Anyone try to add intermittent wipers to an early 73 911?

skinnerd · skinnerd's Garage

Have a 73 911 and wondering what it takes to add intermittent capability to the wipers?

Do you need a completely different wiper motor?
Or just an intermittent switch (potentiometer).....can't believe it could be that easy.

Thinking you need a wiper motor from a 911 that had intermittent wipers, some kind of relay and then the intermittent switch.

Anybody have a clue?
Thanks

I know, I know....why am I driving my car out in the misting rain such that I would need intermittent wipers....don't ask.

HarryD · 09-17-2009, 09:32 PM

Doug,

Back in the day, you could buy a little box that you put on the dash that would do that. You might want to go to an autoparts store or check out the JC Whitney catalog for waht you need.

Most of them work by having a resistor/capacitor circuit that triggers a SCR to pulse the wiper motor. You control the rate the capacitor charges by varing the resistance via a potentiometer. I build one for my 1969 Dodge when I was in college.

skinnerd · skinnerd's Garage

Thanks Harry.
That sounds like the easy & inexpensive way.

I am pretty sure to do it Porsche correct, I'll have to change out the wiper motor et al....

RSTarga · 09-18-2009, 09:11 AM

I would go for the system on the newer cars, but you need all the above plus a new switch too. It has 3 sppeds plus an intermittent plus a rheostat on the dash. The ones on the 71 and older cars where very unreliable and expensive to fix.

Peterfrans · 09-18-2009, 09:52 AM

I have the setup from a 1985 carrera in my 1973T. This is not as straightforward as it seems as the are a lot of differences in the wiring. It definitely is not plug an play. I needed to make some changes to the wiper switch (wiring) and used parts of the wiring loom I took from the carrera. I used the carrera wiper motor too.

I tried to find an aftermarket setup, but these don't seem to be available anymore.

HarryD · 07:39 PM

Doug,

I think this is the one I built:

http://books.google.com/books?id=5dcDAAAAMBAJ&lpg=PA138&ots=8uM2ML8kXt&dq=windshield%20wiper%20scr&pg=PA138#v=onepage&q=&f=false

skinnerd · skinnerd's Garage

Wow Harry.
Got a love that old school stuff.

Looks like a fun science project for over Christmas break.
I am sure retrofitting the new system back into our older cars is a pain.

And I really only drive my car now from May through October.
So how much rain do I really need to put up with??????

Thanks for all the help.

HarryD · 09-18-2009, 07:41 PM

Doug,

There no rain here in the Fall/winter.

To bad I didn't know you were looking to make one. I cleaned my garage out about 6 months ago and threw the thing away!

Missed you at AX last weekend. Coming out to the 10/11 event?

skinnerd · skinnerd's Garage

Wish I was, but heading back to Thailand for the winter on Oct. 4.

Taking Kermie down to LA on Monday, and dropping him off with TRE Motorsports for a "makeover."
He'll be looking swank when I pick him up in April.

I ponder over my obsession to put intermittent wipers in Kermie.
Likely misplaced energy on my part.
Need to get the driving/fog lights hooked up and the old school Frankfurt radio working first I think.

hellblau82 · hellblau82's Garage

Quote:

Originally Posted by skinnerd

Have a 73 911 and wondering what it takes to add intermittent capability to the wipers?

Do you need a completely different wiper motor?
Or just an intermittent switch (potentiometer).....can't believe it could be that easy.

Thinking you need a wiper motor from a 911 that had intermittent wipers, some kind of relay and then the intermittent switch.

Anybody have a clue?
Thanks

I know, I know....why am I driving my car out in the misting rain such that I would need intermittent wipers....don't ask.

Hi there did you fix this?

Peterfrans · 09-12-2015, 10:51 AM

I tried to fit a smart-screen relay (About Smartscreen) that I purchased some time ago. Unfortunately no joy getting it to run. After that I tried a hella relay I had lying on shelf (Hella 5WA 001 871-041) and that one was very easy to fit. Just connect the hella relay with +12v and ground, connect terminal 53s on the relay with the black/purple wire coming from the switch and connect terminal 53m on the relay with terminal 53 on the wiper motor (where the black purple wire was connected). That's all. Timing can be adjusted by turning the knob on the relay.