[C320-list] Alternator for Perkins M30

[Warren Updike]

Dan, I replaced our alternator several years ago with a heavy duty 120A unit. The biggest headache was that the M30 was built to British standards and the original mount and adjustment arm are not compatible. The easiest thing to do is have it rebuilt. However, if you are more than a weekend cruiser, the best bet is to bite the bullet and replace it with a quality marine rated alternator in the 80-100A range. (I say 80-100 because the M30 has a 3/8" belt and the max recommended output is about 100. I actually limit the output to 80A via the regulator settings.) The Balmar 6 series may be the most used; but, there are others. It's also possible that in the intervening years there are new offerings in the market I'm not aware of.

One thing I learned is that the original Lucas alt is rated at 50A; but, once at operating temp on the engine may only reach about 35A, max. The most I've ever seen our new alt output was about 50A and that was not for long, reason being that I never discharge our batteries below 50% so max o/p at bulk charge doesn't last long.

I have an article about our electrical upgrades that includes the alternator project. If you'd like a copy, e-mail me off line and I'll send it.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay

-----Original Message-----
From: dmcnamara3 at woh.rr.com [mailto:dmcnamara3 at woh.rr.com] 
Sent: Tuesday, May 31, 2016 4:55 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Alternator for Perkins M30

Hello,
I have a 1994 (hull 64) Catalina 320 with a Perkins m30 diesel.  It appears that the alternator has gone out. It is a Lucas Marine A-127-55MT  I have looked throught the archives for what people are replacing it with but have not found a difinitive source or model.  I realize I should upgrade to a more efficent system but for now I just want to replace what I have with out making it into a project.  Is there a good replacement that is US sourced? 
Any help would be greatly appreciated.  By the way, I am about 99% sure it is the alternator, when the engine is running (above idle) the volt meter at the helm shows 12.6 volts, the charge light is on and when I put a multimeter on the alternator itself with the engine running it shows 12.6 volts.    
Thanks again,
Dan
Sandusky, Ohio