NOTE: Since the time of this writing the supplier has run out of this alternator at the special price. These alternators are however available through other sources at close to the discounted price I was originally offered by Quick Start Automotive Electric. They still continue to maintain an extensive inventory of alternator and starters and accessory parts.
About a month ago I decided it was time to look into a 12 volt alternator system for my OC-46 project. My first thought was to use a one wire Delco 10SI unit, mainly because they're readily available, inexspensive, reliable and some are easy one wire hook-up. I purchased one for a good price on ebay and when it arrived I set about making the nessesary bracketry to fit it up. I wanted to use the OEM pulley off the generator to keep things looking somewhat close to factory. Surprisingly it slipped right onto the Delco unit and bolted up. After spending much time fabricating a nice solid bracket and getting the pullies aligned and a belt selected I test fit the engine side tin. ARRRGG! Even though I was careful to keep it as close to the engine block as possible the alternator stuck out so much I was now going to have to cut clearance on the tin in order to get it all to fit. This didn't sit too well with me and the Delco unit just looked too darn big hanging on the side of the little Hercules. Well, I decided I was going to start over and try to find a smaller alternator for this conversion.
While doing an internet search I found a company in Comstock Park, Michigan called Quick Start Automotive Electric
I gave them a call and told them what I was trying to do and if they could suggest an alternator for my application. they told me they had just purchased about 250 Nippondenso alternators that are brand new take offs from some gen-sets that the manufacturer was replacing with larger ones. They said these things were tiny and were rated at 40 amps. Sounded like just what I was looking for so I ordered one up. At this time these sell for $69.00 and come with a pigtail connector. This is what the unit looks like.
When I got it the first thing I noticed was, if I was going to use the original generator pulley I was going to have to overcome the issue of a much shorter and smaller diameter shaft. The shaft on the 'Denso unit was not long enough to come out the front of the thick OEM pulley and also was only 14 MM diameter. I thought I might try and make a counterbore nut that would act as the bushing and the nut. I came up with this.
It's a grade 8, 3/4 in. bolt, cut off, turned down, bored and threaded for 14X1.5 mm. The lock washer is 16 mm and was just slightly undersize for the O.D. but was persuaded on with little effort. An 11/16th washer would be proper if I would have had one handy. The pulley was installed backwards (casting number toward alternator) to allow it to turn freely without interfering with the end bell of the alternator. Also note, this nut will have to be installed and removed with an impact gun since there is no practical way to hold the armature from spinning. Just don't over do it with the impact gun when tightening or you'll chance stripping the threads. Two or three wacks with the guns hammer is sufficient.
This picture with the OEM pulley installed shows clearly how small this unit is.
Next I had to position it on the engine block to measure for a new bottom bracket that needed to be fabricated. As I held it in place and sighted across the pullies I noticed I was holding it so close to the engine block that I just decided to bolt it up temporarily through one of the timing gear cover bolts so I could get a measurement.
Well to my surprize, after I bolted it on and resighted, I couldn't believe my eyes. All three pullies were perfectly lined up. No lower bracket needed !
The only bracket I had to make was the simple top bracket that was bolted to a threaded hole provided on the water pump.
Now the engine tin cleared with room to spare.
This alternator is internally regulated and externally excited so in addition to the output wire to the ammeter it also requires one more additional wire from the ignition switch. It comes with a pigtailed connector that plugs into the back of the alternator. I believe one of the wires can drive a charge light for charge/no charge indication
If you're interested in inquiring about this alternator from Quick Start they list it as Item # ND-1170-40A. Another note, The belt I ended up using is a Napa part number 25-22386. It is a 11/16th wide belt and has an outside length of 39 3/8th in. With the fan pulley adjusted up tight I still have about 1/2 in. of adjustment left.
This conversion was actually much easier than trying to use the Delco one wire unit. The only small obsticle was wanting to use the OEM pulley and making the adaptor nut but if you have access to a lathe it only took about 30 minutes to make. This thing was almost bolt on.
It appears Nippondenso used this perticular housing for several of their alternators. If you look at the listing for Kubota
You'll see a good list of them at various ratings. I've found out they were used on Kubota tractors and Yanmar/Isuzu generator sets. Probably other Yanmar/Kubota/Isuzu equipment as well.
Here are the dimentions of the top bracket and the nut.
Below is the common wiring diagram for this alternator. The three terminals are marked on the right side of the alternator nameplate as " P, IG, L"."P"
(red wire) is a frequency pulse that is used as a feed-back signal for tachs or automatic frequency control on a generator set. This will not be used for this application."IG"
(green wire) is the field excitation circuit that is normally switched by an ignition switch or other automatic switching device such as an engine oil pressure switch. This turns the alternator on with a +12vdc signal. This wire could be jumped to the alternator output terminal at the alternator for one wire operation but you should be aware that with the engine not running there will be about 300 ma of parasitic draw on the battery. Enough to drain it over the course of a few days."L"
(blue wire) This is the charge/no charge indicator light if you choose to use it. You will need to add a small incandescent dash lamp between this wire and a +12vdc source such as the ignition switch. With the key turned on and alternator not turning it will be lighted. As the engine is started and the alternator has good output it will go out. Any illumination of the light while the engine is running indicates no or low alternator output.
Connector pin-out on right side of nameplate
The connector pigtail colors will be upside-down from the wiring diagram and nameplate symbol when installed. If you pull the connector off you can identify the symbol orientation by looking at the outline of the connector socket. It matches the nameplate symbol.
I would encourage any of you who want to copy/save any of this information to your own PC to do so. It's all linked from an image sharing website so I can't garrentee it'll always be availible when you want it.