1965 356C Vented Valve Covers or Not?

[Jerry Kolb]

If you are worried about putting a lot of oil saturated blow by through one of your carburetors, route the blobby from the oil filler to an oil catch can. The turbo guys (read Subaru, etc.) understand this very well because all modern engines route excess crankcase "air" through positive crankcase vent (PCV) valves and in the case of turbos it ends up inside of the intercoolers. I flunked out of engineering in my freshman year, but a coating of oil on aluminum rather dramatically interferes with the ability of the aluminum to transfer the heat from the intake air to the outside air via the intercooler. To keep this from happening, crankcase air is routed through an air oil separator or catch can before it gets to the intake side of the system. There are some very sophisticated systems out there.

Jerry

[Craig Richter]

And the least sophisticated system simply dumps blow-by down under the car/motor. Maybe it's not very "green", but it works fine considering the tiny number of "old timers" driving around today. High-tech may be able to take some miniscule advantage of oil-laden air pressure differences in modern motors, but come'on...

[Rich Goold]

Was there a factory standard for the valve covers? My 64 SC has one vented and one non vented. Both covers appear to be the same age and have the same patina. The Porsche PET seems to indicate two non vented covers for the SC but I’m not expert in interpreting the PET. Should both covers be the same?
Should they be vented or non vented? My objective is to be factory original.

[Vic Skirmants]

Both covers same; non-vented for your 64 SC.

[Rich Goold]

Thanks Vic. I have been reading about high performance VW engines and it sounds like some of them have problems with the left side valve cover vent (#3 and #4) especially at high RPM. Something like too much oil being sucked to the left side of the engine. Their solution is to vent only the right side (#1 and #2).

Any chance Porsche had the same idea 50 years ago? Has anybody seen any literature from Porsche addressing the issue?

[Vic Skirmants]

Thanks Vic. I have been reading about high performance VW engines and it sounds like some of them have problems with the left side valve cover vent (#3 and #4) especially at high RPM. Something like too much oil being sucked to the left side of the engine. Their solution is to vent only the right side (#1 and #2).

Any chance Porsche had the same idea 50 years ago? Has anybody seen any literature from Porsche addressing the issue?

NO. 356 is not a VW.

[Jurgen Amtmann]

Are 1965 356C cars supposed to have vented valve covers? My car does not but that doesn't mean somebody swapped out the original valve covers for non-vented types.

I've been sorting through issues with a top end rebuild that generally included blowing oil everywhere. See below:

http://forum.porsche356registry.org/vie ... =1&t=47091

After disassembly and inspection we've basically came to the conclusion the rings didn't seat due to using Brad Penn 20W-50 synthetic oil which caused over pressurization of the case. At this point, we've ordered new rings and cleaned everything up to put it back together. This time we'll use break in oil with Total Seal rings in an effort to avoid the same problem this go round.

The engine as rebuilt now runs 9.2:1 compression and an SC cam effectively making it pretty close to "SC specs." I want to avoid any other issues and wanted to know if I should also have vented valve covers to help with the pressure in the crankcase.

Thanks in advance.

Greg

Greg,
I bought a European Spec 64C off the showroom floor in Hamburg in mid 64 and imported it to the US and I still have it. It has non vented Valve Covers and a vented oil fill tank vented to the right carb air filter can. I'm assuming the '65 had the same even if not built to European specs. Jürgen

[Mike Grant]

My early production (8/6/63) Euro spec SC vents from the oil fill to the top of the right air cleaner as shown in Greg Bryan’s photo. Valve covers are not vented and I don’t know if they are original.

[Al Zim]

The 3 most important things for you to successfully maintain you 356 (or other Porsche) are the factory shop manuals; the correct parts books: and a copy of the factory service letters. It has been our experience that the factory really did know their product. For instance for instance a discussion was posted regarding a factory change in construction of windshields on the 540 series of 356 cars. The Porsche factory parts book gave the VIN number of the first non brass windshield frame. It was years earlier than what I thought. Porsche has been a large company. In any company knowledge and record keeping is essential to maintain their product...in our case the 356. al zim

[Rich Goold]

I have the parts book (PET) and also the Factory Shop Manual. I don’t believe the answer is in there. Based on what I have read there appears to be a theory about venting only one valve cover. Somewhere along the line somebody somewhere may have swapped one of my valve covers for some unknown reason. If so, I bet it was 40 years ago. The car runs fine so I won’t change anything now. Really I just wanted to know if this was a factory configuration or a legitimate modification that was done back in the day. Looks like there is no black and white answer.

[Martin Benade]

Most likely accidental. It is not a known modification as far as I know.

[Greg Bryan]

My May of '64 SC (Euro Heater model) had vented valve covers when I got it, but from what I've read in this thread, maybe someone added them thinking it was an improvement. I put non-vented covers on my motor to try and cut down on the oil mist that accumulates around that vent and then everywhere else.
I assumed the vented covers were the originals, and maybe they were on the German delivered cars which mine was until a US serviceman brought it back to the USA.

[Al Zim]

The non vented valve covers would be in the 356 C parts book supplement Page 1/3C What would be the 3rd page. (pages in this supplement are not numbered)
Item #11. The parts book also shows a S-90 ball check vented valve cover. Since the heads are a new design as shown in this book it is more or less common knowledge that the ball check breather valve space has been taken by the inside sealing for the bolt area of the center manifold bolt.
I did not realize that this book did not have page numbers! Zim
MORE INFORMATION: Porsche factory service bulletin H 14/63 Addresses the beginning of the change to positive crank case ventilation. Dated 16 October, 1963.

[Greg Bryan]

The blind hole for the center manifold hold down bolt was not an introduced until some time during the 67 912 model year - p/n 616 104 301 03.
The C used 616 104 301 02 throughout its production which does not have the extra material added to make the bolt hole blind.

In the C parts book, which also includes the B Super 90 info, two valve covers are shown, the check ball type and one without the check ball. Both are vented - the one without the check ball has an opening at the top with a small screen and a sheet metal cover that goes half way down the outside of the cover.

FF826FA7-174E-4716-9916-6AA819975BDD.jpeg (86.93 KiB) Viewed 106 times

I don’t know for sure, but I think the non-vented cover was introduced during 912 production.

[Wes Bender]

The early C (plain hubcaps) that we bought new in '63 had non-vented covers.