Altenator siezed up

Dlsnow · May 28, 2013, 02:00:38 PM

Smelled and saw the smoke coming from the engine bay yesterday. Found the alternator not spinning and the belts were smoking.

Took off the belts as they are destroyed now.

What should I do about this alternator?

luvrbus · May 28, 2013, 02:16:57 PM

Is it a 50D Delco if so check your amp load probably be a lot cheaper for you to fab and fit a smaller alternator the 50D will run about 900 bucks to have rebuilt unless you find a deal on a good used one or yours has a simple bearing failure only

bevans6 · May 28, 2013, 02:59:04 PM

Well, step one is crystal clear - go outside, turn in a circle three times clockwise and thank the bus sprites that you have a belt drive alternator.

Gear drive would start to look expensive if it took out the cam or the drive gears shrapneled... I would just take the alternator off and assess from there. If it's a 50DN you indeed have options - rebuild, replace with same, replace with different. Until you know what's really broken, you don't know what to fix. I personally think the 50DN belt drive option alternator is seriously good alternator, it's so well built and robust that I trust mine absolutely. I am seriously planning a generator that uses a belt drive 50DN as a generator for the bus. I already will have the inverter, so I would use a DC generator.

Brian

Dlsnow · May 28, 2013, 03:20:01 PM

That is good advice Brian...thank you.

As far as amp load is concerned. I don't have the gear to measure that. All of the electric motors (aside from the starter) have been dsabled (heat ad ac, condenser...). So other than the exterior lights and any engine protection Equipmt. I imagine the amp load is low. Either way I am grateful I can start and run it to the garage.

Am i right? As long as i charge up the batteries beforehand I should be able to make the 60 mile drive.

bevans6 · May 28, 2013, 04:07:16 PM

FWIW I lost my alternator drive pulley 600 km into a 2200 km drive. I took the belts off, didn't run the head lights and didn't worry about it. The bus doesn't use much electricity if the AC is off, the lights are off, etc. Finished the drive and fixed the pulley. If you don't have the factory AC motors and don't use the factory fan for the heat, you can get away with around a 75 - 125 amp alternator easy (24 volts for the bus system), in fact that is probably overkill. If you use the stock heater fans, you need a little more, the heater motor is around 75 amps from memory, and little alternators don't like to run at their "label" current for long, they tend to overheat. Did you still have the big Delco 50DN?

Brian

TomC · May 28, 2013, 06:24:43 PM

I know we sell 12vdc alternators for about a buck an amp. What a 24vdc alternator would run, I don't know-but should be along those lines also. I'd advise looking for a 160amp alternator to replace the big 50DN with. Good Luck, TomC

Melbo · May 28, 2013, 07:55:11 PM

When I had my 8V in the bus I turned on my AC that drew amps from the inverter and from the 50D and just like you I had smoke and belts gone. I checked if the alternator would spin freely (which it did) and replaced the belts. Everything worked til I replaced the 71 with the L10. So for my dos centavos check the alt and see if it spins freely and replace the belts before jumping into the unknown.

HTH

Melbo

Dlsnow · May 28, 2013, 08:05:31 PM

It doesn't spin freely. I was watching it with the engine running. It looked like there was about 1 inch of movement backwards after I shutdown the engine. I'll check it by hand tomorrow to see what it feels like.

Made my destination for the week though.

I am guessing it is a 50D based on it is freaking huge. Probably an 8 inch diameter and 13 inch deep. It has(had) 4 belts about 1/2inch wide each all going to the same wheel on the engine.

bevans6 · May 29, 2013, 03:58:31 AM

It may be air cooled or oil cooled on a MC-7, as far as I can determine. Look for three oil hoses if it is oil cooled, feed to the back, vent on the top and drain from the bottom. If it lost it's oil feed that would probably hurt the bearings in short order.

Brian

Ed Hackenbruch · May 29, 2013, 04:30:11 AM

Those are very heavy for their size, i put mine on a scale and i think it was 100 or 110 lbs. Be very careful when taking it out...you don't want to get your hand or fingers caught between it and anything else. Mine sits above and inside of the shielding for the muffler so i used some lumber and plywood to fill in the space so that it could not drop down into that area between the muffler and the engine. Made it very easy to slide out and not too hard to get back in and in position to put the pivot pin back in.

John316 · May 29, 2013, 05:12:40 AM

Where are you located? There are often alternator/starter shops that will rebuild those. I know we have a couple of joints in Kansas City that rebuild, and they are usually very decent prices.

Hope you get it fixed easily.

John

bevans6 · May 29, 2013, 06:16:22 AM

Ed is yours air or oil cooled on your MC-5A? My MCI parts book shows both, my MCI manual only discusses the oil cooled, circa 1978. It is rated at 225 amps per the book.

Brian

Dlsnow · May 29, 2013, 06:25:28 AM

I am in northern WI. I will see what alternator/ starter shops are up here.

I am guessing it is oil cooled. That would explain all the hoses. If the rain subsides I will get out there today.

Ed Hackenbruch · May 29, 2013, 06:37:27 AM

Brian, mine is air cooled, belt driven.

bevans6 · May 29, 2013, 06:40:01 AM

If you decide not to use it you can run another alternator from the belt drive pulley on the engine, but you don't need all four pulleys, one or two would usually do. But - the four sheave pulley arrangement on the alternator is N/A, and rare as hens teeth, so please save it! It's a three part assembly and you need all three parts to make it work - the pulley itself, the inner flange that it bolts on to with 6 bolts at the base, and the tapered washer under the big bolt that forces the inner part of the flange to clamp onto the splined shaft. None of it is available any more.

Brian