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5500 Samba Member
Joined: October 16, 2020 Posts: 112 Location: Cape Cod
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Posted: Wed Oct 20, 2021 11:53 am Post subject: Generator Light Gremlins |
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Posting in this forum as the generator is on a VS style build in my 57 oval ragtop. Car has about 250 break in miles. Polarized and installed a rebuilt 7v 45 amp generator and regulator (from a reputable Samba vendor). Car has an Optima Red top, new battery cables, revised grounds everywhere, hot start relay. Initially, with the rebuilt Brazilian Bosch regulator, the light would stay on until about 2600 RPM, then go out but eventually come back on at idle. Tried adjusting the air gap on the regulator contacts and points (using specs I found here) and tweaking the tab on the top contact. This resulted in a steady light. Not having anything but a voltmeter and absolutely no knowledge of charging systems, I opted to buy a new electronic regulator (marketed by BBT). Swapped it in and still have a steady red light. Tried pulling the 61 terminal wire with ignition on and light went out. Re-polarized the generator and checked the brushes for contact.
Measuring voltage, got the following readings:
Battery: 7.1
Battery terminal at the regulator:
engine off: 7.1
engine idling:7.1
engine at 3K rpm: 7.9 (max reading regardless of rpm)
With load (wipers and headlights):
6.7 at idle, 7.4 at 3K rpm.
At my wits end trying to figure out whats going on and how to resolve it. Any suggestions on what might be causing this and how to resolve it? Is there any harm in just ignoring the red light and living with the high output?
Add: I'm running a standard 36 hp generator pulley, slightly underdriven with a reproduction OT pulley. Belt shows about 1/2" deflection. |
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FritzCP Samba Member
Joined: October 23, 2005 Posts: 463 Location: Wisconsin
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Posted: Thu Oct 21, 2021 11:38 am Post subject: Re: Generator Light Gremlins |
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install a stock 7" 36hp crank pully or a 356 Generator Pulley if you have one to see if the increase in RPM makes it work normally. _________________ Fritz Custom Products
Fritz 10 - Tin Screw Torquer
Fritz 124 - Crank Pulley Puller
Fritz 70 - 6306 Bearing Puller
Fritz 44 - Dizzy Puller |
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Robert Chambers Samba Member
Joined: August 11, 2005 Posts: 216
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Posted: Fri Oct 22, 2021 5:51 pm Post subject: Re: Generator Light Gremlins |
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Sometimes new brushes plug up the generator copper. Try cleaning the armature. I find this helps. Also were new brush springs installed during the rebuild. They can loose pressure from hot cold cycles. Just some thoughts from experience. I worked om many 6 volt VWs in the past. _________________ '63 OG 117 Herbie Replica
'56 Euro Oval Deluxe
'52 Standard Zwitter
'63 OG 117 |
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5500 Samba Member
Joined: October 16, 2020 Posts: 112 Location: Cape Cod
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Posted: Mon Oct 25, 2021 6:35 am Post subject: Re: Generator Light Gremlins |
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Robert Chambers wrote: |
Sometimes new brushes plug up the generator copper. Try cleaning the armature. I find this helps. Also were new brush springs installed during the rebuild. They can loose pressure from hot cold cycles. Just some thoughts from experience. I worked om many 6 volt VWs in the past. |
Thanks Robert. I have not looked closely at the armature but I did notice quite a bit of carbon dust after the initial run in and assumed it was from new brushes. I did check the brush position and spring tension and both look ok. I'll take a close look today. |
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