Alternator adapter help

[memo43]

Ok as the title says I need help locating a part number or adapter.
I'm gathering everything for an engine swap gen 1 sbc 350 to l31 vortec motor.
I'm using a CS13D alternator.
From the old school 10si.
Every ug I find is the square style an I need the round one.
I keep seeing videos and foogle foo searches but every of of them only shows the square plug.
I'm looking for the round/oval plug to adapt to mine.
Prefer something I can get from Napa or other local parts store.

something similar to this

https://www.ebay.com/itm/324604990006


thanks in advance

[dmjlambert]

What is the year of your truck and do you have a warning light instrument cluster or gauge instrument cluster?

[memo43]

Sorry forgot the most important details

ita all going In a 1985 k20 all stock gauges.

[dmjlambert]

OK, just need to know how does a warning that your charging system not working properly appear on your instrument cluster. Is it by way of a warning light or a gauge?

[memo43]

Justa standard gauge
I dont have any warning lights

[dmjlambert]

The ebay seller for the one you show the link to says "Using this lead on a vehicle without a warning light or resistor will burn out the voltage regulator. I also have a similar lead with a build in resistor for those applications."

I recommend you send a message to the seller and ask for the link to the "similar lead" he has with a built-in resistor for applications that do not use a warning light. Then perhaps he will guide you to the right one to buy. If he does, I recommend buying it.

I don't know if you would have any luck buying a conversion part like that locally.

[memo43]

So no adapters or work around you think

[VetteVet]

Here is a conversion on the CS alternator.

http://67-72chevytrucks.com/vboard/s...d.php?t=457448

[dmjlambert]

Originally Posted by memo43

So no adapters or work around you think

I think the adapter the eBay seller is talking about that he has and that has a resistor in it for non-warning-light applications is your best bet. I suggest at least message him and get some info.

[memo43]

Appreciate all the help, I was able to source the 4 pin adapter
an Google has confused me so far.
For the CS-130D, there are four connections labeled ”S”, “I”, “L” and “P.”
I've read the I terminal will be the excite wire and that's the one that I wire to my harness.
back of alternator terminal strait to either starter or battery (preferred)

So if I understand correctly this is pretty much a 1 wire alternator correct?
My gauge cluster is the standard Volt gauge with no dummy light.

For electrical needs I will be running dual windsor fans
electric fuel pump
truck has power windows and locs
and Summit Efi system.
105 amps should be more than. plenty
thanks again for all the help.

[dmjlambert]

It might work but if it were mine I would not connect the I wire. Connect the L wire to a 500 ohm 1/2 watt resistor, and the other end of the resistor to a source of key-on 12V. That is what turns on the alternator. Connect the S wire to your main battery charge wire at a junction a couple of feet or more from your alternator. This serves as the sense wire that judges how much charge to send. It is better to connect the S wire rather than to just leave it disconnected. I and P are not connected.

Here is a paper describing the connections and purpose of I and F in detail
https://web.archive.org/web/20220703...20IN%203.0.pdf

In the CS series alternators the plug may come with PLIS or PLFS terminals. You can't tell if the regulator in your alternator has a regulator that matches the stamping on the case, unless you open the alternator and read the part number of the regulator and research. So you could end up connecting the I terminal to a key on source of power, when in fact the regulator in the alternator sends a field signal out of the F terminal in that position on the plug. That is why it is safer to use the L terminal. Adapters typically have the L wire with resistor, and the S wire connected, or in some cases the adapter just uses the L wire with resistor.

[memo43]

Thanks for the info dmjlambert
I connected the leads just like you mentioned and the alternator is showing 13.5volts according to the handheld efi display. I only ran the engine for a few
there's still some cleaning up I need to do.
I appreciate all the help.
I'll try an get some pics of both the alternator and 4 pin round plug with napa part number for future reference

[memo43]

Well got the plug installed
Installed the 750 ohm resistor in place on the "L' side of the plug.
I Looped the 'S" terminal back to the positive stud on the alternator. I will move it to the distribution block on the bulk head
Positive stud on the alternator is fed directly to the battery. Should I route this to the junction block or starter terminal?
My charging system is not working as it should. While driving my volt gauge barely reads at 13volts
Is the wire from the junction box to the alternator the only piece of the puzzle that I am missing

I had both the CS130D alternator and the battery tested at the Orileys an they are both good.

[dmjlambert]

Is something different compared to when you posted on 7/5 that it seemed to be working and had 13.5 volts?

Perhaps 750 ohms is too high
or
perhaps it would be better if the S terminal were not looped back to the positive stud on the alternator and instead connected to the battery charge wire at some 3 to 5 feet from the alternator (In the stock wiring on older trucks the sense wire connects at a splice joint that is wrapped with tape near the driver side headlight, I'm not sure what they did on the 1985 models.)
or
perhaps it is OK and time will tell if it lets your battery run down and the alternator never charges it. If it has higher voltage than when the truck is off, it is probably charging.

I don't know much about EFI handheld displays or exactly what you should get for readings in a truck with fancier stuff than a 1st generation plain engine, but others here on the forum can chime in and they know. My knowledge is more in the 67-72 range also, so others can speak with more authority on 1985 models.

I suggest don't rely on your dash gauge, and use a digital multimeter and measure voltage at the battery and at the alternator terminal. If you don't have one, Harbor Freight has a really good one for $6.99 and car parts stores usually have some good ones for $8 to $25.

How much of your stock wiring harness are you using, and have you done anything different such as extend the wiring to put the alternator on the other side of the engine compared to stock configuration, or anything like that? What gauge of wiring are you using? Do you have electric fans and how are they hooked up, or do you have a clutch fan on the engine?

[dmjlambert]

It is also possible I have it wrong about preferring to use L instead of I, when it comes to the "D" series CS alternator with the internal fan I can't claim to be an expert.

[memo43]

Thanks for the response
As far as gauge wiring for the "L" wire I was able to use the same wire from the 10si plug
everything else is 10 gauge alternator to battery
My fans are running on dedicated relays one per fan.
Only thing I can think of is the "S" terminal connected to the junction box on the firewall.
on my way home when the electric fans kicked on my headlights got real dim and both the dash gauge and handheld controller showed under 13 v.
As far as alternator it has always been on the passenger side, even with the gen 1 350 and the l31 350.
I'll get out the testers tomorrow and see what is actually reading.
only thing I can think of is that it's been running on straight battery power an I'm missing the wire to tell the alternator to charge.
I will also take some pictures of my set up tomorrow

[memo43]

Well as promised here are a few pictures of my set up and after reading and reading and going back and forth as to what I am missing, the issue was right in front of me the entire time. I find it both embarrassing and and the same time educational.
But for not here are the first set of pics I can only post a few but I will add the others here shortly

Pictures are the port for the adapter plug
my bulkhead junction block
my NAPA harness with the diode installed
my plug (were I discovered my error)
alternator mount with ground straps, one to directly to the battery the other to the frame

[memo43]

Here is the second set of pictures as well as my mistake.
I read that the "CS130D" alternators came with a 4 pin round plug that i could adapt to my 10SI harness, problem was that all the plugs i could find were all square for the CS130 alternators.
I found a 4 pin round plug at my local NAPA store already WIRED and ready to go, so like a kid at a candy store I grabbed it and quickly installed it, and tried my best to wire it. That's were all the help from this forum came from
Big shout out to VetteVet for posting the like to the alternator conversion
and another big shout out to dmjlambert for the constant replies and trying to help me out.
My already assembled plug from Napa was just that already assembled, but no one said it was assembled or pinned correctly to what I needed it to do.
After taking pictures of everything that when it dawned on my the plug was not pinned to what I needed it to do. Both the L and I/F terminals were pinned.
I needed the L and S terminal to be pinned.
I went from getting volt reading from 13.5 and dropping down to 12.4 depending on what i was running ie EFI, elec fans, and more importantly headlights.
After realizing my mistake while at work i grabbed a pocket knife and paper clipped, switch the pins around to were they should have been i fired up the truck and instantly got 13.7 volts. turned everything that i would normally run, both Elec fans, headlights and my voltage stayed at 13.7.

Hopefully my error I didn't fry and alternator, and it will finally charge my battery back up.

Glad I finally figured it out, nothing is easy with our old trucks, to keep em on the road they require us to pay attention and put in some work.
Speaking of work, ill be back to add more to the adventures

pictures are the pin layout
the way i had my plug pinned front side
the way i had my plug pinned backside side
plug labled

[dmjlambert]

Excellent, good you found that. I see the alternator is stamped with I and F on the same pin. So there's no real telling whether that pin is an output of F or and input of I. I don't know how many of each type of alternator is made for various applications, F could be rare or I could be rare, or it could be 50/50 chance of frying it. Since it's working and giving you a charging voltage it seems you didn't fry it and that pin is probably I. If you ever have to change the alternator, there's also no telling what that new one would have.

I am thinking about hooking up P on mine, it is supposedly an alternator tachometer signal. I am thinking of sending the output to a diode and capacitor and time delay relay, so it can function as an "engine is running" relay controller. I can wire up daytime running lights and whenever the engine is running the headlights will come on after 20 seconds or so. I'm still in the thinking stages on that. I always drive with my headlights on if I can remember to do so.

[memo43]

That's not a bad idea of trying to run the headlights to run with the engine on.
I have both my low and high beams on a relay that is only triggered with the key on.

The alternator is part number N111939A (CS130D), 105 amp. Six groove pulley round plug $176.99
Was contemplating going to part # N111948A (CS144) 140 amp, six groove pulley square plug external cooling fan. $187.99
Both are for a 99 Chevy 2500 with 5.7l engine same year as my engine and accesories
When I first had it wired to what I thought was the S pin to the constant hot at the bulkhead I could hear the alternator whining as soon as I plugged in the harness. I switched it over to a key hot, but will correct it so that its to the junction block vs key hot.
Thanks again for all the help

[memo43]

Well since we cant leave good enough alone
I found the difference between the CS130 alternator and the CS130D alternators
copied from another web sit. https://www.onallcylinders.com/2022/...riginal-cs130/


Sometimes I wish it was easy, wonder why GM would make it so complicated , guess its time to swap out alternators and go for the CS144 for more amps

First question concerns the output connection which is actually the large post terminal with a stud and nut arrangement. This is where the power is sent from the alternator and should be connected with a 6 or 8 AWG large diameter power lead from this terminal directly to the positive post on the battery. Using a large diameter wire allows the alternator to deliver its maximum current to the car’s electrical system. Most stock CS-130D alternators were 105 amp models with some trucks and other vehicles equipped with 145 amp versions.

Addressing his next question, the connector for the CS-130D is slightly different than the CS-130. Each of these wires should be labeled, if not on the connector itself then directly on the alternator. The accompanying illustrations should help you with the conversion. For the CS-130D, there are four connections labeled ”S”, “I”, “L” and “P.”

In your case, Powermaster makes an adapter harness that offers a direct plug-in into the CS130D alternator with the other end the proper connector to accept the original 1993 Corvette alternator wiring harness. This makes the update to the later model alternator extremely easy. That connector is part number is PWM-161.

But let’s also help those readers who may be interested in an LS swap into a 1960s or 1970s GM car like a Camaro, Chevelle, Nova, or pickup and want to use the CS-130D alternator. In this case, the easiest step is to use a generic connector to plug into the CS-130D alternator. We found a connector pigtail in the Standard Products line under part number HP4695 with four white wires exiting the plug.

"To convert this alternator for use in an early GM car, there are only two connections that need to be made.
The “I” terminal would be connected to switched ignition under the dash.
The second connector would be the “L” for a charging warning light on the dash. If you choose to not use a warning light, it’s best to connect a 50 ohm resistor into this circuit connected to a switched ignition source to allow the alternator to function properly. We’ve been told that if the resistor is not used, this will eventually burn up the internal voltage regulator, so it’s best to use the warning light circuit or at least the proper resistor.

This will allow the use of this high output alternator with most all LS engine swaps and all will be right with the world.

[dmjlambert]

I have the CS144. I'm not sure I would do it again unless I really needed that much current. It is an inch taller, and on my 1969 truck I had to file the slot in the top adjustment bracket to fit the big fat bolt. Regardless of what CS series alternator, I don't think I would use a resistor lower in value than 500 ohms, because if you use something like 50 ohms it needs to be a big fat 5 watt rated resistor and the resistor will run hot. And considering the success experienced not connecting the I terminal, and don't know if my alternator has F in place of I, my tendency is to not connect the I/F terminal. I don't think there's a right and wrong way, but I have my preference.

[memo43]

How do you have your CS144 wired, any pics of the wiring by chance
As far as me having to cut the slot in the adjustment bracket "Shouldn't be an issue" since I'm running a Serpentine system, and the CS144 alt was an option for the year of the engine.
By the time I'm done with all this I should be better at wiring alt and what not

[dmjlambert]

Right now it is nothing to show off. I have a 1969 truck so those came with 10DN external regulator alternators. I had a cheap 12SI alternator that lasted a year before the bearings wore out, and for that I used an adapter like this. One piece goes on the plug that I removed from the regulator mounted on the radiator support, and one piece goes on the plug for the alternator for sense and light.


Then I changed to a CS144 and I got an adapter that would go from 12SI to CS1xx. It has a 510 ohm resistor in the L wire.


There is no adapter to just buy that goes from 10DN to CS series. I have a glob of adapters that are zip tied together at the back of my alternator and one adapter on my regulator plug. I have plans to remove that part of my wiring harness that goes to the external regulator area and that goes to the alternator, and re-do the wiring and make solder connections neat with shrink tubing, then re-wrap the harness in new non-adhesive vinyl tape.

The summary is I have the stock wiring for 1969, and plug and play adapters purchased online.

When I re-do it, the final thing will be wired very similar to this diagram. I'll probably add a 6 inch section of 16 gauge fusible link wire at the main alternator output terminal to protect my unfused 12 gauge wiring from mishaps with my high power alternator. In the stock setup there is a fusible link at the battery because it's the battery that could toast the wiring if something bad happens. Now that I have a CS144 I'm thinking it could toast some of the wiring.

[dmjlambert]

glob