C2:67 Alternator 61A aka 37A It Works!

[Gerard F.]

At least I think so. Here it is labelled 37A, but it has the stator, rotar, and heat sink of a 61 A replacement part no 1100644:


I just put it on my 67, replacing the chrome piece of junk I got a full deduct on. Turned the AC blower on full, and it's pulling 20 amps and at idle (650 rpm)
No more slight discharge at idle. Checked it at Kragens but all they could do is give me a voltage output of 14.8 volts.

Here it is in assembly with the toothpick trick in the brushes.

I looked at the difference in each part side by side and could not for the life of me see any differences. Here's a few pictures with my original on the left:


The stators look identical and the only difference I see is the color of the insulation or coating on the winding. Red-caramel vs black on the 37A.
Based upon a members advice I swapped both the rotar and stator as a matched pair. I would have reused the old heat sink although I found one diode out in the heat sink, but the one's in the case checked out Ok. I then swapped the heat sink and brushes and brush-holder.

Here's what the back of the rear case looked like before:

I used hot Simple Green and Eagle Etching Mag cleaner with a Dremel plastic brush. I finished things off with a Nylok wheel, then etched it again. Final coating was Tri-flow for corrosion protection.

Having fun!

Jerry Fuccillo
#42179

[Geoff C.]

Mahhhhh-velous Looking! What is Tri-Flo? *NM*

[Joe L.]

Re: C2:67 Alternator 61A aka 37A It Works!

Jerry-----

I'm assuming that the "61A" rebuilt unit that you used for parts exchange with your original is the 1100644. However, just because the case is labeled "63A" does not mean that what's inside is 61A. That's what was ORIGINALLY inside the alternator that the drive end case half was part of but not necessarily what's inside now. As I've mentioned previously, after an alternator has been through a commercial rebuilding operation, which apparently this one has, the numbers on the case mean absolutely nothing. Commercial rebuilders do not rebuild alternators as complete units, one at a time. They strip down the parts, clean them up and test them, categorize them, place them in bins, and then use the parts to build up the units that they need.

That's also why keeping rotor and stators together as a "matched set" is fairly meaningless. Believe me, commercial rebuilders do not keep them together as matched sets. Besides that, the rotor and the stator are non-contact pieces, so there is no wear-in that exists between them. But, it doesn't do any harm to keep them together if it makes one feel better about it.

The rotors for all DN series, external voltage regulator alternators, regardless of amp rating, are all FUNCTIONALLY the same. There may be minor configuration differences due to slight changes made over the years of their manufacture, but, FUNCTIONALLY, they are identical.

The only way to know the amp rating of the rebuilt unit is to know the rebuilder's part number, either from the box it came in or a tag that is sometimes placed on rebuilt units. Then, one can research the rebuilder's part number to determine what amp rating the alternator is.

As a matter of fact, the "confusion" caused by the numbers stamped on the case in the world of rebuild alternators and starters is such that many rebuilders are now grinding off what some regard as "precious numbers". That "neutralizes" the case half and it becomes just like the new, unstamped case half that existed before Delco Remy in Anderson, IN stamped it in the first place. The rebuilder uses the case halfs just like Delco-Remy did----- as a component to build up alternators.

So, it's possible that when you exchanged stators, the component that is primarily related to alternator output, you just exchanged a 37 amp for a 37 amp. I don't know that, but I raise it as a possibility, especially if you were judging the rating of the donor unit by the stampings on the case. I thought there was an observable difference between the 37/42 and 55/61 stators, but I can't say that I've ever really studied it.

[Gerard F.]

Re: Mahhhhh-velous Looking! What is Tri-Flo?

Geoffrey,

It's actually "Tri-Flow"; It's a spray lubricant/protectant like WD40 but with some teflon. It's used for outdoor sports gear, guns, fishing gear, and you can even use it on your inline skates (heh, heh). I use it to protect any bare or finished metal parts, great on newly finished carbs.

Jerry Fuccillo

[Gerard F.]

Re: C2:67 I think it is empirical, Joe

Not to disagree with you Joe, and I might now have a fully functioning 37 amp alternator. But it is outputing 20 amps at 650 rpm, and is outpacing a less then a year old 60 amp gippo chrome alternator with less then a 1000 miles on it. The donor for the stator and rotor is a 15-20 year old replacement (stamped 61 amp with 1000644) with less then 5000 miles on it.

I have it from an EE I respect, that the amp rating on older original alternators was based upon testing. If something tested out around 61 amps, it was then stamped 61 amps. And it is a combination of both the rotor and the stator which is tested. Rebuilders 15-20 years may have been a little more careful, otherwise they would have had a lot of returns.

I'm not so sure that the amp rating is solely in the stator, and that the combination of the rotor and stator is meaningless. Although by my eye both rotors and both stators were identical, the fit seemed slightly different, the replacement air gap between the rotor and stator seemed to be of closer tolerance. (The repacement rotor was stamped 2D5CS whereas the original was unstamped.) So I chose to use the matched set and I think based upon good advice.

So my own empirical test indicates that I have better output then a gippo 60 amp alternator. 20 amps at 650 rpm ain't that bad. Maybe my modified original is less then 61 amps but I sure it's probably over 37 at more then idle.

Best wishes,

Jerry Fuccillo

[Gerard F.]

Re: C2:67 Rotor Stamped 2D5C5 *NM*