6 Volt to 12 Volt Bosch wiper motor

356 Porsche-related discussions and questions.
Post Reply
Message
Author
Jurgen Amtmann
356 Fan
Posts: 11
Joined: Mon Nov 18, 2019 12:38 pm

6 Volt to 12 Volt Bosch wiper motor

#1 Post by Jurgen Amtmann » Fri Jan 10, 2020 1:25 pm

A vendor in Calif. sells wiper motor armatures to convert the 6V motor to 12V. He claims that this converts the motor to 12V without changing the field coils. Here is the question for the Electrical Engineers among you. Since the motor is more than likely shunt wound, what happens to the field EMF and flux with only the armature being wound for 12V? The 12V wiper motors that the vendor also sells for a '64 VW Bus look very much like the one in my '64 C and I wonder if using a bus motor wouldn't be a better way to go, if possible. I converted my '64 C to 12V back in the 70's and used a 12V to 6V converter at that time (not a dropping res.). During the current restoration the converter seems to have left home, so I'm left with having to do something about the wiper motor. Any suggestions would be welcome. (no dropping resistor allowed)

Hugo Karasawa
356 Fan
Posts: 273
Joined: Fri Sep 09, 2016 10:40 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#2 Post by Hugo Karasawa » Fri Jan 10, 2020 2:45 pm

I think, that armature does not work for the 64-65 C. It only works for the earlier wiper motors.
Please let me know if I am wrong , I am interested in doing this conversion and have not found a 12V wiper motor or armature conversion for a 65C.

User avatar
Mike Wilson
356 Fan
Posts: 5256
Joined: Tue Apr 15, 2008 4:37 pm
Location: SW Los Angeles

Re: 6 Volt to 12 Volt Bosch wiper motor

#3 Post by Mike Wilson » Fri Jan 10, 2020 2:58 pm

You might want to contact Eurtron Electric. They rewire and repair electric motors. They did the one on my fresh air blower.

Mike
Mike Wilson
Lomita, CA
'63 B coupe

Jurgen Amtmann
356 Fan
Posts: 11
Joined: Mon Nov 18, 2019 12:38 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#4 Post by Jurgen Amtmann » Fri Jan 10, 2020 3:12 pm

Hugo Karasawa wrote:
Fri Jan 10, 2020 2:45 pm
I think, that armature does not work for the 64-65 C. It only works for the earlier wiper motors.
Please let me know if I am wrong , I am interested in doing this conversion and have not found a 12V wiper motor or armature conversion for a 65C.
Thanks for your reply Hugo.
I was not aware that there was a difference in wiper motors between C's and earlier models. I'll try to look into this, even if I have to buy one of the armatures. They said I can return it if I havn't installed it (restocking charge and return postage). Where did you get your information? Jürgen

Jurgen Amtmann
356 Fan
Posts: 11
Joined: Mon Nov 18, 2019 12:38 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#5 Post by Jurgen Amtmann » Fri Jan 10, 2020 3:26 pm

Mike Wilson wrote:
Fri Jan 10, 2020 2:58 pm
You might want to contact Eurtron Electric. They rewire and repair electric motors. They did the one on my fresh air blower.

Mike
Mike, I contacted Eurtron and expect a reply soon. I'll post their reply. They seem expensive, but it might be worth it not to have to use the converter and it's wiring. I wonder what Porsche used for their 12V cars. Jürgen

David Campbell
356 Fan
Posts: 74
Joined: Sun Apr 19, 2015 9:39 pm
Location: West Georgia

Re: 6 Volt to 12 Volt Bosch wiper motor

#6 Post by David Campbell » Fri Jan 10, 2020 7:06 pm

Jurgen,
I have found Don West in McMinnville,Oregon to be very helpful in all things related to VW or Porsche wiper motors and parts. He did a wonderful job on the motor for my 1961 B with 6V. He's updated his advertisement at The Samba and lists the best contact as email: westcoastwipers@gmail.com. He provided his address as 3730 NE Grandhaven Dr. McMinnville Oregon 97128; Cell#(503)434-3530 Home#(503)434-6486 He appears to no longer be restoring Porsche wipers but he's probably a great source for information and maybe some parts.
1961 B Coupe

Hugo Karasawa
356 Fan
Posts: 273
Joined: Fri Sep 09, 2016 10:40 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#7 Post by Hugo Karasawa » Fri Jan 10, 2020 7:11 pm

If you look at the C wiper motors these look like a cylinder, the earlier 356s had a wiper motor that looks like a box. Also I think the C wiper motors are Bosch and the earlier are SWF. In most of the catalogs of the usual vendors it states that the 12V armatures are for SWF motors not for Bosch.

I contacted Don West at westcoastwipers@gmail.com

This is his answer
"I have come up with a 12 volt 2 speed wiper motor that replaces the big round Bosch motors on the green frame T6 and C cars
I have seen others like EIS made a 12 volt motor to go on the green frame type but it covers the lower right mounting hole
Mine allows access to all 3 bolts.
It weighs half of what the Bosch motor weighed you can use the original switch but will not have variable speed use. It can also use a 66-67 bus 2 speed wiper switch with it and get 2 speeds then.
Here are some photos of one I did, it fit perfectly "
wiper motor Westcoast.jpg
wiper motor Westcoast.jpg (186.09 KiB) Viewed 255 times

User avatar
Mike Wilson
356 Fan
Posts: 5256
Joined: Tue Apr 15, 2008 4:37 pm
Location: SW Los Angeles

Re: 6 Volt to 12 Volt Bosch wiper motor

#8 Post by Mike Wilson » Fri Jan 10, 2020 10:40 pm

Looks like an excellent option.

Mike
Mike Wilson
Lomita, CA
'63 B coupe

User avatar
Jacques Lefriant
356 Fan
Posts: 3427
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 6 Volt to 12 Volt Bosch wiper motor

#9 Post by Jacques Lefriant » Sat Jan 11, 2020 2:30 pm

Hi
do 912/911/914 wiper motors work?
 

User avatar
Mike Wilson
356 Fan
Posts: 5256
Joined: Tue Apr 15, 2008 4:37 pm
Location: SW Los Angeles

Re: 6 Volt to 12 Volt Bosch wiper motor

#10 Post by Mike Wilson » Sun Jan 12, 2020 12:25 am

Good question, Jacques. I just looked at some on eBay and with some modification of the attachment points, a 911/912 motor just might work. The unknown is how they park the wipers.

Mike
Mike Wilson
Lomita, CA
'63 B coupe

User avatar
Doug McDonnell
356 Fan
Posts: 4035
Joined: Sat Apr 05, 2008 8:21 am
Location: Augusta,Michigan

Re: 6 Volt to 12 Volt Bosch wiper motor

#11 Post by Doug McDonnell » Sun Jan 12, 2020 3:06 pm

Jacques see 12 volt for T6 and C discussion here: viewtopic.php?f=1&t=20554
1965 356C There is never enough time to do it right, but always enough time to do it over.

Hugo Karasawa
356 Fan
Posts: 273
Joined: Fri Sep 09, 2016 10:40 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#12 Post by Hugo Karasawa » Sat Feb 15, 2020 12:40 am

Hello Jurgen,
Did you find a solution to the 6V to 12V wiper motor conversion ?

I found that 356devotion sells a 12V wiper motor that looks similar to the 356C wiper motor, I have not asked them if it is a turnkey installation or if it is needed to do any modifications . It looks that it is a two speed motor like the one that Don West used.
356 devotion wiper motor 12v.jpg
356 devotion wiper motor 12v.jpg (199.75 KiB) Viewed 53 times

Jurgen Amtmann
356 Fan
Posts: 11
Joined: Mon Nov 18, 2019 12:38 pm

Re: 6 Volt to 12 Volt Bosch wiper motor

#13 Post by Jurgen Amtmann » Sat Feb 15, 2020 5:15 pm

Hugo,
I have not found a satisfactory solution, but the 356 Devotion motor looks promising. I'll look into it, thanks for the information. Since my original post, most other solutions seemed fairly involved, so I was procrastinating since I have lots of other work do do yet, and decided that since the wipers worked perfectly before the restoration, I'd keep my voltage dropping device for the time being. When I converted to 12V back in the late 70's, I designed a transistorized 12V to 6V circuit using a Zener and power transistors that kept a constant 6.7V at the output regardless of the current draw (it was over-designed) and worked well at both speeds. When my brother recently converted his B T6 to 12V I used the same circuit for his car. BTW, I used simple Zener reductions for all the low current instruments, all worked well for a couple hundred K miles util I retired the car in the late 80's. It is being restored right now. Jürgen

Post Reply