GTV-S2000 (warning not for the Alfa purist)

[Keven]

Pete, I agree gotta drive defensively, and let the maniacs
just pass..

Erik, Cool, one less thing to weld, I wondered why the
doors were so damn heavy!

[Keven]

While I'm waiting for my 10ft piece of tube to arrive from online metals,
I bent up the front and rear loops of the rool cage. The pattern
and techique from the article worked perfectly!!

Here's a couple of shots of how the loops fit in the car. The are a bit
long, but I will trim them when I get the main loop made.

[gbasile77]

How is the build going Keven?
I am trying to live out my dreams through your build

[Keven]

gbassile,

Well I drove all the way out to Placentia, to buy a piece of 10ft
chrome moly ($130), and started to bend the main loop, and
screwed it all up So I been taking a brake, and working
on my mtn bike the past couple of weeks But should
be back in business when I once more drive out to Placentia
for more tube. Hang in there, more to come....

[Keven]

so still havent gotten over wasting 10ft of chrome moly, so I have started
to sort out the wipers. I have a wiper rack and motor from (you guessed it!)
an S2000, since I have the harness, and switches mounted to the steering
column. So as usual I naively thought that I could just make a bracket
and mount the wiper motor to the Alfa's wiper rack with an adaptor plate.
Turns out that the Honda wipers linkage allows the wiper motor to rotate
in on direction (clockwise), and the Alfa's wiper motor actually reverses
direction. So the Alfa's linkage is incompatible with the Honda's. After
much thinking, I decided to mount a plate with gears and rod ends to get
the same effect as the Honda's wiper rack. I pulled the Alfa's linkage
all appart, and drew up all the mounting locations and am designing the
gears. The tough part was to get the motor driven gear to only pull and
then push the wiper linkage arm 90 degrees, while the end that attaches to
the gear must rotate 360 degrees, with 180 degrees of pull and 180 degrees
of push. Simple math, right? I though that if the radius of the gear were
1/4 of the radiud of the wiper arm linkage, this should work, right? Nope,
I tried drawing this on the plans, and used a hanger wire to simulate the
wiper linkage arms movement, and it does not work! So I did it the
hard way, and experimented with different gear radiuses, and found that
the wiper motor need to drive a 1" radius gear, and this in turn needs to
drive a 1.5" gear that the wiper linkage arm attaches to. I ordered some
rod ends, and the gears, so will update when I get them. Here's the
layout, wiper motor and rack base (took all the Alfa linkage off to trace
it on the paper).

If anyone has a better way to do this please chime in, thanks!

[gattia86]

Uh...

I may have read your post wrong, but I think you may be overcomplicating this. Forgive me if I've misunderstood you.

The Alfa wiper motor simply spins in one direction. The link on the rack is what turns the rotating motion of the motor into recipricating motion of the wiper rack. A

Is the only difference that the Honda motor spins clockwise and the Alfa motor spins counterclockwise?

All wiper motors that I can think of operate in a similar manner, in that they have seperate slip rings for high and low speeds, and a third slip ring with two contacts that short circuits the motor at the correct time to "park" the wipers. All the rest of the facny controls on modern wipers come from the relays and electronics (intermittent function, variable intermittent, etc.) I can't think of any wiper motor that stops and reverses direction to achieve the back-and-forth wiper motion.

I'm thinking you'd be better off using a working Alfa wiper motor, and figuring out how to wire in the Honda electronic controls, to give you intermittent and variable intermittent features. Sorting the wiring will be much easier than trying to re-engineer a mechanical rack system.

FWIW, I've just recently rebuilt my Alfa wiper motor (canabalizing some Mercedes motor parts) after unsuccessfully trying to graft a Ford Mustang motor to my Alfa rack.

George

[Keven]

George,

Yeah, it is too complicated!! But all the newer (90's and above) Honda's
have wiper motors that rotate in one direction. This is actually a better
way to run the electric motor, as you do not need to collapse the
magnetic field and build up another one with the reverese polarity. I think
this takes more time, and you loose torque if you do not fully build up the
field in the motor.

Ok, so I finally got about 90% of the design complete. I made a new adaptor
plate out of 1/4" aluminum plate, with 10mm dowl pin driven in to run
one of the gears. The other gear is diven directly from the motor's shaft.
I still need to get on the lathe and make the adaptor which will screw into
the motor shaft, and have a set screw to keep it from spinning. The top
of the adaptor will be a 10mm shaft with a lip to hold the second gear at
the same level and mesh up with the first gear. I have some linkage arms
from the S2000 wiper rack, which I will cut and weld on 10mm nuts to screw
the ball end joint into that will connect to the pins in the gear and then
to the wiper ends. I hope this thing doesn't all bind up!!

[gattia86]

Keven,

I think you've got this thing pretty well sorted out... where do you get gears like that? Looks pretty well engineered. Do you have the original Alfa wiper motor and/or wiper rack?

I think you may have mis-analyzed the function of the original Alfa wiper motor and how it links to the wiper rack; like the Honda motor, it also spins in only one direction. The only field reversal occurs when the wipers are turned off and "park" themselves in the down position. Short circuiting the motor like this is necessary to get the intertia in the wiper assembly and rack and motor to stop right away in the down position... otherwise they'd freewheel for a while and come to rest in a random position when you turn the wipers off. The motor never turns backwards or reverses direction.

In short, any electric motor can turn the link on the Alfa wiper rack and the rack will make the wiper arms move back and forth. I see no reason why the Honda motor couldn't have driven your Alfa rack.

My rebuilt Alfa wiper motor is slow and pretty weak. When it fails again, I'll figure out how to mount a modern wiper motor in there and wire in an intermittent relay with variable delay.

George

[Keven]

George,

I got the gears on Ebay for $10!!

When I hooked up the Honda wiper motor onto the Alfa wiper rack,
it moved a bit then, siezed. The arm that attaches to the motor
cannot rotate 360 degrees, only 90 degrees, so the Alfa motor has
to change rotational direction. The Honda rack has an (what I call)
an idler arm that converts the 360 degree rotation of the motor
to 90 degrees that are needed to move the wipers across the windscreen.
The gears in my set up acommplish the same function as the Honda's
idler arm. The reason I need two gears is that the Alfa's wipers
move in oposite directions (from the center outward), so I needed
to have the motor pull simultaneously on both wiper arms, so one
gear moves clockwise, the other counterclockwise, thus achieving
the pulling on both wiper arms. Took me a while to figure this all
out, as I am not a mechanical engineer

I also looked into using the linkage from a new Civic as they have
the same wiper movement as the Alfa. But the Civic's distance
between wiper linkage arms is huge! As the wipers themselves
are 700mm long!

[gattia86]

Keven,

Hmmm... my Alfa's a '74, so maybe it has a different wiper motor, but... the idler arm that attaches to the motor DOES rotate through 360 degrees, and the motor does not change direction. I've just recently had mine all apart for rebuilding, so that's why I'm interested in this issue. Maybe something's binding in the Alfa rack, or the Honda motor parked itself? I keep pressing the issue, just in case your mechanism doesn't work out; you can always adapt a modern motor to the original rack mechanism.

At any rate, you'll be miles ahead by using a modern motor; the stock Alfa wipers are pretty weak even under light load, let alone on the freeway with headlights and blower motor going at the same time.

Interesting idea about the Civic wiper assembly. I looked into adapting an older Mercedes rack with similar wiper movement (since I have a few Mercedes projects sitting around), but the orientation of the motor and routing of the rack arms is all wrong for the Alfa. I ended up just using the slip-ring contacts from the Mercedes motor, since, even after 40 years of use, they were in perfect condition. If only Alfa electronics could last as long!

I've been watching your project with great interest. Looking forward to the next installment...

George

[PSk]

Yep Alfa Romeo might sometimes over design some areas, etc. but I'm pretty damn (er, maybe) sure they are not stupid enough to continually reverse the rotation direction of an electric motor when it is so easy with links to solve. Will be interesting to study this area when I get to it on my car . Now the English on the other hand with their stupid cable driving systems ...

Maybe you've misplaced a link?

Anyway you're having fun.
Pete

[Keven]

Here is the latest wiper set up. It all works very well, but will
probably need to buy a slightly larger gear. The wiper arms
appear to not move the required 90 degrees, I think they are
moving about 80 degrees. The miscalculation is due to having to
place the pin inside the diameter of the gear
But I do not think I will change the gear until I get the windscreen
on and can really see how far they are wiping.

Here's a couple of pics...

[Keven]

Here is a link to the YouTube video of the wipers in action:

YouTube - Alfa Tomato Wipers

[gattia86]

Keven,

Ah! Now I see how you've designed it. Pretty slick.

I think you can get more wiper arm movement, to a full 90-degrees, by shortening the effective lever arm(s) on each wiper pivot. Simply relocate the mounting point of the rod-ends on each wiper pivot arm closer to the pivot point, and you'll get more travel for a given input (determined by the size of your gears).

In other words, you'll get the same gear ratio effect by either enlarging the drive gears (as you've planned) or SHORTENING the driven arm (which should be simpler and cheaper).

George

[Keven]

I have been sorting out all the lights (brake headlights, signals, plate,etc)
making harnesses to all of them using weatherpack connectors. These
are very easy to make using the special crimping tool for the pins.
Here's a pic of the connectors and tools.