Engine Alternator Issues

[dickandlois]

This may get to be a bit long, but over the past few years I have had a number of Alternators go bad.

The thing is they do not really quit. They just cause strange things to happen to my speedometer, cruse control, ECM information and the VMSpc operation.

The problems are intermittent. When everything is cool / cold no problem, but as the temperature rises the items listed above take on a mind of there own.

We often drive for an extended time. During the night time everything works fine, nice cool air. During the daytime when things heat up everything starts to go South.

When I install a new Alternator everything works fine for about 12 to 18 months.

This last trip things went bad again, so I stopped and shutdown the engine. Removed the alternator exciter wire. The Alternator is now no more then an expensive pulley.

I then started the generator and used the battery charger / Inverter as my power supply for the engine and chassis electrical.
Everything worked just fine as we traveled down the road for another 6 hrs.

The next morning I reconnected the alternator circuit and started off down the road.Everything worked fine for about 1 to 1 1/2hrs.Then the alternator got hot enough to cause problems.
This required the alternator to be disabled again and the use of the generator.

The way things act for me are:
The speedometer goes nuts, needle jumps from 0 to 50 or 50 to 80+mph. The Tachometer stays right at the set RPM's.
When the cruse control is disengaged it will reset, but the system surges and jumps.
The ECM check engine light will flash on and off never sets a code.
With the Silverleaf running, The alternator over voltage will cause the gauge to jump all over and a warning bell will sound from the software.
Also, a clacking(Audio)sound is produced(By the VMSpc-Silverleaf software I use)when the speed signal is corrupted by the noise present on the 12 volt power feeds to the instrument cluster. This also affects other instruments as the noise level on the 12 volt supply circuits increases.

I will be installing a Delco alternator, in my case that will have a higher operating temperature and a better cooling system.
The price is double the OEM unit, but I have changed out to many not too. Would have saved a lot of money and time had I done this years ago.

The Leece- Neville and Bosch units fail but at a much lower rate in my humble opinion,but all will fail in time.

So if you have an intermittent issue(S), that as you watch Them happen in regards to temperature, Think alternator / regulator failure due to terminal break down...

See my alternator problems photo gallery.

11-6-2014. > Added some additional information and pictures in the gallery section. My thoughts regarding the failure of the alternators in some model coaches when traveling in elevated ambient temperatures. They fail due to the very high temperatures generated from the Exhaust Manifold, Turbo, and to some extent the radiator cooling line location and the Muffler placement on some coaches> due to limited air movement.

I built a air duct, that collects exterior ambient temperature air and directs it to the rear of the Alternator; that appears to reduce the temperature of the alternator. I have only run this modification for 6 months, but I went and installed an alternator that would cause excessive noise on the 12 volt output when it got hot and ran it for well over 7,000 miles this past summer with no issues until it finally failed for good.

The unit I tested would not work when the ambient temperature exceeded 85deg. F. With the addition of cooler air, this alternator continued to work at ambient temperatures in excess of 95 to 100 degs. The same unit worked very well when the ambient temperatures where below 80degs. and when traveling at night with the add load of all the lights. ( Note! I traveled all the way to the west cost and back with no issues) Now! I did carry a replacement, but it was still in the box when we parked at home.

http://community.fmca.com/gallery/album/469-keeping-the-alternator-cool/

I talked to Martin from Silverleaf at the Indy Rally, August(9/2012)and He confirmed my observations of picking up a failing Alternator by the way the software and computer respond to noise being generated in the alternator diodes. Added 9/14/12.

Rich.

Just Wanted to add a possible item that could cause engine alternator problems. It is a remote possibility that the charger / inverter unit could have an electrical item(s) starting to fail. Primarily the diodes or a capacitor starting to brake down putting an intermittently high load on the alternator output.

Look at this link to see if anything sounds familiar.  

 http://community.fmca.com/topic/9148-inverter-on-or-off/#comment-63001

 

 

[desertdeals69]

I had some issues with the alternator on my ISB Cummins. It originally came with a Delco which was the same physical size as an automotive one. After rebuilding it a couple of times I realized I was working it to death. I have 2 group 31's for the engine and 6 golf cart batteries for the coach. The alt was just working too hard all the time. I went to the next frame size larger Delco and had it built for 240 amp output. It has worked fine for the last 7 years and 100,000 miles.

[dickandlois]

A follow up regarding a Delco replacement Alternator for my Coach.

They make a 28SI series that will bolt up the same as the OEM unit.

The 28 SI comes in a 160,180 and 200 amp version. 12 and 24 volts.

They are available in a Pad Mount Version and the J180 Version that has a Long and Short Hinge Mounting.

One needs to do a little rewiring to connect the Alternator Exciter circuit.

They are about twice the cost of the OEM units.

So if the OEM unit is $150.00 the 28 series is around $300.00. There are aftermarket units out there.

I have a complete list of the OEM numbers for them,to many to list; but will post numbers for any particular units if you know what you are looking for.

If nothing else it might get you real close to a match.

I will see if the extra cost is worth it over the next few months and years..

Rich.

[Herman3]

You need to check for a poor connection, check the voltage at the back of the alternator when you first start the engine, when the voltage drops retest, if the voltage is low the trouble could be in the alternator if the voltage is normal ( 13-14 volts) you could have a bad connection this could be in a number of places.

[dickandlois]

Herman, In this case the heat inside the Doghouse is high enough to cause the Regulator Diodes to fail. This has been an ongoing issue since the coach was built.

The first change was to go from a 130 amp alternator to a 160. A change put out by Fleetwood.

Then I went to a 200 amp alternator,trying to compensate for all the load. I even installed a 14.5 volt regulator. This caused the ECM to offer up a check engine light,although it never set a fault code.

When the diodes fail all kinds of issue come up with the electrical system and control modules.

When things are cold everything works, Heat is my enemy. If I power the 12 VDC system from the Generator/charger by turning the Alternator into an expensive pulley, everything works fine for hrs.

Rich.

[Briarhopper]

Rich,

As an added precaution, you may be able to add some shielding to protect the alternator from excessive heat. Just depends on if the heat causing the problem is being conducted, convected or radiated.

Radiated: May be able to shield the alternator from the source.

Convected: Need more cool air, maybe from a deflector, air scoop. Don't really know, just depends on how your engine compartment is designed.

Conducted: Might be able to add something to the alternator mount to draw heat away. Example: We used to put clothes pins on a steel gas line to prevent the gas from boiling and creating a vapor lock.

Just some thoughts that might be useful.

Stuart

[Herman3]

I would like to see one of the alternators that went bad to help correct your problem also what alternator are you using? If you can give me a part number.

[Herman3]

I sent you a response, I didn't hear from you so I am not sure if it was my fault. Any way most people don't know there are extra heave diodes and regulators for most alternators, I can supply both parts if you would like. My email is htrujillo3@comcast.net if I can help let me know. Save your money and stick with the 21/22 SI

[dickandlois]

With the limit to the number of pictures one can attach to these threads. I have added some pictures and notes to my alternator problems photo gallery.

Hope this helps others with similar issues.

Rich.

[dalltop]

Almost makes you long for the old days were the regulators were external. That would solve your issue. If you had an option of a alternator with external regulator you could then position the regulator away from the heat.

[dalltop]

I was curious so I search around for alternators with external regulators and saw this site.

Looking at this site http://www.zena.net/...s/mar_alt.shtml it says you can DC weld with theres. Some versions have a separate rectifier with its own cooling fan. I'll bet nothing on this website is cheap. These are actually generators that look like your alternator.

Looking around further on the sight they also have high end alternators. Below is the sales pitch from their site. They say this alternator is designed for operating temps up to 298 degrees. Never heard of them but I am not big into high end car audio systems.

• Rectifiers in all ZENA power generators/alternators are more than double the size required to handle rated output currents, and are also capable of handling exceptionally high reverse voltage spikes. Rectifier heat sinks are equally robust allowing reliable high amp operation in exceptionally hot operating environments.
  For example, in our SR200 series, which is designed for exceptionally duty, we use twelve (12) individual rectifiers (double the amount found in a typical alternator) -- mounted on double solid copper heat sinks in a separate cooling compartment isolated from the hot internal generating components. (This provides most of the benefits found in an externally rectified alternator without requiring extra engine compartment mounting space or requiring a more complicated installation or extra wiring.
  
• Bearings are oversize, and much higher quality than found in a typical alternator -- equally capable of handling high side loads and high temperature operating environments.
  For example, our 200A alternator's front bearing is large enough for use as a wheel bearing on a small utility trailer!
  
• To further reduce bearing wear, and increase service life, rotors are spin balanced and machined to ultra close internal tolerances.
  
• Internal wiring, including stator and rotor windings is extra heavy duty -- oversize (stator wire is so large in diameter that windings must be carefully hand fitted to stator laminations), and designed with an insulating system capable of withstanding temperatures of more than 150 degrees Celsius (over 298 degrees Fahrenheit) without failure.
  

[desertdeals69]

If we are talking about front engine mh the easiest way to cool the engine compartment by dozens of degrees is to cut two vent holes through the sides, one on each side at the top rear of the wheel well. The problem is not the amount of air coming in but rather the amout of air that can leave the area. Since I was in the boat business as well as the rv business I used a bilge vent made of ss, which was a lovered fin housing which required a 2x5 inch cutout. What this does is allow the hot air to escape that is trapped in the upper corner of the wheel well because of the centrifical air being blown off the rotating tire. I used to turbocharge the 440-3 Chryslers and the heat build up was very high. This is what we did to combat the problem. The latch hardware on the doghouse would burn your stocking feet. After the mods the hardware was cool to the touch.