Alternator ??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ryanroo · 03-31-2005, 02:24 PM

I was wondering if there is a way to find out it the alternator on my truck is extenally or internally regulated. it is starting to howl intermitenly and i have an alternator i took of a 77 chevy that i can toss on it, but im not sure if what i have os internally regulated. thanks for the help
Ryan

sneakysnake · 03-31-2005, 02:30 PM

If it has a square plug its external, blade run (II)
If it has a rectangle plug its internal,blades run(- -)

ryanroo · 03-31-2005, 02:32 PM

thanks very much, must be internal, because i has to use a the (- -) to hook it up
Ryan

nathank · 03-31-2005, 03:13 PM

Externally regualted should have a regulator mounted someplace too.. little black box looking thing.

Bstang · 04-03-2005, 11:12 AM

Sounds like you have a external regulator may be mounted on the rad. support assy. on the drivers side under the head lights a black box about 3 inches square with a flat plug. Sounds like a bad diode in the alternater, pull alt. and reg. off and have both checked repairs to alt. cheap, and if it's been on a while it's time for brushes and bearings anyway.
Bstang

**VetteVet** · 04-03-2005, 12:18 PM

here's some good info on the alternators

http://www.madelectrical.com/electrical-tech.shtml

VetteVet

nathank · 04-03-2005, 05:06 PM

If you do have an externally reg unit, might as well go ahead and convert to an internal reg unit. I picked up a 10si for under $40. Not a bad price for an alternator.

CHEVIBUBBA · 04-03-2005, 08:10 PM

or; you can use the one you have from the '77.
just use the instructions from mad.

LUV2XCLR8 · 04-03-2005, 08:15 PM

External Box

ryanroo · 04-04-2005, 02:51 AM

well the voltage regulator is there, but im not sure if it is being used. the current engine came out of a 76 and has the alternator on the wrong side for our era trucks. i also know i had to convert the wiring harness to the horizontal plug style from the vertical to make it work, and the alternator is the same as the one from the 77. so any advice on how to tell if its being internally or externally regulated? thanks
Ryan

sneakysnake · 04-04-2005, 12:06 PM

eliminate the external reg.

ehjorten · 04-04-2005, 03:57 PM

So...you say that it is starting to howl. Sounds like the rear bearing?! If you converted, or it was converted...does it have the rear bearing support bracket attached? If not, this is accelerating your rear bearing failure! Many times people neglect this bracket when converting their vehicles (the bolt hole location changes from a DN to SI alternator).

67chevemall · 04-04-2005, 04:19 PM

^ good point! Also make sure the grounds are good on the voltage reg!

03-31-2005, 02:24 PM	#1
ryanroo Senior Member Join Date: Apr 2004 Location: sw colorado Posts: 2,720	Alternator ??? I was wondering if there is a way to find out it the alternator on my truck is extenally or internally regulated. it is starting to howl intermitenly and i have an alternator i took of a 77 chevy that i can toss on it, but im not sure if what i have os internally regulated. thanks for the help Ryan __________________ 72 K20 12v build 72 K20 "parts truck" A place for your diesel swap questions

03-31-2005, 02:32 PM	#3
ryanroo Senior Member Join Date: Apr 2004 Location: sw colorado Posts: 2,720	thanks very much, must be internal, because i has to use a the (- -) to hook it up Ryan __________________ 72 K20 12v build 72 K20 "parts truck" A place for your diesel swap questions

03-31-2005, 03:13 PM	#4
nathank resident geek Join Date: Jan 2005 Location: Dusty West Texas Posts: 77	Externally regualted should have a regulator mounted someplace too.. little black box looking thing. __________________ 71 C-10 stepper 88 Moostang T-Top w/ lots of goodies

04-03-2005, 12:18 PM	#6
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,709	alternators here's some good info on the alternators http://www.madelectrical.com/electrical-tech.shtml VetteVet __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

04-03-2005, 05:06 PM	#7
nathank resident geek Join Date: Jan 2005 Location: Dusty West Texas Posts: 77	If you do have an externally reg unit, might as well go ahead and convert to an internal reg unit. I picked up a 10si for under $40. Not a bad price for an alternator. __________________ 71 C-10 stepper 88 Moostang T-Top w/ lots of goodies

03-31-2005, 02:30 PM	#2
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	If it has a square plug its external, blade run (II) If it has a rectangle plug its internal,blades run(- -)

04-03-2005, 11:12 AM	#5
Bstang Registered User Join Date: Mar 2005 Location: Camrose, Alberta Posts: 26	Sounds like you have a external regulator may be mounted on the rad. support assy. on the drivers side under the head lights a black box about 3 inches square with a flat plug. Sounds like a bad diode in the alternater, pull alt. and reg. off and have both checked repairs to alt. cheap, and if it's been on a while it's time for brushes and bearings anyway. Bstang

04-03-2005, 08:10 PM	#8
CHEVIBUBBA got boost? Join Date: Mar 2005 Posts: 123	or; you can use the one you have from the '77. just use the instructions from mad. __________________ '70 chevy lwb w/'67 hood. 357 s.b.c. built, 4l60 w/vigilante lockup high stall converter, edelbrock pro-flo,brodix heads,comp cams rollerized w/ belt drive, one piece d-shaft, yada, yada, yada..... '82 honda v45 sabre"the black"

04-03-2005, 08:15 PM	#9
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,475	External Box __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Big Piggy: "Goliath" 07 Kodiak C4500 Lil Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T

04-04-2005, 02:51 AM	#10
ryanroo Senior Member Join Date: Apr 2004 Location: sw colorado Posts: 2,720	well the voltage regulator is there, but im not sure if it is being used. the current engine came out of a 76 and has the alternator on the wrong side for our era trucks. i also know i had to convert the wiring harness to the horizontal plug style from the vertical to make it work, and the alternator is the same as the one from the 77. so any advice on how to tell if its being internally or externally regulated? thanks Ryan __________________ 72 K20 12v build 72 K20 "parts truck" A place for your diesel swap questions

04-04-2005, 12:06 PM	#11
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	eliminate the external reg. Attached Images

04-04-2005, 03:57 PM	#12
ehjorten Registered User Join Date: Jan 2001 Location: Kirkland, WA, U.S.A. Posts: 32	So...you say that it is starting to howl. Sounds like the rear bearing?! If you converted, or it was converted...does it have the rear bearing support bracket attached? If not, this is accelerating your rear bearing failure! Many times people neglect this bracket when converting their vehicles (the bolt hole location changes from a DN to SI alternator). __________________ '68 Chevy Stepside in Frame-up Restoration process. 292 CID Clifford Performance Modified T56 6-speed Tranny Slammed, Custom IFS and IRS Money?...Too Much!

04-04-2005, 04:19 PM	#13
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	^ good point! Also make sure the grounds are good on the voltage reg!



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