71 240z Alternator Upgrade

[OniZ]

Yes I know there are about a dozen write ups or questions about upgrading the early Z's alternator, but this one is a little different. The upgrade that I did was a 95 Nissan Quest alternator, which is rated at 110amp output. High for most Z guys but helpful none the less. I'm not done with the install yet but I will be soon and will give a full write up with pictures to help others with the install. So everyone knows now there will be modifications required for this, i have also tried to address the issue of the belts breaking with the higher output alt. as well.

Let me know what you think of this as I go along any and all feed back is appreciated.

Kevin

[Maples71240Z]

I did a similar upgrade to this with my 71, but used a GM CS-144. I found the Z's stock harness was not up to the task, I took the output from the larger alternator and took it straight to the battery. Actually connecting it at the starter. I then added grounds from the alternator to the block and to the chassis, all these these and the alternator output are 4 ga but I would guess that 6 ga would be fine

for your upgrade.

My next issue was the ammeter, I swapped it out for a voltmeter from a 76 280Z.

I have dual electric fans, electric water pump, fuel pump and H4 head lights. I added Daves relays for the head lights. All these pull power straight from the battery and not from the existing harness.

My battery positive and negative cables are now 2 ga.

Dave...

Edited November 23, 2009 by Maples71240Z

[OniZ]

For the connector you ran to the battery, and starter did you use a different wire or one of the existing wires.

[Maples71240Z]

For the connector you ran to the battery, and starter did you use a different wire or one of the existing wires.

I ran a 4 ga from the alternator to the battery & did not use the stock wire that went to the stock alternator. That stock wire is not up to carring the added amps of the new alternator.

If you unwrap the harness in the area of the alternator you will find the regulator wiring is just taped into the harness with the other end going to the stock alternator. There is a switched positive wire that ends up at the regulaior. The stock white existing wire that went to the alternator output is hot all the time.

Once I removed the regulator wiring I just taped the harness up with 3M 333 electrical tape and ended up with a very stock looking harness less the regulator and regulator wiring. Just follow the factory tharness wrapping style. I left the switched positive wire and the white 10 ga wire that went to the stock alternator output sticking out of the re-wrapped harness for future use.

Dave...

Edited November 25, 2009 by Maples71240Z

[ktm]

The GM alternator swap is not a straight swap. You do need to make some modifications. Maples probably learned of the GM 12si swap from Hizandherz over at Hybridz in this thread: http://forums.hybridz.org/showthread.php?t=115550 and I was the one who explored the CS144 swap in this thread http://forums.hybridz.org/showthread.php?t=135557&highlight=CS144.

I also provided neat solution for the top alternator bracket in this thread http://forums.hybridz.org/showthread.php?t=137235&highlight=CS144

[Maples71240Z]

Maples probably learned of the GM 12si swap from Hizandherz over at Hybridz in this thread: http://forums.hybridz.org/showthread.php?t=115550 and I was the one who explored the CS144 swap in this thread http://forums.hybridz.org/showthread.php?t=135557&highlight=CS144.

I also provided neat solution for the top alternator bracket in this thread http://forums.hybridz.org/showthread.php?t=137235&highlight=CS144

Actually not from "Hizandherz" my 71 is running a small block Chevy, The issues OniZO is facing are the same as I was, the stock wiring can't handle the additional output if a bunch of accessories are added and you can't move a bunch of amps through the stock ammeter without burning it up.

[OniZ]

so i have to change the ammeter, also dave do you have any pictures of the wiring you did i understand you dont have the L series but it will still help me. do you know where i can find a picture of the diode install i've seen it mentioned but I would like to see an example. thank you again for your feed back, it really helps.

[ktm]

Running a GM CS144 on a SBC is not the same as running one on an L-series. It helps to specify your setup otherwise you may confuse people. You can run a CS144 on a L-series (or 12si), but you have to modify the lower mount as well as remove the voltage regulator.

Alternator upgrade: http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

Discusses the diode and where to install it.

You can run a GM CS144 with a stock ammeter if you are running the high draw items off relays. External car stereo amplifiers have a built in relay. An electric fan should be setup off a relay as it is a very high draw item (30 amps on startup). The same for an electric fuel pump.

[Maples71240Z]

so i have to change the ammeter, also dave do you have any pictures of the wiring you did i understand you dont have the L series but it will still help me. do you know where i can find a picture of the diode install i've seen it mentioned but I would like to see an example. thank you again for your feed back, it really helps.

No you don't have to change the ammeter, just don't add accessories that pull through the ammeter. That diode has to be put in the small wire that is hot when switched that ran to the regulator. That wire is used to excite the the new alternator to get it charging. Once its charging the alternator will backfeed the ignition and keep the car running when the key is turned off, the diode stops the power going backwards.

The alternator you are using should have a excite wire to start the charging process and the sense wire to tell the internal regulator how many volts to charge at. A GM alternator has to have a light and/or resistor wired in series in that sense wire. Your's may or may not, someone else will have to chime in on that.

The 280Z voltmeter has a charge light that I used to indicate when the alternator was charging. The only problem I had was when the charge light burned out and the alternator would not start charging. After that happened I wired in a LED and a resistor.

Dave...

[OniZ]

So anyway here's where I am at with the project right now. Alternator is almost done modifying just need to grind down a little more to get everything to line up the way I want. I'm thinking an 1/8 of an inch or less, already removed about a 1/4 with plenty of support area to spare. I haven't started the wiring since I've been sick and busy the last few weeks (was really hoping to have this finished by now). So here are some pictures like I said of a few of the things I've done while doing the upgrade.

[OniZ]

Ok the first picture shows the alternator after I got it and cleaned it up the arrow points to the lip on the front, that will need to be grinded down to be flush with the rest of the alt.

Picture 2: show's the after math and what it will look like you will need to get a spacer to fit around the shaft to prevent the pulley from rubbing against the facing, I will get a picture of this so everyone can see.

Picture 3: Is the back of the external regulator after I cut off all the wires to make the harness to connect to the new alternator.

Picture 4: Is the new harness using the leftovers from the regulator harness and the Nissan Maxima Alternator plug, I used this one because the wires were thicker than the Quest wires however the units are identical other than that.

Picture 5: The stock wires RED=power BLUE=ground WHITE=alternator connector LIGHT BLUE=external regulator

Picture 6: The alternator together and you can see the mark where I'm going to grind down some more metal, maybe don't even have to grind down as much as I've marked.

Comments about this are appreciated, especially if you notice something I've done is wrong, .

Edited December 4, 2009 by OniZ

[OniZ]

Well I have good news the swap to this alt is a success.....so far. I finished earlier tonight after many trips to Kragen (couldn't get the right belts). Car starts and runs just fine. I didn't have to install the diode...so far I may need to later but as of right now it's not needed. I'm also not sure the car is charging yet either I don't have the tools to check it so I will have to test it tomorrow. If this really works I will be sure to include everything I've done to help anyone that wants to do this conversion.

I also wanted to thank everyone that gave me their input about this everything really helped the project.

Edited December 9, 2009 by OniZ