1965 356C Vented Valve Covers or Not?

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Greg Bryan
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Re: 1965 356C Vented Valve Covers or Not?

#46 Post by Greg Bryan »

Well, like Mike W is fond of saying, Porsche, consistently inconsistent ...
Maybe for the USA market only?
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Re: 1965 356C Vented Valve Covers or Not?

#47 Post by Greg Bryan »

How about these - someone had a better idea …
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Martin Benade
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Re: 1965 356C Vented Valve Covers or Not?

#48 Post by Martin Benade »

For up to 20 percent more power!
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Mike Wilson
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Re: 1965 356C Vented Valve Covers or Not?

#49 Post by Mike Wilson »

😜 at least!

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Paul Lima
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Re: 1965 356C Vented Valve Covers or Not?

#50 Post by Paul Lima »

Here is a slightly different take on this subject. There is plenty of evidence that engines with vented valve covers have varying amounts of oil around the valve cover and underside of the shrouding. I have build several engines that, after a few thousand miles, leaked small amounts of oil from many different places. Putting these two observations together and reading about many advanced high performance engines that attempt to draw a vacuum in the crankcase, I decided on my latest engine to add vents to both heads (this engine has JPS Aircooled heads, but SC and 912 heads have this hole in the casting for a vent; Porsche only used the hole on the 1-2 head for the vent to the carb). I put one-way check valves on each head vent and hoses into a catch tank. In theory, at least, the check valves would tend to lower the pressure in the heads. In practice, this engine now has about 7000 miles and is absolutely dry on the outside. I make no claims for additional power with the lower crankcase pressure, but I love the no-leaks and the engine does have awesome power.

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Re: 1965 356C Vented Valve Covers or Not?

#51 Post by Mike Smith »

My `C `built in DEC 1964 - Chassis No. 131 899

Both Rocker Covers were Vented with the Ball and Screen system
The Crankcase is vented, via the Oil Filler Canister, to the underside of the Right Hand Std. Zenith Air Filter

There are no Oil Leaks (well not from the Covers anyway)

However, it is RHD and that can make a difference to what Porsche decided to use
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Bill Lawless
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Re: 1965 356C Vented Valve Covers or Not?

#52 Post by Bill Lawless »

jim nelson wrote: Sat Nov 03, 2018 7:51 pm My Euro S90 has vented covers, and I think I’ve about had it with cleaning up that mess.
+1 on this, Cleaning it up is a lot of work....
 Thanks,
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Re: 1965 356C Vented Valve Covers or Not?

#53 Post by Vic Skirmants »

Greg Bryan; non-vented covers began with C production as part of the US-specified emissions stuff. As stated earlier, sometime in late 1963.

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