





I faced it down, but there's no reason not to use an angle grinder. If you are having adapter sleeves machined, you may as well press this out and use a single sleeve instead of a sleeve inside a sleeve.

The pulley I used was the 60mm pulley referenced earlier.





Fitment was fairly easy. The rear of the pulley needs to be faced flat. Once this is done, the pulley bore's length will be exactly the same as the step height of the shaft. This means a washer is necessary. The correct dimensions for this washer are .895" ID x 1.620" OD with a thickness of .125".

Here is the pulley size information for this alternator:



And a few more pictures of the finished install:





As for wiring, I re-used both cables. The only other difference is that this alternator has a remote sense terminal. I ran this reference wire over to my under-hood PDC, so the alternator is sensing system voltage after the voltage drop from both batteries. This alternator seems to maintain a more consistent charging voltage than the Leece. I'm not sure if this is primarily due to better output, the more modern design, or the remote sense, but I'm happy with it.
 

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Well,I've been shopping around for a while to find a big alternator to replace my sad CS-130 with a bad diode when I came across this Ebay ad.

These 240A jobbies normally go for over $500 new, so $165 was a smoking deal. A friend of mine wanted one for his Jeep as well, so I bought two of them. They showed up in due course, and besides some scratches, dings, and broken back plastic they were brand new, just as advertised.









I ordered a pair of new rear plastic covers to replace the broken ones,as well as a pulley for my buddy. As you can see, they are direct mount, so some mods to my mounting setup will be necessary. With this alternator, running by big 12V air compressor will be no problem :party018:

Here's the pr0n for this alternator: http://www.prestolite.com/literature/alts/FL1204_AVI160_Series.pdf

The max RPM listed in the little amperage curve chart says 8000RPM, but that's not really the max RPM. The AVI160T2001 is identical to my AVI160P2003 except for the case mounting arrangement and amp rating, and it specs 12,000 continuous, 14,000intermittent: http://www.prestolite.com/literature/alts/AVi160T_Navistar_Ford_applications_FL1022.pdf. I'm more inclined to believe an explicit rating than a teeny footnote in the corner of a chart. In any case,my buddy is using his on a Chevy LQ4 gas engine, so we will see if it holds up to the occasional ~17,500RPM excursion :eek:

BTW, D89? You got a source and part # for that 60mm pulley?
 

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Discussion Starter #19
I ordered the 60mm pulley from a different source this time. Smith Co Electric had it with a slightly different part number (7940-1755) for a little cheaper than Battery Systems, and free two-day shipping.
 

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I ordered the 60mm pulley from a different source this time. Smith Co Electric had it with a slightly different part number (7940-1755) for a little cheaper than Battery Systems, and free two-day shipping.
Smith Co. was out of stock, but I was able to find the same part at Find It Parts for about $12. By the time shipping, handling, and discounts were applied I thing it was about $23 shipped.
 
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