Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Technical question re Porsche 12V generator
Forum Index -> Porsche - 356 Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
monomanx
Samba Member


Joined: September 25, 2004
Posts: 715
Location: Southeast
monomanx is offline 

PostPosted: Thu Aug 01, 2013 12:52 pm    Post subject: Technical question re Porsche 12V generator Reply with quote

Hello,

I do not own a porsche but I am using a Porsche 12V Generator (smaller diameter) on a 6V generator stand in a VW to maintain the small body generator look. I had it rebuilt a number of years ago and the charge light always has been on at idle. At speed it does charge.

Is there a smaller diameter pulley available to turn these faster? The Pulley I have is a stock 12V pulley from a VW.

Thanks in advance

Chris
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
saddlesore1
Samba Member


Joined: November 20, 2006
Posts: 548

saddlesore1 is offline 

PostPosted: Thu Aug 01, 2013 2:21 pm    Post subject: Reply with quote

I have the same issue. I spoke to the guy that rebuilt the generator and he says there is no issue. It is annoying yes but not to worry. He said he can adjust the regulator to make it go away when at idle but there will be no purpose. At Idle the generator does not charge sufficiently anyway. The only thing he would be doing is adjust the point the light comes on.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
bbspdstr
Samba Member


Joined: May 11, 2012
Posts: 494
Location: PA
bbspdstr is offline 

PostPosted: Thu Aug 01, 2013 4:30 pm    Post subject: Reply with quote

I know very little about VW pulley diameters, but from the few VWs I've had, the generator pulley was much larger in diameter than that of a 356.

The adjustment of the regulator is a true possibility, but obviously the regulator has to be of the adjustable type.

I have done quite a few 12v 356 conversions over the years, and the 'problem' most often seen is the one described here, even with the 'proper' 356 pulley parts. The most success in getting the red light out, sorta, at a ~900rpm idle, is the transistorized regulator available through most 356 parts vendors and it's most likely a VW replacement anyway.

The least problems have been with originally 12v generators and the most with the 6v>12v conversion units using VW parts....but none of the results are predictable...it's in the rebuild and the 'mix' of parts used with it.

Most of those units that balk make the red light go out at about 1500 rpm +/- and unless you have the headlights and wipers on at idle for a long time, the idiot light is merely annoying or distracting...unless the battery is weak to begin with.
_________________
Bruce Baker
www.356restoration.com
Back to top
View user's profile Send private message Gallery Classifieds Feedback
monomanx
Samba Member


Joined: September 25, 2004
Posts: 715
Location: Southeast
monomanx is offline 

PostPosted: Fri Aug 02, 2013 9:43 pm    Post subject: Reply with quote

thanks for the input on this issue. It is interesting that the mixture of parts could be the culprit. Regarding the smaller pulley thought, could a generator be over revved?
i do note that at around the 1500 rpm range the light does go out.

thanks again for the help!

chris
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Tall Bloke
Samba Member


Joined: October 07, 2005
Posts: 234
Location: UK>Ohio>UK
Tall Bloke is offline 

PostPosted: Wed Oct 08, 2014 7:02 am    Post subject: Reply with quote

bbspdstr wrote:
I have done quite a few 12v 356 conversions over the years, and the 'problem' most often seen is the one described here, even with the 'proper' 356 pulley parts. The most success in getting the red light out, sorta, at a ~900rpm idle, is the transistorized regulator available through most 356 parts vendors and it's most likely a VW replacement anyway.


bbspdstr - when you mention the transistorised regulator- does this refer to the solid state regulator ? see image - If yes - would the 30 amp or 38 amp be the correct part ?


Image may have been reduced in size. Click image to view fullscreen.


Thanks .
_________________
-------------------
All of 30 horses !
Back to top
View user's profile Send private message Gallery Classifieds Feedback
sam_w
Samba Member


Joined: March 07, 2002
Posts: 1479
Location: Petaluma, CA
sam_w is offline 

PostPosted: Thu Oct 09, 2014 7:44 am    Post subject: Reply with quote

Interestingly I have info on the early 356 generator pulley.
My 63 singlecab with a 1600 engine was getting too hot when I drive on Interstate 5 with the temperature at 105 degrees outside!
This was because I put in a 3.88 Ring and Pinion to get 3000 RPM at 60 MPH.
With high outside temps the fan was not going fast enough, so I got a 356 pulley from Pelican parts, this is 10% smaller in diameter that a VW generator pulley, and the engine now can run at 60 MPH in 100+ weather.

Generators never generate any output at idle and that is one of the reasons that alternators have taken over, they give output at lower RPM.
_________________
63 singlecab
73 thingster
74 Thing
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Tall Bloke
Samba Member


Joined: October 07, 2005
Posts: 234
Location: UK>Ohio>UK
Tall Bloke is offline 

PostPosted: Thu Oct 09, 2014 10:05 am    Post subject: Reply with quote

Sam-W
What diameter is the 356 pulley, so I can check what I have ?
Thanks
Tim
_________________
-------------------
All of 30 horses !
Back to top
View user's profile Send private message Gallery Classifieds Feedback
sam_w
Samba Member


Joined: March 07, 2002
Posts: 1479
Location: Petaluma, CA
sam_w is offline 

PostPosted: Thu Oct 09, 2014 11:20 am    Post subject: Reply with quote

I really do not know, I can go and measure it, I did have to go through many different belt sizes.
I will measure & take piccies.
_________________
63 singlecab
73 thingster
74 Thing
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Tall Bloke
Samba Member


Joined: October 07, 2005
Posts: 234
Location: UK>Ohio>UK
Tall Bloke is offline 

PostPosted: Thu Oct 09, 2014 1:18 pm    Post subject: Reply with quote

Hello Sam
The pulley OD on my converted to 12v 356 generator is 99mm (4 inch) - assuming this is a 6 volt VW pulley ?
_________________
-------------------
All of 30 horses !
Back to top
View user's profile Send private message Gallery Classifieds Feedback
sam_w
Samba Member


Joined: March 07, 2002
Posts: 1479
Location: Petaluma, CA
sam_w is offline 

PostPosted: Thu Oct 09, 2014 2:13 pm    Post subject: Reply with quote

I measured mine and it is 3 9/16ths or 3 3/4 "
_________________
63 singlecab
73 thingster
74 Thing
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Tall Bloke
Samba Member


Joined: October 07, 2005
Posts: 234
Location: UK>Ohio>UK
Tall Bloke is offline 

PostPosted: Fri Oct 10, 2014 4:49 am    Post subject: Reply with quote

Thanks Sam - I will try if that works for me.
_________________
-------------------
All of 30 horses !
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Porsche - 356 All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.