|
|
21-05-2015, 11:36
|
#1
|
Registered User
Join Date: Oct 2013
Location: Slidell, La.
Boat: Halmatic Nelson 40
Posts: 141
|
Alternator for a Perkins 4-108
I need to find out what the largest belt driven alternator is that I can put on my Perkins 4-108. Thanks
Sent from my iPhone using Cruisers Sailing Forum
|
|
|
21-05-2015, 11:51
|
#2
|
Registered User
Join Date: Oct 2008
Posts: 357
|
Re: Alternator for a Perkins 4-108
I have a 85 amp alt with a single belt. Anything larger probably requires a double belt. Bob
|
|
|
21-05-2015, 11:55
|
#3
|
Registered User
Join Date: Apr 2015
Posts: 54
|
Re: Alternator for a Perkins 4-108
I had a 130 from cruising specialities but it was dated 30 years ago.. went with the new Balmar 6 series with a smart charger.. works great..
|
|
|
21-05-2015, 12:03
|
#4
|
Registered User
Join Date: Jan 2011
Location: Cowichan Bay, BC (Maple Bay Marina)
Posts: 9,704
|
Re: Alternator for a Perkins 4-108
I have a 21 hp engine, single belt, 100A alternator. That's where the external regulator shines: then you MANAGE the belt load (to avoid belt slippage). Heck, ya could put a 200A alternator on that engine.
And, the MAX output of the alternator is determined by the SOC and size of your house bank.
Then you manage the load with the regulator. Pretty full bank after one night: either use the small engine mode I described or de-tune the alternator always with amp manager. It is a PITA to re-program all the time, so if you use amp manager you're always de-rating the output. Which I find is counter-productive, others use it all the time. All covered in my links.
Good luck.
__________________
Stu Jackson
Catalina 34 #224 (1986) C34IA Secretary
Cowichan Bay, BC, SR/FK, M25, Rocna 10 (22#) (NZ model)
|
|
|
21-05-2015, 12:16
|
#5
|
Eternal Member
Join Date: Jul 2006
Posts: 4,046
|
Re: Alternator for a Perkins 4-108
To directly answer the OP's question:
You can easily drive up to a 100-amp alternator with the 1/2" belt on a Perkins 4-108. I've had a Balmar 100A alternator on mine for 14 years.
Two things:
1. With a good external regulator -- like the Balmar MC-612 or 614 -- you can de-rate the alternator's output to any desired level. For example, you can de-rate a 100A alternator to 80A or 70A or anything you like. Using this feature, you could mount a very large output alternator, and de-rate it to no more than 100A and you'd be fine. There might even be some advantage in doing this, particularly with AGM and gelled batteries which have a higher acceptance rate than FLAs; and
2. You must be very careful to align the alternator pulley with the drive pulley and the water pump pulley. Any misalignment will quickly lead to excessive belt wear, belt "dust", etc.
Bill
|
|
|
21-05-2015, 12:34
|
#6
|
Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
|
Re: Alternator for a Perkins 4-108
How do you align a pulley? It seems like the only thing you could align is an alternator that has a lot of slop in the large mounting hole. The alternator mount on the engine is pretty solid, so no adjustment there.
|
|
|
21-05-2015, 12:46
|
#7
|
Eternal Member
Join Date: Jul 2006
Posts: 4,046
|
Re: Alternator for a Perkins 4-108
Quote:
Originally Posted by Guy
How do you align a pulley? It seems like the only thing you could align is an alternator that has a lot of slop in the large mounting hole. The alternator mount on the engine is pretty solid, so no adjustment there.
|
http://www.gates.com/~/media/Files/G...0Alignment.pdf
|
|
|
21-05-2015, 13:47
|
#8
|
Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
|
Re: Alternator for a Perkins 4-108
Quote:
Originally Posted by btrayfors
|
That's nice but it does not tell you how to change the alignment.
|
|
|
21-05-2015, 13:53
|
#9
|
Eternal Member
Join Date: Jul 2006
Posts: 4,046
|
Re: Alternator for a Perkins 4-108
Pulley adjustment on shaft, shims, mount adjustment. If you need more, get a qualified engine mechanic or machinist.
|
|
|
21-05-2015, 14:19
|
#10
|
Registered User
Join Date: Oct 2013
Location: Slidell, La.
Boat: Halmatic Nelson 40
Posts: 141
|
Re: Alternator for a Perkins 4-108
Thanks so much for the good information.
|
|
|
21-05-2015, 14:19
|
#11
|
Registered User
Join Date: Jan 2011
Location: Cowichan Bay, BC (Maple Bay Marina)
Posts: 9,704
|
Re: Alternator for a Perkins 4-108
Quote:
Originally Posted by Guy
How do you align a pulley? It seems like the only thing you could align is an alternator that has a lot of slop in the large mounting hole. The alternator mount on the engine is pretty solid, so no adjustment there.
|
Guy, all engines, of course, are different, but here's how we do ours. Also scroll up to reply #33 about using the right bolts.
CRITICAL UPGRADES - DO THESE OR ELSE!!!
__________________
Stu Jackson
Catalina 34 #224 (1986) C34IA Secretary
Cowichan Bay, BC, SR/FK, M25, Rocna 10 (22#) (NZ model)
|
|
|
21-05-2015, 16:08
|
#12
|
Registered User
Join Date: May 2011
Location: San Diego CA
Boat: Liberty 458
Posts: 2,205
|
Re: Alternator for a Perkins 4-108
Quote:
Originally Posted by thebootlegger
I need to find out what the largest belt driven alternator is that I can put on my Perkins 4-108. Thanks
Sent from my iPhone using Cruisers Sailing Forum
|
Once you start pushing over 90A you'll want to consider dual v belt or similar.
Sent from my SM-N900T using Cruisers Sailing Forum mobile app
|
|
|
21-05-2015, 16:41
|
#13
|
Registered User
Join Date: May 2008
Location: daytona beach florida
Boat: csy 37
Posts: 2,976
|
Re: Alternator for a Perkins 4-108
I have a plain old Delco 12si that puts out 95 amps as tested at a shop. Any alternator rebuilder will sell you one for $120 including the wire to drive your tachometer. Cheap enough to get a spare. This on a perkins 4-108.
|
|
|
21-05-2015, 17:41
|
#14
|
Registered User
Join Date: Feb 2013
Location: Oregon
Boat: Seafarer36c
Posts: 5,563
|
Re: Alternator for a Perkins 4-108
Quote:
Originally Posted by Stu Jackson
|
Yes engines are different but the engine in question was a Perkins. Our Perkins which looks perfectly stock, has no provisions for adjusting alignment. The mount the attaches to the engine is fixed in all directions. No adjustment is possible without welding up holes and redrilling them etc. etc. If the lower mount hole is badly worn or the lower alternator mount hole is elongated, you can loosen things up and try to reposition the alternator but then you are depending on a tight bolt to hold things in alignment, not an accurate hole. Maybe that is enough for a boat?
|
|
|
22-05-2015, 08:30
|
#15
|
Registered User
Join Date: Aug 2014
Location: St. Joseph, MI
Boat: 42' Heritage East Nova Sundeck
Posts: 76
|
Re: Alternator for a Perkins 4-108
Kind of expensive, but if you are going to be on the hook for a long period of time, this might be an option. I have heard some horror stories about bent cranks on the 4 cylinder engines with bigger alternators and too much tension.
Perkins 4.108 Serpentine Belt Conversion Kit | Foley Engines
This was just a quick google. I'm sure there are cheaper alternatives but I have 6.354 motors that I will do this upgrade on to prepare fort the loop in 4 years.
Good luck.
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|