case and head vents, do I need to run a breather box? Options

[wayne1234]

Ok dual webber carbed 2.0, I think the PO had the head vents running to a T then to the oil breather near the oil cap... Is this right?? I did a search and now I'm really confused,,,,

[ME733]

You could do what the V8 drag racers use. Crank case vacuum scavenger tubes welded to the exhaust. They create negative pressure in the crank case and help to seat the rings better and reduce blow by. This setup is not legal to run on the street but know one really checks for this set up. To use it correctly you will need check valves on the scavenger tubes. You would also run a sealed case, no vents other than the valve covers.

.....................well you have brought up another way to vent the crankcase, which has been used. I disagree that this system helps to "seat the rings"..it,s an old wifes tale. Rings seat, or not, based on assembly, type,cylinder wall preperation, type rings,and poor/or good assembly techniques,among other factors, etc., and if there is negative crankcase pressure..it would tend to increase ring blowby not reduce it. I Have used , the (negative pressure) crankcase ventelation, to exhaust system...collector...on race engines in the past.(quite a few years ago). The problem with a stock exhaust system (on the 914) is there is no collector .(except the bursche) and it,s too far away.(a plumbing zoo).routing to just one cylinder exhaust tube would be the solution, but not very effective. The essence of this system is that it CAN create NEGATIVE crankcase pressure. this too can cause engine leaks, valve cover seal problems, etc. The best installation is to have an open -to the atmosphere-vent for the crantcase itself. (some v-8s) have valve cover "breathers". Replacing the filler cap, on a 914,(or something similar) with a filtered, screened cap would probabley work, or a filtered breather hose connected to the filler box, just something to help,equalize the the crankcase pressure...when routing to the exhaust system. Murray

[johnnie5]

Here are a few pics of my CB/Empi setup.... seems to work fine for me.

[Cap'n Krusty]

Rich Towle said earlier, "Older American cars just ran a hose with no filter down underneath the car and used the venturi affect to suck the vapors out of the hose."

That's true. In 1965, it became illegal to run a "road draft tube"in the United States, and it remains illegal today. Just because something "looks messy" isn't justification to choose the laws you wish to obey. Many of you are too young to remember what REAL smog was, and you should thank the "powers that be" for reducing it to the level it is today. While Los Angeles is fabled to have been (and still is, for many people) the epitome of smog, it's far from it. Try Denver, the San Francisco Peninsula, and Phoenix. I grew up in LA County, and I remember well experiencing whole summers where there were maybe 3 days of somewhat clear, safe, breathable air. Now there may be 3 really bad days in the entire summer. Those of you who think YOUR car won't make a difference, and YOUR personal tastes supercede the will (and the right) of the rest of us to have a clean environment, should rethink your role in society. End of Rant.

The Cap'n

[Gint]

While I understand your point John and I agree with you, your facts with regard to polluted cities are in dispute. (IMG:style_emoticons/default/poke.gif)

http://www.citymayors.com/environment/polluted_uscities.html
http://green.yahoo.com/blog/daily_green_ne...ir-quality.html

[ME733]

Rich Towle said earlier, "Older American cars just ran a hose with no filter down underneath the car and used the venturi affect to suck the vapors out of the hose."

That's true. In 1965, it became illegal to run a "road draft tube"in the United States, and it remains illegal today. Just because something "looks messy" isn't justification to choose the laws you wish to obey. Many of you are too young to remember what REAL smog was, and you should thank the "powers that be" for reducing it to the level it is today. While Los Angeles is fabled to have been (and still is, for many people) the epitome of smog, it's far from it. Try Denver, the San Francisco Peninsula, and Phoenix. I grew up in LA County, and I remember well experiencing whole summers where there were maybe 3 days of somewhat clear, safe, breathable air. Now there may be 3 really bad days in the entire summer. Those of you who think YOUR car won't make a difference, and YOUR personal tastes supercede the will (and the right) of the rest of us to have a clean environment, should rethink your role in society. End of Rant.

The Cap'n

...................I couldn't agree more. I grew up in ATLANTA georgia. As a kid it was all too common for cars to bellow smoke down the street, down the highway and down the expressway., sometimes to the extent it was dangerious to follow them.(much less the smell) And it was the obvious sign the car owner was a fool, and unconserned about anyone else. It,s just unfortunate that a few damn irrresponsable asses have forced all of society into the situation we find ourselves in today. Regulation of idiots,and everybody has to pay. The annual emmission inspections are a time consuming pain in the Ass and another cost of owning a car.I have never had a car fail Emmissions inspection but it,s still 2-3 hours out of your life ....for me waisted time, and 25.00 bucks.

[HAM Inc]

Oil runs cooler and returns to the crankcase faster if you leave the heads unvented. BTDT, proved it on the street and the race track.

[DBCooper]

Rich Towle said earlier, "Older American cars just ran a hose with no filter down underneath the car and used the venturi affect to suck the vapors out of the hose."

That's true. In 1965, it became illegal to run a "road draft tube"in the United States, and it remains illegal today. Just because something "looks messy" isn't justification to choose the laws you wish to obey. Many of you are too young to remember what REAL smog was, and you should thank the "powers that be" for reducing it to the level it is today. While Los Angeles is fabled to have been (and still is, for many people) the epitome of smog, it's far from it. Try Denver, the San Francisco Peninsula, and Phoenix. I grew up in LA County, and I remember well experiencing whole summers where there were maybe 3 days of somewhat clear, safe, breathable air. Now there may be 3 really bad days in the entire summer. Those of you who think YOUR car won't make a difference, and YOUR personal tastes supercede the will (and the right) of the rest of us to have a clean environment, should rethink your role in society. End of Rant.

The Cap'n

Amen.

You really had to have been there to understand how bad it was. Here's a Tim Buckley album cover from the 70's, above and below the smog layer. You can make out the brown buildings down below. When you flew into town this is what you descended into:
(IMG:http://ecx.images-amazon.com/images/I/315F1A2TR4L._SS500_.jpg)

[Cap'n Krusty]

While I understand your point John and I agree with you, your facts with regard to polluted cities are in dispute. (IMG:style_emoticons/default/poke.gif)

http://www.citymayors.com/environment/polluted_uscities.html
http://green.yahoo.com/blog/daily_green_ne...ir-quality.html

On some summer days in 1961, the air quality in Phoenix was poorer than Los Angeles. You have to remember that the photochemical components of smog aren't always present in the same quantities, but the other harmful components may still be there. I was in Denver in the summer of 1978 or 1979 for a swap meet at Storz Garage, and the smog was TERRIBLE! As for the SF Bay area, have you been there recently? Nasty.

I stand by my statements.

The Cap'n

[pbanders]

While I understand your point John and I agree with you, your facts with regard to polluted cities are in dispute. (IMG:style_emoticons/default/poke.gif)

http://www.citymayors.com/environment/polluted_uscities.html
http://green.yahoo.com/blog/daily_green_ne...ir-quality.html

On some summer days in 1961, the air quality in Phoenix was poorer than Los Angeles. You have to remember that the photochemical components of smog aren't always present in the same quantities, but the other harmful components may still be there. I was in Denver in the summer of 1978 or 1979 for a swap meet at Storz Garage, and the smog was TERRIBLE! As for the SF Bay area, have you been there recently? Nasty.

I stand by my statements.

The Cap'n

The emissions issue is one of the main reasons I've stuck with D-Jetronic on my car and have worked to keep all of the emissions controls on it functioning properly. The '75-76 systems were even better for emissions, but were a stopgap measure on the way to the use of true three-way cat with O2 sensor mixture control, which came after the 914's demise.

Early D-Jet is still pretty good for emissions when properly tuned. Overrun fuel management, idle timing retard, fuel tank evaporative control and management, PCV system, and part-load mixture management all reduced emissions over the previous generation of cars.

[sean_v8_914]

just drive across the border and you will experience the difference our emmisions laws have made. I try to put everythnig in place on stock engines.
viva la EFI!

[bandjoey]

Oil runs cooler and returns to the crankcase faster if you leave the heads unvented. BTDT, proved it on the street and the race track.

OK. Up to here everything was making sense. Now I see this from HAM saying oil runs cooler with UnVented heads. ??? (IMG:style_emoticons/default/huh.gif) Please explain.

...and, Is this using a single line from the Oil Filler neck to a vent box and back to where? or no vent there either?

confused as usual.. Thanks

[jaxdream]

Oil runs cooler and returns to the crankcase faster if you leave the heads unvented. BTDT, proved it on the street and the race track.

OK. Up to here everything was making sense. Now I see this from HAM saying oil runs cooler with UnVented heads. ??? (IMG:style_emoticons/default/huh.gif) Please explain.

...and, Is this using a single line from the Oil Filler neck to a vent box and back to where? or no vent there either?

confused as usual.. Thanks

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/WTF.gif)

I , too , was ok with this line of reasoning , untill this.??????????????????
I have 2 ( two ) 1.7 engines , one has head vents the other doesn't, I was planning on using the vented head engine as the direction of this thread was logical as to the evacuation of crankcase gases is helpfull to an extent , espeacilly on carbed engines , which is what I have on both of my 1.7's. Now that the head guy spoke up and said it didn't do jack for the engine , I want to hear more of this new info please, Len ???

Jack / Jaxdream

[Gint]

While I understand your point John and I agree with you, your facts with regard to polluted cities are in dispute. (IMG:style_emoticons/default/poke.gif)

http://www.citymayors.com/environment/polluted_uscities.html
http://green.yahoo.com/blog/daily_green_ne...ir-quality.html

On some summer days in 1961, the air quality in Phoenix was poorer than Los Angeles. You have to remember that the photochemical components of smog aren't always present in the same quantities, but the other harmful components may still be there. I was in Denver in the summer of 1978 or 1979 for a swap meet at Storz Garage, and the smog was TERRIBLE! As for the SF Bay area, have you been there recently? Nasty.

I stand by my statements.

The Cap'n

Yeah, it used to get bad around here for a few days a year back then. But that one occasion was 30 years ago. In LA every day in 1978 or 79 probably looked like that. Your statement:

While Los Angeles is fabled to have been (and still is, for many people) the epitome of smog, it's far from it. Try Denver, the San Francisco Peninsula, and Phoenix.

is misleading at best. Actually it's just wrong. While it may be better today then it was 30+ years ago, LA is still worse than Denver, then and now.

[HAM Inc]

Now that the head guy spoke up and said it didn't do jack for the engine , I want to hear more of this new info please, Len ???

It does do something; it slows the return of oil to the crankcase and therefore the pickup and it causes the oil to run a bit hotter.
I'm going to let you guys stew on this one for a while and see if you can figure it out. I'll give you a hint; it has to do with pressure differentials between the crankcase and rocker chambers.

[JFJ914]

Now that the head guy spoke up and said it didn't do jack for the engine , I want to hear more of this new info please, Len ???

It does do something; it slows the return of oil to the crankcase and therefore the pickup and it causes the oil to run a bit hotter.
I'm going to let you guys stew on this one for a while and see if you can figure it out. I'll give you a hint; it has to do with pressure differentials between the crankcase and rocker chambers.

So, I should just put pipe plugs in the holes you drilled and taped in the heads you built for me? I guess development marches on, my heads are still in the boxes after 3 years! Maybe this year!

[luvatenor]

Now that the head guy spoke up and said it didn't do jack for the engine , I want to hear more of this new info please, Len ???

It does do something; it slows the return of oil to the crankcase and therefore the pickup and it causes the oil to run a bit hotter.
I'm going to let you guys stew on this one for a while and see if you can figure it out. I'll give you a hint; it has to do with pressure differentials between the crankcase and rocker chambers.

So, I should just put pipe plugs in the holes you drilled and taped in the heads you built for me? I guess development marches on, my heads are still in the boxes after 3 years! Maybe this year!

Great info- Most of the info is for a two Carb setup. What about a single 2Bl Weber? Everything seems to have been removed from the engine compartment- just want to make it efficient and healthy- thanks

[underthetire]

While I understand your point John and I agree with you, your facts with regard to polluted cities are in dispute. (IMG:style_emoticons/default/poke.gif)

http://www.citymayors.com/environment/polluted_uscities.html
http://green.yahoo.com/blog/daily_green_ne...ir-quality.html

On some summer days in 1961, the air quality in Phoenix was poorer than Los Angeles. You have to remember that the photochemical components of smog aren't always present in the same quantities, but the other harmful components may still be there. I was in Denver in the summer of 1978 or 1979 for a swap meet at Storz Garage, and the smog was TERRIBLE! As for the SF Bay area, have you been there recently? Nasty.

I stand by my statements.

The Cap'n

Actually, smog here is way better than LA. It is bad during fire season for sure though.
And my dads 57 tbird still has the road draft in it. First stupid smog check guy wanted him to drill a hole in his factory bird aluminum valve covers and install a PCV. Second guy smoged it no problem. Those valve covers in the condition they are in are worth 500-1000 bucks a pair!

[bandjoey]

NO VENTS?
(IMG:style_emoticons/default/popcorn[1].gif)

[jaxdream]

Ok , Len I'll give it a shot ( I am not an engine rugu , probably never be , so I'm up for some learnin ).
Slow drain of oil back to the crankcase- less oil in the bottom for the pickup to pickup = hotter running engine with a lesser oil supply to run , hotter oil froths more causing cavitation and starvation to the oil pump( could this be the presure differential you mentioned ??) Would the small amount of oil up in the breather box and lines be that significant of an oil supply loss ??
Presure differential , hummmmmm...... I would dare to say that there is more presure in the crankcas area than the rocker box area , sucking the crankcase gases through the rocker box area will lessen the presure in the crankcase , but may increase the presure in the rocker box area =more of a chance that the pushrod tubes leak more as well as the rocker box cover gasket to leak more??

Or as some will say that I been into the rootcellar medicine too much , oh what the hell , a few shots won't hurt, much.

Jack / Jaxdream

[ME733]

,,,,,,,,,,,,,USE THE DAMN HEAD VENTS.........MURRAY.