c34d.gif (1515 bytes)

Projects: M-25 Alternator Mount Conversion 


                                      M-25 Alternator Mount Conversion Kit  "B/M 256891" 

Click on any picture to enlarge it
Thanks Stu Jackson "Aquavite" for the pictures! Sorry that you were the one to experience this horrible problem!
altold-bracket.gif (92878 bytes) altnew-bracket.gif (65636 bytes) 
Old Bracket still in place New bracket Installed

altnew-bracket2.gif (77187 bytes)  altold-broken.gif (35500 bytes) 
Close-up of New Bracket Broken Parts

altnew-kit.gif (114156 bytes)

oil-bilge.gif (72971 bytes)

M-25 Alternator Mount Conversion Kit Bracket "Broke" and Out Came the Oil!
Don't let the Coast Guard see THIS!

Re: Catalina 34, M-25 Alternator Mount Conversion Kit
Ron,  Enjoy the technical column in mainsheet. We have a C34 hull number 287 (Confetti) that we sail on Lake Michigan out of White Lake.
In the recent copy of mainsheet, you mentioned upgrading the alternator bracket. I'm not sure mine was ever done, although it hasn't presented any problems yet. I ordered the past tech notes collection, and read the article on the bracket. Unfortunately, the copy quality of the pictures that show the old and new bracket are not good. I wondered if you had a better copy  that you could send, or a description that would help me determine if I have the old or new?

Re: Catalina 34, M-25 Alternator Mount Conversion Kit
Dave : Universal (now Westerbeke) came out with the modification to the M25 that moved the bracket from over the top of the alternator to underneath - the same as the M25XP. They have the mod. kits. (SEE ABOVE)
Ron APACHE #788 

Re: Catalina 34, M-25 Alternator Mount Conversion Kit
Bob, I am in the process of doing this repair right now. My gear cover was cracked by the alternator. On the original design the alternator bracket is bolted through an ear cast into the gear cover. This ear is not substantial enough and cracks the gear casing just under the ear and out of sight. The alternator upgrade bracket mounts to the exhaust manifold which removes the strain on the gear cover. I am buying the alternator upgrade bracket today for about $100.

I removed the sink and cabinet over the back of the engine to gain better access (C30) as I was originally going to pull the engine to do this job. However after looking at it last night I think I may just take a dremmel tool down to the boat tonight and clean up the area around the crack and put some aluminum epoxy or one of the products available for that type repair and see if I can save a lot of work and several hundred dollars. I see no real reason to remove the gear cover since I only have a small leak though a hairline crack and there is no oil pressure on the cover. Once the alternator is relocated to the bracket on the exhaust manifold and I put some aluminum goop on the hairline crack it should stop the leak. Works in theory. You may be able to do the same if your hole is not a big one and doesn't affect the gasket surface. Anyone see any flaws in my thinking?
John McCuiston

Subj: [C34] Alternator Bracket M25 Engines
Ron; Enjoy the technical column in mainsheet. We have a C34 hull number 287 (Confetti) that we sail on Lake Michigan out of White Lake.
In the recent copy of mainsheet, you mentioned upgrading the alternator bracket. I'm not sure mine was ever done, although it hasn't presented any problems yet. I ordered the past tech notes collection, and read the article on the bracket. Unfortunately, the copy quality of the pictures that show the old and new bracket are not good. I wondered if you had a better copy that you could send, or a description that would help me determine if I have the old or new?
Any information on suppliers of the necessary parts?
Thanks, Dave Rinard, Confetti #278

Subj: [C34] Alternator Bracket M25 Engines
Universal (now Westerbeke) came out with the modification to the M25 that moved the bracket from over the top of the alternator to underneath - the same as the M25XP. They have the mod. kits.
Ron, APACHE #788

Subj: [C34] Alternator Bracket M25 Engines
Dave; I have the pics of the bracket, old and new, Thanks to Stu Jackson. I will put them on the C34 Projects page ASAP. You will see the difference.
Good luck, Capt Al, "kindred Spirit

Subj: [C34] Alternator Bracket M25 Engines
If for some reason you haven't changed to the new alternator bracket on your older (1986, early 1987) M25 21 hp Universal diesel engines, DO SO IMMEDIATELY.
I learned the hard way yesterday. I'd bought the retrofit kit from Universal a year ago, and was going to do it "soon." I'd just motored over to a friend's dock for a visit, less than 5 minutes away from our slip. When my friend used the head, he came back and said, "Houston, we have a problem!" He'd noticed oil dripping from the underside of the alternator access door onto the head sole. When we took off the stairs to expose the engine, the old "over the top" alternator bracket had sheared, the alternator was lying back to port dangling from the old fan belt, and there was oil everywhere. As it disintegrated the bracket and alternator had clobbered the oil filter, which spouted oil onto the fan belt and blew it all over the engine compartment. It also nicked the fresh water cooling hose. The oil filter kept the alternator from slamming into the casing of the engine.
I got out the new bracket kit, and with generous help from George and Don, I removed the old parts, and fitted in the new "underneath" bracket in about three hours. George went out to get cleanup pads, newspaper to cover everything with to keep the cabin clean, and a gallon of new oil. Don helped with assembling everything in order from the kit and the diagram. When George got back he was Mr. Toolman for me. Most of the time was spent adjusting the hose clamps on the new fresh water line which goes under the new bracket, since there is only a very small amount of clearance between it and the top of the oil filter. I also had to use a rubber bicycle tube with a hose clamp as a patch over the dinged fresh water hose, which, of course, was within a half inch of the end of the hose on the new copper elbow. Also, we had to drop the alternator again to move the alternator ground wire further back to one of the other studs since the wire was in the way when it was replaced on its old stud.
Lessons Learned:
1. If you haven't, replace the older style bracket TODAY. It'll give NO NOTICE of failure: it will just GO! I was fortunate that I had all the spare parts including the bracket kit, spare oil filter, bicycle tire for water hose patch, extra hose clamps and all the tools. Also was very helpful to have assistance. Once you get your hands oily (with or without gloves) you need a lot of help getting things you need without trashing the cabin.
2. One of the tricky parts is installing the hose and its new clamp underneath to provide clearance for the alternator and making sure you position the hose clamp to permit access to the screw for future tightening and checking.
3. The existing studs on the fresh water reservoir were just fine. The retrofit kit comes with new studs, but I didn't have to replace them.
4. Put the new belt on before you pop the alternator into place with the new adjusting bracket. The kit comes with two new fan belts. They're shorter than the original ones.
5. It's a heck of a way to do an oil change AND replace the antifreeze!
6. The recent List contributions about plugging the hole between the bottom of the engine compartment and the bilge leave me inclined to recommend keeping the hole, rather than plugging it. While I've got a mess in the bilge to clean up, if the oil and antifreeze hadn't gone into the bilge, it would have filled up the engine pan and spilled over into the cabin, the head, and probably back into the area underneath the aft cabin - not as easy to clean as the contained mess in the bilge.
Stu Jackson #224 Aquavite San Francisco

Subj: [C34] Alternator Bracket M25 Engines
More on Alternator Brackets February 1988 Vol 6, No. 1
by Herb Schneider
Most of us who have read the last several issues of Mainsheet know that the alternator bracket on the Universal Model 25 diesel engine can fail, which can crack the valve cover, resulting in a loss of engine lubricating oil. The manufacturer changed the bracket during 1987, and the current C34 production incorporates the improved engine, although dealers still have some boats with the uncorrected engine. Several owners have asked me how to verify that their engines have the correct bracket, so I photographed two engines, one with the correct bracket and one without. The correct bracket uses an adjustment arm below the alternator. Factory supplied engines will also have "Model 25 XP" affixed to the top of the coolant reservoir. The old arrangement, which is likely to fail in time, has the adjusting arm above the alternator. By the way, the manufacturer does not acknowledge this as a problem, and requires about $115 for the upgrade kit. (NOTE: I paid $95.00 for mine in 1998. It's worth every penny!)

Subj: [C34] Alternator Bracket M25 Engines
Stu, Also read your msg to Al on the saga of your bracket replacement. Let me give you a couple of thoughts. First the best chafe guard that I've found for around that metal tube that carries coolant above the oil filter is a piece of 1" ribbed black plastic hose (at any marine store -- el cheapo stuff). All you have to do is cut a piece the length that you need and then slice it lengthwise to slip it on where you want chafe guard.
The shortest filter that I've found (which I also use) is a Kubota 70000-15241. See the May & Aug 96 issues of Mainsheet for more filter #'s and important discussion. As far as the oil filters the Kabota 70000-15241 was only 1/4" longer than the miniature Fram filters. What I didn't like about the miniature Fram filter was the diameter. It only seated on a small portion of the facing surface of the engine. I also question how much filter material was really in there because of the smaller diameter. Can't remember if it had a clogged filter bypass or not, but don't think it had an anti-drain back valve. Your engine -- your choice.
Another thought. I changed my belt from a 3/8 #395 to a 7/16 #400 which is a "tad" larger & LONGER. If you have trouble and have the space toward the alternator door try a #405 length belt.
Ron APACHE #788

Subj: [C34] Alternator Bracket M25 Engines
As far as belt tensioning - in the dark ages they use a mallet or pry bar. If you go to an auto parts store you can buy a "belt tensioning" tool. It's like a turnbuckle with a left & right thread at a whooping cost of $6-$8! Screw it out till you get the correct tension then tighten the alternator retaining nuts. Easy as pie. Then screw the tool off. Meant to put this in the Mainsheet as a tip.
Don't overtension or you'll be buying a new internal water pump. To get better alternator spacing maybe a washer might help. I replaced all the bracket bolts with longer ones as the holes were threaded all the way thru. I also recommend that alternator upgrades be limited to 90 amp for side loading and spacing.
Ron, APACHE #788

Subj: [C34] Alternator Bracket M25 Engines
Same story. New, bigger alternator, new bracket, pierced oil filter and now a life time of oil seeping into the bilge!
We solved the problem by attaching a turn buckle to the alternator and the attaching it to the wooden block upon which the engine is mounted. Easy to adjust, won't rub and is not awkward.
Frank, Puff #691

Subj: [C34] Alternator Bracket M25 Engines
Hello Frank,
Although my boat is newer and has a MP-25XP engine with the bracket below, I wore out two 7/16" wide Gates heavy duty belts on my new Balmar 100 alternator in less than 500 n.m. It was impossible for me to keep adequate tension on the belts. To adjust the tension one must loosen the alternator bracket and the alternator mounting bolt, pull the alternator back and tighten the alternator bolt while keeping tension on the alternator and then tighten the bracket. Having done this several times during a passage while burning hands and arms and having to shut down the engine. I figured there must be an easier way to add tension to the belt and keep it there. I thought like you, add a turnbuckle between the alternator bolt and the support beam of the engine. The only thing I was afraid of is that by pushing the alternator out, one also pushes on the engine and one could mess up the engine alignment. I have not done this yet, but I really want to. What are your thoughts about this? What size turnbuckle did you use, and how did you mount it?
Looking forward to seeing your response or anybody else.
Leo Missler, Dutch Lion, C34 #1183, 1992

Subj: [C34] Alternator Bracket M25 Engines
I did this on the advice of my mechanic who has lots of experience but obviously is not perfect. We did it upon packing up Puff prior to putting her on the hard for the summer (Florida), so I don't have lots of experience with the turnbuckle.
However, I used a 3/8" turnbuckle a shorter one. Pressed a nut into the eye of one end and then a couple of big washers and then bolted all that to the port side of the alternator.
Screwed in a eye bolt to the engine mount platform and repeated the process on that end. Also put another nut on so I could "lock" it in by running it up against the tube.
Wasn't brain surgery and seems to be very solid. It is not on tight enough to change the alignment, I think. It could be a problem if the engine vibrates and the platform doesn't but we will see.
It will be a year before I actually try it.
Frank, Puff #691

Subj: [C34] 25-XP belt tension
Just a thought about belt tension and the XP-25.
If you are just having problems putting normal tension on the belt, then the turnbuckle solution would be ok especially if you relaxed the turnbuckle after tightening up the adjusting bolts on the alt. bracket. Flex mounts are supposed to do just that. I would think that sooner or later the tension of the turnbuckle would either pull things out of alignment or transfer noise and vibration into the engine bed. If you are trying to provide more than "normal" tension then please check out below and confirm this information for yourself.

When I was researching putting a high output alternator on "Family Affair" a tech at Maryville Marine, the Universal representative said that they didn't recommend beyond the factory belt tension settings because the front bearing and seal will not put up with a lot of side stress. It seems that the front crank pulley is pretty far in front of the actual front bearing on the block. Belt tension therefore has a lot of mechanical advantage. Much more so than if the crank bearing was right behind the pulley. That front housing is aluminum and full of timing gears. The crank bearing is way back (aft) behind them. Their suggested solution was to add an additional pulley (making 2 belts) on any alternator 100amp or above. They then say you can pull about 5hp off of the stock front pulley. They have the kits available on special order.
Ken Dickson, Family Affair, C34 #876

Go to Capt Al's Catalina 34 #55,  Upgrades page

Return to Catalina 34  National Association Projects Page

Important: The opinions expressed here are those of the individual contributors to this page, and not those of the Catalina 34 National Association or Catalina Yachts, Inc. Additionally, this material has not been reviewed by Catalina Yachts, Inc. for technical accuracy. This page's maintainer cannot guarantee the accuracy of this information or the desirability of suggested modifications or upgrades. Please obtain assistance from a competent marine mechanic or boatyard prior to making any significant modifications to your vessel.   



Last modified by Phil Imhof, Wednesday, August 11, 2004 . Copyright 2001 by Catalina 34 International Association.  All rights reserved.