Wiper puzzlement

[Richard McDonel]

Just when I thought I was in the finish straight on my '71 240, another puzzlement pops up.  Before installing the windshield wiper motor, I did a bench test.  Works OK.  Installed the motor, and drive assembly, then turned on the wiper switch, and everything seems OK, with the splined drive stubs rotating just fine at both speeds. Install the wiper arms and blades, and they twitch perhaps a quarter inch, then stall.  Turn off and on, and absolutely nothing.  Take off the arms and the cowl; everything looks OK.  Put the cowl back on and the drive stubs again rotate on command, but put the wiper arms and blades back on, and same thing - a quarter-inch twitch, then nothing.  Been through this three times now.  

Anybody else been through this, or have any thoughts on it?
Thanks,

[zerpie2]

The Datsun Z wiper motor is too weak. I did a motor swap from a Honda Civic (I think). It's an easy swap that will require drilling new holes in the mounting bracket and some wiring changes. A standard relay will have to be wired in so that the wipers will park correctly when turned off. You'll have to do an internet search for this swap in a 240Z because the wiring changes between the 240, 260, and 280. I got the motor from eBay for $30 and the relay was maybe $5. Now my wipers are better than stock.

[zerpie2]

 

[SteveJ]

Did you clean & lube the mechanical link before installing?

[Zed Head]

Weak battery is a possibility also.  Try starting the engine and getting the RPM up to where you have about 14 volts from the alternator.  Might put you over the top.

[Richard McDonel]

Thanks for all your thoughts fellows.

The old battery seemed OK, but I put in a new one just to be sure, and got the same result.  The connections are well lubed and rotate nicely,  but here is where the problem is:  When I test the wipers with the blades standing straight out, they are trying to move the wrong direction, so what is happening when they stall in the park  position, it is because they are trying to go down against the cowl instead up across the glass.  The only way around this seems to be to mount the blades in the full upright position at rest, which is obviously not what's supposed to happen. 

I went on MSA's catalogue and found that they list (but don't have in stock) two different motors  for 240s; one for '70-'72, and another for '73.  By coincidence I have in my garage bits and pieces from a '70, a '71, and a '73.  Unfortunately, I did not label the three motors I have, but here is a photo, and as you can see one appears to be the reverse of the other two.  Having said that, the screws on the oddball unit weren't really tight, so someone might have been fiddling with it at some time over the past four and a half+ decades.  

I like the idea of replacing the stock motor with the later-model Honda as Zerpie suggests, but  right now I'm running out of time for hot-rodding.  As the previous registration for the chassis I'm using (28726) was out-of-province, I need a safety inspection before I can get it licensed, and that ain't going to happen without wipers.  Son and I have prepaid for our tickets ($325 each) and an RV stall for Pebble Beach (first time since 1999).  The plan is to haul the 240 down there behind the motor home (1,500 miles / 2,400 Km.) and then spend five days driving the newly restored car to the various events.  Dream vacation for DadSon (that's the vanity plate I've reserved) bonding.  Gotta get this sucker going!  I'm sure that either my Taurus or his Infiniti would get us there, but a lot of charm would be lost.  

Any further suggestions would be appreciated.  

  

[motorman7]

You need to rotate the short arm that attaches to the motor 180 degrees.  This should fix the running into the cowl problem (Don't ask me how I know that ?)

Edited August 1, 2018 by motorman7

[Zed Head]

24 minutes ago, Richard McDonel said:

Thanks for all your thoughts fellows.

The old battery seemed OK, but I put in a new one just to be sure, and got the same result.  The connections are well lubed and rotate nicely,  but here is where the problem is:  When I test the wipers with the blades standing straight out, they are trying to move the wrong direction, so what is happening when they stall in the park  position, it is because they are trying to go down against the cowl instead up across the glass. 

Motorman is right, I think.  At least as far as the linkage being the problem, not 100% on the short-arm 180 off.  This problem has been seen before, not uncommon.  I thought of it after your first post, as others probably did too, but you said that everything was rotating correctly with the wipers off.

At least you got everything super-lubed up now.  Good luck.

[zerpie2]

Yep, rotate the short arm 180 degrees (I think that should help). Also try running the wipers on a wet windshield. If that's enough to pass inspection then great. Just get past inspection then use rainex. The Honda motor swap really works well. Here's a video of the Honda motor at work on the intermittent setting on a dry windshield. Please ignore MC Hammer music in the background.?

[SteveJ]

6 hours ago, motorman7 said:

You need to rotate the short arm that attaches to the motor 180 degrees.  This should fix the running into the cowl problem (Don't ask me how I know that ?)

Been there, done that, have the marks on my cowl to prove it.

[Richard McDonel]

Done!

Many, many thanks to everyone who replied.

Bearing mind I've never driven a 240 in the rain, I am disappointed at the speed of the wipers, and definitely will be following Zerpie's advice and switching to a more powerful brand of WW motor.

This forum is really exceptional, with so many knowledgeable people ready to share their experience and wisdom.    I think I'd better sign up for a monthly contribution.

Cheers,

Richard

[Mark Maras]

3 hours ago, Richard McDonel said:

Done!

Many, many thanks to everyone who replied.

Bearing mind I've never driven a 240 in the rain, I am disappointed at the speed of the wipers, and definitely will be following Zerpie's advice and switching to a more powerful brand of WW motor.

Cheers,

Richard

 You'll be pleased to know that the slow wiper speed isn't an issue at higher mph. The wipers will lift off the windshield.