Kerry's 250 GT Pininfarina Coupe Restoration (1643GT)

Radiator Blind

One thing that came with my coupe that's usually missing is the radiator blind.  This sits in front of the radiator and in cold weather can be raised to block some of the air flow, similar to the zip-up cover you see on the semis.

I'm not sure if I'm lucky to have this or not.  Lucky that's it's there or unlucky that it is something more to restore.

Anyway, I was doing some sand blasting back at my neighbors, so I decided to pull this out and get the old paint off it.  The first step was to remove the fabric and slide.  This works just like a roll-up window shade except that it gets pulled up by a cable from the top and doesn't lock in place.  Inside the car, there is a rotating knob that winds up the cable attached to the slide.

Rotating it the other was loosens the cable and the spring in the roller winds the blind back down.  After sand blasting, I spent some time in straightening the sides where the slide goes up and down.  These were pretty crooked.  A short piece of 1/8" bar stock just fit into the slot, making it easier to keep things aligned.  You can see before and after pictures.

Once that was done, I turned my attention to the cloth and roller.  The roller is a brass rod with a spring and rod on the inside.  The cloth is attached by a U-shaped (originally) piece of thin steel soldered onto the roller.  Then the cloth was inserted and the sides of the U flattened down to hold the cloth edge.

The cloth is like a heavy oil cloth, coated on one side with fabric on the other.  So I need to find some heavy black oil cloth, thin steel that I can bend into the U-shape and replacement aluminum solid rivets that hold the cloth to the slide.  And also, the cable and sheath to connect it to the mechanism inside the car.

According to David Carte, Re-Originals has the correct cloth.  I ordered  a pound (minimum amount) of solid aluminum rivets (3/16" body and 3/8" length).  There are about 690/lb and I need five, so if anybody else needs to restore their radiator blind, you know where to get the rivets as I'll have enough for several life-times.  McMaster-Carr has the thin steel along with some brass tubing that I'll need.  If you notice the one end in the picture above, there is no cap to keep the axle centered.  A short section of the tubing I ordered will just fit into the existing tube and I'll solder on a cap with a hole for the axle in it.  The other end looks like a solid piece of brass turned on a lathe to fit, but my solution will work fine, particularly since I don't have access to a lathe.

The parts I ordered came in last week while I was away.  The brass tube fit perfectly inside the original.  I took a 3/4" hole saw to cut a disk of brass for the end cap on the tube.  The diameter of the shaft is 6mm, close enough to 1/4" bit that is part of the hole saw.  After the disk was cut, I screwed it onto a bolt so I could chuck it in a drill, thus allowing me to turn it against the belt sander to grind it to the ID of the new tube.  Then I sweat soldered it into the end of the tube.  The end is held in place simply by a couple of dimples peened into the outer tube.

After that was done, I turned my attention to the channel that traps the end of the cloth part.  I had ordered a 6x24" piece of .030 steel for the material.  I cut off about a 1" strip to form the U-channel.  First I clamped it and some 1/4" thick aluminum bar in the vise and beat one edge over.  Then I put that edge down with the aluminum bar flat over it and beat the remaining side down.  Finally I trimmed off the excess metal with some shears.  Now it's ready to solder back onto the roller tube but I'm going to wait for the fabric so I'm sure of how I want it oriented.

The last parts that came were the replacement rivets for holding the cloth to the draw bar.  I only needed 5 (plus a couple extra in case I screw up), but had to buy a pound.  They were also anodized, so I used a wire wheel to get the natural look back.  You can see the many hundreds of rivets along with an original that I removed by grinding off the clinched end.

I was in Monterey last week and stopped by to see Tom Shaughnessy at The Quail.  In looking through his parts, I found a radiator blind pulley along with the original cable.  I borrowed it so I can find the correct cable at a bicycle shop.

As I was comparing it to mine, I realized that mine didn't lock properly but would slip.  After quite a bit of looking, I realized that the ratchet gear would slip on the shaft.  I ended up having to take apart the housing by grinding off the peen marks that hold it together.  I didn't really want to do that, but there was no other possibility.  Once I had the housing apart, it was clear what the problem was.  The ratchet gear has a D-shaped cutout that fits over a similar piece on the side of the pulley.  However, somehow, about 1/2 of the thickness of the gear was worn so it could slip.

After thinking of a solution for a while, I decided to just drive the gear tight against the pulley.  That made the two fit together again.  Then I added a thin brass washer on the outside of the gear so the housing would prevent the gear from coming loose.  What I can't understand is how a radiator blind crank could get worn out.  Perhaps someone didn't realize the there was a release to the ratchet and just forced it to release the blind.  Once I had everything re-assembled, I used a center punch to flare out the pins to hold the housing together.


Next, I took the borrowed cable to a bicycle shop.  The sheath is about 76" long while the inner stranded cable is longer at about 96".  One end is soldered into a small brass plug that fits through a hole in the pulley.  The other end gets a larger plug that fits into a slot at the top of the fabric section. 

The bike shop had some sheath about the right size, but the cable they had was pretty thin.  I ended up getting some 1/16" stranded cable from McMaster-Carr that fits into the sheath OK.  The small plug was made from a 6-32 brass screw.  I drilled a 5/64" hole in one end and ground the outside down to 3mm.  Then I soldered it onto the end of the cable and threaded it through the cable pulley and then through the sheath.  I used a 8-32 screw for the other end.  I just threaded it onto the far end of the cable as I can't solder it on until I install the radiator and cut the lengths to fit.

The next thing was to grind off the rivets and remove the bar from the top of the blind material so my wife could sew the pocket in the new material to fit the bar.  Once that was done, I fastened one end to the roller after soldering the U-channel onto the roller.  As you can see, the fabric is just caught when the sides of the U are flattened.

Note that in the above picture, I have the material clamped in the wrong way.  It needed to be fabric side out when rolled up.  So I had to uncrimp the U-channel, which destroyed the material.  So my wife had to sew up a new piece.

The next thing was to re-rivet the top bar into the fabric pocket.

Tensioning the spring was interesting.  The one end of the roller had a D-shaped rod which gets wound up and then inserted into a matching hole in the frame.  That end can be pushed into the roller to clear the frame for insertion. But I had to figure out how to tension the spring and then keep it wound while putting everything put together.  In the end, I had to make a special tool that could slide onto the D-shaped end but be thin enough to fit between the roller and frame.  Yet another special Ferrari tool that I will probably never use again.

Now everything is done until the radiator gets installed.