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#1 |
Registered User
Join Date: Jan 2010
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Does anyone know anything about 20dn alternators?
I have 2 different 20dn alternators. Both have the same plug on the back side our trucks use. There are 2 series of them. The 20dn series 150 # 1117765 and is off a 67 I had and the other is a 20dn series 250 #1117756. Both would inter change and look the same except for the back side. What is the difference between the series and which is better? Any information out there?
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#2 |
Registered User
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Re: Does anyone know anything about 20dn alternators?
Any info at all? Searched the Internet and there is no info on these at all. My one alternator is #1117767 not 1117765. My mistake.
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#3 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,430
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Re: Does anyone know anything about 20dn alternators?
Give it some time for responses. I'll admit that I know zip point zit about these alternators.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#4 |
Msgt USAF Ret
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Location: Kalamazoo, Michigan
Posts: 8,714
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Re: Does anyone know anything about 20dn alternators?
I googled them and came up with not much. They were used on larger vehicles like busses and large trucks. I think the different series were just different amperage outputs.
They are listed as obsolete on some sites.
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VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. |
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#5 |
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Re: Does anyone know anything about 20dn alternators?
Yeah Impossable to find info. Vettevet do you have any info on the transisterized regulators like this. I am just not sure if this regulator requires to be grounded to the rad support. Also not sure it this regulator needs to be mounted with the rubber well nuts the points type needs.
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#6 |
70+ ( Old Skool Club )
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Re: Does anyone know anything about 20dn alternators?
subscribed
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#7 |
Registered User
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Location: portland oregon
Posts: 156
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Re: Does anyone know anything about 20dn alternators?
Call Delco Remy
1-800-372-0222 |
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#8 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,437
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Re: Does anyone know anything about 20dn alternators?
There are several finned aluminum Delco-Remy regulators. I'm not sure of their application.
There are two with a flat 3 or 4 pin plug. Yours looks like it has a field relay, which is used to operate an idiot light if one is used. If you compare the wiring with the standard mechanical, 4-pin regulator, they both need a chassis ground that is not included in the plug wiring. I thought 63-up Corvettes had them, but an internet search shows that at least in most cases they were included if a Transistor Ignition was used and the ones I found had a round 3-pin plug.
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'67 GMC 2500, 292, 4spd, AC |
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#9 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
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Re: Does anyone know anything about 20dn alternators?
There is some information at the GM Heritage Center web site if you download a copy of the 1967 Chevy truck manual from the vehicle information kits. 1967 seems to be the only year that has any information outside of C30's. There is a section on alternators and batteries that may help you. I can tell you that those are pretty old school and we phased them out in the mid 1990's at work, due to the inability to get replacement parts. Because they are designed for commercial vehicles they came in 24 and 32 volt versions, so if you looking at buying used stuff make sure of the voltages. If you can find an old rebuild shop they may be your best bet for information. Good luck.
https://gmheritagecenter.com/gm-heri...tion-kits.html
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 Last edited by HO455; 08-29-2016 at 03:36 PM. Reason: forgot link |
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#10 |
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Re: Does anyone know anything about 20dn alternators?
When I get the second one I'll take it into a local shop. Want to find more info on these and make sure if I wire this regulator the same as the points type I won't burn it or the alternator. If anyone has any more info on these please still post it here. This old stuff is hard to find info on.
Last edited by chewychevy67; 08-29-2016 at 09:47 PM. |
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#11 |
Senior Member
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Location: Los Angeles
Posts: 1,332
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Re: Does anyone know anything about 20dn alternators?
Heavy truck/bus alternators. Externally regulated (same plug connection as any non-regulated early Delco alternator), use the finned electronic alternator. As the earlier posters commented, be sure of the voltage, there were many versions of these things. They are capable of very high charging rates at low r.p.m.'s, so if you do use one be sure to adjust the voltage regulator accordingly. Any late-60's Chevy or GMC heavy duty truck manual will cover these.
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1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90. |
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#12 | |
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Re: Does anyone know anything about 20dn alternators?
Quote:
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#13 |
Registered User
Join Date: Jun 2008
Location: santa maria,ca.
Posts: 312
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Re: Does anyone know anything about 20dn alternators?
Both of these are 12 volt 62 amp the type 150 has 1 brush holder with 2 brushes used in light and medium duty it is negative ground. the type 250 has 2 brush holders using 4 brushes. used in medium and heavy duty applications can be positive or negative ground the one pictured above is negative ground. The two numbers referenced above both used the same voltage regulator. Delco service bulletin #1G-271 for type 100 and 150 #1G-272 for type 250
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1957 3100 ![]() 1950 5 window |
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#14 |
Registered User
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Re: Does anyone know anything about 20dn alternators?
ok i I will try to find those. is there a benefit to having 4 brushes as to 2? I have added quite a few options to my truck that use electrical power. Being that they are both the same amperage would one be better than the other for operating more power equipment such as heated seats, power windows and a/c?
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#15 |
Registered User
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Re: Does anyone know anything about 20dn alternators?
the tag in the box was loose from the alternator when I got it. must have been removed when rebuilt. I have had people suggest that the series 250 is part # 1117777. cant confirm though.
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#16 |
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Join Date: Jun 2008
Location: santa maria,ca.
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Re: Does anyone know anything about 20dn alternators?
#1117777 is 62 amp 12 volt 250 series. The major parts in both the 250 series numbers are all the same. The 150 series uses a different rotor but the stator was the same. the output is your limiting factor on running added accessories so both should do equal.
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1957 3100 ![]() 1950 5 window |
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#17 |
Post Whore
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Location: Portland Oregon
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Re: Does anyone know anything about 20dn alternators?
Bumping this back up to the top. I found a 67 Burban in a wrecking yard and got the 1117777 alternator and its regulator and brackets off of it, but someone had cut the wiring harness off the truck leaving all the plugs. There are two junction points on the core support near the horn that obviously were part of the factory wiring. These are the same style as the junction that is commonly found near the battery on our trucks. (Which was also present on this truck too.) So in all there were 3 junctions for 12 volt positive side. My question is does anyone have a wiring diagram for the 62 amp system? It has a heavier wire at the alternator than the 38 amp alternator system. AWG 8 I believe. Since I have a NOS regulator I found on a forgotten shelf at work I may convert to this old school system in order to put some electric heat in the back of the WMB.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#18 |
Registered User
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Re: Does anyone know anything about 20dn alternators?
Mine has the 2 distribution blocks by the regulator as well and I don't believe my wiring is any thicker than the other harness I have. My question is was the regulator mounted with the rubber well nuts or straight to the rad support and did the regulator have the ground wire mounted straight to the regulator like the points style one had or no ground wire to the regulator case at all?
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#19 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,154
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Re: Does anyone know anything about 20dn alternators?
This one was mounted on the rubber isolation mounts and there was a ground wire to the core support. I don't remember where the other end when to on the regulator, but I can dig it out and get back to you on it.
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#20 |
Registered User
Join Date: Jan 2010
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Posts: 5,491
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Re: Does anyone know anything about 20dn alternators?
Ok that would be great. I can send you a picture of my harness that I have later today as well. Was it a transistorized unit with the fins like pictured above or a unit that looks like the other common regulators? Just curious.
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#21 |
Post Whore
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Location: Portland Oregon
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Re: Does anyone know anything about 20dn alternators?
It is one of the solid state units.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#22 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
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Re: Does anyone know anything about 20dn alternators?
Sorry it took so to get back with the photo.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#23 |
Registered User
Join Date: Jan 2010
Location: Here
Posts: 5,491
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Re: Does anyone know anything about 20dn alternators?
That is awesome. It does have a ground directly too it. I've been searching that for over 5 years! I'll get you a picture of the positive wires tomorrow and I'll check the gauge of them.
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