Well, like Mike W is fond of saying, Porsche, consistently inconsistent ...
Maybe for the USA market only?
1965 356C Vented Valve Covers or Not?
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Re: 1965 356C Vented Valve Covers or Not?
Greg Bryan
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Re: 1965 356C Vented Valve Covers or Not?
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Re: 1965 356C Vented Valve Covers or Not?
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?
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
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
Mike Smith (Essex - UK)
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Re: 1965 356C Vented Valve Covers or Not?
+1 on this, Cleaning it up is a lot of work....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.
Thanks,
Bill
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Bill
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Re: 1965 356C Vented Valve Covers or Not?
Greg Bryan; non-vented covers began with C production as part of the US-specified emissions stuff. As stated earlier, sometime in late 1963.