AN ENGINEER'S VW INSTALLATION
First, refer to the photos . . . Photo 1 - side view. Note EGT probes on each exhaust. The gascolator box at the firewall is to keep the gascolator cool with blast air. Safety wire on the valve cover bolts. White, high temperature exhaust paint keeps heat in the exhaust tubes and out of the engine compartment. The spinner has both back and front plates. Photo 2 - top quarter view. The oil cooler sump baffles direct the inlet air. The slide valve carburetor has since been replaced with a Tillotson. The carburetor is converted to updraft for safety using hose, hose clamps and 1-1/2" OD exhaust mild steel tube. The fire sleeves on the fuel line at the gascolator box to the carburetor prevents vapor lock from heat and also protects the lines. The air exit ramp at the bottom of the cowl was put on later Sonerai M's and enables a tighter fitting of the cowl, reducing drag somewhat. I have since added carburetor heat. I initially used the standard Rochester mechanical oil temperature gauge which I calibrated using boiling water.
Photo 1 66 APRIL 1990
by Fred Keip 11428 Six Mile Road Franksville, Wl 53126 414/835-7714 The oil temperature pick up at the left front corner cover of the sump read low (130-140 degrees F. maximum). It was replaced with a Stewart-Warner marine 12 volt electric gauge with the probe mounted in the oil cooler bypass block. Now the oil temperature reading shows over 220 degrees F. on a warm day and in the winter it reads 195 degrees F. with 30-40 degrees F. OAT. I feel this is a more realistic reading. The temperature is taken right after the oil leaves the oil pump and, therefore, is the temperature the bearing "sees". I firmly believe that the VW engine needs to have an oil cooler since they are both air cooled and oil cooled. There is a top mount oil cooler adapter available for mounting a late model Type 1 or 3 VW oil cooler to VW engines. This works well with one exception - the cooler doesn't fit inside a standard Sonerai II cowling! I designed an adapter that top mounts and moves the
cooler rearward 1.58 inches and .31 inches towards the centerline. It is made of 2024-T351 or equivalent 3/4" thick plate stock. It is relatively simple to make if one has access to a small vertical mill or a good drill press and the proper milling cutters. It uses standard VW rubber oil cooler seals and bolts directly to the engine. My engine is set up with the Cessna or Piper style plenum baffling arrangement with the top center baffle directly behind the cooler. Holes are cut in the baffle to allow air to pass through the cooler. With outside temperatures running well over 80 degrees F., my oil temperature would run over 230 degrees F. With the oil cooler installed, the oil temperature dropped some 45 degrees, down to around 185 degrees F. In winter I expect the cooler will need to be blocked off entirely. I have a small detailed drawing available. Just send a stamped self-addressed envelope with 45 cents in postage to the address listed above. I would like to thank Ed Brannon of Racine, Wl for coming up with the basic idea for this type of adapter.