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Alternator with 420 hours fails and destroys engine

Justin Eagle
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Justin Eagle Newbie

Justin Eagle

Posted
Posted

My first post here.

I'm a partner in a 95 Mooney Ovation (M20R). On a 2.5 hour flight back to home airport, day VVMC. Hear a whir and then silence in the headset, and then alt/volt light starts flashing on the annuciator panel. Cycle the alternator switch and circuit breakers several times and get nothing. Shed excess electrical load, just running #2 radio and transponder, led beacon and nav light. I have about 80 miles and 11,000 feet to lose. Decide to continue to home. Both batteries are new, figure I can switch batteries if the gear won't come down. Land with no issues.

Buy replacement alternator, pull the old alternator out. The shaft of the alternator had snapped off and dropped the elastomeric washer, gear and shaft. IT was just sitting there grinding against the crankshaft gear. Only reason I didn't have catastrophic failure is because the gear was to big to properly wedge against the crankshaft gear.  Lots of metal shavings. Oil pump is destroyed. Camshaft is ruined. I'm hoping the crankshaft is still ok, but will let the shop decide. Will have to replace the gears though. 

Prior to event, oil analysis and oil filter visual inspection showed very small pieces of orange substance. Blackstone labs said it was probably intake manifold couplings getting older. The engine was making slightly more metal, but nothing of immediate concern.

Alternator is a Hartzell ALV-9610. The castle nut on the end of the shaft broke in half. We found it in the oil pan. 420 hours since installed. Didn't even make it to the 500 hour inspection. I don't know what the lesson is, but orange stuff in the oil filter could be the elastomeric washer on your alternator giving up.

 

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carusoam Grand Master

carusoam

Posted
Posted

welcome aboard Justin!

Yikes!
 

Great pirep for elastomeric stuff in the oil…

that is a big no go…

not normal to get it from the intake either…

PP thoughts only… not a mechanic.

Best regards,

-a-

MIm20c Grand Master

MIm20c

Posted
Posted

I don’t care if the ovation has two batteries and a backup alternator.  If the main one fails I’m landing ASAP. Same failure killed an A36 pilot a few years back, the engine sometimes stops if the chunks get in the wrong spot. Looking back I would absolutely get a reman vs overhauling the engine. 

Shadrach Grand Master

Shadrach

Posted
Posted
1 hour ago, 1980Mooney said:

He said above “Alternator is a Hartzell ALV-9610.”……

My guess is Byron is using “built” as a euphemism for overhaul. Hartzell built my prop but someone else has been responsible for all of the overhauls. 

 

MarkD34M Enthusiast

MarkD34M

Posted
Posted

I had a very similar thing happen on a 100 hour overhauled engine. On two oil changes we found small orange material and when I called the shop they told me to ground the plane and pull the alternator. As it turns out the overhauled coupler was protruding out too far and causing wear on the crank gear. The engine was pulled and IRAN'd at a heavy expense to the overhaul shop. The shop is a well known overhauler and as a result they do two things going forward. 1) they stopped using that particular shop for the overhauled coupler 2) they build a jig now check the mating of the alternator gear to the crank gear before they assemble the 550's with the direct drive.  

During this process I researched this extensively (lot's of good info on Beechtalk).  In some cases, they use a thinner gasket and in others, they have found that the shipping washer was installed when it should have been removed before install. The net is, do the 500 hour inspection and make sure to use a good coupler when replacement is needed. 

Very sorry about your engine and glad you didn't have any catastrophic issues. Best of luck.

Mark

MikeOH Grand Master

MikeOH

Posted
Posted

Okay, not an A&P, but I've never heard of a 'shipping washer'...is that really a thing, or is it cover term for the washer is correct for all applications except THIS particular engine.  Reading the SB sure makes it seem like the latter!

I mean, why do you need a washer to ship the alternator??  What is it 'protecting' during shipping.  Just leave it out if it needs to be selected for different applications.

What am I missing, here?

LANCECASPER Grand Master

LANCECASPER

Posted
Posted
1 hour ago, MikeOH said:

Okay, not an A&P, but I've never heard of a 'shipping washer'...is that really a thing, or is it cover term for the washer is correct for all applications except THIS particular engine.  Reading the SB sure makes it seem like the latter!

I mean, why do you need a washer to ship the alternator??  What is it 'protecting' during shipping.  Just leave it out if it needs to be selected for different applications.

What am I missing, here?

What Hartzell says: 

As the alternator manufacturer, we’ve addressed this by recently changing to a cardboard spacer, however there are still units out in the field that were shipped with a metal spacer and separate shipping washer. These pieces are in place purely to protect the alternator’s drive assembly from damage during transport. They are NOT part of the installation. The mechanic must remove these pieces and then securely attach the Continental alternator coupling to the alternator’s drive shaft prior to installing the assembly on the engine. It’s a simple process, but if it’s not done correctly, the alternator gears will not mesh properly with the drive gear inside the engine.

MikeOH Grand Master

MikeOH

Posted
Posted
30 minutes ago, LANCECASPER said:

What Hartzell says: 

As the alternator manufacturer, we’ve addressed this by recently changing to a cardboard spacer, however there are still units out in the field that were shipped with a metal spacer and separate shipping washer. These pieces are in place purely to protect the alternator’s drive assembly from damage during transport. They are NOT part of the installation. The mechanic must remove these pieces and then securely attach the Continental alternator coupling to the alternator’s drive shaft prior to installing the assembly on the engine. It’s a simple process, but if it’s not done correctly, the alternator gears will not mesh properly with the drive gear inside the engine.

@LANCECASPER

Thanks!

So, it's really a thing.  The switch to a cardboard shipping spacer sounds like a smart move!  Using a metal spacer and washer that are supposed to be removed is just asking for trouble, IMHO.

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GeeBee Grand Master

GeeBee

Posted
Posted

Uhhhh, belts are no picnic either. If you're lucky they just break and fall to the bottom. Seen some pretty hefty cowling damage from belts that have let go. I've also seen cases where they wound so tightly around the crank pulley and alternator bracket they caused RPM loss. It is an item to carefully pre-flight.

0TreeLemur Grand Master

0TreeLemur

Posted
Posted
On 5/21/2022 at 3:10 PM, GeeBee said:

Uhhhh, belts are no picnic either. If you're lucky they just break and fall to the bottom. Seen some pretty hefty cowling damage from belts that have let go. I've also seen cases where they wound so tightly around the crank pulley and alternator bracket they caused RPM loss. It is an item to carefully pre-flight.

Sure, belts are not 100% trouble free, but extremely reliable and unlikely to trash the entire engine.   I suspect most belt preflight inspections consist of pulling on it to check the tension.  That's what I do.  Replaced mine last year when we had the prop off.   Old one was 16 y.o. to the best I could determine from the log books, and still functioning.

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Yetti Grand Master

Yetti

Posted
Posted

Seems like a -1 for the oil analysis.   I thought that was the whole point was to identify the specs of stuff to prevent failures.

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