Anything wrong with venting crank case vent to atmosphere?

[Jon K]

Read topic. If you're not sure, please don't answer, trying to finalize some stuff up.

[Anthony (M5 in Calgary)]

Bad for the environment 'cuz you're pumping HCs into the air.

Bad for the engine unless you install a draft tube like they used in the early '60s. Essentially a tube with an angle cut at the bottom, inserted into the air stream. Air passing by created a slight vacuum to pull out blow-by components. Your oil life will suffer.

HTH,
Anthony

[Jose]

No problems at all, just the enviromental thingy. A lot of BMW trackers also use open ventilation, nothing wrong with that. Oil life will not suffer if you use a crankcase filter on the end of the tube as this will prevent junk etering the tube. Just keep a closer eye on your oil level. The only downside I could think of, warm oil smell could get into your interior due to the open system.If you want it, get it.

[Jon K]

No problems at all, just the enviromental thingy. A lot of BMW trackers also use open ventilation, nothing wrong with that. Oil life will not suffer if you use a crankcase filter on the end of the tube as this will prevent junk etering the tube. Just keep a closer eye on your oil level. The only downside I could think of, warm oil smell could get into your interior due to the open system.If you want it, get it.


Well, i was reading that this will cause positive crank case pressure? Something about hurting main and rear seals? Any insight?

[Jose]

Do you have An M50 or M30 ? The M30 is very sensitive on changing the vacuum routing ,the M50 has completely diffirent system. I know a lot of guys I know use a catch tank for the crank ventilation as they have no other option and it' s a trackrule to be able to compete. I' ll check with them tomorrow, to verify the bearing issue. I' ll keep you posted.

[Anthony (M5 in Calgary)]

Well, i was reading that this will cause positive crank case pressure? Something about hurting main and rear seals? Any insight?

you couldn't get positive pressure within it. I'd disagree about no issues with the oil though. The way the factory sysem is set up, a contolled vacuum bleeds crank gases into the inlet system to purge the blow by. With an atmospheric vent you'd get much less circulation as the pistons would just be moving the vapours around inside the CC.

My $0.02CDN.

Anthony

[Jose]

I can see the meaning of your point Anthony, but I really doubt it would make that big of a difference. I have a car fitted wit a 2 L 16 valve engine with 48 mm Webers on it and this engine has a K&N CC filter on it and it' s amazing how much fumes this puts out. I think there is enough pressure to push the vapours out anyway. It' s hard to say if the engine will suffer damages due this change in the vacuum system. Tomorrow I' ll check with the trackers. They take their engine apart each month so I hope they can help us out a bit. Thanks for sharing your view.

[632 Regal]

since your engine is designed to be a "sealed" system it will probably mess up the idle and running quality, maybe even throw a bunch of codes.

If you are thinking about this in order to control the blowby issue you will have with the supercharger than I would do something a bit different.

I dont know how much blowby the boost will make and the pressures involved with it either. The racecar used to make a tremendous amount of it and simply putting 4 breathers on the valve covers failed so I ran 2 lines down into the collecter part of the hedders which served 2 purposes. When the engine would smooth out over the obnoxiously large cam at about 4ooo rpms it pulled a vacume kinda like a pcv does to get vapors out and at full throttle the draw helped pull the blowby out and it stopped popping gaskets.

With your engine being a fraction of the size I would still run a sealed system but would somehow have a valve connected to the valve cover or wherever you add oil. Make the valve so it would self close but open with positive crank case pressure. Make it large enough so that it will actually release the pressure not like a little 3/8 hose but larger. And yes it will blow oil out too so you could run a hose into some kind of catch can.

I hope this makes some sence to you cause I'm having a real hard time trying to describe myself here.

[632 Regal]

Well, i was reading that this will cause positive crank case pressure? Something about hurting main and rear seals? Any insight?

it shouldnt cause a positive pressure if its vented. if its sealed with no breather or pcv system it would,

[Robin-535im]

I'm really not sure. Wait - what was the topic again?

[632 Regal]

http://store.summitracing.com/default.asp?target=partdetail.asp&Ntt=check+valve&N=4294821958&part=MOR%2D97800&autoview=sku&Ntk=KeywordSearch

[Jose]

you gotta love the guy......

[Jon K]

you gotta love the guy......


Jeff, I just dont want to blow gaskets. I am going with a catch can, home made... here's how.

1) 1 - Campbell Hausfeld IronForce Series 1/4" NPT Mini Air Filter from Lowes. Here is product (http://www.lowes.com/lkn?action=productDetail&productId=221024-1126-IFA106)

2a) 2 - AMFLO 3/8" Hose Repair Kit. Here is product (http://www.lowes.com/lkn?action=productDetail&productId=3390-000075041-412-RET)

-OR-

2b) 2 - 3/8" Male barb X 1/4" NPT Brass fittings

3) Assorted zip ties

4) 4 - Small hose clamps

5) Approx 4 feet of 3/8" fuel line or other hose suitable for this mod. If you can find Crank Case Vent Hose, this stuff works PERFECT! DON'T USE THE HIGH PRESSURE HOSE FROM LOWE'S! IT WILL HEAT UP AND COLLAPSE!!!!

My question is. I will have a hose from the crank case vent to the catch can, then factory-wise, i'd have a hose from catch can to the vacuum side of the supercharger intake tube. But, I don't want to have to create that tube, so I was thinking of just running a 2 or 3" hose with a K&N filter on the end and venting to atmosphere. The oil would be caught. The fumes would be vented. Emissions would improve slightly, and with the oil mist out of the system, the octane shouldn't decrease.

[Jon K]

Also... where do these lead?

http://e34.digital7.com/dubateeff.jpg

I think (4) goes to intake tube? Ie, thats the vent?

And I THINK (5) is a vacuum? But, wouldn't it be sweet if (5) were an oil return... wishful thinking. so, what are they!?


If (5) is a vacuum, i'd be able to run to atmosphere without worrying about crank case fume build up because vacuu, would draw it out. But if its a oil return, thats sick too, because that would make the supercharger system so much easier.

[632 Regal]

you still wont have a sealed system at idle which will probably not be beneficial. Your catch can setup is good but I think its not going to be large enough to release the amount of pressure the supercharger is going to create resulting in a positive CC pressure popping gaskets and seals.

The check valve I linked to (not sure about that one as it was the first example) might or might not have a light spring to "check" vacume at idle but would be large enough to release the pressure. There are many different styles of them for the racers.

If you used brass fittings it should be big enough but 1/4 inch I think is a lot of effort for something that I would definetly deem questionable in size.

I know you have put a ton of effort in research here and your idea is good but even 3/8 is small. If you route the end into the vacumme side of the charger it will introduce too much oil and cause preignition or detonation...not a good thing even though you have the seperator cause it will be flowing too fast to catch and seperate the oil vapor.

If you use one of the check valves I linked to and put a hose into a catch can you will be good to go, you will have to periodically empty the residual oil though.

Let me see if I can fine anything at summitracing.com as to a catch can.

[632 Regal]

If (5) is a vacuum, i'd be able to run to atmosphere without worrying about crank case fume build up because vacuu, would draw it out. But if its a oil return, thats sick too, because that would make the supercharger system so much easier.

at open throttle there is CC pressure and no intake vacuum thus rendering it useless (I think)

If its an oil return you could tap a small line to the catch can and never need to empty it.

[632 Regal]

the "fumes" arent the issue its pressure blow by at full throttle. The racecar would blow the breathers off the valve cover (bending the metal tabs) so I know that there is a LOT of pressure. My stuff was normally asperated so to add a boost would have made things worse.

[Jon K]

you still wont have a sealed system at idle which will probably not be beneficial. Your catch can setup is good but I think its not going to be large enough to release the amount of pressure the supercharger is going to create resulting in a positive CC pressure popping gaskets and seals.

The check valve I linked to (not sure about that one as it was the first example) might or might not have a light spring to "check" vacume at idle but would be large enough to release the pressure. There are many different styles of them for the racers.

If you used brass fittings it should be big enough but 1/4 inch I think is a lot of effort for something that I would definetly deem questionable in size.

I know you have put a ton of effort in research here and your idea is good but even 3/8 is small. If you route the end into the vacumme side of the charger it will introduce too much oil and cause preignition or detonation...not a good thing even though you have the seperator cause it will be flowing too fast to catch and seperate the oil vapor.

If you use one of the check valves I linked to and put a hose into a catch can you will be good to go, you will have to periodically empty the residual oil though.

Let me see if I can fine anything at summitracing.com as to a catch can.

Jeff,

the stock crank case vent tube size is adequate. its not a purge, its just a vent. the crank case wont go to positive pressure unless i plugged it. which, would be bad. few people are using valves (essentially bypass valves) because there's no need to.

[632 Regal]

Jeff,

the stock crank case vent tube size is adequate. its not a purge, its just a vent. the crank case wont go to positive pressure unless i plugged it. which, would be bad. few people are using valves (essentially bypass valves) because there's no need to.

the stock "vent" will not be enough. Blowby will cause positive pressure in the CC cause the vent is too small. Been there done that, just wasnt a small 6.

[Jon K]

the stock "vent" will not be enough. Blowby will cause positive pressure in the CC cause the vent is too small. Been there done that, just wasnt a small 6.


How would you recommend enlarging the vent? Notice in the diagram the vent tubing is based on a plastic insert with what i believe to be a vacuum line. I want to use that adapter.

[632 Regal]

adapt the valve to the oil cap.

[Jon K]

adapt the valve to the oil cap.


Thats not easy nor typical Jeff... for all the setups i've seen.

[632 Regal]

Probably not, arent there pics of peoples setups on this?

[Jon K]

I will slowly post some as i find them..

http://e34.digital7.com/bpv.jpg

[632 Regal]

I will slowly post some as i find them..

http://e34.digital7.com/bpv.jpg

this is exactly what im saying but with a check valve so it will be a sealed system.

[niall]

dunno if you still want answers mate, disregard this if you know already,
negative crankcase pressure(vacum) is benificial but by no means essential,
it will help keep oil temps down, but as long as you are not concerned with
the environment, then a road draft is fine, although you might find
a few oil drips on your driveway now and then, the best system is with
poppet valves in the exhausts like small block chev dragsters. they maintain
a negative crankcase pressure even on idle and i have heard oil temps drop by 30F

[niall]

you could get a postive pressure, atmospheric pressure alone is 14.8psi,
if you dont have positive pressure, you have negative pressure which is a vacum