Alternator Bracket upgrade

[jibes138]

I bought the kit several years ago but delayed installation figuring I'd break the studs off and need to do a major engine overhaul to fix it. Anyway I went ahead this week and put in the new bracket. It went better than expected. The existing studs were long enough so I didn't have to replace them. The first stud, the front lower stud came out instead of the nut coming off so I put in the new longer stud in that location. The other three were left alone. I noticed the pulley grooves get pretty corroded so I spent some time with some emory cloth cleaning them up. Here's a couple shots of the new installation. If anyone hasn't done this yet you should, and let me know if any questions on the install.

 

[Stu Jackson]

Nice work, here's my story (1999):

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

 

[jibes138]

Interesting reading about the wrong size bolts in the kit. I did notice the alternator pivot seemed a little sloppy and I thought the gap between the bracket ears might be a little too wide. Your thread suggests the bolt needs to be metric and the kit is an English size. Next stop will be to the hardware store to find the right metric bolt. Thanks for the link.

 

[Stu Jackson]

Dave, that's where I got mine. ACE hardware is my favorite marine store!

 

[Maine Sail]

Seems like a good spot to re-post this:


Guts don't feel bad the Universal engines are not the only ones that have improperly sized pivot bolts. MANY factory engines including Yanmar, Volvo/Perkins and Universal often ship with the wrong sized bolt for the alternator to pivot on. With a 35A alt this is rarely a problem but when you go to 80A+ it quickly becomes belt dust bonanza.. Universal also shipped a number of engines where the Motorola alts had SAE holes and yet others with metric, go figure. The alt bracket upgrade, IMHO, is a rube Goldberg fix and rather poorly engineered, but still far better than the original.

Please be aware that the long alternator 3/8" bolt that comes with the kit is most often the WRONG size. It is much to sloppy a fit in the bracket. The hole in the bracket works MUCH better with a metric bolt. I replace it with a metric bolt and occasionally need to then drill the alt to the proper fit. The problem is the Motorola alts shipped in both metric and US sizes over the years. The upgrade bracket is drilled for metric but Westerbeke ships a 3/8" bolt.. Belt issues with the new bracket are often due to the sloppy incorrect bolt Westerbeke supplies. It allows the alternator to "cock off" and create uneven belt wear and creates wear on the alternator foot mount.

Also the new bracket has oval holes for a reason, but every one I have seen installed has never taken advantage of them. You may not need to but you really should align the bracket fore/aft on the motor so the belt is in proper alignment.. This may mean spacer washers under the thermostat end of the mount. The one I just did required two metric washers to shim it forward..

Sloppy Fitting Westerbeke Bolt

A much better fit:

New bolt on left, Westerbeke supplied "sloppy" bolt on right:

Forward Align

If you forward align place shim washers in the space:

Aft Align:

As for adjustment bolts I also go a step further...

I get a real long bolt, split washer and nyloc nut. I then adjust the arm and tighten the bolts hard. Once tight I install the "locking" nuts. I've yet to have one vibrate loose after this fix..

Alternator Ear End (gets both split washer and nylock nut. If the alt over heats it could melt the nyloc feature.)

Slotted end of adjusting arm: (this should never get hot enough to melt the nyloc if it does you have bigger issues.)

 

[jibes138]

Good advice Maine Sail, thank you. I'll double check the alignment of the belt next visit to the boat and replace the pivot bolt. I assumed bottoming the bracket on the thermostat would position the alternator and that the slotted holes on the manifold side were to allow for tolerances of the stud locations. I ran the engine for quite a while to make sure it didn't overheat after draining and refilling the coolant reservoir. I didn't see any problem with the belt other than re-tensioning as I had it a little too loose to start with.

All your lock nuts and lock washers seem like overkill but you see a lot of boats and engines so I assume experience taught you this lesson.

I do have a bone to pick with you but will send a PM regarding another thread on filters :>)

 

[Maine Sail]

All your lock nuts and lock washers seem like overkill but you see a lot of boats and engines so I assume experience taught you this lesson.

They tend to work loose under high loads..... With a small factory alt it may be over kill but when you start pushing 70A+ they can become problematic...

 

[Old Skool Neil]

With an automatic belt tensioner the alternator is allowed to pivot. The sloppy factory fit of the pivot bolt in the mounting bracket is resolved with bronze bushings. Without the bushings there's no way proper belt alignment can be maintained.

Here's a pic of the tensioner on my engine.