M925A2 Delco Style Alternator

74M35A2

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Thanks for the heads up. As another time saver, the new civilian J-180 short mount may be slightly thicker on the side which mounts to the block/head. Mine seems to be though I have not mounted it yet. Pull out one of the existing bracket mounting bolts from the J-180 long alt bracket, and go fetch the next size longer from your favorite fastener store. I'd hate to see this be a show stopper for you after you not only paid full price for the right bracket, but then also overnight delivery. The stock belt will fit with no length mods to the lower alt brace. May need to notch the brace or lower alt ear small portion.
 

silverstate55

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I meant to pass this along earlier; the alternators used in A2s is a AMA-5108UT. Erik's has parts for the 5104 & 5102, but didn't see anything for the 5108s used in A2s. I had 2 alternator shops search far & wide, but couldn't find any parts anywhere for it.

One shop did provide me with some info about a fellow in Washington state who will rebuild a 5108 alternator with parts he has stashed on hand... Romaine Auto Electric, (800) 426-5005, ask for Tom. Anybody here heard this before, or know Tom?

I'm finalizing a swap with a Bosch 130-amp alternator, but if this info helps someone else then so much the better.

The stock lower alternator support bracket does allow use of the stock/existing serpentine belt, but I've only got about 3/8" of free travel left in the belt adjuster.
 
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silverstate55

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I purchased a Bosch 130-amp 24V alternator (J180-style), as well as the new short engine mounting bracket, and installed them on my M931A2. I added an additional 2-gauge charge wire to the "B+" terminal on the starter (and traced wires back to battery box to ensure proper hookup), and connected the red wire on the alternator (switched 24V) to the stock wire labeled/numbered 568. I did not lengthen the stock lower bracket, and there was sufficient tension & clearance left on the serpentine belt setup to run it this way.

For the short engine mounting bracket, no junkyards in my area carried this bracket as a separate item...if they were on engines, they had to be sold with the entire engine. The salvage yards that allowed parts picking said that they can't keep any 8.3 Cummins motors in stock; they sell as soon as they get them in. Hmmm. So, I created a cash account at the Las Vegas Kenworth dealer, and they had to special-order it for me. I also paid for 2-day delivery, but the KW dealer still beat the other dealers on their prices (even Rocky Mountain Cummins). I used longer bolts & nuts where necessary.

I've been testing this alternator for several weeks now, and I must say that I am IMPRESSED. It is a phenomenal unit, and even has made my batteries healthier! Whenever the engine is not running, I could never get the batteries to read out of the yellow on the voltmeter in the dash....now the gauge needle will stay in the lower green zone, and none of the batteries feels extra warm to the touch after extended drives (post-charging). When the engine is running, the voltmeter gauge reads exactly where it should (right on the little white tick-mark!). I am very very happy with this alternator setup!

I recently made a 850+ mile round trip between Las Vegas & Phoenix/Tucscon, once I got down to Tucson I started having trouble starting the engine (fuel issues, driver's side tank looks to have a cracked line on the pickup tube, immediately thought of member MtnSnow's issues for a fix when I get home). This involved some extended cranking times to draw the fuel back up to the IP, and the batteries never once thought of fading! The fuel fix will go into another thread, as it involves other problems and previous fixes.

The green silicone heater hose in the photos has since been replaced with a longer one, to move it away from the exhaust manifold. Again, the local KW dealer gave me a great per-foot price on new silicone hose.

Many many thanks to fellow member 74M35A2 for all of his helpful advice and patience; he has been a tremendous help to during all of this.

20160201_M931A2-Alternator_01.jpg 20160201_M931A2-Alternator_01a.jpg 20160201_M931A2-Alternator_01b.jpg
 

74M35A2

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Thanks for the accolades, your install looks good. The unit you have from me is rated at 24V (28v) and 130A with 200F under-hood cooling air temps. It actually spit out 177 amps on my tester before I shipped it out to you. I test everything before I ship out. It has twin internal fans, includes 8 rib serp pulley, and the internal voltage regulator is not an adjustable potentiometer (thank goodness). Instead, it is temperature compensated, so it will automatically set a slightly higher charge and system voltage in the winter, and slightly lower in the summer, as in the winter one can expect longer cranking and a desire to push more energy back into the battery quickly, batteries will not out-gas as easily in colder temps so they can handle a bump in recharge voltage. You won't have to study the voltmeter anymore, these are close the hood and drive pieces, same as what is used on todays vehicles, not that of 40 years ago like what it replaced. These are not low cost, because they are genuine, new, and not reman or $100 Chinese clones, plus they are more than double the output capacity of what it replaced. At 28V and 130A, it is a 3640W generator head, and even more when cold at first start up. Also nice to be about half the length, allows more room under hood to work. Sorry you had to buy the bracket at full price, but you did it right and should never have to look at it again. These work even left outside when pushed into the junkyard ground and full of mud, as we have designed and tested them to do so. I added one on a scissor lift I have, it has lived outdoors uncovered for over 15 years now, and it works same as the day it was new. I have never touched it, it is heavily oxidized on the outside, and it spits out great power. Because of this, like ss55 said above, I have not even had to replace the battery on it in 10 years also, still works perfect, cranks right up even in 10F January temps. Correct NHC-250 and 8.3 bracket p/n's from Cummins are published in other threads, I am considering to combine all info into one. The above alternator will not over-volt if improper shut-down sequence occurs, which is also an added bonus to protect the ABS and PCB modules. PM for price if you are done pouring money and worries into your stock one.
 
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Stranger

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On Friday I finished installing a "Delclone" 21SI alternator using the wisdom supplied in this thread. I found that no matter what RPM or load I placed on the alternator I could not get it to go above 27.5V. I called the place from which I order it, East Lake Marine Electric in Floriad, and asked about the low voltage. They told me that is the spec voltage. I thought that was odd so I started looking around and found that replacement Delco Remy voltage regulators (real deal, not clones) for the 21SI are set at 27.5V.

In fact, it looks like almost all of their other standard, heavy duty alternators have a 27.5 volt max on their non-adjustable voltage controllers. The 12V alternators voltage regulators are all 14.7V.

So.... I am assuming that 27.5 is going to be just fine for my M923.
 

Stranger

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I've been testing this alternator for several weeks now, and I must say that I am IMPRESSED. It is a phenomenal unit, and even has made my batteries healthier! Whenever the engine is not running, I could never get the batteries to read out of the yellow on the voltmeter in the dash....now the gauge needle will stay in the lower green zone, and none of the batteries feels extra warm to the touch after extended drives (post-charging). When the engine is running, the voltmeter gauge reads exactly where it should (right on the little white tick-mark!). I am very very happy with this alternator setup!
What is your actual voltage? Have you checked it with a volt/multimeter?

I ask because the gauges often do not read correctly. On my M923 the alternator has to be pushing out 32V for the gauge to touch the tick mark. I would boil my batteries trying to get the gauge to read "correctly".
 

silverstate55

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What is your actual voltage? Have you checked it with a volt/multimeter?

I ask because the gauges often do not read correctly. On my M923 the alternator has to be pushing out 32V for the gauge to touch the tick mark. I would boil my batteries trying to get the gauge to read "correctly".
Yes I did test it with my multimeter when I first installed it, and it was spot-on for what it was guaranteed to do....but that was several issues/repairs ago and I don't remember right off the top of my head. I'm right in the middle of putting both fuel tanks back together AGAIN to resolve what I hope is the last of my fuel supply issues, so as soon as that's done I'll fire her up & take a pic of the voltage reading to post here.

[Thread Hijack]{I think I've had just about every M939A2-series fuel issue known to happen on my truck, so I'll post a thread containing ALL of the fixes and pics soon....the last one involved the pickup tube breaking loose & falling out of the supply elbow inside the driver's side tank during a trip to AZ.}[/Thread Hijack]
 
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silverstate55

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As promised, here are a couple of pics of my alternator running in my M931A2.

28.3 Volts. [thumbzup]

20160416_M939A2-Alternator_01.jpg 20160416_M939A2-Alternator_01a.jpg
 

Stranger

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Sweet! Thank you for the update.

Mine is still putting out a constant 27.7V.

The back of your alternator looks different than mine. Maybe I got a different one?
 

74M35A2

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SS55's alternator pictured above is one he purchased from me. It is a 130A rated 24v unit made for the European heavy truck market where most all on and off road heavy trucks are 24v (his tested @ 177A actual room temp output before shipping). Big bucks, not a nameless $89 unit from China. J-180 short mount and comes with correct 8 rib pulley, twin internal fan, has automatic temperature compensated internal voltage regulator (higher recharge voltage during colder temps, lower during warmer temps, due to battery out-gassing thresholds). Even at 130A x 28V, that makes it a 3640 watt power head. More than a small home power generator! Recommend to abandon the factory alternator charge wire and instead run a heavy gauge cable direct to starter rear B+ solenoid terminal if you plan to pull more current from it than the truck was originally equipped to do, which, I believe he did.
 

jarhead1086

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I will be installing the alternator I bought from 74M35A2 on my friend's A2 for now. I have a few other projects going and haven't had a chance to draw up a v belt pulley for my A0 that will attach to the short keyless shaft on this alternator. Send the .stp file to the CNC shop. Sure be nice to have the manufacturer put an A0/A1 shaft in that alternator and reuse the original pulley as a plan B. I will order a low draw starter when I reorder another alternator.
 

74M35A2

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The gear reduction starters pull 200 amps less initial inrush current, and 50 amps less continuous average current during cranking. They do not necessarily crank faster, but they are more efficient (hence the lower current draw), and they do spin their speed consistently, be it cold, room temp, or hot. Direct drive starters have performance losses at temperature extremities, gear reduction ones are rated and tested down to -40. They are also light (28lbs which is about half), and about 1/3 smaller than the original. Sorry about the high output alternator only being available with the unique serpentine pulley. The short shaft helps keep the shaft from breaking off under serpentine belt tensioner pressure. One could take both pulleys to a machine shop and have them bore the V belt pulley out just larger than the fastening nut diameter, and then cut both pulleys just behind where the belt rides, set the same belt alignment offset as if the v belt pulley alone was on it, and TIG weld the serpentine pulley mount portion onto the V belt pulley groove portion. Make a hybrid pulley if you will.
 

silverstate55

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Recommend to abandon the factory alternator charge wire and instead run a heavy gauge cable direct to starter rear B+ solenoid terminal if you plan to pull more current from it than the truck was originally equipped to do, which, I believe he did.
Yes, I had a spare battery cable to run in addition to the stock charge wire; both run to the B+ terminal and seem to work quite well.
 

Tinstar

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Yes, I had a spare battery cable to run in addition to the stock charge wire; both run to the B+ terminal and seem to work quite well.
What was the gauge of the wire?
Standard battery cable?

If not, did you use crimp terminals or copper lugs?

Ordering new setup from 74M35A2 and want to have everything ready as possible.

Thanks
 

74M35A2

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If you don't have any additional loads added, the stock one is OK. Or, you can use a 4ga-6ga automotive starter cable from the alt to the starter. Don't go larger than 4ga, as it is just excessive weight and stress in the alternator stud and cable terminal. Support and protect any added wires appropriately.
 

silverstate55

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What was the gauge of the wire?
Standard battery cable?

If not, did you use crimp terminals or copper lugs?

Ordering new setup from 74M35A2 and want to have everything ready as possible.

Thanks
I used 4-ga cable and soldered on copper terminal ends, then applied heavy-duty heat shrink over exposed wiring.

HTH.
 

Tinstar

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If you don't have any additional loads added, the stock one is OK. Or, you can use a 4ga-6ga automotive starter cable from the alt to the starter. Don't go larger than 4ga, as it is just excessive weight and stress in the alternator stud and cable terminal. Support and protect any added wires appropriately.
Ok
Good advice

sent at you a couple of PMs and haven't heard back. FYI
 
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