The mounting gasket on my generator was replaced last year, and on the past couple of trips I'm again noticing a leak. This time it's a tiny amount coming from the mounting nut in the 3 o'clock position. Not a lot, but enough to be noticeable after only a few hundred miles.
Question #1 - Is this worrisome or just an annoyance?
Question #2 - Is there some type of copper crush washer involved here that could make for a simple repair?
Hate to think about pulling the 50DN again, but if it's necessary then it's necessary.
Have you simply tryed to tighten those bolts..>>>Dan
Quote from: Utahclaimjumper on September 12, 2020, 01:43:07 PM
Have you simply tryed to tighten those bolts..>>>Dan
Was my first thought. Couldn't even budge them with a 14" breaker bar. I imagine the shop torqued them properly.
Try a soft copper washer. Little lost for the effort.
If the nut has a spiral washer under it,, it's probably your problem..>>>Dan
In the end there was some seeping from a few of the studs. They were removed, cleaned, and resealed with some thread sealant and the addition of a copper washer. Everything looks dry and tight for now.
Apparently my starter gasket had also given way creating quite a mess on the rear of the engine, so it was dealt with. For now I have a dry engine. For now.
Seems that time and non-use don't help gaskets last any longer. Nearly four years later and I'm still discovering gaskets & seals which went bad from lack of use.
All 2 cycle Detroit Diesel engines in our coaches will develop leaks as the miles accumulate and natural blow by increases. Same as air leaks. You just need to keep after them. Boat owners use Walker Air Seps to keep their engine rooms clean. They will work on coaches, but at 400 some bucks for one, most wont spring for one.
Same technology GM uses on their car and truck diesels since 1980 to control blow by. Just a lot larger for ours.
Most of the time a leak at around 3 clock on the 50D is from the 1/8 inch supply line has a hole or the fitting is cracked ,and the leak around the starter is the air box drain
Quote from: luvrbus on September 26, 2020, 03:32:40 PM
Most of the time a leak at around 3 clock on the 50D is from the 1/8 inch supply line has a hole or the fitting is cracked ,and the leak around the starter is the air box drain
The oil line on my 50DN comes to the tail end of the alternator. The leak(s) were around the mounting gasket - is there another oil line I'm missing?
Quote from: richard5933 on September 26, 2020, 06:17:55 PM
The oil line on my 50DN comes to the tail end of the alternator. The leak(s) were around the mounting gasket - is there another oil line I'm missing?
It has to oil the front bearing too,this not a great photo but you can see the line going to the front bearing
There was an update to add oiling to both ends. Last I saw, the old ones can be upgraded to new oiling. Go to their bulletins to see the info. They used to sell the upgrade kit.
Quote from: chessie4905 on September 26, 2020, 07:30:16 PM
There was an update to add oiling to both ends. Last I saw, the old ones can be upgraded to new oiling. Go to their bulletins to see the info. They used to sell the upgrade kit.
I found the bulletin you're talking about, and now I can confirm that I don't have the second oil line to my alternator. From the looks of the installation instructions, it's way beyond my abilities right now. Assuming I can find the kit, the alternator must be pulled and disassembled to install it.
My engine only has 55,000 miles on it, so my hope will lie in the alternator lasting for a while longer.
That was a weak point on the 50D surprises me it wasn't done Delco paid for the upgrade for 2 years, those require a lot of oil flow 2gpm at highway speed and .5 gpm at idle bus people got into trouble restricting the flow more than specs call for trying to increase the oil pressure
Bus was bought new in 1974 and used as a motor home for a few years, up to about the early 80s from what I can tell. It had only sporadic use after that. I'd bet that the bus was just forgotten about when the upgrade kits were being paid for by Delco.
Unless this is something which is more likely than not to cause a problem in the near future, it's going to have to wait for now. I've got upcoming surgery (hernia repair) which is going to make it impossible for me to do the work, and my paying the medical bills will make it unlikely we'll want to spend the money to have it done at the shop right now.
Do you have any stats on when problems with these 50DN alternators would typically appear? As in, after how many miles? Just trying to get an idea of what kind of time bomb we have or don't have.
I doubt Delco Remy posts stats. They just list service bulletins. There is a coach website that has for info though. I believe they went to a wider bearing also. Ill see if I can find that site/ info.
All depended on the owner some pulled the alternator at 50,000 miles for new bearings some would stretch it to 100,000 you had to replace the bearing with a 2 roll bearing, seals and the alternator drive on the engine
Quote from: luvrbus on September 27, 2020, 11:08:38 AM
All depended on the owner some pulled the alternator at 50,000 miles for new bearings some would stretch it to 100,000 you had to replace the bearing with a 2 roll bearing, seals and the alternator drive on the engine
I bought the bus with just over 41,000 miles on the odometer, and I doubt the original owner changed the bearings with low mileage like that.
Seems odd that they put an alternator on the bus that required bearing service so soon. Isn't this the same alternator that was on GM buses for decades before this one? Or did they change to a different type with problematic bearings.
I hate having an alternator that could be a ticking time bomb, but I don't have many options right now. Just how many of these things self-destruct so soon?
Are there shops that still work on the alternators or is getting the upgrades done not a realistic option? Maybe better to just R & R the thing once I have the budget? Seems like paying for it to be removed & replaced and then paying for a shop to replace the bearings and do an upgrade might be only slightly less expensive than just replacing it outright.
>My engine only has 55,000 miles on it, so my hope will lie in the alternator lasting for a while longer.
This is a good resolution because most parts give signals of pending problems. The 50DN is pretty big and hard to imagine it blows up and stop working, most likely make noise or lose o less output.
Quote from: windtrader on September 27, 2020, 01:20:08 PM
>My engine only has 55,000 miles on it, so my hope will lie in the alternator lasting for a while longer.
This is a good resolution because most parts give signals of pending problems. The 50DN is pretty big and hard to imagine it blows up and stop working, most likely make noise or lose o less output.
Never heard a 50D make a noise before it blows,they caused problems Detroit even made special camshafts to drive the 50D because the 50D would break the normal camshaft.belt drive 50D's wouldn't destroy a engine like the gear drive 50D's would,only GM used the gear driven alternator up to the late 70s Eagle never used 1 till the late 80's
What happens when a 50DN gives out? What's the collateral damage?
If no warning signs, did all the buses in revenue service get alternator service done every year? Even at 100,000 miles between bearing service, it would seem excessive for a coach in revenue service.
Richard,
Do a bit of reading of the maintenance manual and it clearly suggests alternators should last for quite awhile. The 8v71 manual calls for looking it over a 100k interval, so you should be fine.
Quote from: windtrader on September 27, 2020, 05:14:37 PM
Richard,
Do a bit of reading of the maintenance manual and it clearly suggests alternators should last for quite awhile. The 8v71 manual calls for looking it over a 100k interval, so you should be fine.
That's good to hear. I have been through the GM manual for my coach a few times and can't find anything about maintenance intervals. Are you seeing this in the Detroit Diesel Manual? If so, where abouts?
Do some searching for Delco Remy 50dn oiling and bearing upgrade. There is a pdf showing parts in kit and instructions.
Elreg distributors show the kit. Probably a different kit number for gear drive units.
The 8v71 manual is section 7 for electrical DD tells to inspect the drive that is as far as it goes, collateral damage when one fails is a new engine you can use the block ,valves cover and oil pan if you are lucky, keep a eye on yours if the oil leak get worse then change it out gear train damage on the old 8v71 or 92 series is not a pretty sight
Does anybody have a new gear for the end of the 50dn? I've found nos, but wrong tooth count. I have a new cup gear for it.
This thread makes me wonder about the status of my belt driven 50DN on my Series 60 with 666,000 miles. It has the oil lines on both ends, but is there any way to check bearing wear without taking it all off? The Eagle manual only indicates that "if generator is noisy or vibrates excessively, it should be removed for inspection and repair", and that "whenever rotor and drive end frame are disassembled for any reason, the single row ball bearing must be replaced with a new one due to the possibility of it being damaged during disassembly". Maybe it should be removed and gone over every so many XXX miles, or is it a matter of it's not making noise, so don't fix it? ???
richard -Better listen to Clifford, what he says sounds scary, geez. And he is spot on about the reference. I read it in a couple places but the main one is here:
So I'm still left with one main question as I try and figure out my odds here...
Engine has 55,000 original miles only and has been relatively well cared for. Is the alternator likely to blow tomorrow and take out the engine or am I more likely to have a bit of breathing room here?
You guys are starting to scare me about this, especially since I don't have ability or resources to upgrade it now (and likely not in the spring either).
Just doesn't seem logical that every alternator takes out an engine if left alone.
OMG, Richard. Take a chill pill and go back to bed. Hum.. for that matter I think I'm going to bed. Chances of dying of anything else will occur before that alternator explodes.
Damn Clifford, quit freaking folks out, especially as a veteran like Richard. Every other person considering a bus conversion is running away and Gary does not like that!
tick,tick,tick. There are thousands out there that have the original setup haven't failed. Cliff only sees the thousands that did.
Quote from: chessie4905 on September 28, 2020, 04:21:57 AM
tick,tick,tick. There are thousands out there that have the original setup haven't failed. Cliff only sees the thousands that did.
I have seen the 50D out last 2 engines,takes awhile to set one up the right way DD goes into great detail on setting the sun gear up since the 50D spins 2.95 times faster than the engine when you use a dial indicator to install a gear and alternator that is close tolerances ,The 50D has always been a PM item .LVMCI was the last one I know of that had a gear train failure a couple of years ago
Unfortunately, many just "slap it on". Dont have a clue about the precise centering of the adapter ring. I guess many are just lucky.
Quote from: chessie4905 on September 28, 2020, 08:40:57 AM
Unfortunately, many just "slap it on". Dont have a clue about the precise centering of the adapter ring. I guess many are just lucky.
Adapter ring? Help out someone not well versed on the 50DN yet - is this the piece that fits between the actual generator and the engine block? As in the part with the mounting flange?
Yes the manual describes the procedure for centering the ring.
Do the reman units purchased from places like Luke at US Coach come with the adapter ring already in place or do they have to be reused from the old one?
They shouldn't. The ring stays on the engine.
Quote from: chessie4905 on September 28, 2020, 02:54:00 PM
They shouldn't. The ring stays on the engine.
I've read through the manual page on this and see what you're talking about regarding using the dial gauge.
Question...Is the drive gear that mounts to the engine changed every time the alternator is changed? Manual indicates to change it if signs of wear or damage are present, so if the alternator is changed as a routine maintenance item would it automatically need a new drive gear?
Personally, I think with your mileage, it should be fine. Just inspect the teeth for tooth depression wear. I'm going to change both gears on mine because previous owner had it removed to gain some horsepower, I guess. I purchased a take off generator from Nimco Bus several years ago and it happens to have the updated bearings and line. Didn't know anything about the update till a couple of years ago.
Right now I'm leaning towards waiting until the end of next season to have the alternator swapped out as a precaution. That will be about 65,000 miles total on it. Luke has them in stock regularly, and mine doesn't look like it's going to crap out on my in the immediate future.
I spoke with a tech at Elreg today about my alternator, and he didn't think that one with only 55,000 miles would be at death's door as long as basic maintenance like oil changes have been done over the years. As far as I can tell from internals I've seen it has been.
It sounds like I might be safe going a bit longer even, but since I've had other things fail from issues caused by lack of use I'm thinking of hedging my bets about this time next year. Gives me time to get the budget together for it.
Quote from: richard5933 on September 28, 2020, 03:29:28 PM
I've read through the manual page on this and see what you're talking about regarding using the dial gauge.
Question...Is the drive gear that mounts to the engine changed every time the alternator is changed? Manual indicates to change it if signs of wear or damage are present, so if the alternator is changed as a routine maintenance item would it automatically need a new drive gear?
The dial indicator and fixture is for checking the run out on the Sun gear hub so it spins true,the adapter spacer I call has a adjustment screw in the bottom to to align the alternator gear to the drive hub,and the only way you check that is gear marking like Prussian Blue if you do it right
Once set, you shouldn't need to change that setting unless cup gear or adapter is removed or changed, although you should verify it is still correct.