Crankcase Breathers |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Crankcase Breathers |
McMark |
Sep 12 2017, 04:58 PM
Post
#41
|
914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
I was looking at the factory manuals and talking with someone about crankcase breathers. We were talking about breather setups for carbs specifically. And I realized as I was looking at the breather diagram that it appears that the breather ports on the heads were included to supply extra air to flow through the engine case. And then I read this little snipped in the manuals which seems to support my thought:
QUOTE Crankcase ventilation has been considerably improved in the engine by ducting fresh air from the air filter. This modification reduces crankcase condensation and icing at low outside temperatures. So following that logic... If the crankcase breather (at the oil filler neck) isn't connected to a vacuum source, then the ports at the heads should/could be plugged instead of connected to a breather box. Thoughts? Contradictions? Agreement? I realize people have been connecting breathers all sorts of different ways and most work just fine. I'm more interested in the theory aspect, and refining an 'ideal' installation since we already know many ways to 'make it work'. Attached image(s) |
gothspeed |
Jan 5 2018, 07:20 PM
Post
#42
|
Senior Member Group: Members Posts: 1,539 Joined: 3-February 09 From: SoCal Member No.: 10,019 Region Association: None |
Do type 4 engines use a negative crankcase ventilation check valve? Stock D-jet engines use a PCV valve. If that fitting on the oil tower box is used for a vent hose the guts need to be removed first. This is true but AFAIK only through '74. '75 2.0s had a larger open vent with no PCV that connected to a larger port on the air cleaner assembly. I Believe I have one of these air cleaner assemblies in my part stash somewhere. Not sure if the 2.0s ditched the head vents but I know the 1.8s did. Funny watching all this discussion/testing come to the same conclusion that Porsche appears to have come to sometime in 74. JamesM, as you mentioned it seems the factory itself had a few different venting configurations for their engines. However most if not all of those venting configurations were for emissions purposes. Whereas many of the venting methods being discussed here are primarily for performance and engine longevity. Different goals will reach different conclusions, hence the discussions. (IMG:style_emoticons/default/smile.gif) |
Lo-Fi Version | Time is now: 1st June 2024 - 10:43 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |