Re: Question for you custom guys

Posted by HH56 On 2021/6/6 10:55:39

It is an air duct placed in the fan air flow to direct and force air into the crankcase because of some of the 356 engines developed a condensation and rusty valve issue. There are numerous articles starting after the 1940 356 debut about sticky valves, noisy tappets and related issues where they changed this or that to try and alleviate problems that occurred on some but not all engines.

All the changes more or less go together and later changes may be somewhat dependent on a previous change being done. For the complete story you need to review the changes all in order but on the reasoning and introduction of the air tube, it is mentioned in the sticky valve article in this service letter.https://packardinfo.com/xoops/html/downloads/SC/SL-VOL15NO3.pdf

After introduction the tube was used on all the 356 engines but eventually eliminated with the 49 or 50 production.