'98 Cutter Alternators

[Pam]

We have gone through two alternators. Looking for parts to rebuild...something about finding the diode pack. Delco makes the alternator. Has anyone else tried to rebuild?

(I'm helping my husband....he hasn't been able to get the model numbers, part numbers off anywhere.)

He upgraded to very heavy duty batteries for the coach and it seems the alternator doesn't like that. We need something heavier duty. I'm thinking that instead of rebuilding, we should just buy the bigger, more heavy duty...I think it's a $350 investment.

Any ideas about this?

[Jim & Susan]

Sounds like you are overloading the OEM alternator. Time for something more heavy duty. It's always possible that this particular alternaror is simply poorly designed. I wonder if you took it to a a GM automobile dealer, they could help you I.D. what you have and suggest something that can carry a larger load. (but buy the new one from O'reilly's, much cheaper)

ANybody know a quick/accurate way to determine the actual load the RV is pulling?

JIm

[swebster]

Many of us have upgraded motorhome alternators to 130 amp versions. Search for "motorhome alternator" on these forums and you'll find some info on models and links to sites.

The Alternator on there now should have a placard on it with the model number. Sometimes they are on the bottom (looking down from the doghouse opening). A small mirror and flashlight (not to mention the ability to read backwards) can help you see the placard.

[Pam]

Originally Posted by swebster

Many of us have upgraded motorhome alternators to 130 amp versions. Search for "motorhome alternator" on these forums and you'll find some info on models and links to sites.

The Alternator on there now should have a placard on it with the model number. Sometimes they are on the bottom (looking down from the doghouse opening). A small mirror and flashlight (not to mention the ability to read backwards) can help you see the placard.

Thanks. He hasn't been able to see any identifying marks on the alternator that he already removed. Now this next one is shot too. This has been ongoing. It's freezing here, but we are going to crank up the MH this weekend just to run it. Maybe he can try to see again.

My thought is that since it is ongoing as a problem, lets just get the heavier duty alternator. We will have spent the cost of the upgrade if we mess with this anymore.

I will try the alternator section for more information.

[Pam]

Originally Posted by swebster

Many of us have upgraded motorhome alternators to 130 amp versions. Search for "motorhome alternator" on these forums and you'll find some info on models and links to sites.

The Alternator on there now should have a placard on it with the model number. Sometimes they are on the bottom (looking down from the doghouse opening). A small mirror and flashlight (not to mention the ability to read backwards) can help you see the placard.

Checked with my husband, and it's the 130amp that keeps failing. I will check the other site you mentioned to see if anyone else has upgraded. Thanks for the help though.

[Pam]

Update; Husband found the numbers needed so that he could track down the replacement diode packs. Ordered and they got here Friday. He got the first failed alternator and is rebuilding as we speak. We are hoping for success until we get around to the larger alternator.

[Beginner]

Are you putting the 130 amp diode packs back in the alternators that you are rebuilding or going to larger capacity (more amperage) diode packs?

[Pam]

Hi,

One alternator is already rebuilt at the 130amps and will be put back in the motorhome. The one that is going to be removed will be rebuilt also, as back up and we'll just keep it with us. If I were a betting woman....I would bet that he will want the larger capacity alternator in the near future, but this should get us by. (It's pretty cold here right now and we leave for Florida in about 4 weeks, so want to get this much done for now).

[Beginner]

I'll probally stir up a hornets with this but here goes:
1. On an automobile an altenator is strictly for maintaining a battery. Even though the altinator is rated at putting out 130 amps, it can only do so for short periods. Usually the internal voltage regulator dies. Occasionally the diode trio and the rectifiers will die.
Heat is what kills these semiconductor devices. You can't get enough cool air to the fresh air intake of the alternator to cool the electronics (rectifier(diodes), diode trio(three diodes) and the internal voltage regulator(transistors, diodes,fets, etc) when the alternator is under full load the 200 degree air in the engine compartment does not help much.
What can you do?
1. Charage your batteries with shore power (power company power) as much as possible.
2. Pipe in an outside fresh air source to the back side of the alternator.
3. Go to a higher output altinator(which will have bigger heat dissapating capability.
4. Go to an industrial grade alternator(very expensive).
5. Go back to a generator(requires maintenance but is almost unaffected by heat due to no electronics in the case of the generator itself)
6. Carry a spare alternator or two.
Any other suggestions?
Beginner

[Pam]

The first alternator got rebuilt, still didn't work right. Husband pulled the second and rebuilt that and it works perfectly. He's back to the drawing board on the first one and will work a bit more and get it going or save it for parts while on the road. Either way, we get to head south for Florida in a few weeks. Hooray!

[scottanlily]

Beginner ,

Excellent points made ,correct analasys there .The heat and constant amperage load does kill the alternator .The GM units (Cage style) are crappyand do fail often .The older big cadillac alternators worked great lasted for years.I would look into an aftermarket high performance unit that will last.also a blower to blow cooler air over the unit will drastically help to keep the alternator cool .Toyota landcruisers had a blower unit (12volt) to blow cool air over the exhaust manifold and can be found at wrecking yards ,maybe new from toyota .you can mount it in a cool spot at the front of the coach under the front hood and then run flexible ducting (automotive store has it )over to the alternator to blow air over it .The cooling engine fan is not always engaged so it won't provide enough cooling most of the time until the fan clutch engages .the blower idea will help ,but a better alternator or heavier duty is in order.Most rebuilts are ok ,but a factory new unit will be much better .Bosch Rebuilts are the best in the industry ,so go bosch if you can on a rebuilt unit .

Scott of scottanlily

[Beginner]

Scott
My 1984 Camaro was purchased in El Passo Texas. It has a carburator. It also has a fan that blows cooler outside air at the base of the carburator via some neatly shaped duct work. It carries a GM part number and the electric blower is controlled by a second switch in the thermostat housing (goose neck).
The circulation of air through the GM alternators that I have seen is back to front to cool the electronics first, so, be sure to point the cool air tube at the rear in order to assist the fan that is part of the drive pulley.
Beginner