External Regulator or GM one wire alternator?

[nosigma]

Motor is a 4.7L Stroker. The OBDI system really hates the cam and head flows. Leans out super bad as it comes on the cam (wide band 02 sensor). I am going to build a MegaSquirt and remove all the stock engine wiring and computer. This entails a new distributer, coil and various sensors be removed replaced. I got all that under control....

My question is regarding the alternator of all things. Has anyone ever installed a GM one wire system (internal regulator) on a 4.0? Alternatorvely (pun) has anyone ever installed an external stand alone voltage regulator on an XJ alternator (my preferred solution)

John

 

[Johnnie Walker]

Internal/external doesn't matter. As long as it is being properly regulated. Quite a few people that do alt. swaps in renix use XX alt + ext regulator. No reason it will not work.
You may want to message 5-90, if he doesn't chime in.

 

[N8N_99xj]

A 10/12SI isn't really a "one wire" alt - it will work much better if you run the sensing wire to the battery or starter solenoid. Not such a big deal in an XJ where the wire is short but I swapped one into a Studebaker where there were probably 10 feet of 8AWG between the alt and the solenoid. I think this is what I used

http://www.speedwaymotors.com/Alternator-Wiring-Harness,2373.html

the wire with the diode in it is necessary because that car had an ammeter. If you have an idiot light you could just use a parts store plug and wire the red wire to the battery and the yellow wire to the idiot light. The yellow wire is the exciter that tells the alt to turn on and the red is the voltage sensing wire that the regulator uses to determine proper voltage output level, that harness is set up so you pigtail it to the B+ terminal on the alt but I don't like that, a proper installation runs that wire in parallel to the big alternator wire so the regulator compensates for the voltage drop in the wiring.

 

[nosigma]

I will PM 5-90 and ask him to chime in.

The motor is in a 66 Rambler American convertible and it does have an idiot light (not currently hooked up). An external regulator on the XJ alternator would be the easiest solution.

Sounds like the hook up should be: Field + and - to the regulator and the ignition + to the field +. No diode needed in the ignition + line.

John

 

[5-90]

Two reasonably simple solutions here, that I can think of:

1) Buy an external regulator (like a PrestoLite marine unit) and install it with an external-regulator alternator, following instructions included with the regulator. Pretty much any externally-regulated alternator should work.

2) Get an internally-regulated alternator (Delco SI or CS series are most common for this,) with a "one-wire" regulator, and install that. Connect B+ and go.

POTENTIAL PITFALLS:

1) You'll have to find a useful external unit (most alternator/starter houses should have "universal" externals, or check at a marine supply house. I wouldn't use an automotive OEM, since they can use funky plugs and you have to figure out how to wire them. A "universal" should come with an instruction sheet.) Although, were not Rambler harnesses set up to accept an externally-regulated Motorola?

2) Little to no downside, but installation of an accurate voltmeter or accurate ammeter is a must. The primary issue you can run into with a "one-wire" or "self-exciting" alternator is that it can "go to sleep" at extended idle, but this may be corrected by blipping the throttle briefly to "wake it back up." I believe you can get a "one-wire" regulator and refit a Delco yourself, but I'd have a shop go through it anyhow, if it's not new. I'm paranoid, but I don't get stranded.

 

[nosigma]

Is there any reason I cant use and external regulator on the STOCK 95 XJ alternator?

It fits very cleanly inside the aluminum frame off the side of motor (it was designed for that bracket after all) and tucks in very nicely inside the chassis. Switching to some other alternator is possible, it would just take a lot of fab work for brackets, pulley and belt alignment.

John

 

[Johnnie Walker]

IIRC, HO, or at least later ones are externally regulated. If this is correct, then you can use a regulator for it.

 

[MoparManiac]

I used a newer 136A durango alternator on the 440 in my MJ. It's the one people upgrade their XJ's to, and was also a bolt-in for my 440.

I just used a Chrysler external voltage regulator from Rockauto (they even sell a plug pigtail, look up an '87 Dodge Ramcharger) and wired it up according to the diagram below. Works great, but the plug leaves a big to be desired. I wish there was some positive clamping mechanism to keep it on. No issues during wheeling, but during racing it has popped off. It's ziptied in place now.

 

[5-90]

Is there any reason I cant use and external regulator on the STOCK 95 XJ alternator?

It fits very cleanly inside the aluminum frame off the side of motor (it was designed for that bracket after all) and tucks in very nicely inside the chassis. Switching to some other alternator is possible, it would just take a lot of fab work for brackets, pulley and belt alignment.

John

You may.

Know that you'll get a persistent CEL/MIL. Rumour has it that there is a workaround for it, but I do not know what it is.

 

[N8N_99xj]

2) Little to no downside, but installation of an accurate voltmeter or accurate ammeter is a must. The primary issue you can run into with a "one-wire" or "self-exciting" alternator is that it can "go to sleep" at extended idle, but this may be corrected by blipping the throttle briefly to "wake it back up." I believe you can get a "one-wire" regulator and refit a Delco yourself, but I'd have a shop go through it anyhow, if it's not new. I'm paranoid, but I don't get stranded.

I find myself in the very odd position of disagreeing with Jon, but if I were to use a 10/12SI rather than splash out for a "one wire" regulator I would just buy the harness instead and hook it up as a three wire. Then it never goes to sleep, and it's not a lot of extra work. Again, that's what I did on my old Studebaker; I had to use the harness with the diode as that car has an ammeter rather than an idiot light, but no real problem. I hooked the exciter to the ballast resistor (I also used a MoPar "orange box" ignition and a Stude Prestolite distributor with RB MoPar electronic guts in it - had I to do it over again I would have used a HEI module instead of the orange box, but live and learn) and ran the voltage sense wire to the starter solenoid where the +ive battery cable connects, and used the old 6V wiring harness otherwise (which worked great as it is heavier than that of a modern car, so no worries about handling the 63A output of the alternator. Only real risk is pegging the ammeter if the battery goes flat.) No problems at all but I did have to get a smaller pulley for the alternator as the Stude 289 crank pulley is smaller than that of a SBC, so charging was weak at idle until I sped it up a little.

Now whether that is the best solution for a 4.0 I do not know. Just sharing my experiences.

nate

 

[kastein]

I used a newer 136A durango alternator on the 440 in my MJ. It's the one people upgrade their XJ's to, and was also a bolt-in for my 440.

I just used a Chrysler external voltage regulator from Rockauto (they even sell a plug pigtail, look up an '87 Dodge Ramcharger) and wired it up according to the diagram below. Works great, but the plug leaves a big to be desired. I wish there was some positive clamping mechanism to keep it on. No issues during wheeling, but during racing it has popped off. It's ziptied in place now.

It is things like this that make me love Chrysler parts binning :laugh:

Alt field coils are pretty easy to control. I am surprised megasquirt doesn't have a built in driver for it - connect one side of the field coil to the switched B+ that runs the engine, the other to a ground side switch output on the ECU, then pulsewidth modulate it to reach the desired charging level. If you can get the software to agree, you can probably use a spare fuel injector driver output for it, as long as MS uses a ground side switch for those.

(I know nothing about megasquirt in particular, just about hardware. There's a chance that hijacking an injector line for a field coil driver is verboten in MS-land.)

 

[5-90]

I find myself in the very odd position of disagreeing with Jon, but if I were to use a 10/12SI rather than splash out for a "one wire" regulator I would just buy the harness instead and hook it up as a three wire. Then it never goes to sleep, and it's not a lot of extra work. Again, that's what I did on my old Studebaker; I had to use the harness with the diode as that car has an ammeter rather than an idiot light, but no real problem. I hooked the exciter to the ballast resistor (I also used a MoPar "orange box" ignition and a Stude Prestolite distributor with RB MoPar electronic guts in it - had I to do it over again I would have used a HEI module instead of the orange box, but live and learn) and ran the voltage sense wire to the starter solenoid where the +ive battery cable connects, and used the old 6V wiring harness otherwise (which worked great as it is heavier than that of a modern car, so no worries about handling the 63A output of the alternator. Only real risk is pegging the ammeter if the battery goes flat.) No problems at all but I did have to get a smaller pulley for the alternator as the Stude 289 crank pulley is smaller than that of a SBC, so charging was weak at idle until I sped it up a little.

Now whether that is the best solution for a 4.0 I do not know. Just sharing my experiences.

nate

If you cba watching the voltmeter, or don't trust yourself to, the regular SI (or CS) conversion makes sense - I won't argue it. It's just a matter of how much work do you want to do now, vice how much work do you trust yourself to do later...

 

[N8N_99xj]

Diff'rent strokes... I wanted to make the car "toss the keys to my mom" driveable... was going to wire up electric fuel pump w/ VW fuel pump relay so it'd prime the carb for instant starts, but never got around to it (for some reason I have rebuilt many fuel pumps but on this car they'd all knock, and it drove me nuts... plus with modern gas if it sat too long the fuel would evaporate out of the bowls)

If you know how to watch an ammeter or voltmeter and understand how a one wire works, it's not really that bad, but since I was reworking some of the wiring anyway adding two extra wires was no big deal.