Need to get rid of Monster Alternator on 8V71. Who has parts I need?

[GM0406]

Another concern on this alternator is the power to run it.  My '06 has a switch that activates the alternator on the left of driver panel that has to be turned on after the engine is started and turned off before the engine is shut down.  When I got the coach, only one 8D battery was in use.  When the switch was flipped on after starting, the engine rpm would drop, indicating that this big unit is definitely a power consumer.  I got rid of the 8Ds as they were too heavy to deal with.  I went to Orbitals and so far they are holding up fine with the Iota Converter that is on all the time the coach sits here and is not used.  Now I'm sure the alternator cuts back after dealing with the batteries, but it would be interesting to know power consumption in the different running modes.  The oil leak in or around this unit is annoying and I am spoiled with the '04 as it doesn't leak at all with the Walker oil recovery unit on it.  I know all DDs are supposed to leak, but the '04 only leaks at the trans, and I hope we can get that cured.  Maybe I just need to add a Walker to the '06?  A little more weight!  LOL!

This week should be interesting.  The flywheel wear plate and rear motor mounts that were ordered from Luke should arrive.  I think the DD shop is now pushing to get the '04 out of there after two years, as it is now inside their shop with the trans out.  If they get it done in time, we plan to take it to the GM Rally in Monterey at the end of the month.  If they don't get it done, then we plan to take the '06.

I suspect some of you here will be at Monterey and we look forward to seeing you there.

Bill T. 

   

[Barn Owl]

By having a separate switch to start your alternator, it sounds like there have been some modifications to your starting/charging circuit. The original setup does not require any additional switches to be thrown to start charging. Most likely something to do with the back isolation relay setup or up front with the selector switch or starting switch. At some time someone jacked the front and back of mine. It took a couple of days to straighten up the mess, but the experienced I gained, has really increased my confidence in my ability to tackle future electrical problems. One thing I couldn't find was a DPST starter switch locally (old one long gone) so I used some inexpensive automotive relays to replicate the operation of the original setup.

[buswarrior]

I've always thought a 50DN weighed around 85 lbs, but I'll stand to be corrected.

happy coaching!
buswarrior

[luvrbus]

If the guy has his doubts about the 50dn by all means let him change it out, it would do no good to change the gear on the alternator and still have 5 more worn gears in the gear train.  I had a gear train fail caused by the $15.00 bearing on the timing idler gear and it does quote "bomb" the engine.FWIW  Belfert the 2 stroke use a fiber gear on the power steering and compressor to keep a failure from happening. one other point I can not understand is how a 50dn with 200+ degree oil would cool better than a air cooled model with 85 degree air temperature so what is the purpose of a oil cooled 50dn

everybody have a good day

[TomC]

Like any other piece of equipment, the sealed pressure lubed and cooled by oil 50DN is made to run in 200 degree oil-the clearances are set up that way.  It makes for a long lived alternator, mainly being sealed and not allowing dust and dirt in.  I know that the air cooled non 50N 300 amp alternators will have a air intake hose to get the air from the engine air cleaner.
I can tell you from experience that the 50DN is advertised at 100lbs and it weighs all that.  Good Luck, TomC

[Gary '79 5C]

TomC, BusWarrior may just be that much younger than at least me, the alternator was all I wanted to lift and slide into the rear cradle mount for my 5C.
85, 100, 125 lbs, all were a handful, without helper..

Take care,

Gary

[Sojourner]

About saving fuel with large or smaller alternator.....example if it needs 60 amps of charging to bring it up to full state of charge, either large 270 amps or small 70 amps will take no more but same amount of fuel. However, if you wait while engine is running with the switch off, then it will need more charging time or more amperes then otherwise. Gear drive will require less HP than belts. Unless you go for single ½ inch belt, nearly same HP.

About remote switch to shut down charging......You don't gain any fuel savings because it still needs charging. Whenever battery is fully charged, it will be spinning freely....no load on alternator with a voltage regulator. In other words, switching alternator at your own desire will result in shorter battery life by being not charged before extra draining taking place.
Bottom-line about getting the most life from the battery is to avoid any draining at any time.
However, the one advantage having that switch is to turn "off" while climbing for fuel saving or maintain higher speed and help keep engine cooler and "on" while going down hill to help braking or drag. You have to keep in mind that the switch needs to be back on after hill climbing.

If you already have a battery cut-off switch, a caution -- never, never cut-off switch while engine is running or you may have regulator problems. Been there...I forgot to turn engine off first before the main cut-off.

FWIW

Sojourn for Christ, Jerry

[pvcces]

Bill, we run the 50DN, and if it failed, I would install another before converting to a different setup. I think that they give a lot of peace of mind. There are no moving or wearing parts that I know of besides the drive gear, the internal reluctor mounted on the input shaft and the bearings on that shaft. This beats any other design that I am aware of.

One thing that you ought to check out is that many of the internals of the generator are servicable without removing it from the engine. And these are readily available used in many parts of the country.

One other thing that you might check into. The oil in the generator is not under pressure, so far as I know. Buy the right o-ring, disconnect your batteries and you can change the o-ring very easily, if it is under the end cover. Check it out in your manual.

It's funny that I discovered this post tonight after not being on the boards for a while. We are at a friend's house in southern Washington and we just today discovered that his generator has a bad field winding.

I haven't heard a word from him about changing to a different generator. He just wants to get his fixed. What is ironic is that he has only about 1500 miles on a recent generator overhaul.

The repair looks easy enough to do on the coach if we can round up the right o-rings and the field winding.

For what it's worth.

Tom Caffrey

[TomC]

The oil coming to the alternator is under pressure from the engine-but with low volume with the size of the line feeding it.  The oil goes first to the two bearings then falls into the alternator to cool it.

As far as a switch to control the alternator to create more drag or to eliminate drag on a long grade- my 12v (actually 14.1 volts when running) 300 amp creates 4,230 watts maximum.  That works out to (750 watts=1 horsepower) 5.64hp.  In my opinion, a little better than 5 horsepower isn't going to make any difference in your engine performance.  And the peak power output of the alternator would only be happening for a few minutes until the batteries started to get recharged.  Personally-don't think the alternator switch is worth it-just one more thing to go wrong and to think about. Good Luck, TomC