| Author |
Message |
cmaxcliff
Samba Member
Joined: November 07, 2009
Posts: 176
Location: S.E. PA
|
 Posted: Mon Dec 02, 2024 8:26 am Post subject: Re: Theory behind valve cover venting |
 |
|
When you race bikes with big single piston engines or big 360* vertical twins you get an education on venting. What is dry on a road bike is going to be wet at a constant 7000rpm. You have to deal with the problem unless you like oil on your tire.
Big diameter vent hose is not always better than something smaller but that requires experimentation to determine. I always start large.
Since I don't know VWs yet I refer to the 356/912 engine. The factory started with holes in the top center of the valve cover that had fine screens with a deflector over them that directed escaped oil down the cover to drip to the ground. No hose, no nipple. Then they went to the higher revving S90 and they put check valves inside the cover with large steel balls that rolled to stop flow during cornering. Finally as they prepared for emissions regulations they vented through the 1/2 carburetor with a line that came from the oil fill. Also they added a vent hose from the 1/2 cylinder head in the top of the rocker box and the valve covers were no longer vented.
When racing those engines at a constant 7500rpm venting is important and I vent both rocker boxes along with a vent hose from the oil fill. I took the same approach with my big bore stroked 2133cc engine and it stayed very dry for the 32000 miles that I had it. That engine might have needed more venting if I were racing it.
I hope the same approach works on the Type 1 race engine I am building.
|
|
| Back to top |
|
 |
BFB
Samba Member
Joined: November 03, 2014
Posts: 2110
|
| Posted: Mon Dec 02, 2024 7:37 pm Post subject: Re: Theory behind valve cover venting |
|
|
| oprn wrote: |
Venting the valve covers does help vent the crankcase. It also allows oil to return to the sump much faster.
That one defies logic! How does air flowing UP the pushrod tubes help the oil flow DOWN the pushrod tubes? |
You’ve never shotgunned a beer bottle using a vent tube neck on it have you..
_________________
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 |
|
| Back to top |
|
|
BFB
Samba Member
Joined: November 03, 2014
Posts: 2110
|
| Posted: Mon Dec 02, 2024 7:43 pm Post subject: Re: Theory behind valve cover venting |
|
|
| raygreenwood wrote: |
| Vanapplebomb wrote: |
| BFB wrote: |
| raygreenwood wrote: |
| Vanapplebomb wrote: |
I’m not in favor of “venting” the valve covers. To me, it’s moving the gasses the wrong direction.
This is very evident when comparing used heads from PCV equipped engines (Type 3 & 4 with Djet), and those without. The PCV system had the fresh air inlets in the rocker covers. Clean filtered air enters the rockers, pulled through the pushrod tubes into the case, then out the top of the case into the intake. The PCV engines always have very clean rocker boxes with less buildup. Case internals are often cleaner too, with less pitting in the sump. The engines with the most crap in the heads are usually ones where people added vents to the heads. Just my observations. 
In my opinion, it takes a very special engine to actually require more venting volume capacity than was available stock. Unless it is a very high rpm big bore engine, it shouldn’t need more than a 1/2” hose. All those sub 2.0 engines that people claim need the rocker boxes vented probably just have crap ring sealing and need to be rebuilt. |
Beat me to it. The type 4 cars and 914's with the same engine and t9 some respects the type 3 cars with D-jet.....used vented rocker boxes.....but they vent INWARD pulling in filtered air from a special section of the air cleaner.....through a flame trap.....and through the PR tubes....through the case....out the top at the oul bagel as Vanapplebomb noted.
Very clean. Runs a little cooler in some climate. Ray |
Really sounds like a contradictive statement, yall are saying your not in favor of vented covers yet the mentioned engines with vented covers are all around cleaner. Only real difference is the design in flow. |
It is the direction of flow and what is flowing that makes the difference. One method purges the case with fresh air. The other doesn’t. Hope that makes sense.  |
Yes...to add to this....it works on the type 4 engines (specifically with D-jet injection)....because this venting system uses full manifold vacuum through a 12mm hose sucking on the PCV valve at the oil vapor seperator chimney.
The PCV valve cracks open for 10ths or hundreths of a second dues to a combination of case pressure (if any) and vacuum from the manifold. It sucks any gases out of the case into the intake. A totally different concept from venting OUT of the valve covers into a low vacuum carburettor air cleaner and just hoping it sucks in any gases.
The type 4 case has a Z shaped baffel at the top of the case into the oil chimney that takes out a ton of oil vapor. The top of the oil chimney itself is an oil baffel...and a pretty good one.
Its a really good system but you need high vacuum to make it work in this direction...meaning sucking/pulling air THROUGH the rocker boxes and THROUGH the PR tubes and THROUGH the case and out the top.
You really can't do this well with carbs unless maybe you somehow plumb to the balance tube and then its a vacuum leak.
Its already a little bit of a vacuum problem with D-jet. Some of us fix this issue by going to a uniform 2-3mm orifice flowing full time instead of the factory PVC valve. We then adjust the fuel mixture accordingly (its a MAP based EFI system).
If you look at what gets baked onto the inside of the rocker boxes and case in a type 4 engine that does NOT use this system....you get an idea of exactly whatr its venting....so yes....it is effective. Ray |
Honestly, ive never seen the D jet in person… so how does it pull full manifold vacuum? I guess it really wouldnt matter from where it pulled it as its not carbureted so it wont lean it out…
Post some pictures of this if you feel like it?
_________________
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 |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 22477
Location: Oklahoma City
|
| Posted: Mon Dec 02, 2024 8:17 pm Post subject: Re: Theory behind valve cover venting |
|
|
| BFB wrote: |
| raygreenwood wrote: |
| Vanapplebomb wrote: |
| BFB wrote: |
| raygreenwood wrote: |
| Vanapplebomb wrote: |
I’m not in favor of “venting” the valve covers. To me, it’s moving the gasses the wrong direction.
This is very evident when comparing used heads from PCV equipped engines (Type 3 & 4 with Djet), and those without. The PCV system had the fresh air inlets in the rocker covers. Clean filtered air enters the rockers, pulled through the pushrod tubes into the case, then out the top of the case into the intake. The PCV engines always have very clean rocker boxes with less buildup. Case internals are often cleaner too, with less pitting in the sump. The engines with the most crap in the heads are usually ones where people added vents to the heads. Just my observations.
In my opinion, it takes a very special engine to actually require more venting volume capacity than was available stock. Unless it is a very high rpm big bore engine, it shouldn’t need more than a 1/2” hose. All those sub 2.0 engines that people claim need the rocker boxes vented probably just have crap ring sealing and need to be rebuilt. |
Beat me to it. The type 4 cars and 914's with the same engine and t9 some respects the type 3 cars with D-jet.....used vented rocker boxes.....but they vent INWARD pulling in filtered air from a special section of the air cleaner.....through a flame trap.....and through the PR tubes....through the case....out the top at the oul bagel as Vanapplebomb noted.
Very clean. Runs a little cooler in some climate. Ray |
Really sounds like a contradictive statement, yall are saying your not in favor of vented covers yet the mentioned engines with vented covers are all around cleaner. Only real difference is the design in flow. |
It is the direction of flow and what is flowing that makes the difference. One method purges the case with fresh air. The other doesn’t. Hope that makes sense. |
Yes...to add to this....it works on the type 4 engines (specifically with D-jet injection)....because this venting system uses full manifold vacuum through a 12mm hose sucking on the PCV valve at the oil vapor seperator chimney.
The PCV valve cracks open for 10ths or hundreths of a second dues to a combination of case pressure (if any) and vacuum from the manifold. It sucks any gases out of the case into the intake. A totally different concept from venting OUT of the valve covers into a low vacuum carburettor air cleaner and just hoping it sucks in any gases.
The type 4 case has a Z shaped baffel at the top of the case into the oil chimney that takes out a ton of oil vapor. The top of the oil chimney itself is an oil baffel...and a pretty good one.
Its a really good system but you need high vacuum to make it work in this direction...meaning sucking/pulling air THROUGH the rocker boxes and THROUGH the PR tubes and THROUGH the case and out the top.
You really can't do this well with carbs unless maybe you somehow plumb to the balance tube and then its a vacuum leak.
Its already a little bit of a vacuum problem with D-jet. Some of us fix this issue by going to a uniform 2-3mm orifice flowing full time instead of the factory PVC valve. We then adjust the fuel mixture accordingly (its a MAP based EFI system).
If you look at what gets baked onto the inside of the rocker boxes and case in a type 4 engine that does NOT use this system....you get an idea of exactly whatr its venting....so yes....it is effective. Ray |
Honestly, ive never seen the D jet in person… so how does it pull full manifold vacuum? I guess it really wouldnt matter from where it pulled it as its not carbureted so it wont lean it out…
Post some pictures of this if you feel like it? |
I can see the diagram I need to look for in my head. I just need to dig around.
But understand....it's a fuel injection system with a central plenum with all four cylinder runners attached to it.
So even though each cylinder is drawing at a different time, there is always at least one cylinder drawing fully and one partially drawing (close to valve closing point).
So the vacuum in the center manifold is high, constant and somewhat of an average.
There is a 12mm hose running straight from this center manifold to the top of the oil breather chimney (which is an oil baffel system).
Typical constant vacuum on this hose at WOT is about 5-7" hg. At part throttle low rpm cruise....it's about 10-15" hg. At idle and at high rpm part throttle cruise it can be as high as 20"hg.
It's controlled on and off by a PCV valve connected to the 12mm hose and mounted in the oil filler/baffle chimney. That PCV valve....operated mostly by the vacuum and only a small percentage by internal case pressure oscillates open and closed at a fairly high rate. It kind of "chatters" at one rate or another depending on throttle postion and rpm....which is exactly what wears it out.
So it's pulling all of that vacuum on the top of the case. But it cannot really pull much of a suction of the case because the air cleaner is flowing air freely through a 14mm hose to a combination splitter Tee fitting with a flame baffle in it. From there a 12mm hose goes to each rocker box.
Clean/cool air flows into each rocker box, through the pushrod tubes, into the case, pushing any gases with it on its way to the oil baffle and PCV at the top of the case.
That odd off and on chatter of the PCV is actually a limiting factor on how closely you can adjust the fuel mixture on these engines (meaning if you want to tune better than factory settings) because that 12mm hose dumps into the center manifold right next to the 8mm hoses that feeds the MAP sensor. At certain rpms, when the PCV valve dumps air to the center manifold...it spikes the MAP sensor RICH. The MAP sensor sees free air as "throttle open".
So, we replace the PCV with a small constant flow orifice. It's the same amount of "pull through PCV air all the time....with no strangely timed oscillations. We adjust the MAP sensor a little leaner and adjust the idle down.
Tighter fuel tuning with the same PCV function. Ray |
|
| Back to top |
|
|
chrisflstf
Samba Member
Joined: February 10, 2004
Posts: 3748
Location: San Diego
|
| Posted: Tue Dec 03, 2024 2:00 pm Post subject: Re: Theory behind valve cover venting |
|
|
In Jim Martins case he has a vent hole of 1 inch. Which has an area of .7854 sq inch. The latest factory breather vent was 19mm or .75” which has an area of .44 sq inch. So the 1 inch tube Jim has is effectively 75% larger than the factory 19mm ( .75”)
For reference adding a AN8 fitting is only an additional .152 sq inch ( inside diameter of hose)
An An10 adds an additional .248 sq inch. ( inside diameter of hose) This with the factory 19mm would almost equal a 1 inch vent
Would be nice if there was a way to have a 1 inch fitting on a factory style breather ( Dont like the aftermarket style add on boxes. Berg is ok, but $250 or so?) |
|
| Back to top |
|
|
oprn
Samba Member
Joined: November 13, 2016
Posts: 14105
Location: Western Canada
|
| Posted: Tue Dec 03, 2024 3:18 pm Post subject: Re: Theory behind valve cover venting |
|
|
Actually the factory one had two outlets. The draught tube was 3/4" and the tube to the air cleaner was 1/2". The sum of both is 0.635 square inches so Jim's solution is only a little bit bigger than factory.
_________________
Our cars get old, we get old but driving an old VW never gets old! |
|
| Back to top |
|
|
chrisflstf
Samba Member
Joined: February 10, 2004
Posts: 3748
Location: San Diego
|
|
| Back to top |
|
|
oprn
Samba Member
Joined: November 13, 2016
Posts: 14105
Location: Western Canada
|
| Posted: Tue Dec 03, 2024 4:35 pm Post subject: Re: Theory behind valve cover venting |
|
|
That looks better. You could turn it a bit to about 2 o'clock, put an elbow on both ends and eliminate those restrictive banjo fittings.
_________________
Our cars get old, we get old but driving an old VW never gets old! |
|
| Back to top |
|
|
jim martin
Samba Member
Joined: January 14, 2004
Posts: 270
Location: Vancouver, BC
|
| Posted: Wed Dec 04, 2024 2:37 pm Post subject: Re: Theory behind valve cover venting |
|
|
D-JETRONIC injection is another topic , But Orifice or PCV controlled crankcase vent systems is most likely something people building performance motors will shy away from , i would not want my intake tract or combustion chambers becoming contaminated with oil saturated vapors .
- someone was mentioning ID of hoses / area == this is exactly what i learned after many failures along the way .
think of all you crankcase vapors trying to exit through a small id hose , the velocity will be increased and because of this so will the movement off oil saturated vapors , With a large ID hose the movement back and forth will be easy, allowing for non restrictive breathing . and since the movement of vapors will be greatly reduced it will allow time for the oil in the vapors to fall from suspension much easier , that's why i mount as high as possible .
- its easy to make large ID hose adapters by welding steel or aluminum tube or fittings to threaded aftermarket threaded adapters for the alternator stand , thats what i do as always have something laying around i could use
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0 |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 22477
Location: Oklahoma City
|
| Posted: Wed Dec 04, 2024 3:36 pm Post subject: Re: Theory behind valve cover venting |
|
|
| jim martin wrote: |
D-JETRONIC injection is another topic , But Orifice or PCV controlled crankcase vent systems is most likely something people building performance motors will shy away from , i would not want my intake tract or combustion chambers becoming contaminated with oil saturated vapors .
- someone was mentioning ID of hoses / area == this is exactly what i learned after many failures along the way .
think of all you crankcase vapors trying to exit through a small id hose , the velocity will be increased and because of this so will the movement off oil saturated vapors , With a large ID hose the movement back and forth will be easy, allowing for non restrictive breathing . and since the movement of vapors will be greatly reduced it will allow time for the oil in the vapors to fall from suspension much easier , that's why i mount as high as possible .
- its easy to make large ID hose adapters by welding steel or aluminum tube or fittings to threaded aftermarket threaded adapters for the alternator stand , thats what i do as always have something laying around i could use |
Yes....as you note.....going through a small orifice multiplies velocity. This is why going through a 3mm orifice at high velocity can net you just as much gas flow as a 12mm hose cross section at several times less velocity.
And yes.....D-jet really is another conversation...especially since with the VERY effective multi-pass centrifugal baffels the system uses.....we get virtually no oil vapor. That cannot be done easily as a "slap it on" mod to every engine.
The other issue specific to the D-jet PCV....but from what I have seen it's probably quite sim8lar to any other PCV......is that the valve inside of the PCV is a simple 12mm, spring loaded plastic disc capping a 10mm orifice venting in the 12mm hose.
When it vents...maybe 1 or 2 times per second give or take, it lifts about 0.002" to about 0.005"on one edge opening a thin wedge of space. You can see the lift range from the wear mark inside.
I did some fudging figuring.....and it works out to roughly a 2.0mm orifice at any given time. Most PCV are similar.
But, as you note.....on a high performance vehicle you would not use a PCV anyway. Ray |
|
| Back to top |
|
|
jim martin
Samba Member
Joined: January 14, 2004
Posts: 270
Location: Vancouver, BC
|
| Posted: Fri Dec 06, 2024 9:26 am Post subject: Re: Theory behind valve cover venting |
|
|
Found some old photos , figured they would kinda be fun to
Post up on this topic .
This motor ran nitrous and turned 11.0’s shifting at 8000 rpm
Using all 5 gears in the berg 5 speed box . Yes 5th was swapped out.
So oil control was a big concern .
Looks like I started like everyone
looks like I modified the system with a berg breather , must of still been moving oil , added some catch bottles to catch overflow
looks like I was progressing . aluminum breather box gone
next step appeared to be remove from fuel pump port and take fro alt stand .
most of been learning something
looks like I got something nailed down and next progression step was vacuum pump .
here is a 1" id adapter , you get the idea
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0 |
|
| Back to top |
|
|
chrisflstf
Samba Member
Joined: February 10, 2004
Posts: 3748
Location: San Diego
|
| Posted: Fri Dec 06, 2024 2:37 pm Post subject: Re: Theory behind valve cover venting |
|
|
Good pics Jim. I agree most blowby issues are with poor ring sealing. I also think the stock breather is adequate for a stock motor. But when the displacement and rpms go up, adequate is not enough. There is also, in my opinion, no down side to increasing the breathing capabilities on a performance motor, like Jeff Paull mentioned
The fuel pump port seems to be a poor place to vent as its directly above the crank/cam. Lost of oil in a direct line from below
Im working on a mod to the stock breather to increase the diameter to 1 inch and use a AN10 on the pass side valve cover. I currently don’t have any blow by issues and have 2 to 3% leakdown |
|
| Back to top |
|
|
modok
Samba Member
Joined: October 30, 2009
Posts: 27235
Location: Colorado Springs
|
| Posted: Sat Dec 07, 2024 12:04 am Post subject: Re: Theory behind valve cover venting |
|
|
| jim martin wrote: |
D-JETRONIC injection is another topic , But Orifice or PCV controlled crankcase vent systems is most likely something people building performance motors will shy away from , i would not want my intake tract or combustion chambers becoming contaminated with oil saturated vapors .
- someone was mentioning ID of hoses / area == this is exactly what i learned after many failures along the way .
think of all you crankcase vapors trying to exit through a small id hose , the velocity will be increased and because of this so will the movement off oil saturated vapors , With a large ID hose the movement back and forth will be easy, allowing for non restrictive breathing . and since the movement of vapors will be greatly reduced it will allow time for the oil in the vapors to fall from suspension much easier , that's why i mount as high as possible .
- its easy to make large ID hose adapters by welding steel or aluminum tube or fittings to threaded aftermarket threaded adapters for the alternator stand , thats what i do as always have something laying around i could use |
BINGO
the majority of problems are due to people not understanding..... how big a hole is. I use thin wall steel fittings so the path is not restricted, and I'm too cheap to actually buy a fitting anyway when I can just use old steel tube and weld it on or press fit it in a hole. That how normal cars do it. I don't know what's with the obsession with complicated fancy fittings, some kind of try-hard fashion contest I guess.
It's not going to rust out, so why not use steel?
Now that I'm a machinist, I have to machine the barbs, because I'm a machinist, so I guess I'm vain too. But when I was a normal gearhead that just wanted to go fast I'd happily just weld in a circle around the outside of a slice of used bicycle tubing and that makes a lovely breather fitting. I do think barb with a SINGULAR bulge is the right design for a low pressure hose connection. Where to find nice flexible low pressure hose that's fully oil resistant might be the hardest part.
Vents to the valve covers have pros and cons, but it's just not that important, it can be done wrong either way, or right either way.
I've been meaning to make a PCV system someday, but, never have got around to it, I've been saying that for a decade now, so....probably not gonna happen. |
|
| Back to top |
|
|
oprn
Samba Member
Joined: November 13, 2016
Posts: 14105
Location: Western Canada
|
| Posted: Mon Dec 09, 2024 5:04 am Post subject: Re: Theory behind valve cover venting |
|
|
I too do not understand the fascination of the high pressure fittings that most use on their crankcase vent systems. Except of course for the "Oh Wow! Look at how much money I spent!" value when you open the hood. Those fittings as Modoc pointed out are very restrictive for their size. That is how they get their high pressure rating! Thick walls and small ports. The exact opposite to what we need.
_________________
Our cars get old, we get old but driving an old VW never gets old! |
|
| Back to top |
|
|
jim martin
Samba Member
Joined: January 14, 2004
Posts: 270
Location: Vancouver, BC
|
| Posted: Mon Dec 09, 2024 4:36 pm Post subject: Re: Theory behind valve cover venting |
|
|
| oprn wrote: |
| I too do not understand the fascination of the high pressure fittings that most use on their crankcase vent systems. Except of course for the "Oh Wow! Look at how much money I spent!" value when you open the hood. Those fittings as Modoc pointed out are very restrictive for their size. That is how they get their high pressure rating! Thick walls and small ports. The exact opposite to what we need. |
not being a you know what and dont take this in anyway hurtfully but i don't think i would agree with all these comments. there's many ways to look at .
-even Thoe this is off topic of valve cover venting .
if im spending good money on my new motor and im proud of my attention to my engines detail i would spend the few extra dollars on nice looking AN fittings and hose over hose clamps or push lock regardless if its overkill or not or what pressure is running through them .
- if you are using those fittings you need to be smart and inspect the ID of the fittings with the ID of the hose you are using , fyi many hose and fitting manufactures have some unique size differences compared to others .
- in any performance application things have a tendency to be removed and installed many times and hoses over barbs with a clamp is not going to last and they usually require replacement due to damage to the hose ,where as its way faster to undo a AN fitting with a wrench .
and in a crash im sure a properly connected AN hose assembly will take a lot of force to pull apart .
so are they overkill in a low pressure application yes , or maybe but they just make more practical sense depending on the individuals situation ,
- myself i have and continue to modified many steel or aluminum fittings external and internal dimensions to work as i need them . and yes, i have fittings on my breather and dry-sump setup which are hose clamped but over modified fittings or homemade fittings . I always consider Maintenace and safety first and i take pride in my craftsmanship and attention to detail when i can .
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0 |
|
| Back to top |
|
|
slalombuggy
Samba Member
Joined: July 17, 2010
Posts: 9272
Location: Canada
|
| Posted: Mon Dec 09, 2024 6:28 pm Post subject: Re: Theory behind valve cover venting |
|
|
| I agree with Jim about the AN fittings for vent systems. I use cheap Chinese fittings for non critical things like case venting because spinning off an AN fitting is way easier then dealing with hose clamps and barbed fittings. |
|
| Back to top |
|
|
vwracerdave
Samba Member
Joined: November 11, 2004
Posts: 15575
Location: Deep in the 405
|
| Posted: Mon Dec 09, 2024 6:57 pm Post subject: Re: Theory behind valve cover venting |
|
|
If you're racing you may be required to use AN fittings to pass tech.
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK |
|
| Back to top |
|
|
slalombuggy
Samba Member
Joined: July 17, 2010
Posts: 9272
Location: Canada
|
| Posted: Mon Dec 09, 2024 7:26 pm Post subject: Re: Theory behind valve cover venting |
|
|
| Yup that's true but even on street engines I like to use them. You can buy cheap hose ends on fleabay and use steel or brass JIC fittings that are WAY cheaper than aluminum race parts. |
|
| Back to top |
|
|
BFB
Samba Member
Joined: November 03, 2014
Posts: 2110
|
| Posted: Mon Dec 09, 2024 8:39 pm Post subject: Re: Theory behind valve cover venting |
|
|
This ain’t a bad discussion…. I think to each there own as far as AN vs hoses & barb fittings but me personally i dont like AN lines. I think there overrated and cost too much just for something that looks “better” , other thing i dont like is that yes they may be able to be unscrewed and screwed together without damaging a hose like a barb fitting will, until the aluminum galls. I.cant count the aluminum a/c condensers and coolers ive replaced and had to replace the lines as well because the aluminum nuts threads bound up. And God forbid if your out somewhere and an AN lines or fitting needs replaced, your best bet is if Amazon will deliver to you next day, but a rubber hose can be had from about any parts or even hardware store.
I used to know a guy that built 4x4’s , rock crawlers and such. And he wouldnt use heims for the availability reasons, instead he used tie rod ends from a semi. He said they were rated for 80,000 psi ( if i remember correctly ) and were readily available from any auto parts stores. Smart man
_________________
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 |
|
| Back to top |
|
|
chrisflstf
Samba Member
Joined: February 10, 2004
Posts: 3748
Location: San Diego
|
| Posted: Mon Dec 16, 2024 2:51 pm Post subject: Re: Theory behind valve cover venting |
|
|
Here is my change to the stock breather. I cut the top off the 3/4" pipe, enlarged the hole to 1" and welded on an AN16 Male fitting , then an AN 16 female, some 1" pushloc hose and 2 T bolt clamps, plus the 1" breather I had along with some 1" alum tubing.
Since the hole in the Alt/Gen stand is 1" all the way, it makes sense to have it stay that way, all the way up, to me.
Also I welded an AN10 fitting a pass side valve cover. Dont know if I will add that yet or not, until I do some driving/testing
Samba is putting the pic upside down, Dont know why 
|
|
| Back to top |
|
|
|
