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  #1  
Old 09-09-2010, 10:12 AM
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65A alternator on 1981 cars

Hello,

Though there is lots of info on here about alternators, one thing I have noted looking at parts catalogs is that for 81 cars, only 55A alternators are offered. On 82 cars, both 55 and 65A alternators are offered.

Curious if there is a fundamental difference from 81 to 82 (e.g. gauge of wires comeing from the alternator) that keeps them from offering 65A versions on the 81 cars. E.g. a liability thing or similar. The parts numbers are the same...

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Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1996 Dodge Ram CTD (438k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #2  
Old 09-09-2010, 10:45 AM
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Run new wires and use a Saab 80 or 120 amp alternator.
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  #3  
Old 09-09-2010, 11:04 AM
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2x. I wouldn't go through the bother to install a wimpy 65a alternator.

-J
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1991 350SDL. 230,000 miles (new motor @ 150,000).

2013 Fiat 500E. 20,000 miles, 80 miles at a time.
2012 Passat TDI. 95,000 miles. More space, power, and fuel economy than the Benz
2004 Touareg V10 TDI. 150,000 miles. One of 450.
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1992 Jetta ECOdiesel. 156,000 miles. 1 of 48. Sold.
1991 Jetta ECOdiesel. 430,000 miles. 1 of 700. Sold to VeeDubTDI, totaled in front of our house
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  #4  
Old 09-09-2010, 11:51 AM
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but to answer your question...
yes, in 82 the Turbo was added to most models, so there is at a minimum a tach addition. I think the climate control changed that year also. monovalve, etc.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #5  
Old 09-09-2010, 09:49 PM
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probably the change from 55 to 65 was only a change to the reg. You can get much more than 65 amps out of them if you put 12v across the rotor with no reg, the output voltage is very high & they dont last long though & I dont suggest you try it in a car. You can build a welder from an old alt.
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1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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  #6  
Old 09-10-2010, 07:16 AM
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Amperage capacity has to do with the number windings in the rotor and stator.
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  #7  
Old 09-10-2010, 07:22 AM
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It also is controlled by the voltage across the rotor. If you put a 65amp reg on a 55amp alt you will get 65 amps from it. I have done that, If you put 12 volts across the rotor, depending on the load, you will get much more, The flux saturation of the frame will have a bigger effect on the voltage & current.
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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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  #8  
Old 09-10-2010, 08:20 AM
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I believe the way the regulators are rated, they are or a family of alternators, like 55-115A
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1996 Dodge Ram CTD (438k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #9  
Old 09-10-2010, 08:31 AM
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JHZ,
I believe you are right !!
The reg dictates the output
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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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  #10  
Old 09-10-2010, 09:03 AM
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Quote:
Originally Posted by Gillig View Post
Run new wires and use a Saab 80 or 120 amp alternator.
How much work is it to adapt a Saab alternator to my 83? Does it have the same 3 terminal connector? Does the mounting have to be customized? Last week my alternator stopped charging. I replaced the regulator and cleaned the terminals and got it charging again but in the process one of the screws on the regulator broke (the one that's an electrical connection). It is charging now but I don't trust it without a screw to make a good connection so I am in the market for another alternator.
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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
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  #11  
Old 09-10-2010, 11:38 AM
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Steve, the saab alt bolts directly in but it's much larger physically than the original. and you have to swap the pulley over.
the wiring is different, as no spade terminal can handle 120A
LOTS of wiring posts here
search for "al129" enjoy!
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #12  
Old 09-11-2010, 06:07 PM
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Yes, the wiring must be upgraded to handle the current.
You may also need to reclock the rear half if you still have the A/C lines installed. Otherwise the power terminals will be close to the tube.

As noted, the pulley diameter is different to reduce the alternator maximum rpm for the high revving gasser. It won't hurt to leave it as-is, it just means you won't get the optimal charging potential at idle.
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  #13  
Old 09-11-2010, 10:59 PM
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I wonder if the pulley diameter is an issue with my car. Just swapped in a beru 14.2V regulator, and it was only putting out 13.7-8V at idle. I wonder if the wrong pulley was used and so it is not spinning fast enough?

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1996 Dodge Ram CTD (438k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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