78 Camaro internally regulated Alternator Swap

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jmikulec
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Joined: Mon Jan 25, 2016 6:47 pm

Re: 78 Camaro internally regulated Alternator Swap

Post by jmikulec »

A weird thing happened today where I just stopped from driving and pulled up my hood to the engine compartment and hear the battery sizzling from inside! What is the problem Here. I am just using a stock alternator on my 65 monza.
jmikulec
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Re: 78 Camaro internally regulated Alternator Swap

Post by jmikulec »

I put a multimeter on it and it was 13.1 volts while off! This is a brand new battery.
cnicol
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Re: 78 Camaro internally regulated Alternator Swap

Post by cnicol »

Possibly a bad regulator is overcharging the battery. What's the voltage when it's running?

Note that right after you shut off the engine, battery voltage will be a little higher than the usual 12.8 volts. This temporary higher voltage (13.1 is in this range) is called a "surface charge". After some time, the surface charge will dissipate and drift down to 12.8.
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DAVECS1
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Re: 78 Camaro internally regulated Alternator Swap

Post by DAVECS1 »

66 vairguy I went and double checked. I believe this is the alternator I used.

http://www.oreillyauto.com/site/c/detai ... &ppt=C0330
1964 Monza Convertible
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66vairguy
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Re: 78 Camaro internally regulated Alternator Swap

Post by 66vairguy »

Dave - that looks like the Delco 12SI and had a serpentine pulley on it - did the link show the wrong atlerntor?
Frankly I've forgotten if you can bolt the 12SI up to the Corvair 10DN front frame. The only issue I could see would be that the 12SI front housing and fan were designed to increase cooling airflow (considerably) over the 10DN/10SI fan. Based on what I've read the Corvair alternator fan cooling limit is 80Amps sustained output - which I doubt you are using.

Needless to say the 12SI housing and fan work in the OPPOSITE rotation of the Corvair - so adapting the 12SI fan is not doable. I had a buddy put a lot of time in on doing it until I had the unfortunate task of informing him the Corvair alternator turns in the opposite rotation of the 12SI fan design - ooops.
DAVECS1
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Re: 78 Camaro internally regulated Alternator Swap

Post by DAVECS1 »

I cant remember if I used the serpentine or this one.
http://www.oreillyauto.com/site/c/detai ... &ppt=C0330

Which ever one it was, the Corvair front housing and fan bolted up no problems. With the 4 awg wire for the starting and charging circuits, I have never had a starting issue. 60 dollars and some wire, make for a pretty bullet proof solution.
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notched
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Re: 78 Camaro internally regulated Alternator Swap

Post by notched »

I have a 12SI I converted here. They convert the same way as the 10SI.......use the Corvair end frame and fan and pulley.
Not all 12SI models used serpentine pulleys.
1966 Corsa turbo
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skipvair
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Re: 78 Camaro internally regulated Alternator Swap

Post by skipvair »

So are you saying that rotation direction does mot matter as lpng as fan is correct for corvair?



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Frank Metasavage

65 Corsa 140 4 speed with Weber IDAs
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notched
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Re: 78 Camaro internally regulated Alternator Swap

Post by notched »

skipvair wrote: Mon May 08, 2017 4:35 pm So are you saying that rotation direction does mot matter as lpng as fan is correct for corvair?



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Correct. The pulley and fan are one piece. Use the correct one for a 65-69 Corvair along with the end frame.
Stay away from the 1 wire alternators as you will lose the warning lamp which is your only indications that the belt has come off should that occur.
1966 Corsa turbo
1969 Monza convertible
1987 Buick Grand National
66vairguy
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Re: 78 Camaro internally regulated Alternator Swap

Post by 66vairguy »

skipvair wrote: Mon May 08, 2017 4:35 pm So are you saying that rotation direction does mot matter as lpng as fan is correct for corvair?



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This is an old thread come back to life. Not sure about your question. The REVERSE rotation of the Corvair engine requires the UNIQUE Corvair alternator fan and pulley. If you buy a rebuilt original style 10DN alternator make sure it has the UNIQUE Corvair fan and pulley. It has been reported that sometimes the rebuilt units have the WRONG fan and pulley (the one used on all other Chevrolets). Often the used fans are corroded or bent and rebuilders replace them with the WRONG fan (apparently nobody makes a new replacement Corvair fan and pulley).

If you upgrade from a 10DN to a 10SI, or 12SI you must install the original Corvair fan and pulley AND the front mounting frame that was unique to the Corvair 10DN. Do NOT use the fan and pulley that comes on the standard Chevy alternator as it will not provide adequate cooling.

That said - I run into a number of folks who say "I used the non Corvair fan and it works fine" - to which I reply - "Until it doesn't". The alternator fan is designed to PULL in cooling air into the back of the alternator (were the electronics are) and expel hot air at the fan side. Improper cooling results in HOT electrical components and that shortens the life of them.

I hope that answers you question.
skipvair
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Re: 78 Camaro internally regulated Alternator Swap

Post by skipvair »

I have a failing alternator on a car i just bought that i have suspected has an incorrect fan. I just received the car and it has a different looking fan on it which was suspect. Doesnt charge after driving a while (probably heat frying it). Am in Mexico til friday and cant even look at it til then, but I suspect that is issue. Have an old correct alternator and will compare. Thanks.


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Frank Metasavage

65 Corsa 140 4 speed with Weber IDAs
66 Corsa 140 4 speed Stock
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