Miscellaneous
Windshield Wipers and Windshield Frame
7-5-2012 Dan had gotten the windshield frame out and was studying it when Mary Ann and I went out to visit the shop. This windshield frame was a replacement that some craftsman made back in the '50's or '60's when Ray Dodds owned the car. The frame is very nicely crafted, chrome plated, and was in a box that came with the car when I acquired it. Dan was looking at three holes that only exist on one side of the upper rail. The center hole is slightly larger than the outer two. "What do you plan to use for the windshield wiper on the car?" he asked.
My first response was that I intended to convert the vacuum-operated wiper motor to an electric unit. The original vacuum wipers operated off of the partial vacuum that exists in the intake manifold. A thin hard rubber hose connected the windshield wiper "motor" to the manifold. When a lever was pulled to the "on" position, a small paddle within the wiper motor housing was sucked in one direction, and alternately in the opposite direction, moving a shaft that extends through the windshield frame. The tiny 6-inch blade is mounted on an arm that fastens to the end of this oscillating shaft, supposedly clearing the rain off of the windshield (or at least a little segment of it). The passenger didn't have a wiper unless the buyer opted to spend an extra ten dollars. The buyer of this car didn't bother.
The more I looked into it, the less likely it appeared that any of the available electric conversion units would work. They would interfere with the forward bow that supports the top, and whenever you need windshield wipers is exactly the time you might want to raise the top. I started looking for my stash of windshield wiper drives. The first thing I noticed when I found the collection was that the wiper motor used in a closed car (I had a marked new-old-stock one) would not work in a roadster. The roadster obviously used a wiper motor with some kind of mounting holes spaced 4-3/4" apart. Then I spotted another wiper drive with tabs formed on each end of the body. It had a tag on it stating "Dodge '31, Ply. '30-32. Pont. '29." Quickly, I measured the holes. They are correct. This is the right replacement motor. I did a Google search for the Trico part number (KSL-114) and found that one of these units sold in 2010 on eBay for $154.00. I count my blessings that somewhere along the line, I bought this one.
The drawback to the vacuum-driven wipers is the inconsistent level of vacuum available from the car's engine. When you accelerate, your wipers tend to slow down or stop. When I drove the 1932 coupe on 4 Great Races, I solved the problem by coating my windshield with Rain-X. In even the heaviest rainstorms, the rain simply beaded and ran off the glass.
On my 1948 Lincoln, they solved the problem of inconsistent vacuum wiper speed by installing a "vacuum reservoir." It's a hollow canister with a check valve to prevent a backflow of air into the can. When in use, the engine sucks air out of the can during times when it's idling or operating under light load. When accelerating, the lessened engine vacuum is cut off from the canister by the check valve. The wiper motor is attached to the canister rather than directly to the manifold. We'll simply install a similar reservoir on this car.
The Windshield Frame...
The windshield structure on roadsters is totally different from the convertible coupes, which have rigid windshield frames. On roadsters, the windshield can be rotated about an axis near the top of the frame, or the entire windshield can be laid down by rotating the side supports around an axis near the bottom of the frame. Here's a picture of the setup:
The upper pivot has a small thumbscrew that is hidden behind the post (facing the driver) that may easily be loosened and tightened when tilting the bottom of the windshield out to improve ventilation.
As is visible on the bottom pivot, there is a handy thumbscrew to be used when laying the windshield down. The massive bottom element has a 3/4" threaded shaft that goes through the cowl sheetmetal and mounts in a substantial forging that is rigidly attached to the cowl structure. In the pictures that follow, you can see all the components that make up this arrangement.
Click on any of these pictures to get a better look.
Shown here is the replacement windshield frame. The small mounting hub attached to the side of the frame was missing when I acquired the car. Another 1932 Plymouth roadster was destroyed in a fire a few years ago. I was able to purchase the mangled windshield frame from that car and retrieved its hubs to use on my car. The tiny wedges shown in the right hand picture above were missing on my car. We were able to borrow a sample from some friends who are restoring another 1932 Model PB Plymouth roadster and have the sample replicated by a local machine shop. The hub that we acquired from the burned car will have to be polished and chrome plated, but it fits the windshield frame perfectly and is an original part.
