Datsun Roadster Forum-311s.org

I decided to to replace the giant delco 10 si alternator that had been retrofitted to my 1500 decades ago. It was a reliable old beast that still works fine but it looked out of place hanging off the little inline 4. So when eBay emailed me a flash sale coupon for 15% off anything i pulled the trigger.

These alternators are equipped on kubota tractors and many other industrial applications. They are also popular as mini alternators for race cars and can be found easily often described as Chevy mini race alternators or denso mini alternators.

Performance wise this one is rated at 40 amps. The delco was rated at 35 amps. Not sure on weight (maybe 4-5lbs?) but definitely weighs less than the big delco. I would think it can handle high rpm just as well as the old alternator if not even better due to its compact size.

On to the pictures. I apologize for the poor quality pictures. The lighting in my garage is not that great and it was hard to take decent shots. I tried taking before and after shots from the same perspective but I was a little off.

Side by side comparison. Before and after.
If anyone is interested in more details on the alternator or install just ask. I'll report back on function soon. Car is still on jack stands waiting for me to finish wheel bearings and brake redo.

I use this one on one of the complete Right Hand Alternator kits I sell. The ones I have used have been trouble free.

Please make sure you use a protective device on the alternator output to limit the current in the old harness. Meltdowns due to a fault condition are not pleasant

Yep! I had done that with the delco already. I actually have 2 fuses, one directly off the alternator and another at the starter. I figure the 40 amp denso shouldnt anger the roadster gods too much over the delco (perhaps it is even a good will jesture haha)
But regardless always a good thing to mention.

What a difference , rerouting the windings makes huh .
The 60s alts could have been half the size of a alt. Back then .
Wish I would have come up with it . ...genius

Hey Dan any update on the alternator? Any issues? Was the install pretty simple? I am looking to replace my alternator on my 67.5 1600 and I'm looking for advice. My car also already has the alternator relocated to the right side. Thanks!

The 67.5 should have always had the alternator on the right side.

spl310 wrote: ↑Mon May 14, 2018 2:47 pm The 67.5 should have always had the alternator on the right side.

Oh ok I thought it was originally on driver left side 1st. Well at least it's on the correct side either way

The alternator under the manifolds started because of emission controls. The air pump replaced the alternator on the right.

Mackn367 wrote: ↑Mon May 14, 2018 2:19 pm Hey Dan any update on the alternator? Any issues? Was the install pretty simple? I am looking to replace my alternator on my 67.5 1600 and I'm looking for advice. My car also already has the alternator relocated to the right side. Thanks!

Yes working perfectly. My install was very easy, but that may have been because the alt. Mount had already been modified to fit the Delco style alternator. Otherwise it was a bolt in affair. Wiring was also very simple for my car with a charge light (no ammeter) 1 wire to charge lamp, the other a key on 12v to excite the alternator and last the "big" wire to the battery(starter)
The only other change I had to make was go to a shorter drive belt, although the stock one would have worked it was putting the adjustment at the far end of the bracket.

Hi Dan, I've been meaning to do this conversion. If you might be able to post a part number or designation for the Denso alt and maybe just a few pics of the way it mounts to block would be helpful. Is it mounted pretty much the way most conversions are done with extended bolts and smog mount? Thanks.

My car never had emissions so not sure about smog mount, but I would be happy to take a few pics and post part numbers when I get home from work this evening.

I just did this conversion. or you might say I am in the middle!
Everything works fine, I still have the 30 amp meter, so I need to let it idle for 30 seconds to keep the current below 30A.
So here are my questions:
Has anyone ever found a shunt to change the meter to 60A?
I am concerned about the MAX RPM of the alternator.
There is about a 2:1 ratio, so 6,000 engine RPM = 12,000 alternator RPM.....
The paperwork only shows testing to 6,000 RPM.
Anyone ever replace the pully on the Denso Alternator? or Know the shaft size.
I would be happer with a 4" pulley.

I need to find the pdf but I found somthing from denso claiming it can handle high rpms and tested to 12000 rpm. When I get home I'll look for that in case I'm off on my facts lol.
I also did find a fancy billet 4 inch pulley but it cost more than the alternator did. I decided to risk it. For what it's worth my old Delco 10si had a pulley nearly the same diameter and it never had any problems. I figure this one should be able to handle high rpms no problem.

Well i cant find the specific information i was looking for but powermaster lists their version as 20,000 max rpm.
I will post some more pics of my install and part numbers very soon.