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Alternator help - please.

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JPSmit

JPSmit

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Well friends, I need some help. Ms Triss has been off the road for about a month with a strange noise. I presumed it was the water pump so, finally put it together and the noise didn't go away. Took the fan belt off and the noise immediately went away. So, presumably the only other thing is the alternator.

Now the shrewder among you will recall clearly that 12 years ago when I was putting the engine back in that I went with a Delco alternator. Who among you remembers what car it originally came off of? (I seem to recall 90's V6). One thing I did notice as I was removing the alternator was that it wasn't perfectly parallel to the other pulleys. It was in line for the belt but twisted ever so slightly toward the engine as the belt pulled it.

So, I have added some video - the noise is regular but random - mostly when I accelerate. It sound more like sheet metal than solid internal metal.

Any thoughts? alternators are cheap enough, so if it is cooked, no problem, and if a new one, any suggestions? OTOH am I missing something? (the vanes don't appear to be touching)

help?

IMG_2779.jpg


 
I don't recognize the sound. I understand that the water pump is new but have you tried a "screwdriver stethoscope" to confirm it's the alternator and not somewhere else?

The alternator appears to be a Delco 10SI. Rather than repeat what you and others probably already know I'll just post a link to a webpage about them. (Used in many GM cars... just about any 1970s/1980s Camaro, Impala, etc. )
http://www.madelectrical.com/electricaltech/delcoremy.shtml

The 10SI was once very common and rebuilt units would be at the local parts store. Today you may need to have one ordered if you want a replacement.
 
SD Bugeye said:
Take the belt off see if it persists
Click to expand...

did. noise went away immediately. took the alternator to a shop today. he could find nothing wrong. so it may be an alignment issue it may be a harmonic. Went to try to get a new bracket at Canadian tire tonight - kid didn't even know what a bracket was (or an alternator for that matter) so no help there. Decided to do the next job and pull the switches off the steering column and soak them for a while in citric acid.

then the last job - replace the rear drivers spring (easier than loosing weight he thought to himself) I had bought a new used one (really is almost new) got the bushings, jacked up the car and noticed the oil dripping off the shock. hmmm. (can you bench test a lever shock?)

Pulled off the spring,. started removing the shackle thing at the end and - knowing full well that I was going to do it mind you - sheered off the nut. So I think there is a road trip tomorrow. sheesh.
 
I had a 302 that would make a wierd slapping noise similar to what I’m hearing in your recording
it was the thermostat
busted and when you would rev it it would make a slapping noise and zinging noise as water would rush through it.
 
SD Bugeye said:
I had a 302 that would make a wierd slapping noise similar to what I’m hearing in your recording
it was the thermostat
busted and when you would rev it it would make a slapping noise and zinging noise as water would rush through it.
Click to expand...

Interesting - who would have thunk it, will take a look
 
Do you still have a fan clutch? They are notorious for failing. I you are removing the belt the pump and fan wouldn't be turning would it?

Kurt
 
nomad said:
Do you still have a fan clutch? They are notorious for failing. I you are removing the belt the pump and fan wouldn't be turning would it?

Kurt
Click to expand...

do still have a fan clutch - how might I diagnose it?
 
The genertor on our BJ7 appears to be very unhappy, particularly when first starting it up. Diagnosis was the traditional approach of holding a long screw driver to my ear, and then putting the blade on various potential points (dynamo, block adjacent to water pump, etc. etc.). Sure lots of mechanical noises, but also sure looks like the 'dynamo'. The car is tucked away for the winter and I'll worry about replacing it/rebuilding it come Spring, as it'll be warm a month before I really want to get it out on the roads (waiting for the City guys to have a chance to clean the sand and gravel off). Similar timing for the motorcycle. Doug
 
JPSmit said:
do still have a fan clutch - how might I diagnose it?
Click to expand...

I guess first I would see if there is any play in it but the only way to be sure would be to remove the fan and clutch. Maybe just removing the fan would stop it from making the noise and that would be a pretty good indication of the problem. Your vid sure sounded like something a bad fan clutch would do.

Kurt
 
nomad said:
I guess first I would see if there is any play in it but the only way to be sure would be to remove the fan and clutch. Maybe just removing the fan would stop it from making the noise and that would be a pretty good indication of the problem. Your vid sure sounded like something a bad fan clutch would do.

Kurt
Click to expand...

I will say that the old clutch got pressed on to the new water pump - so I could have transferred the problem
 
well friends, I am stumped. I got the engine back together, and nothing has changed.

To recap, it still makes the noise.

It did go away when the fan belt was off.
I have a new system for holding on the alternator and it is straight.
I had the stethoscope on it and the alternator doesn't seem to be it.
I find that the closer I get to the fan the quieter it gets and the further (on the water pump housing) the noisier it gets.
(Remember I did change the water pump)

When I rev the engine it seems to "push through" the sound and at higher revs I don't hear it - remember, it comes and goes.

I took it for a test drive and it is definitely there, and, troublingly, I can feel it in the clutch.

So, could it be something as ominous as the thrust washers?

I am open to any and all ideas right now.
 
If you’ve got a 1500 under the bonnet that could be it. A BF Screwdriver to see movement on the harmonic balancer might be in order.
 
Just got around to listening to the vid. Could the fan on the alternator be loose? I believe that they are held in place just by tightening the nut and nothing else. Sounds like that or perhaps the fan clutch.

Kurt
 
nomad said:
Just got around to listening to the vid. Could the fan on the alternator be loose? I believe that they are held in place just by tightening the nut and nothing else. Sounds like that or perhaps the fan clutch.

Kurt
Click to expand...

I did have an alternator guy spin it up on a machine and he heard nothing - but I will certainly check - thanks
 
JP, I'm guessing, like everyone else, but that noise doesn't sound like something that could be coming from inside the engine. Still if I had a 1500 I would check for crank end play to see if it was out of spec just from others experience. It seem's to be in concert with accelerating and decelerating. If the alternator isn't the issue i would sure suspect the fan clutch. Process of elimination. BTW, my engine diagnosis listening device has always been a piece of heater hose. I always though that worked the best.

Kurt
 
Or a cracked fan blade. Look closely. And do NOT lean over the fan or the known blade escape routes while listening.
 
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