Hi, I have an 8V71 by don't need the great big alternator on this original. I would like to change over to a 150 amp belt driven unit. Would like to know if anyone did it and especially if someone has an 871 take out that they are willing to sell the alternator conversion parts from. Bill Thomas
I guess I would ask why? The belt driven alternator is going to use more HP just to turn the belts and you have another maintenance item; adjusting and replacing belts. And the bigger alternator doesn't use more power than the 150 amp at the same electric load plus you have the reserve if you ever need it. But its your bus. Enjoy the ride.
ditto, why go to the headache of fabrication a mount, getting everything lined up etc. if what you got is working let it work.
The big Delco 50DN is really a work of engineering art. It is completely sealed (no dirt problems), it is both lubricated and cooled by the engine oil, it has no brushes. I had to replace mine-with a new regulator it was right at $1500. Granted you can get a 130-160 amp truck type alternator for around $350.00, and then you have to make the mounting brackets and find the conversion kit to belt drive. I like the 50DN-that's why I stayed with it even though it was expensive. On my V drive engine I have NO belts. The only two belts I have on the entire bus is one for the generator engine and one for the remote mounted generator radiator. Good Luck, TomC
I replaced the diode sets in mine many years ago and thats the only maintinence its seen in many years, if it ain't broke don't fix it.>>>Dan
Is your large alternator 24v and want to change to 12v at 150a?
If so....you are asking more problem in the long run.
Reasons are:
1) 24v system is stronger & quicker cranking
2) All of what TomC quoted) and the rests
3) Already wired to be design for 24v
All future vehicles will be in the 42v range.
Hope your choice is in your best interest.
FWIW
Sojourn for Christ, Jerry
Don't listen to these guys. Box it up, send it to me and enjoy your new 150 amp alternator. :)
Or, you could heed the advice of some very knowledgeable people....
Either way, it is your bus, do it your way....
Frank
PS: I will send shipping directions alter :)
Bill,
What is (or possibly by now was) your reason for wanting to make the change?
Laryn
:o Well, Didn't think I would get such a response!!! I understood that there can be problems with the drive on this unit. I have an oil leak that may be coming from this unit, and I just thought that I didn't need the extra mass as I have been trying to eliminate any extra stuff I really don't need on the coach. If these units can crash the gear drive train, I don't know if I really need that kind of a marig marall. And if repairs are so expensive on these monster alternators, why would I want to be hung up in the middle of Nevada with a dead one? Anyway, I trust Tom C. to any electrical issue and I am not about to get rid of this big unit if he and the rest of you knowldegable coach pilots disagree. I guess I just need to be reassured that these things can't bomb the gears?? Bill Thomas
I have a P8M4905A with the 50DN oil cooled alternator.
And it's been a very trouble free unit.
I would never do a change over to a belt driven alternator that' asking for more trouble and work for what it's worth.
You can buy a "O" ring kit to seal up the oil leaks on these 50 DN's.
I bet Luke at US Coach can help you out with advise and the necessary parts.
jlv
GM0406, the unit is not prone for many failures but when it does happen look out it will do the things you mention and when the gear train goes it is not a pretty sight.Cost the Bluewater Casino in Lake Havasu $23,000 for a engine for a nut coming loose( probably was never tight) on the alternator so do what you think is best for you to have peace of mind
Modern buses with the Series 60 no longer have a gear driven alternator. A lot of buses still use the 50DN, but it is now belt driven. The power steering pump, air compressor, and water pump are all gear driven on the Series 60.
I think you're putting a lot of effort into fixing a problem that only might happen. You're still going to have other stuff that is gear driven.
Hello GM0406,
If it would give you piece of mind, pull the alternator to fix the oil leaks, and install a fresh drive gear.
The failures of drive gears and the resultant gear train damage are often a result of re-using drive gears that should not have been returned to service by unknowing or unscrupulous individuals. There are measurements you can take to check for wear on them, if you can find the tolerances in print somewhere. Big Transit had books full of pictures and diagrams about wearing out parts and whether it should be re-used or re-placed. I wish I had paid more attention earlier in life....
Remember the excuses the shady wrench turner uses: Blame the failure on the equipment user, the designer or some previous wrench turner. And then the story becomes Gospel.
happy coaching!
buswarrior
Ok, So I am going to bring this coach to the DD doctors when I get the '04 back. I will have them listen to the engine and see if they feel that there is a need to deal with this alternator and gears. I hear noises back there that I don't like. One is a possible gear train noise, and the other is that 730 that wines like a siren until it warms up. Noises and oil leaks really bother me and that is why I went after problems on the '04 like I am doing. I think it will pay off as we found several problems and I am pretty confident that we have them all resolved now. FWIW, the '04 has a belt driven alternator and the modified drive gear with pulley. Seems to work fine and I just thought that this was a way to get rid of mass on the '06. It also frees up a lot of room in the engine compartment on the '04. I am not looking forward to a modification unless I can find all of the mounting hardware and gear-pulley setup from a take-out engine or from someone who has removed it. Maybe I am worrying unecessarily over the weight of this alternator. Does anyone know what it weighs? Bill Thomas
Me and my back remembers that the weight is about 100 - 125 lbs, Less than an 8D AGM battery. I replaced me alternator with Luke's reccomendation that if it goes on the road he knows exactly what I have VS a custom job that I may do.
Best of Luck on a Monday
Gary
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.
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.
I've always thought a 50DN weighed around 85 lbs, but I'll stand to be corrected.
happy coaching!
buswarrior
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
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
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
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
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
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