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Not the typical Honda wiper motor upgrade question

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I'm doing the Honda wiper motor upgrade for my '71 (with the nifty electrical adapter harness), and everything is pretty clear except for one thing: how the stock wiper mechanism attaches to the motor.

If I've read various posts correctly (here and elsewhere), the stock 240z motor has a "reverse feature" that stops the motor in the forward direction and briefly runs it backwards to the park position. Because of that feature, the connection between the mechanism and the motor shaft has some kind of a rotational clutch which includes a cam and a spring (with a tang) and a tabbed washer to make it work. I guess it was pretty state-of-the-art back in '71.

Here's the question: is that complicated assembly needed with the Honda motor? The adapter harness has a relay needed to park the wipers in the correct place, so unless the Honda motor has that same kind of reverse rotation, the clutch seems as necessary as an appendix.

Part of my curiosity is to make sure my upgraded motor works with the oddball Datsun connection, but also because I'm creating a page for my website (Ace240z.com) to show the upgrade process in detail and this is something I want to include. It might be possible to 3D print something less complicated, so now's the time to investigate.

Thoughts? Comments? Suggestions?

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The 'reverse-park' feature is real, but it resides in the motor electricals and has nothing to do with the wiper mechanicals*.

Rule #1 of trying out your newly-installed motor:  Do not install the wipers arms until you are 100% convinced that you've got things installed correctly -- both electrically and mechanically.  Use old-fashioned laundry-line clips as proxies for the wiper arms.

There are elements of the Z's wiper linkage (springs, oddball tanged washers, etc) that defy understanding.  I'm reluctant to say that they make no difference, but I can tell you that I installed a custom-made, reverse-wound version of the key hairpin spring in the mechanism and it made zero difference to the reverse-park feature.

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Posted (edited)
12 hours ago, Namerow said:

"The 'reverse-park' feature is real, but it resides in the motor electricals and has nothing to do with the wiper mechanicals*."


I beg to differ. Take a look at the discussion here:

Datsun/Nissan would not have made something so complicated for the fun of it. They could have very easily used the same type of bronze bushing like at the end of the arms. The assembly is there for a reason and I'm trying to find out why. I appreciate the advice about using clothespins - I had a pair of nice gouges in my long-ago first car, a '64 Beetle, when I bolted the arms in the wrong place.

If the feature is purely within the stock motor, then I shouldn't have to worry about the multi-piece assembly with the Honda motor. I can either glue it together into one piece, or replace it entirely with something easier.


Edited by Acemon

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