The existing alternator arm to my now dead Mando 51A alternator does not come even close to working for the CMI-105. The CMI-105 is so long the alternator needs to rotate clockwise to keep connectors from touching the exhaust manifold.
Unless someone knows of an "off-the-shelf" bracket that will fit, it looks like I'll need a custom solution. I'm all ears if someone has a suggestion. Short of that, this is my approach:
I temporarily installed the 105. With the existing arm mounted, I over-laid the template print-out of the universal arm from Compass Marine and adjusted the template to a position that appeared to be a good fit. I taped the print-out to the old arm then removed the arm with the template attached. I fabbed a piece of starboard out the new arm "template" along with faring the junction between the two arms. I'll took the mock-up to the boat and checked the fit. With a few minor adjustments, it looks like it'll work pretty well so, I made a drawing based on the tweaks and will start looking for a machine shop to fab in 1/4" steel.
Any alternative ideas?
Call Maine Sail, Bill.
Quote from: Stu Jackson on November 23, 2020, 09:15:47 AM
Call Maine Sail, Bill.
I exchanged emails with Rod and his suggestions were cutting my current arm and bolting another arm to it or getting a piece of plate steel bolted to the block then bolting a balmar arm to it. I prefer not to introduce more "connections" than are absolutely necessary. I see more connections as additional possible points of failure. That said, if fabricating what I prefer is cost prohibitive or fabbing it myself is too much of a pita I'll probably go with mounting a piece of plate steel to the block then bolting that to a new balmar arm.
Pics, Bill?
Bill
Looking at RC's alt obviously it's the slap-on regular conversion to external. How much does it lack fitting? Would the slap on case fit if the terminals weren't present, or would the case itself hit?
See where I'm heading?
-k
Quote from: KWKloeber on November 23, 2020, 09:54:54 AM
Pics, Bill?
First pic with the old bracket to illustrate the fit or lack there of
Second pic shows the terminal, in the same position, hitting the exhaust manifold. Rod said some remove one of the nuts and shorten the stud to get clearance which is, understandably, not recommended. Even if I were willing to do that, it wouldn't solve the problem.
Hi Bill this is Glenn I met you in the fall at your marina, Hope all is well. Just thinking maybe with a longer belt you could get the clearance you need.
Hey Glenn, hope all is well and nice gauges! Yeah, I'll definitely need a longer belt modifying the bracket. If my pre-fab measurement is accurate, I'll need a 41" belt.
A friend, who has changed alternators on several Yammers and a Volvo, is telling me the upper bracket on this configuration is just for belt tension and the lower bracket, which is substantial, is the structure to keep the alternator in position and aligned, other than belt tension. He's also said two block mounting bolts for the tension arm is unusual.
This is the first alternator upgrade I've ever done and I'm interested in input from the forum as I was assuming I also needed support from the upper arm. This approach could really simplify my approach. 2 machine shops want $210 - $230 to fab the bracket i have in mind
Update: I just saw this on Marine How To, I guess I should've drilled further in to his site sooner:
Adjuster Arm Issues & Solutions
Issue #1
excerpt: An alternator adjuster arm is normally just a piece of plate steel that connects to the engine on one end and the alternator on the other end. Its sole purpose is to keep tension on the alternator belt.
Bill, I had a bracket arm made like that for my M25 in 2013 for $50 (I just looked it up) thicker but identical to the original. And it was much thicker than the one that came with the bracket replacement kit.
I apologize for not noticing your M25XPB in your signature. So few of us have this engines in our C34s. The C310s have them OEM, and their website redirects to the sbo.com website for their forum. I don't recall hearing of this on that site.
There are many options here:
Option #1 is how Beta Marine does it. All it requires is a small piece of 1/4" thick plate steel (any home center will have it) and no machine shop is necessary. Cut, shape and all you do is drill three three holes. You will usually need a spacer at the alt ear end. You then attach a Balmar UAA or UBB arm to the plate steel as seen below:
(https://pbase.com/mainecruising/image/171237485.jpg)
Or you can make an entire custom arm:
(https://pbase.com/mainecruising/image/171237486.jpg)
To deal with the field ground wire stud, you can carefully open the ER plate, cut the studs shorter and remove the bottom locking nut but not the nickel plated washer that is over the fiber insulating washer. When you put it back together use blue LocTite. If you also cut the field stud it will be best to permanently wire a field pig tail to that stud.
(https://pbase.com/mainecruising/image/171237500.jpg)
That said we prefer to see the alt with a longer belt and moved out a bit into cooler air rather than crammed in behind a hot manifold..
P.S. make sure the alt foot fits snugly between the ears of that OE bracket as they are cast aluminum, very brittle and we've seen a lot of them crack. On Westerbeke engines these brackets are billet machined steel. No idea why they thought it would be a good idea to make them out of cast aluminum..?
Maine Sail - Thank you!