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DerrickfromNC1 Samba Member
Joined: October 24, 2008 Posts: 1293 Location: North Carolina
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Posted: Tue Apr 13, 2021 4:58 pm Post subject: Proper crankcase ventilation? |
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A friend of mine will be connecting the following filters directly to his valve covers:
https://www.spectreperformance.com/cat/air-filters-breather
He asked me if it would provide proper ventilation to his newly built 1904cc engine. I told him I would check with the experts here on Samba.
Thanks |
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BFB Samba Member
Joined: November 03, 2014 Posts: 1693
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Posted: Tue Apr 13, 2021 5:32 pm Post subject: Re: Proper crankcase ventilation? |
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they'll vent and they'll also get saturated in oil then collect dirt & dust. _________________ Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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txoval Samba Member
Joined: January 23, 2004 Posts: 3540 Location: The Woodlands, TX
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Posted: Tue Apr 13, 2021 5:40 pm Post subject: Re: Proper crankcase ventilation? |
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Not good to install those directly to the valve covers as stated above.
Install a breather box on the firewall and run hoses to it
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QRP Samba Member
Joined: April 27, 2008 Posts: 1703 Location: NORTH HOLLYWOOD,CA
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Posted: Tue Apr 13, 2021 5:55 pm Post subject: Re: Proper crankcase ventilation? |
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DerrickfromNC1 wrote: |
A friend of mine will be connecting the following filters directly to his valve covers:
https://www.spectreperformance.com/cat/air-filters-breather
He asked me if it would provide proper ventilation to his newly built 1904cc engine. I told him I would check with the experts here on Samba.
Thanks |
Let him do it then post pics after he drives it for a while. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Apr 13, 2021 5:59 pm Post subject: Re: Proper crankcase ventilation? |
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A breather box separates the oil mist from the air. The oil drains back into the engine and the air vents to the atmosphere. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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74 Thing Samba Member
Joined: September 02, 2004 Posts: 7374
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Posted: Wed Apr 14, 2021 10:13 am Post subject: Re: Proper crankcase ventilation? |
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Just vent the 1/2 side |
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kangaboy Samba Member
Joined: August 28, 2010 Posts: 1062 Location: St. Louis, Mo
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Posted: Wed Apr 14, 2021 10:18 am Post subject: Re: Proper crankcase ventilation? |
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Breather on crank case only. A 1904 doesn't need valve cover venting. _________________ -74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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Posted: Wed Apr 14, 2021 3:23 pm Post subject: Re: Proper crankcase ventilation? |
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Two guys with quite a bit of engine experience had different opinions as to were to sent the crankcase gases, in an recent post.
Rich Hunt is my carb rebuilder and Alstrup engine specialist
Frist of all I agree you do not need get the gases from the valve covers unless you have a much larger engine.
The discussion was were to send the crankcase gases to the carbs or atmosphere
Rich Said Atmosphere, knowing from his experience it may create issues in the carb like the oil collecting dirt and causing problems.
Alstrup said to the carb or carbs.
Well in my photos I went to Atmosphere and my bug started smelling of burned oil.
Then went to the Carb and the smell went away.
If it did not smell I for sure would have went to Atmosphere.
Sorry Rich, smell won over your logic.
To show how little a breather you need, check out mine made from a aftermarket oil filler tube turned upside down.
Oil and gas go in and up, gas has no problem going to the carb, oil gets slowed down in my inner tube with the holes and drops down the tube (see slots cut at the bottom of that tube) and falls back into the crankcase.
My aftermarket upside down oil filler tube works great.
_________________ email: [email protected]
The TYPE IV UPRIGHT CONVERSION MANUAL
BEETLE MAGNETIC DEFLECTOR SHIELDS
LETS TALK DUBS https://www.youtube.com/results?search_query=joe+cali+ghia https://letstalkdubs.libsyn.com/ep-200-joe-cali-ty...qI3xJTCzjs |
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k-weaver Samba Member
Joined: November 27, 2012 Posts: 69 Location: Santa Maria, CA
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Posted: Wed Apr 14, 2021 3:41 pm Post subject: Re: Proper crankcase ventilation? |
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kangaboy wrote: |
Breather on crank case only. A 1904 doesn't need valve cover venting. |
There is not enough information about the engine to make this determination. You have big cam with heads to support it turning high RPM; you will need to vent more than just the case. |
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BFB Samba Member
Joined: November 03, 2014 Posts: 1693
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Posted: Wed Apr 14, 2021 5:18 pm Post subject: Re: Proper crankcase ventilation? |
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k-weaver wrote: |
kangaboy wrote: |
Breather on crank case only. A 1904 doesn't need valve cover venting. |
There is not enough information about the engine to make this determination. You have big cam with heads to support it turning high RPM; you will need to vent more than just the case. |
yup. then add a turbo and see how much venting you need, especially if the engine is older and has any blow by. _________________ Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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Jason37 Samba Member
Joined: April 21, 2004 Posts: 1027
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madmike Samba Member
Joined: July 11, 2005 Posts: 5291 Location: Atlanta,Michigan
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Posted: Thu Apr 15, 2021 4:43 am Post subject: Re: Proper crankcase ventilation? |
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Nextgen, how high do you rev that Type IV? _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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Ohio Tom Samba Member
Joined: February 09, 2006 Posts: 1657 Location: Marshallville Ohio
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Posted: Thu Apr 15, 2021 6:02 am Post subject: Re: Proper crankcase ventilation? |
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A few things that Shoptalk forum article has wrong:
Porsche 912 motors only vented the 1/2 side. The 3/4 remained sealed.
It's not the oil ring that "flutters" with high crank case pressures. It's the top compression ring.
Has more to do with ring gaps, but excessive crank case pressure contributes.
ONe of the big points that is missed for dealing with case pressure is ring gaps.
Most folks don't think about it too much. But gaps make a big difference in the amount of blow-by at high rpms (when you are worried about it).
Another one is "internal case porting". This is blending and smoothing the breather ports in the #2 main bearing web. The ports are usually full of sharp corners and very restrictive. Blending and smoothing will allow the case to breather easier and will reduce the amount oil spray in the gasses that vent. |
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kangaboy Samba Member
Joined: August 28, 2010 Posts: 1062 Location: St. Louis, Mo
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Posted: Thu Apr 15, 2021 10:53 am Post subject: Re: Proper crankcase ventilation? |
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richardcraineum wrote: |
k-weaver wrote: |
kangaboy wrote: |
Breather on crank case only. A 1904 doesn't need valve cover venting. |
There is not enough information about the engine to make this determination. You have big cam with heads to support it turning high RPM; you will need to vent more than just the case. |
yup. then add a turbo and see how much venting you need, especially if the engine is older and has any blow by. |
I guess I'm just lucky then. Actually hit 24psi at the track last weekend. _________________ -74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Thu Apr 15, 2021 11:23 am Post subject: Re: Proper crankcase ventilation? |
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Just for the record....that conversation is missing a lot of info for type 4.
And....it is only speaking of case venting with a carb system.
The factory type 4 system for fuel injected 411/412 and 914 (and to some extent the L-jet injected bus)....is actually a "pull through" system.
It pulls filtered air from the air cleaner (it has a special outlet on the AC).
Then...it pulls this air through a flame trap/splitter....
Then...through 12mm hose into each rocker box where It helps to pull excessive oil and any gases....through the pushrod tubes into the case
Then......gases from the case pass through the "Z" baffle cast into the type 4 case losing some oil vapor....
Then the gases pass through the oil chimney baffle (which works very well by itself for oil separation)....and this is where the "chore boy" scouring pads would be installed........
Then through the factory PCV valve.....and into the intake manifold through the 12mm hose.
So.....type 4 factory injection used manifold vacuum to pull fresh air from teh AC...through the rocker boxes....through the case....out the top and through the manifold.
Most effective PCV and oil separation system I have seen in an air cooled VW.
It takes more vacuum than most carbs generate.
The whole point I was getting at is that in type 4....the vent tubes on the rocker boxes from the factory....were NEVER designed to vent OUTWARD. Why would you want to pull all of that crap through your valve gear?
Ray |
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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Posted: Thu Apr 15, 2021 11:39 am Post subject: Re: Proper crankcase ventilation? |
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Madmike, do you think I rev it high if it lasted 30 years, ha.
Seriously like anyone with a T-1 or T-4 Normal revving unless I am showing off on a highway.
It was not built for racing, the engine came out of 914 with a top speed of 127 mph.. I have done 100 easy, 60 to 100 is seconds BUT I will never do it again.
With all the stuff I did to make it hold the road, after 90 the steering gets light.
Freaked me out, but what freaks out cars like BMW's is when they tailgate an hit the gas. W T F!!!
It is a 2.0 71 mm stroke 66 mm. a bit more torque.
Highway speeds it what I wanted and what I got.
_________________ email: [email protected]
The TYPE IV UPRIGHT CONVERSION MANUAL
BEETLE MAGNETIC DEFLECTOR SHIELDS
LETS TALK DUBS https://www.youtube.com/results?search_query=joe+cali+ghia https://letstalkdubs.libsyn.com/ep-200-joe-cali-ty...qI3xJTCzjs |
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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madmike Samba Member
Joined: July 11, 2005 Posts: 5291 Location: Atlanta,Michigan
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Posted: Thu Apr 15, 2021 1:31 pm Post subject: Re: Proper crankcase ventilation? |
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Just wanted to know what rpm's you shift at? ,is all _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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nextgen Samba Member
Joined: August 19, 2004 Posts: 6008 Location: CONGERS, N.Y.
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