[C320-list] Alternator replacement

[Warren Updike]

I have replaced the original Lucas alternator on our Perkins M30; and,
learned a lot in the process. That was 6 or 7 years ago. It is running fine
and I never regretted the effort.
That said, let me offer some ideas:
-- Given that the belt and pulleys on the M30 are 3/8", the largest
alternator they will support is in the range of 80-100 Amp. I learned this
after I bought a 120A unit, and even now throttle it down to 80A via the
regulator. Also, the bigger the output, the bigger the unit. Given that
space is a premium here, don't buy bigger than 80-100 amps.
-- Unfortunately, the Perkins was not built to US auto standards so the
mounts available from Balmar and others don't fit the Perkins. I had to
modify both the lower mount attachment on the engine and the upper
adjustment arm. This was a project in itself involving a machine shop and a
welder. These changes were necessary to get the new alternator pulley to
line-up with the pulleys on the engine. Maybe there are better options
available on the market today.
-- I highly recommend you add an external regulator. Do not even consider
internal regulation. 
-- You may also need to consider a heaver positive cable from the
alternator. The original cable from the Lucas alternator was connected to
the positive on the starter so the charge was sent back to whichever battery
bank was selected. This cable may not be of sufficient gage to carry the
higher amperage. Because I was also adding a start battery, paralleling the
two 4D's as the house bank, and changing the master switch more wiring
considerations were necessary. 

I urge you to understand the current wiring of the charging system and
consider carefully what changes you should/must make. Be sure to read the
two approaches to alternator upgrade on the C320 web site, and consult a
marine electrician if you feel this is over your head. 

I have an article on the changes I made I'm happy to send to you. Send a
message off-list and I'll send it to you.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62

-----Original Message-----
From: Alan Goodman [mailto:goodmanalanlee at hotmail.com] 
Sent: Thursday, July 31, 2014 5:07 PM
To: c320-list at lists.catalina320.com
Subject: Re: [C320-list] Alternator replacement

Greg - I too have the Perkins and will follow this thread with interest.
That said, DO NOT replace your alternator with an automotive part.  Aside
from the differences in construction (tinned windings, salt resistant
internals, painted case to prevent corrosion), if you sell your boat and the
prospective owner's surveyor detects this 'cheap out' solution, it might (at
least to me) raise questions about the quality of your overall maintenance.
IMHO, YMMV.  
Alan Hull 67 Holland MI


> Message: 2
> Date: Wed, 30 Jul 2014 19:44:54 -0400
> From: GREG SUTTON <sutt47 at msn.com>
> To: C320Email <c320-list at lists.catalina320.com>
> Subject: [C320-list] Alternator replacement
> Message-ID: <SNT152-W523E8A44256FB4E3714E14C0F90 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> The alternator on my Perkins M30 died and I need a replacement.  Has
anyone replaced theirs and can give me a comparable substitute to the
original and where I can buy one?  I have been canvasing all the marine and
auto parts stores with no luck so far.
> 
> Thanks
> Greg Sutton
> Liberty
> #128 		 	   		  
> 
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