persh
Frequent Contributor
Posts: 1498
Loc: Tucson, Arizona
Reg: 07-19-00
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10-12-23 04:42 PM - Post#2863286
I'm using an '83 350 in my '65 truck and am looking for an alternator that can keep up the air conditioning and an electric fan from a '90s Thunderbird. My current 10SI alternator gives me 14 volts with nothing being used. When to fan and A/C are on it gives me about 10 volts at idle and goes to about 11 volts when driving at speed.
I was wondering if I can out an alternator from a newer vintage to help my problem. Can the new high amp units be converted to a single groove v-belt pulley to replace the multi-V pulley they come with?
Thanks for your input....
Van
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 Shepherd
Valued Contributor
Posts: 3182
Loc: Lake George, NY
Reg: 11-11-15
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10-12-23 05:06 PM - Post#2863287
In response to persh
What is you alternator rated at now?
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bobb
Super Senior Member
Posts: 6461
Loc: paradise
Reg: 09-05-03
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10-15-23 10:44 AM - Post#2863340
In response to persh
https://www.amazon.com/dp/B007NNH0FK/ref=ssp a_dk_d...
make sure to upgrade your alternator wire to at lease 10 Gauge. might be nice to add a dedicated ground too.
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
Edited by bobb on 10-15-23 10:45 AM. Reason for edit: No reason given.
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65_Impala
Very Senior Member
Posts: 4991
Reg: 12-29-02
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10-17-23 12:06 PM - Post#2863398
In response to persh
Look at a CS144 alternator. They can do 2-3 times the idle output of any 10SI based alternator. You can get them cheap enough and they'll bolt right into the same brackets, take an impact and swap to the V-belt pulley from your old unit.
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 Magnetocheck
"2nd Year" Silver Supporting Member
Posts: 295
Age: 69
Loc: Charlotte, NC, USA
Reg: 09-05-22
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10-17-23 12:45 PM - Post#2863399
In response to 65_Impala
100 Amp is probably sufficient for normal upgrades (electric fans, A/C, stereo) You might need more if you have a massive electrical load (A/C, power windows and seats, air suspension, earthquake subwoofers, etc. As Bobb says, make sure you upgrade your wiring. An extra ground is never a bad idea and easy to install, but probably not necessary if you've got an excellent ground to the block through the alt mount. -- check it, don't guess.
I put a new 150 Amp PowerMaster on my '65 and used the 1-groove pulley it came with. Easy installation. 150A is more than I need but gives me some buffer for those earthquake subwoofers down the road!  The tech guys were very helpful with selection and wiring advice. Give them a call:
Powermaster Manufacturing Facility:
1833 Downs Drive
West Chicago, IL 60185
http://www.powermastermotorsports.com/
Tech Center: 630-849-7754
tech@powermasterperforman ce.com
Sales/ Customer Service: 630-957-4019
Fax: 630-876-2967
Bob
'65 Impala SS 396 Convertible |
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65_Impala
Very Senior Member
Posts: 4991
Reg: 12-29-02
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10-17-23 04:15 PM - Post#2863402
In response to Magnetocheck
The fan he mentioned draws over 40A at idle. A 100A 10SI will maybe produce 40A at idle, so there'd be no extra capability for the other things.
He does need to update the wiring to handle the extra current. Seeing 10V implies the wiring isn't capable of handling the draw when the battery supplies it.
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Magnetocheck
"2nd Year" Silver Supporting Member
Posts: 295
Age: 69
Loc: Charlotte, NC, USA
Reg: 09-05-22
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10-17-23 05:03 PM - Post#2863403
In response to 65_Impala
Didn’t realize the fan would pull that much- you’re correct- 150A would be better.BTW, I have dual fans, upgraded sound system with dual amps, and Vintage Air a/c. My 150A Power Master keeps up no problem
Bob
'65 Impala SS 396 Convertible |
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65_Impala
Very Senior Member
Posts: 4991
Reg: 12-29-02
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10-19-23 12:43 PM - Post#2863441
In response to Magnetocheck
Powermaster makes decent stuff, so that 150A alternator would crank out lots of current at engine idle.
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monty56
"19th Year" Gold Supporting Member
Posts: 1565
Loc: Chandler(it's a dry heat)...
Reg: 04-26-04
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10-20-23 08:23 AM - Post#2863460
In response to 65_Impala
Mine keeps up with my two air pumps for my air bags just fine.
Monty
'56 3100 Short Stepside Someday
2001 Chevy Suburban 2500
2009 Saturn Vue w/20's
Member: Desert Classic Chevy's Inc.
Monty's 56 Truck
Avatar is my Truck
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persh
Frequent Contributor
Posts: 1498
Loc: Tucson, Arizona
Reg: 07-19-00
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10-20-23 02:26 PM - Post#2863467
In response to monty56
Thanks a million for all the input. It never occurred to me that lack of hefty wiring would be a big consideration, so I'm going start there. I had an alternator shop redo my 10SI to a higher voltage - they said it was good for 140 amps but I'm not sure that's really the case. So, wiring first and then on to a more "modern" alternator.
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Magnetocheck
"2nd Year" Silver Supporting Member
Posts: 295
Age: 69
Loc: Charlotte, NC, USA
Reg: 09-05-22
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10-20-23 11:47 PM - Post#2863473
In response to persh
Hey Persh: Any shop that can rebuild an alternator should be able to test it and confirm that it is putting out the correct number of amps. They should be able to get you some sort of chart of amps@rpm that would be helpful. In any case, if it is really good for 140 Amps at cruise, it should be sufficient for what you said you need at idle. As 65_Impala says, you still need to look at your wiring to make sure it can handle the additional amps.
Bob
'65 Impala SS 396 Convertible |
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persh
Frequent Contributor
Posts: 1498
Loc: Tucson, Arizona
Reg: 07-19-00
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10-21-23 01:32 PM - Post#2863482
In response to Magnetocheck
Update: I ran a piece of #4 battery cable directly from the alternator to the + side of the battery. Now with the A/C on high and the fan running I still get the 10 volts at idle but off idle the volt gauge jumps right up to between 12 and 13 volts. So, yes, definitely a wiring issue. Problem solved!!
Thanks again for all the help. You guys are the greatest!!
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Magnetocheck
"2nd Year" Silver Supporting Member
Posts: 295
Age: 69
Loc: Charlotte, NC, USA
Reg: 09-05-22
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10-21-23 02:42 PM - Post#2863485
In response to persh
Glad it's running better, but your alt. is still not putting out enough IMO. Ideally it should be generating ~14 volts at idle with no load and maybe 12-13v with everything "on" (lights, a/c, fans). It needs to be > 12 all the time or it won't charge the battery sufficiently.
You could call the shop and see what they think. I am wondering if you got a real 140 Amp unit from them.
Bob
'65 Impala SS 396 Convertible |
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65_Impala
Very Senior Member
Posts: 4991
Reg: 12-29-02
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10-22-23 09:00 AM - Post#2863496
In response to persh
I consider a charging system below high 13's at ide and below 14V at speed lacking.
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persh
Frequent Contributor
Posts: 1498
Loc: Tucson, Arizona
Reg: 07-19-00
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11-12-23 01:33 PM - Post#2864095
In response to 65_Impala
It turns out the volt meter that's mounted under the dash isn't the highest quality and appears to be reading about a volt or so too low, so I think I'm about where I need to be with the alternator. I've been using the truck almost every day for the last month and everything seems to be working as it should.
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Magnetocheck
"2nd Year" Silver Supporting Member
Posts: 295
Age: 69
Loc: Charlotte, NC, USA
Reg: 09-05-22
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 11-12-23 01:40 PM - Post#2864096
In response to persh
Good job!
Bob
'65 Impala SS 396 Convertible |
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bobb
Super Senior Member
Posts: 6461
Loc: paradise
Reg: 09-05-03
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11-23-23 09:54 AM - Post#2864421
In response to persh
always test using a multimeter at the terminal post and the wire terminal on anything you test.
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
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