Another Alternator Question

I need to find an automotive alternator that fits my O-320 Narrow Deck engine. I prefer a Nippon Denso unit. All of the suggested part numbers found with the search function appear to be for the newer wide deck engine case which has a different alternator mounting boss system. My engine has the bracket that bolts onto three of the case half bolts. The alternator mounting ears on the bracket force the alternator I bought to be too far forward or rearward for the pulley to line up. Anybody have a solution to this problem, other than going to B&C or PP?

Go to a local auto junk yard. You will probably find a low mileage unit at not too high of a cost.

Alternator

You most likely can use your alternator by replacing one maybe two parts so you don't have to search for an alternator to fit your engine. The two parts are the voltage regulator and the diode rectifier, both are inexpensive. Go to an alternator shop with your alternator and they will be able to test the stator to determine if there are no shorts.

The voltage regulator is pretty easy to replace. The rectifier is too but the wires on the stator connect to the rectifier. It's hard to explain but easy once you know. The person at the alternator shop can easily show you how to straighten 1 of the 4 wires going through the rectifier.

Good luck

Sometimes it's just easier to make a new bracket that fits the altornator you have, rather than trying to find an alternator to fit the bracket.

Bob burns
Rv4 n82rb

n82rb said:

Sometimes it's just easier to make a new bracket that fits the altornator you have, rather than trying to find an alternator to fit the bracket.

Bob burns
Rv4 n82rb

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I did this on my RV-10 and used a brand new Nippon alternator. Worked great for a little over 90 hours, then without warning on a short XC went out on me. I was able to get back home with my dual Odyssey PC680 batteries. The unit failed the auto parts counter test. I could have easily obtained a replacement on the spot but decided to replaced with a B&C setup and never looked back. Lots of folks here seem to have good luck with automotive alternators though!

We can't see your setup (there have been multiple alternator mounts over the years) & don't know which ND model you have. But I've been running an NDs on narrow deck 320s for over 20 years. Is it possible to shim your alt forward or back, using washers?

Pretty sure we have a similar set up. My journey: found the automotive 50 Amp alternator I wanted to use after researching here, configured the bracket to work by reversing it, putting alternator mount tabs on the proper side of the bracket to get close, then shimming with round bar stock spacers I manufactured to get the pulleys to line up exactly. Then I wrote the NAPA part number for the alternator on the belt tension arm so that I make sure I replace like with like, and don't have to change the mount geometry a second time (hopefully ).

It?s hard to give good advice based on your post since you don?t say how far out of align you are.
I am using a 35 amp nd alternator and had the same problem with the pulley not lining Up.
Using an impact wrench, I removed the pulley and fan. Then I had to turn down the sleeve bushing on the shaft a little to get the pulley back a little more. Reinstalled the pulley and it was perfectly in line with the starter ring pulley.
If you do this, make sure you add another washer under the nut that holds the pulley on, to make up for the removed fan, or it will spin under power and ruin the alternator shaft.
The alternator I used has a lifetime warranty so I can get another one at AZ for free if it fails. I actually have a spare in my hangar just in case since they are so cheap.
Hope this helps.

9GT said:

I did this on my RV-10 and used a brand new Nippon alternator. Worked great for a little over 90 hours, then without warning on a short XC went out on me. I was able to get back home with my dual Odyssey PC680 batteries. The unit failed the auto parts counter test. I could have easily obtained a replacement on the spot but decided to replaced with a B&C setup and never looked back. Lots of folks here seem to have good luck with automotive alternators though!

Click to expand...

Same here. Had to do some cutting and welding on the old generator bracket to get an ND alternator to line up.

Thanks for all the advice. I can't shim the alternator forward or backward, as the forward mounting ear on the bracket hits the forward boss on the alternator smack in the middle of the boss. Moving the boss in front or behind the bracket ear pushes the pulley out of alignment by about a half inch either way.

I will take another look at modifying the bracket somehow, although I hate to cut up a stock unmolested rare bracket. The case mount brackets are more convoluted than the later brackets used on wide deck engines.