Re: Kimes' 1937 Super 8 1500 Touring Sedan Needs TLC

Posted by HH56 On 2017/4/10 10:58:22

As I understand it, the original problem with the 356 crankcase ventilation was twofold. Because of the layout of the casting and resulting "pockets", air was trapped and unable to circulate freely to remove the moisture. The second issue was because of the oil filter present on that engine there was an area of turbulence behind the filter where the only air inlet to the crankcase was positioned. The turbulence was actually found to have caused a low pressure or suction effect with the round canister and original shape and height of the oil filler and vent cap.

First attempts to correct the problem raised the fill tube out of the worst area of turbulence but kept the original cap with vents on the bottom. That was not entirely satisfactory so the second attempt changed the cap to one with the vent on the side facing the fan in order to catch a bit of air flow. While that worked in conjunction with the suction effect of the draft tube while the car was moving, the oil filter turbulence was still present and caused the loss of ventilation when the car was stationary. To force ventilation when the car was not moving, the horizontal tube was added to catch air from the fan and blow it directly into the side opening on the fill cap.

IMO, adding PCV would help while the car was stationary but when the car is moving and utilizing the relatively large draft tube and the forced air from the horizontal tube I would wonder which would provide more flow. I don't know if PCV was available on Packard taxis of the prewar era. If so and would have been the better overall option -- even postwar when it was available, I would have thought Packard would have used it instead of all the time and engineering that went into the various fixes they did come up with.

Since they discontinued the horizontal tube toward the end of 356 engine production I wonder if it was ever that effective or else what they did to correct the interior ventilation problem.