My '51 has had a tendency to run hot and try to vapor lock on hot days (wasn't sure that was what was going on but found it never acted up until warmed up). The general solution is to install an electric pump, but I really didn't want to go there except as a last resort. I decided to attempt a fix that would address the underlying problem, running hot. The engine is rebuilt and almost everything you can think of has already been done. such as new fuel pump, carb, cleaned and coated gas tank, new radiator, water pump, insulated fuel lines, etc. So I felt the best approach was to improve the cooling system with an aftermarket solution. I got a Hayden 3568 flex fan (steel with stainless steel blades) and a 2" spacer. This blade is 18.25 inches, ideal size probably would have been 17. The fan to radiator space is really tight on these cars, I was able to remove the old fan but to get the new assembly in I had to remove the radiator. Once installed, the blade was a bit too close and I had to use spacers to move the radiator out about 3/16". The perfect spacer would have been 1 3/4", changing the radiator position would have not been required, but clearance between the fan and generator pulley would have been tight. In either spacer, an inset of about 1 and 1/8" must be machined in the back of the spacer to fit the water pump hub. Any machine shot with a milling machine can do it. I used a 1" drill on a drill press to do it, but the machine shop job would have been preferable.
Once the radiator was back in place, I replaced the 100% antifreeze solution with 50% (the more water vs antifreeze, the cooler it will run- downside is winter protection not as good). Button it all up, checked clearances and took for a test drive on an 86 degree day. The temp gauge used to creep up anytime I would sit at a traffic light, now stays within normal zone. Engine now runs probably 15 to 20 degrees cooler. For the first time on a hot day- no sign of vapor lock. No electric fuel pump necessary.
