alternator reinstallation
 

Hi Guys

This is my fist post to this boards and I hope my first question is not seen as a "newbie"one. I am a regular on rennlist and am now cautiously entering the " big leagues"

anyway here goes

I just finished rebuilding my alternator and am putting it back in the housing ( 78SC ). The Bentley and other sources indicate there should be 3 nuts holding the alternator to the housing and another 3 holding the air duct to the alternator via the housing holding it on. On mine all six hold the air duct to the alternator via the housing. What this means is the alternator and fan will not stay in place while hooking up the wiring before I put the air duct on. Do you guys think it would be okay to cut off the mounting holes in the air duct ( every other one ) so I can just bolt the alternator straight on the housing like the Bentley shows ? or am I on the totally wrong track.

Thanks guys.

Put the air duct in the hole first with the wires thru it. Make sure you know the orientation of the fins. I used red paint to mark them.
All six nuts are used. The alternator should not fall off if the fan is back on. Normally it is pretty tight in the housing ring.

http://forums.pelicanparts.com/uploa...1139005967.jpg

Thanks for the tip , nice job by the way . It is a REAL tight fit in there. I found myself rotating everything upside down to get the other nuts off.

By the way did you powdercoat ?

thanks

ah yes..the infamous air duct. i treasure every encounter i have to have with that mother****er..
ryan

oh good then it is not just me .. I had every knuckle bleeding, I had the whole assembly jammed up ... and that was taking it out and I could just let the nuts fall on the floor of the engine.. I still have to put it back . The big problem I had was the housing jamming against the back of the car.. what if I jacked the engine up ? would that give me more clearance ?

sometimes the fan will now rub if the 6 nuts are twisting the alignment. The nuts are low torque tightening or the air duct area will destruct.

double or triple jointed fingers helps. Being a double jointed midget is probably the best imo?

The 1980 alternator has an external regulator. The air duct is bolted to the alternator studs wth all six nuts

Later alternators with internal regulators use a different air duct. On those alternators, you install 3 nuts WITHOUT the air duct, then the remaining three AFTER the airduct is put into place.

Your Bentley describes the alternator with the internal regulator.

not just you iceman..i feel and have felt your pain. i prefer a cold enema to reinstallation of this part. i have spontaneously created entirely new curse words in the process while intently staring down any unfortunates who should happen to walk up during this time with 'suggestions' for me, the uber-mechanic. did i mention the air duct's no fun?? ;)
ryan

I have had mine out way too many times in the last year. A real easy fix is to go get a multi-pin connector. Make a little wiring harness for the alternator that is long enough to come out of the back of the air deflector. Attach the other half of the multi-pin to the existing wires on the engine harness. Plug and play from there, after you assemble the whole works (alternator, fan, housing, deflector, mini harness) at the comfort of your work bench. The big red positive will need its own connector; a simple one plug or spade type will work. Once everything is plugged together in the fan shroud, I zip-tie it for good measure. Then pull any slack out through the hole in the front of the fan shroud and zip-tie it to something so it doesn't flop around.

You know I actually thought of the molex connection set up . If my hands start the bleed gain I'll go this route. They just healed up from taking it out .. i'll report back my frustrations. Great info about the external regulator , that explains things. Strange though .those low torque nuts are the only thing holding in the alternator !! so I can see the tendancy to want to over tighten.

Make, make, make, make sure that when fitting the alternator back into the fan guide that it's totally on center. Hand spin the fan within the housing to make sure that its on center and does not rub against the housing. I was real anal about this procedure when I did my alternator. Too many scary stories of fan blades hitting the housing once the whole damn thing is back on the car and having to redo it again. Good luck!

I wrote this some time ago..it might help...

notice the use of ignition wrench sets.. small ... work *real* nice in this small space....

http://www.pelicanparts.com/techarticles/911_volt_reg_replace/911_volt_reg_replace.htm

- Wil

I'd still be concerned that your alternator is loose in the housing ring. That makes very little sense given most people have to literally pound the thing out of there.

Two points if its loose:

1. Alignment and blade contact with the housing but more importantly...

2. Grounding..... the alternator is grounded thru the mounting ring in the housing thru the housing to the car. Not thru a wire nor strap.

Some people put so much powder paint on the housing itself they loose the ground and if the ring is painted the alternator should be darn tight - not loose. Bad ground and you will have problems....

External grounding straps are/can be added to secure a good ground in those situations and is a good idea anyway when the whole assembly is out.

But why is your alternator so loose in the ring????

There is...I'm quite sure..... a major ground wire running from the alternator to the top bolt that holds the engine case halves together...it does not ground soley through contact on the housing to the body....

I was "in there"... as part of the write-up ... but it has been some time :)

-Wil

yes, there is a quite thick ground strap from the alternator to a top bolt, which holds the engine case halves together.
ryan

An alternator ground strap is what I'm talking about. They're not necessarily on there. Take a look. If you got one, fine......

well, yeah..that's what i said.
ryan

Okay here is the reult and maybe I can clear up a few points.
I did in fact have to "tap" my alternator out of the ringa after allmost 30 years of sitting there. When I cleaned everything including both the alternator and the housing everything fit back together but did not Jamb in by any means. When it sits flat everything spins okay with no interference. however if I were to tip the housing over without the bolts done up the alternator would fall out. But the fan did help it stay in place while I buttoned everything up .
Pateince was definitely the key. after I put all the wires on ( yes there is a big brown one that goes to the case. ) I took them off again because I forgot they have to stay inside the circle where the air duct fastens on ( Basically all the wires have to lead towards the middle of the alternator ) . I had them oriented any which way .. no wonder it was so easy. Took a break defrosted hands.. I had towels layed down around the back of the car so the fan didn't get dinged.
Back to work- alligned shroud with markings I made and got the first ....uh oh dropped the nut .. used telescopic lighted magnet and snagged it . Did it again more carefully. I then rotated the housing carefully anticlckwise and put each nut on ( had to lift it a little when the coil mounting studs got to the bottom ) . Then rotated it clockwise. and tigtened them all up. Not as bad as I thought it was going to be. The engineering part I did not agree with ( but who am I to judge ) . Was that all the nuts that held the alternator also tightend down the plastic air duct. THis means you have to have low torque or you will crack it all. Yet these same nuts are the only thing holding the alternator and you have to put a pulley and belt on the other side. Must say I like the later revision better that uses 3 nuts JUST for the alternator and you can torque them a little more... the other three for the alternator and air duct. Anyway project completed, thanks to everyone for their help ..and now how about those sway bar bushings hmmm....

ice

yeah..i agree..it's amazing it all holds together with the low torque. my shroud has been taken out so many times it looks like it's been hit more times than joe louis..
ryan

I wouldn't put a Molex connector inline. The wire from the B+ terminal, depending on which year car you have, can carry 35, 55, 70 or 90 amps. A 90 amp Molex connector is probably big enough to block cooling airflow and the kind of thing that could come loose, get caught in the fan, melt on the engine case, etc.

There should be plenty of slack in the wires to allow you to pull the alternator rearward to access the nuts with a wrench.