88 alternator pulley
12-04-2018, 07:27 PM
#1
Safety Car
Thread Starter
88 alternator pulley
Greetings All,
A QUESTION OR TWO -
88 vette and stock alternator....Alternator went out a week ago but, was fortunate enough to have one with a life warranty (bought in 2008 but, with minimal miles on it)....After installing and on a cool day, voltage reading was about 14.0v at start up and as we all know, that will drop once battery charges and as heat infiltrates the alternator and the outside air temps get higher....However, at idle with battery charged, ac on, brake lights on - the output dropped to barely 12volts maybe just barely a bit higher.
Is there a smaller drive pulley that is obtainable or cross fits from another vehicle that fits here?...There is NOTHING wrong with the charging system in the car and I have even temporarily ran heavier wires to "+ and -" accordingly to see if any effect(s).
A QUESTION OR TWO -
88 vette and stock alternator....Alternator went out a week ago but, was fortunate enough to have one with a life warranty (bought in 2008 but, with minimal miles on it)....After installing and on a cool day, voltage reading was about 14.0v at start up and as we all know, that will drop once battery charges and as heat infiltrates the alternator and the outside air temps get higher....However, at idle with battery charged, ac on, brake lights on - the output dropped to barely 12volts maybe just barely a bit higher.
Is there a smaller drive pulley that is obtainable or cross fits from another vehicle that fits here?...There is NOTHING wrong with the charging system in the car and I have even temporarily ran heavier wires to "+ and -" accordingly to see if any effect(s).
12-04-2018, 08:27 PM
#3
Safety Car
Thread Starter
Except that is NOT WHAT I ASKED ABOUT and I know the system is well.....Did an alternator upgrade on my 81 (internal kit) and had to put a smaller pulley on that to keep it spinning at a higher rpm to get it's full output or potential.
The following 2 users liked this post by gpierce:
ctmccloskey (12-06-2018),
Red 91 (12-05-2018)
12-06-2018, 01:48 PM
#5
Safety Car
Hello again Da Mail Man!
There are differences in alternators that could explain why it is not charging as fast. If it was near 14 volts after a start up you should be all set. How full was the battery when you started it up any Guess? The more power in the battery will make your alternator not need to make a ton of power and therefor your voltage. Do you have a multi meter with the "Min-Max" function on it? If you do, watch the low voltage during cranking, typically it should drop to 11+ volts, once it starts hitting the 10 volt mark the battery is questionable.
What is the source of your Indicated Voltage? If it is not from a Multi-meter then it is probably not too accurate. People find this problem when they think their temperature gauge is showing what is actually the real temperature. Dash gauges are just a hair above idiot lights in their accuracy.
After starting a car the battery gets recharged fairly quickly as the normal flooded lead acid battery like about 14.7 volts peak and from there it tapers down as the battery needs it.
If you really have 12.0 volts at idle with everything "On" in the car, your new alternator might not be charging like it should be right after startup. Are all the connections clean with no corrosion? How old is the battery and what brand?
Beware of aftermarket hi amperage alternators, I have a 125 amp unit on my C3 and it is the typical one wire alternator. When my car starts up and idles the darn alternator would not start charging until it hit close to 1000 rpm. I simply kicked the idle above that speed and it started charging the poop out of my system. After a while it does get old worrying about this so I wired the alternator to start upon the key turning on the car. It is a simple fix for that but running large enough battery cables was a pain with a C3 as the battery is behind the driver. I simply ran the new 4 gauge wires directly to the starter where it met with the cable from the battery.
I hope this helps a little!
Merry Christmas!
There are differences in alternators that could explain why it is not charging as fast. If it was near 14 volts after a start up you should be all set. How full was the battery when you started it up any Guess? The more power in the battery will make your alternator not need to make a ton of power and therefor your voltage. Do you have a multi meter with the "Min-Max" function on it? If you do, watch the low voltage during cranking, typically it should drop to 11+ volts, once it starts hitting the 10 volt mark the battery is questionable.
What is the source of your Indicated Voltage? If it is not from a Multi-meter then it is probably not too accurate. People find this problem when they think their temperature gauge is showing what is actually the real temperature. Dash gauges are just a hair above idiot lights in their accuracy.
After starting a car the battery gets recharged fairly quickly as the normal flooded lead acid battery like about 14.7 volts peak and from there it tapers down as the battery needs it.
If you really have 12.0 volts at idle with everything "On" in the car, your new alternator might not be charging like it should be right after startup. Are all the connections clean with no corrosion? How old is the battery and what brand?
Beware of aftermarket hi amperage alternators, I have a 125 amp unit on my C3 and it is the typical one wire alternator. When my car starts up and idles the darn alternator would not start charging until it hit close to 1000 rpm. I simply kicked the idle above that speed and it started charging the poop out of my system. After a while it does get old worrying about this so I wired the alternator to start upon the key turning on the car. It is a simple fix for that but running large enough battery cables was a pain with a C3 as the battery is behind the driver. I simply ran the new 4 gauge wires directly to the starter where it met with the cable from the battery.
I hope this helps a little!
Merry Christmas!
12-09-2018, 07:22 AM
#6
Safety Car
Thread Starter
Hello again Da Mail Man!
Greetings
There are differences in alternators that could explain why it is not charging as fast. If it was near 14 volts after a start up you should be all set.
It was
How full was the battery when you started it up any Guess?
Unknown but, almost fully charged if not already charged since I had a large charger on it for a while.
The more power in the battery will make your alternator not need to make a ton of power and therefor your voltage.
Agreed
Do you have a multi meter with the "Min-Max" function on it?
No
If you do, watch the low voltage during cranking, typically it should drop to 11+ volts, once it starts hitting the 10 volt mark the battery is questionable.
What is the source of your Indicated Voltage?
External volt meter known to be accurate and dash gauge BOTH reading the same.
If it is not from a Multi-meter then it is probably not too accurate.
n/a
People find this problem when they think their temperature gauge is showing what is actually the real temperature. Dash gauges are just a hair above idiot lights in their accuracy.
-see above-
After starting a car the battery gets recharged fairly quickly as the normal flooded lead acid battery like about 14.7 volts peak and from there it tapers down as the battery needs it.
Agreed, I know this
If you really have 12.0 volts at idle with everything "On" in the car, your new alternator might not be charging like it should be right after startup.
I have seen it drop to that level with everything on and if i up the idle, so does the voltage comes up - thus the reason for the pulley question...I have a lot of conversion kits in my garage that converts the older style alternators from 6pI to about 100-105 and it specifically tells you that the idle (or pulley alteration) should be necessary to "turn the alternator to full on" so-to-speak.
Are all the connections clean with no corrosion?
yes, of course.
How old is the battery and what brand?
6 months old and don't recall brand
Beware of aftermarket hi amperage alternators,
The clearances for a high amp alt is limited w/out alterations do, that is something I would not consider....I think the issue is or will be resolved as soon as I clear out some other projects and purchase the new pulley.
I have a 125 amp unit on my C3 and it is the typical one wire alternator. When my car starts up and idles the darn alternator would not start charging until it hit close to 1000 rpm. I simply kicked the idle above that speed and it started charging the poop out of my system. After a while it does get old worrying about this so I wired the alternator to start upon the key turning on the car. It is a simple fix for that but running large enough battery cables was a pain with a C3 as the battery is behind the driver. I simply ran the new 4 gauge wires directly to the starter where it met with the cable from the battery.
Greetings
There are differences in alternators that could explain why it is not charging as fast. If it was near 14 volts after a start up you should be all set.
It was
How full was the battery when you started it up any Guess?
Unknown but, almost fully charged if not already charged since I had a large charger on it for a while.
The more power in the battery will make your alternator not need to make a ton of power and therefor your voltage.
Agreed
Do you have a multi meter with the "Min-Max" function on it?
No
If you do, watch the low voltage during cranking, typically it should drop to 11+ volts, once it starts hitting the 10 volt mark the battery is questionable.
What is the source of your Indicated Voltage?
External volt meter known to be accurate and dash gauge BOTH reading the same.
If it is not from a Multi-meter then it is probably not too accurate.
n/a
People find this problem when they think their temperature gauge is showing what is actually the real temperature. Dash gauges are just a hair above idiot lights in their accuracy.
-see above-
After starting a car the battery gets recharged fairly quickly as the normal flooded lead acid battery like about 14.7 volts peak and from there it tapers down as the battery needs it.
Agreed, I know this
If you really have 12.0 volts at idle with everything "On" in the car, your new alternator might not be charging like it should be right after startup.
I have seen it drop to that level with everything on and if i up the idle, so does the voltage comes up - thus the reason for the pulley question...I have a lot of conversion kits in my garage that converts the older style alternators from 6pI to about 100-105 and it specifically tells you that the idle (or pulley alteration) should be necessary to "turn the alternator to full on" so-to-speak.
Are all the connections clean with no corrosion?
yes, of course.
How old is the battery and what brand?
6 months old and don't recall brand
Beware of aftermarket hi amperage alternators,
The clearances for a high amp alt is limited w/out alterations do, that is something I would not consider....I think the issue is or will be resolved as soon as I clear out some other projects and purchase the new pulley.
I have a 125 amp unit on my C3 and it is the typical one wire alternator. When my car starts up and idles the darn alternator would not start charging until it hit close to 1000 rpm. I simply kicked the idle above that speed and it started charging the poop out of my system. After a while it does get old worrying about this so I wired the alternator to start upon the key turning on the car. It is a simple fix for that but running large enough battery cables was a pain with a C3 as the battery is behind the driver. I simply ran the new 4 gauge wires directly to the starter where it met with the cable from the battery.
12-15-2018, 08:03 AM
#7
Greetings All,
A QUESTION OR TWO -
88 vette and stock alternator....Alternator went out a week ago but, was fortunate enough to have one with a life warranty (bought in 2008 but, with minimal miles on it)....After installing and on a cool day, voltage reading was about 14.0v at start up and as we all know, that will drop once battery charges and as heat infiltrates the alternator and the outside air temps get higher....However, at idle with battery charged, ac on, brake lights on - the output dropped to barely 12volts maybe just barely a bit higher.
Is there a smaller drive pulley that is obtainable or cross fits from another vehicle that fits here?...There is NOTHING wrong with the charging system in the car and I have even temporarily ran heavier wires to "+ and -" accordingly to see if any effect(s).
A QUESTION OR TWO -
88 vette and stock alternator....Alternator went out a week ago but, was fortunate enough to have one with a life warranty (bought in 2008 but, with minimal miles on it)....After installing and on a cool day, voltage reading was about 14.0v at start up and as we all know, that will drop once battery charges and as heat infiltrates the alternator and the outside air temps get higher....However, at idle with battery charged, ac on, brake lights on - the output dropped to barely 12volts maybe just barely a bit higher.
Is there a smaller drive pulley that is obtainable or cross fits from another vehicle that fits here?...There is NOTHING wrong with the charging system in the car and I have even temporarily ran heavier wires to "+ and -" accordingly to see if any effect(s).
When I purchased my car and drove it home everything worked perfectly. I bought a beautiful freshly painted, flame red, 1985 Corvette, everything working and well maintained, all GM AC Delco, parts. Except for one. ($5K for the car). The previous owner said he had just gotten a new alternator installed by his "friend". He told me a short story about how his "friend" had to return the first one because it was bad or the wrong one and exchange it at Advance Auto Parts. It was a 120 Amp alternator by the receipt he gave me. At home, going over, and admiring my new engine I noticed the new drive belt looked a bit frayed on the outside. I went to AutoZone and bought a new Gator Back belt. I installed it, and it seemed a bit tight, side to side, but just thought, well, it was because it was a new belt... I started the engine and right away heard this thwap thwap thwap sound. It turned out to be that the outer edge of the belt had sheered off completely. I was stunned and thought that AutoZone sold me the wrong belt. But after closer inspection, the previous owner had installed an alternator with a pulley that only had 5 grooves. The pulley sheered off the outer edge, and then just kept going, without any other sound.Damn thing worked but it's integrity was greatly suspicious. I went to eBay right away. I found the alternate size pulley by accident, really. and bought it and a new belt. It worked/works as advertised. At stop lights, the lights don't dim and the voltage (which on the dash gauge matches the voltage reading on my DVM) don't drop, reads 14 volts. My battery stays freshly charged. I highly recommend it. Do a search on eBay, I'm sure you'll find one for your car.