jutny

FD ALTERNATOR SWAP: COMPLETE

Process:

1. Swap pullies, which involved boring out the Rotorhead.ca dual belt pulley to an inside diameter of .670", and making a spacer of the same ID to keep the pulley from riding on the FD Alt Casing (this will make much more sense if you see it in person)
2. Make 2 jumper wires (male spade lug on one end, female on the other) to connect from my stock plug (didnt want to take the stock plug off in case i ever need to use a FB alt again, Read: if the FD alt dies) and connect the BW wire (top of the "T") to the top of the two FD alt lugs, and the WB to the bottom of the FD alt lugs
3. Use a spacer of 5 washers held together with electrical tape instead of the FB spacer (it's too long). The FD alt has the nut captive into the mounting ear, which is nice, but the upper (adjuster) mounting ear is not threaded like it is in the FB alt, so i had to get a bolt and some washers and a nut to hold it in place.
4. Run a 4ga charge wire directly to the battery (had some 4ga audio power cable lying around that was the perfect length)
5. Crimp a larger ring terminal onto the stock charge wire so that i could connect it to the FD alt as well. So the all the things that get powered from that wire still also have power to them (my voltmeter wouldnt work without it for example... NOTE: SA's have different voltmeters than FB's so.. YMMV)

Results:

• At idle: 15.08v with nothing running, ~14.8 w/ stereo cranking, ~14.6 w/ stereo, lights, wipers, blower, foglights, (2) 10" E-Fans... It falls steadily but slowly, however with the old alt, i'd be at like... 11.5v/12v with all that running.

• Anything above idle: around 15v. Rock Solid.

Problems:

My tach kind of freaks out now. On acceleration, its fine and normal, but on engine deceleration, it kinda jumps around erratically (never higher than real RPM's but sometimes lower) It just goes about its business kind of jerkily... i checked my connection at the coil, as i was messing around in that area with all my battery terminal re-doing.... but that didnt fix it.

Still is yet to be found out if i am one of the "lucky" few to experience the nasty battery drain that has come to be associated by using the "LS" alternators in a car with "LR" wiring (whatever the **** that means ) But Max7 said his was fine, and hopefully mine will be too.

Additional:

I also decided to add a 4ga ground cable directly to the engine block, I use an 8mm x half an inch bolt with lock washer to hold my cable one of the bosses sticking up from the front rotor housing on the drivers side. I figured doing this was a good idea for the health of the alternator, and of my electrical system in general. In case you're wondering, i also had run a 4ga ground wire to the strut tower nut as well, so i have 3 4ga grounds in total. One to the starter, one to the strut tower, and one to the motor itself. GROUNDS ARE YOUR FRIEND FOR A HEALTHY ELECTRICAL SYSTEM!!!

Along with that, i bought copper ring terminals for my 4ga starter cable, 4ga audio power cable, 4ga charge wire from the alt, and ring terminals for my ignition feed (relay for my DLIDFIS) and the main feed for the car's electrical system. Previously, all these (save for the 4ga charge wire) had been clamped into one of those extra heavy duty battery terminals, and recently i'd been experiencing bad connections there, that at one point in combination with the weak *** alternator left me stranded on Rt81, and made me pay $100 for a damn tow. Now with these ring terminals, i clamped them down with the screws that normally hold the wire clamp down, and i get so much less voltage drop while cranking, (and thus, much faster cranking) and i dont have to worry about the wires losing connection again.

Hopefully now all my electrial woes will be solved, and my car wont leave me stranded without power ever again (not to say it wont for some OTHER reason but that remains to be seen) Now i also get to enjoy the privilege of driving at night and listening to the stereo (which i could not do before if i wanted the car to start after i shut it off).


PICTURES:(click pic for full size pic)











Conclusion:

except for the tach freaking out... but still

-Kurt

pillage6

Sounds like just ONE issue, if your tach is freaking I would think it is your trailing coil either not grounded right or not performing right for some reason.

Looks really good, I had an FD alternator but didn't take the time or effort to install it, just sold it. Looks like you have a really nice car!!

shm21284

could also be his ignitor, cap, rotor, or plug wires. Yes, those last 3 will do it, dont ask why, but i replaced them one at a time until my tach stopped freaking out

jutny

well, it only started after i put the FD alt in, i'm running a custom DLIDFIS install, where my tach is driven off ONE of the leading coils. Plus, my ignition is in perfect condition. Nothing changed between the tach working perfectly and now except for the alternator and one additional ground wire.

pics of the rest can be seen here if you care: http://hroman.slac.com/rx7/Kurt/

the tach works perfectly as long as i'm stepping on the gas, its only if i free-rev the motor, when the tach should be going down smoothly it kind of freaks out. When i'm revving it, its fine, crusing at constant RPM, its also fine.

confusing

Siraniko

iTrader: (13)

the t-connector is hooked up correctly but what about the regulator? did you remove it and place 2 jumpers @ the 6-wire connector?

YL to BY
WB to BLg

I converted my bro's SA last night and so far, there is no problem.

jutny

my SA had no regulator when i got it, and when i put a motor in it i used an 83 12 a with the corresponding harness, so i never had an external regulator on this car. So no, i didnt have to do an jumpering of the 6pin connector.

Siraniko

iTrader: (13)

OIC. then the erratic tach could be caused by voltage drop of some sort since the SA are equipped with tach/Volt Meter combo gauge.

jutny

thats kinda what i was thinking, i really need to get a voltmeter hooked up in the car so i can monitor the voltage while i'm driving.

but with 15v at anything off idle, i really doubt that its the voltmeter cutting into the tach's working time... i dont particularly understand what the cutoff between voltmeter operation and tachometer operation is on this car though.

Siraniko

iTrader: (13)

YUP, that’s the only part I didn’t like about my two prior SA’s. If I were you, I will add an EL CHEAPO tach (say sunpro) to get a second opinion. That’s in addition to your volt meter If you have extra $$.

jutny

yeah we also didnt get the oil pressure gauge.

anyway, i have a crappy tach lying around, what position do i set the 4,6,8 switch to for a rotary?

in the long run i'm gonna be making a custom panel to replace my instrument cluster with all autometer sport-comp gauges, 5" Tach, 3 3/8 Electronic speedo, 2 1/16" for everything else i can fit in the stock location, and then whichever else will go in the stereo console. But that's a long way off due to the prohibitive cost of the damn gauges.

Siraniko

iTrader: (13)

I think 4 cylinder but please do a search. I dont have my notes in my office.

BadAssRX-7

dam 15 volts at idle.... thats a little high... the big thing is amps not volts. but hey more power is beter and if you can get 14.4 when the amps are on HELL yea i just installed a sr5 80 amp alt on my 87 b2000