I think I toasted my alternator - now what?

[Cheechako]

Originally Posted by bobconnie

Ive been useing GM 100 amp truck alternators. Ya can buy em a dime a dozen at junk yards! Same cost to rebild as any other alt out there! works as well as the Big Boys sold for ten times the price! Ya may need to work out the mounting, but Ive put them on a bunch of different diesel boats over the years useing stuff from other cars and trucks! makes it nice when your way off some place to get parts or your alt fixed localy!! just a thought

Yep, those old Delcos are available anywhere from 45 amp on up and are great.
OP: you can take the alternator to most any big name auto parts store nowdays and they will test for free.

[Celestialsailor]

There is a product called Zap stop which protects the Alternators diodes.

[Rusty123]

Repair quote is $200. Plus, I learned that this is the 35 amp, not 55 amp that I thought. I don't really want to spend those type of dollars on a undersized alt.

I looked, but haven't been able to find any similar sized (60 amps or so) alternator that mounts to a Yanmar from anyone but hitachi (or Chinese clones). Balmar makes a 70 amp one that fits, but it's very expensive. Plus, I worry that even 70 amp might be a little big for my engine. If I bought a Balmar regulator, I could "detune" a larger alt, but we're talking major bucks for that.

Anyone know of a good quality, mid sized alternator, that will mount up? At this point, finding a used or rebuilt hitachi 55 seems like my best bet.

[bill good]

Like I have said already!! I put a so called 50A same size on my 1GM & result was hard starting belt slipping & so either get yours repaired or freplace with a 35 A.

regards Bill

[Cheechako]

You should be able to go to up to 75 amps with external regulator without much belt slippage. I've done 100 amp ones on single yanmar belts. They did slip a bit too much at times. If you're used to living with the 35 amp output, then you are probably on the right track, find a 50-55 amp one. I forget the Yanmar footprint.. two mounting "feet" right?
Try perusing some of the marine alternator sites, they have info and pictures for certain applications that might help, Balmar, Ample Power etc...
They're all over the internet: $69 here: http://www.spidermarine.com/showitem...p%20Alternator

[FlyingCloud1937]

Originally Posted by bill good

Like I have said already!! I put a so called 50A same size on my 1GM & result was hard starting belt slipping & so either get yours repaired or freplace with a 35 A.

regards Bill

Bill,

An alternator doesn't start making any charge current until it reaches it's cut in voltage, which is going to be 1200 to 1500 rpm. Starting a diesel engine will not be affected by any size alternator unless it had a serious underdrive pulley ratio like something more then 5-1.

A diesel ticking over on the starter is barely turning 300-400 rpm, so the alternator is using no appreciable horse power at start up. And will ramp up as the diesel reaches 900-to 1100 rpm. An alternator needs 1 HP to each 25-30 amps output.

lloyd

[Rusty123]

The Hitachi 55 amp was an option on this engine, so I'm not too concerned about an alternator in this general size overloading the engine or belts. But I do have a friend whose boat has the same engine, and he did experience some belt slippage with a Balmar 70 amp alternator, before he "detuned" it with a Balmar ARS5 regulator.

As far as aftermarket alternators, I've looked at several brands: Balmar, Ample Power, Electromaax, Grasser, ZDF, Hamilton Ferris, and many others. With the exception of the Balmar 70 amp, the smallest available is 80 amps, with 100 amps much more common. I fear these are just too large for my engine (without regulator detuning).

I've also looked for alternators made by Delco, Leese Neville/Prestolite, etc., but these don't seem to be available in the Yanmar saddle mount. Hitachi (and Chinese knockoffs like the one Cheech linked to) seem to rule the roost here.

Despite the appearance of myriad options, the reality seems to much more limited.

[DeepFrz]

Rusty, have you checked out Maine Sail's web site and articles on upgrading alternators. Nothing specific to your engine but lots of good information.

http://pbase.com/mainecruising/boat_projects

[Rusty123]

Originally Posted by DeepFrz

Rusty, have you checked out Maine Sail's web site and articles on upgrading alternators. Nothing specific to your engine but lots of good information.

Compass Marine "How To" Articles Photo Gallery by Compass Marine at pbase.com

Yes, I've read a great deal of what he has written, as well as many others. His advice (on this as well as other topics) has been golden.

Russ

[Cheechako]

Yeah, I have built three 12v gen sets . Two used a Kubota 1 cyl 6 hp engine. Both of those had single belt 100 amp alternators with hard driving regulators. If you are having trouble with belts on a 50 amp alternator, you've got other problems... alignment, pulley type, belt type....etc

[pbiJim]

Originally Posted by forsailbyowner

I will second this, I have 100 amp one wire Delco 10si alternator on my diesel and a modified one in my homemade wind generator. Its like the chevy 350 of alternators. Parts are cheapest because they made so many of them. They are available new for less than $70 delivered on ebay. Bolted in with no mods to my perkins 4.108. Puts out 20-25 amps, never seen anything close to the 100 that its rated at.

I seem to remember that the 10si Delco alternators came in various amp capacities. I think that some were like 35 amp, some were 60-something amp, etc. I don't know how to tell them apart by looking at them though. How do you know that yours is a 100-amp? Is there a tag or a casting mark or something like that?

[DeepFrz]

There were 10SI alternators with 37amp, 42amp, 55amp, 61amp, and 63amp ratings. The smaller amp output rated alternators were installed on cars with no air conditioning, and few electrical accessories. The 61amp output rated 10SI was very commonly installed on 8cylinder cars, with factory air conditioning option.

Catalog

[Rusty123]

Originally Posted by DeepFrz

Catalog

That's a great link. Anybody have experience adapting a Delco alternator to a Yanmar-style mount?

[Maine Sail]

Originally Posted by Rusty123

That's a great link. Anybody have experience adapting a Delco alternator to a Yanmar-style mount?

Most conversions of that single fan Delco style alt are done with the 10DN case not usually the 10SI case as the 10DN was originally set up for external regulation.

The difficulty becomes matching the 3.15" ID saddle mount. Companies like Ample Power, myself, Balmar etc. all have custom 10DN cases to fit Yanmar engines but a large part of the cost is in adapting the 10DN to a saddle mount to fit the Yanmar. Many HO alt builders have moved onto the Delco 130D cases, such as Mark Grasser, Balmar and Electromaaax The conversion of these to Yanmar is even harder and more costly but other parts are easier to get and the alt frame is a tad smaller..

This is an example of one of my own custom built 10DN alts on the right (125A) and Balmar's new hairpin wound AT series (165A). Both are manufactured to fit a Yanmar 3.15" saddle mount. You won't likely find a Delco style alt to fit a Yanmar unless it is a custom build..

[Rusty123]

Originally Posted by Maine Sail

The difficulty becomes matching the 3.15" ID saddle mount....You won't likely find a Delco style alt to fit a Yanmar unless it is a custom build..

Which essentially circles back to my post #22 above -- there seems to be a gap in the marketplace for moderate cost (<$300), moderate output (~55 amps), continuous duty alternators that will fit a Yanmar engine. (Prime use would be sailboats with small Yanmar auxiliary engines (~15 HP) that are relied upon to charge house battery banks).

Hitachi and Hitachi clones will fit, have moderate output, and are moderate cost, but they're not continuous duty.

Many non-Hitachi OEM alternators (such as the Delco and Prestolite) are moderate cost, moderate output, and continuous duty, but (as far as I know) they don't fit.

Custom alternators (such as MS describes) will fit, and are continuous duty, but they're not moderate output (all are too large, as far as I know), and are not moderate cost.

Custom alternators with sophisticated regulation (i.e., Balmar) will fit, are continuous duty, and can be set up for moderate output, but are most certainly not moderate cost.

Russ