M-18 alt bracket vs M-25 alt bracket

[Skipper]

I'm looking at starting the alt bracket upgrade task for my M-18.

However, upon further investigation, I've inadvertently discovered that all of the notorious failures have been on the M25.

I know all the "better safe than sorry" ideology, of which I'm an advocate, but I'm not sure that I should delve into an upgrade that may be wholly unneeded.

The apparatus is sturdy. The belt is properly fit and aligned. There's no sign of fatigue. And the engine is 30 years old with 1,200 hours.

3 things:

1. Is there even 1 documented failure on an M-18 with the stock alternator?

2. Which part of the bracket fails? The solid portion of the lower bracket is also attached to the front of the heat exchanger as well as the timing case, so I can't physically figure out how the alternator can drop down to contact the oil filter, unless it's this heat-exchanger attachment that breaks.

3. The manual says 55 amp alt, but others says it's a 35 amp. Can someone clarify?

Thank you

 

[Donnybrook]

Failures have occurred on the M-18. Both the M-18 and M-25 use the same gear case cover. Several have done the mod. Take a look here for our experience.
http://forums.catalina.sailboatowners.com/showthread.php?p=1136688&highlight=
Or do a search on Donnybrook. Usually, the ear on the gear case breaks off, allowing the alternator to smash the oil filter. I think that what you are calling the heat exchanger, is actually the exhaust manifold. You can take your chances and not do the mod, but keep in mind that so many have broken that there are no longer any spare gear case covers to be found, although, you may find a used one somewhere.

 

[Stu Jackson]

I'm looking at starting the alt bracket upgrade task for my M-18.

However, upon further investigation, I've inadvertently discovered that all of the notorious failures have been on the M25.

I know all the "better safe than sorry" ideology, of which I'm an advocate, but I'm not sure that I should delve into an upgrade that may be wholly unneeded.

The apparatus is sturdy. The belt is properly fit and aligned. There's no sign of fatigue. And the engine is 30 years old with 1,200 hours.

3 things:

1. Is there even 1 documented failure on an M-18 with the stock alternator?

2. Which part of the bracket fails? The solid portion of the lower bracket is also attached to the front of the heat exchanger as well as the timing case, so I can't physically figure out how the alternator can drop down to contact the oil filter, unless it's this heat-exchanger attachment that breaks.

3. The manual says 55 amp alt, but others says it's a 35 amp. Can someone clarify?

Thank you

Skipper, I suggest you read what Donnybrook wrote, and then read the links in his post and the links inside that post.

I'm tired of repeating the same stuff over and over again. :naughty:

They don't make your timing case anymore.

What's your entire engine worth to you?

The old bracket is a casting which can, and in my case in 1999, DID fail catastrophically. I had about 1,000 hours on my engine back then.

It worked great until it f-ing BROKE.

http://www.c34.org/wiki/index.php?title=M-25_Alternator_Mount_Conversion_Kit_"B/M_256891"

Your boat, your engine, your choice.

Good luck, you'll NEED it.

PS - If your car company called you about a recall, would you ignore it?:cussing:

 

[Skipper]

I think that what you are calling the heat exchanger, is actually the exhaust manifold.

Yes, oops. Brain snap. Exhaust manifold.

So is it this attachment that breaks? If the lower bracket is attached to both the timing case and the manifold, I don't get how the alt can swing down and hit the oil filter, even if the adjustment bracket fails. The lower bracket is solid, no hinge points. Maybe mine is different (?)

 

[Skipper]

Skipper, I suggest you read what Donnybrook wrote, and then read the links in his post and the links inside that post.

I'm tired of repeating the same stuff over and over again. :naughty:

They don't make your timing case anymore.

What's your entire engine worth to you?

The old bracket is a casting which can, and in my case in 1999, DID fail catastrophically. I had about 1,000 hours on my engine back then.

It worked great until it f-ing BROKE.

http://www.c34.org/wiki/index.php?title=M-25_Alternator_Mount_Conversion_Kit_"B/M_256891"

Your boat, your engine, your choice.

Good luck, you'll NEED it.

PS - If your car company called you about a recall, would you ignore it?:cussing:

I tried to avoid this type of reply with the up-front disclaimer "I know all the "better safe than sorry" ideology".

Again....I haven't seen anyone show an actual failure on an M-18. If they don't fail, what's there to be sorry about? I wasn't saying they don't exist nor that upgrade is not prudent, I'm merely asking for verification before I blindly go about upgrades, for...again...I have not seen an M-18 failure. It's a logical question. Just because the engines share a part does not automatically mean they will both fail in the same fashion, hence my curiosity of not seeing any....again....M-18 failures.

So was your failure on an M-18?

 

[Stu Jackson]

So was your failure on an M-18?

This just indicates that you haven't read the links provided.

I give up.

 

[Skipper]

This just indicates that you haven't read the links provided.

I give up.

OMG - It doesn't matter. My point was that the original question was logical. Donnybrook's link showed a failure, thereby answering the question, and fulfilling the (I think) intended use of the forum.

 

[Skipper]

Yes, oops. Brain snap. Exhaust manifold.

So is it this attachment that breaks? If the lower bracket is attached to both the timing case and the manifold, I don't get how the alt can swing down and hit the oil filter, even if the adjustment bracket fails. The lower bracket is solid, no hinge points. Maybe mine is different (?)

Unless the alternator swings around the bottom of the lower bracket then hits the filter? I still don't get the mechanics of the failure. Not that it's important, just curious. Your link shows a potential full failure, but not the type of failure described by (seems like) MainSail previously, where he said the bracket broke 1st, the alt punctured the filter, and then timing case gave in. I'm wondering what the sequence is.

 

[Stu Jackson]

Unless the alternator swings around the bottom of the lower bracket then hits the filter?

Yes, yes, yes. That's exactly what happened to me. I wrote that in 1999!!!

I want a new emoticon:

:read the blinkin' links:

Please, please, please.

Mine even have photographs!!! :dance::dance::dance:

...since you're curious...

 

[Skipper]

Yes, yes, yes. That's exactly what happened to me. I wrote that in 1999!!!

I want a new emoticon:

:read the blinkin' links:

Please, please, please.

Mine even have photographs!!! :dance::dance::dance:

...since you're curious...

I did. Donnybrook's shows an impending failure of the timing case on an M-18, good enough for me.
Your link described the failure of an M25, with an upgraded alt. Still, thanks for verifying the mechanics of the failure. It makes sense now, looking at the setup. I think mine would actually bang against the side of the engine compartment if the alt pivoted on the lower bracket as such. The alt is about 1\2 inch from the wall. I'll listen for that banging sound till my new bracket kit arrives

 

[weinie]

Skipper...

I concur with you. I was putting off the upgrade on my M18 because couldn't find any incidences on the internet where any failure had actually occurred....until I read Donnybrook's case. (Correction: it was Richard's post that got me started on this job)

I did the upgrade and it took probably over 12 hours of tough work to get it done. Had a high pressure system not moved in and squash all the wind, I would have also lost at least a week of sailing while I waited for additional parts.

If you have good access to the right side of the engine it might be easier for you. I know the larger Catalinas with the M25 engines tend to have a much more accessible engine. On my Catalina 27, I was practically working by feel.

The boat has lasted almost 30 years as is....probably would have lasted some more. Every Catalina 27 I see advertised has the original bracket in pictures of the engine. If I had to make the decision today, I'd probably leave it factory. I guess it's like f-ing without a condom... 99% chance you won't get AIDS, but it's that 1% that'll end it for you.

 

[Richard19068]

I'm looking at starting the alt bracket upgrade task for my M-18.

However, upon further investigation, I've inadvertently discovered that all of the notorious failures have been on the M25.

I know all the "better safe than sorry" ideology, of which I'm an advocate, but I'm not sure that I should delve into an upgrade that may be wholly unneeded.

The apparatus is sturdy. The belt is properly fit and aligned. There's no sign of fatigue. And the engine is 30 years old with 1,200 hours.

3 things:

1. Is there even 1 documented failure on an M-18 with the stock alternator?

2. Which part of the bracket fails? The solid portion of the lower bracket is also attached to the front of the heat exchanger as well as the timing case, so I can't physically figure out how the alternator can drop down to contact the oil filter, unless it's this heat-exchanger attachment that breaks.

3. The manual says 55 amp alt, but others says it's a 35 amp. Can someone clarify?

Thank you

Skipper:

I have an 1985 M-18 with unknown hours that had a failure. Fortunately I discovered it before it was too late. I had a very small oil leak and found it was coming from a hairline crack in the gear case cover just below the ear where the alternator adjustment / pivot arm or whatever you want to call it attaches to the gear case.

I just installed the new bracket a couple of months ago.

Very glad I found this because if I hadn't I'm sure that ear would have broken off of the gear case with a very bad result.

I was in the same camp as you with having read about the issue but not wanting to spend the time, effort and money making the upgrade. I got lucky and dodged a bullet here. I would highly recommend making the change.

There is a thread in the engines and propulsion forum back in July where a couple of us (Weinie included) talked about issues with the upgrade kit. You might want to take a look at that. http://forums.oday.sailboatowners.com/showthread.php?t=164535 Also, I made some comments in Maine Sail's photo article about the upgrade where my experience was a little different due to having an M-18 rather than the M-25 in the article.

My alternator says it is 55 amps. Pretty sure it its the original.

Good luck whatever you do!

Edit: Sorry the link in my post is a duplicate of one from a previous post. I was in a hurry to respond and hadn't read the link which was to my original post. What a circuitous world.

 

[Stu Jackson]

1. I did. Donnybrook's shows an impending failure of the timing case on an M-18, good enough for me.

2. Your link described the failure of an M25, with an upgraded alt.

1. Great, glad we helped.

2. Nope, old OEM 55A Motorola in 1999.

Good luck, happy aligning.

 

[stevec22206]

Upgrade

I'm looking at starting the alt bracket upgrade task for my M-18.

However, upon further investigation, I've inadvertently discovered that all of the notorious failures have been on the M25.

I know all the "better safe than sorry" ideology, of which I'm an advocate, but I'm not sure that I should delve into an upgrade that may be wholly unneeded.

The apparatus is sturdy. The belt is properly fit and aligned. There's no sign of fatigue. And the engine is 30 years old with 1,200 hours.

3 things:

1. Is there even 1 documented failure on an M-18 with the stock alternator?

2. Which part of the bracket fails? The solid portion of the lower bracket is also attached to the front of the heat exchanger as well as the timing case, so I can't physically figure out how the alternator can drop down to contact the oil filter, unless it's this heat-exchanger attachment that breaks.

3. The manual says 55 amp alt, but others says it's a 35 amp. Can someone clarify?

Thank you

I did mine at the beginning of the season. Really straight forward and took about 2 hours. The bolt issue has not been resolved. CD sent my kit with the undersize bolt. I purchased the larger bolt but haven't put it on. I'll need to run a drill bit through the alternator hole to accommodate the larger bolt. I've checked it throughout the season and all is well. We have an 87' and was fortunate that the original studs in the manifold were long enough to accept the bracket. I can see where it would take more time if one had to remove the old studs and/or manifold. Just do it. The piece of mind is worth it.

Steve

 

[Skipper]

Skipper...

I concur with you. I was putting off the upgrade on my M18 because couldn't find any incidences on the internet where any failure had actually occurred....until I read Donnybrook's case. (Correction: it was Richard's post that got me started on this job)

I did the upgrade and it took probably over 12 hours of tough work to get it done. Had a high pressure system not moved in and squash all the wind, I would have also lost at least a week of sailing while I waited for additional parts.

If you have good access to the right side of the engine it might be easier for you. I know the larger Catalinas with the M25 engines tend to have a much more accessible engine. On my Catalina 27, I was practically working by feel.

The boat has lasted almost 30 years as is....probably would have lasted some more. Every Catalina 27 I see advertised has the original bracket in pictures of the engine. If I had to make the decision today, I'd probably leave it factory. I guess it's like f-ing without a condom... 99% chance you won't get AIDS, but it's that 1% that'll end it for you.

Yeah, and here's another oddity: Since yesterday I've searched the internet high and low again, with every search string I could think of, and the only M-18 failure I can find is Richard's.

One hairline crack, in the whole of the 2,400 M-18's out there?

Still, I'm going to upgrade. It's only <$200. I like the piece of mind. I don't want to worry about finding the hairline crack in the middle of the ocean. It's the worrying that's irritating

 

[pogo2]

m18 bolt failure

I have the original 1987 alternator on my Newport 30, after sailing in a storm on Lake Erie and taking a pounding. I checked over the engine the next day to make sure everything was ok. What I found was not good, the bolt that holds the alternator bracket to the engine block was sheered of at the block. This is a metric bolt and was not easy to find, but I did. I now carry 3 extra bolts on the boat.