How intensive is replacing the alternator in a 1980sc
 

Thank for your knowledge. I have a intermittent, deep grind noise coming from the fan housing alternator area, use a hardwood 1.5x3/4x30" stick to my ear, definitely the vibration is emitting for that location. Funny thing is is that is comes and goes and is audible at various levels. Checked Pelican for a new alt $650 and read the tech article on replacement ,just wondering if there other tips a guy sound know prior to jumping in.

Thank you for your time-


JS

You ask two different questions...I am not much help on the second regarding the sound and diagnosis.

As far as replacing the alt it is an easy job if you ahve done it before, takes about 2x if its your first time. There arent any special tools needed, just some patience. You need to remove the belts, remove the holder strap, and get your arms in there to pull it out. It is a dirty job.

Pelican carries this one which I have had good esperience with in SC engines on the street and track.

I think the 101 book or the manual carries the step-by-step directions for replacement. You should have both of those books on hand if not already.

Other "while you are in there" items to order inc new belts and alternator ground strap.

hth

After you remove your alternator take it to a alternator rebuild shop. Cost about $100.00. Make sure you disconnect the battery before removal.

It is fairly easy, the hard part is getting big hands behind the alt. to get the 5 nuts loose holding on the air deflector. And yes, take it to a good armature shop.

+1 on the above
don't forget to use your pulley tool, and
search here for John Walker's method for separating the alt from the housing once out.
you can do it. (I did and I have a desk job) :-)

First step would be to remove the belt and spin the alternator by hand to see if it rotates smoothly.

Use the J-wrench in the toolkit plus a socket for the nut. If you don't use the proper J-wrench and use the fins on the fan to counter-hold, you''ll be sorry because the fins can easily break throwing the fan out of balance.

Neanderthals do it quite often; not good!

Count the shims on both sides of the pulley and re-use when installing a new belt. Bentley 030-13 and 270-13 for noise diagnosis. Common mistake is to mis-align the shims during assembly.

If it's just bearings, there changable and can be a DIY project. Or you can have the whole unit rebult at a shop. Cost is the big factor. New bearings about $50 New alt. $650, your choice.

I removed the alternator from our '86 twice for servicing.

Once for a VR.

Once for brushes.

My suggestion, as above would be to verify that the intermittent noise is indeed emanating from your alternator.

Then, while still in the car, take it to some place like Sear for testing (voltage/amps) under load along with the intermitent noises, or if you remove the unit, have it bench tested.

If you need to have the unit re-built, do it all.

The primary advantage of retaining your alternator is O&M (existing outline and mounting compatibility).

Several members have purchased alternators only to discover that the new unit does not fit for various reasons.

good luck,

Gerry

The alternator is the only part where I've gone away from our site sponsor. Rock Auto has them for about $160 plus core charge. I was going to go with the OEM unit until a friend (who has been running a rebuilt "cheap" unit in his SC for years) pushed me away from the $600+ price tag. I put mine in a week ago and the fitment was perfect.
Replacement is an easier job than you'd think. Just go to the Tech Info Center tab here and follow the instructions for alternator replacement.

Thank you to all for your time and assistance.

first thing is disconnect battery!
 

before you do anything with the alternator, disconnect the battery,,,,you have a direct feed from the battery to the alternator via the starter. It will cook you and your car if it shorts.

Removing the alternator housing and replacing the alternator was my first 911 project. Here's what I learned.

(1) Read this article about three times before you start: Pelican Technical Article: 911 Alternator and Fan Replacement & Upgrade

(2) USE THE PULLY TOOL. I didn't know about it and found that the blades of that $300 fan chip off like pottery.

(3) Once the housing / fan / alternator assembly is out of the car, play some relaxing music and enjoy a nice dinner before starting stage 2 of the disassembly. It can be frustrating, but if you do what the article says it will come apart, eventually. I have 2 things to add to the article regarding this part...

(4) When it comes time to tap on the 6 alternator studs on the back of the housing, go easy on them if you plan to reinstall that alternator, otherwise you will have to clean the threads back up. Also, do it very evenly in a star pattern if you don't want to scratch up the fan or the housing as the alt/fan slides out.

(I did my second take apart,when I learned my alt was bad, with freshly painted parts)

(5) I leaned this trick when I disassembled the assembly the second time, there are plenty of opinions on this, and mine sounds pretty silly, but it worked great. Once you have the alternator/fan out of the housing, and it's time to remove the fan from the alt shaft; sit cross legged on the floor with the fan fins resting on your legs and the alternator housing loosely off the back of the fan in your lap. Then, gently and slowly tap the alternator shaft with a hammer until it slides out of the fan and falls gently to the floor. Your legs might hurt a little from the blades of the fan, but it worked great for me and is way gentler on the alternator and the fan than some of the other ideas I have heard.


Feel free to correct me everyone, I don't claim to really know anything, but this is what I leaned when I did this.

Just a thought, if you haven't pulled the alternator yet. Check the tension on the belt, I thought the bearings were going on my alternator as it was making the same intermittent rattling sounds, turns out the belt had just stretched. I just rearranged the shims to get the proper deflection, and it's been fine since. Worth checking before disassembly.

Funny but that was my first 911 project too! I belive I just followed Wayne's book and replaced brushes. Marked wires and scribbled a schematic on a piece of cardboard. Buttoned it up, re-shimed the fan pully and done!

Another thought - does the 80 still have the separate voltage regulator? On my cars they were replaced with the built in regulator and the VR and it's corresponding wires/plugs removed. I believe the easiest way you tell what you have is the pulley nut size but don't remember which is which right now.

Make sure the fan is not touching the fan housing. That could also explain the noise.
You would then see marks on the fan housing, and shiny fan blade tips.

This can happen with a cracked fan housing, or bad alternator bearings.
The clearance between the fan and the housing is pretty small.

-Guillaume

[removed - Double post]

Built in regulator started in '82.