Took the alternator off and while doing so found a lot of suspect connections, cleaned them up and still had the same indications, high voltage with low load and 11 volts with the head lights on and A/C running.

Took it to the friendly parts guy down the street and they confirmed that it was dead.

I am investigating putting in a much larger alternator, the stock one that came in the chassis is only 105 amps, (confirmed by the engine serial number)with all of my electronic junk going, I definitely need more. I can get a 160 amp unit fairly easily but that still isn't big enough for my needs. I have loacted a shop that has a 200 amp unit that will fit into the same mounting rackets and use the same belt length. Has an external regulator but that is no big deal to wire it in. Supposed to pick it up Monday.

New alternator is in! I didn't get the 200 amp with external regulator as it was way over priced, got a 200 amp marine unit that fits in the same brackets as the old unit but had to fab a rear bracket, didn't like the orignal bracket because it was attached to one of the exhaust manifold bolts. Can't think of a worse place to attach a bracket that goes to an alternator--Heat---.

Only other problem is the front fan on the alternator has a baffle that is so close to the belt tensioner that is does touch as the tensioner dances. Took off the tensioner and milled down the back side a bit so got lots of clearance now.

Ran an experiment by letting the batteries run down a bit (11.5 volts) and then starting the Cummins, at idle, with headlights, A/C, computer, all coach lights, furnace fan, voltage was 14.1. I am happy with the results!

Only thing left to do is to run a 5 inch tube from the side rear vent to the back of the alternator, I want it to have the coolest environment possible.

UPDATE!

The new alternator died only after a few miles, It worked great after installation at idle but as soon as I took it on the road the voltage started to swing back and forth from 12.4 to over 14. Within a minute or two, the voltage stayed at 12.4 and was declining, started the generator to maintain the batteries 'till I got back home.

Took the alternator off and down to a friend's shop and tested it, sure enough, was dead. looks like the regulator died for some reason. I have gone back and double checked the system and put a smaller alternator in (105 amp unit laying around my shop) and it worked fine! Returned the defective unit to the vender.

In my quest for higher output, I have gotten all the Cummins part numbers for brackets to use the J180 alternator mounting and will go to the Cummins West today to see if these parts will fit the particular model engine I have. With the J180 mount, the selection of alternators is much better.

Holy cow, that is absurd.

Whether it is new or rebuilt, whatta crime to make you go through all that for a defective unit.

Good luck with your continuing repair...

quote:

Originally posted by Windsor Dalrymple:
Holy cow, that is absurd.

Whether it is new or rebuilt, whatta crime to make you go through all that for a defective unit.

Good luck with your continuing repair...

I have also had bad luck with rebuilt alternators. Even so-called lifetime ones.

I would advise P30 owners to carry a spare regulator. Buy ONLY Delco.

I think, in the past 20 years, I've had to return at least 2 rebuilt alternators, which is about 1/3 of the number I've bought for my toys.