open crankcase vents vs closed?

[shady1701]

I was wondering if there's any good things that come from venting the crankcase into the intake like on most cars except emmissions?

I was wondering what the idea was on that and possible ideas on retro-fiting eather taking off or adding.

i have tractor and the oil mist smell is pretty bad since it has a mushroom type vent that vents 360 degrees around.

I also have some equipment i'd like to take off and put a road drip tube on...

 

[5030]

If you are getting oil mist from the breather, It sounds like it's time for at least a ring job or valve guide seals. I presume it's a gas tractor as you didn't say.

If it's a diesel and you are getting that much blowby, it most certainly needs an overhaul.

 

[Richard]

</font><font color="blue" class="small">( If it's a diesel and you are getting that much blowby, it most certainly needs an overhaul )</font>

Hmmm...

Might you expand a bit more?

We have an International 444 that has a breather vent on the front of the engine, sticking straight up out of the hood.

When puttering around, no biggie, but when cutting the fields and the temp of the machine starts to get to about the middle of the range, a steady stream of "smoke" (but not billowing) eminates from this tube and right back to the operators face. /forums/images/graemlins/mad.gif

I've always presumed it meant the machine was getting hot and the oil in the head was just "cooking" a bit and tossing off some smoke.

You are implying that we might have some deeper issues?

(truth be told, I hope this machine blows up and forces the 'elders' to contemplate a larger machine...hehehe...dastardly of me, I know /forums/images/graemlins/crazy.gif )

Richard

 

[slowrev]

Tractor abuser !!! Shame on you. You could give it to me I would come and get it /forums/images/graemlins/smile.gif

 

[s1120]

The closed system is really a better way to go, but it could be tough to retrofit on a tractor that did not come with it. Hear are some advantages to a closed system.......

Not as much pollution.

Better control of crankcase pressure

A little more power [stay with me here, I will explain]

Less oil leaking

No oil vapor smoke

Less sludge in the motor

OK, now there are more, but it is before 6am and I am not awake yet. Now to that power thing. Most people will say"its emission controls. They hurt power" "It makes the engine burn oil vapor, that's not as good as gas vapor" OK true, the engine will lose a little power from burning the oil vapor, but that will be over come. For the people that don't know what a closed system is, here you go. The engine will have a hose that goes from the intake manifold or carb to the crankcase. Somewhere in that line will be a one way check valve [The PCV valve] that meters the amount of vacuum drawn, and will only let the intake pull from the crank case, not the crank case pull from the intake. The crankcase will also have another opening to the outside. This will have some kind of a filter in it. This is incoming air, to displace what the PCV [positive crankcase ventilation] system is pulling out. In a open system, the oil vapors are pushed out by the pistons moving in the crankcase, and by blown by combustion pressure.[that's why you get the oil smoke out of the breather with a worn out engine] A lot of the vapor, and the water, crud, etc it carries stays in the crankcase. [that is one of the ways you get sludge] Now the closed system will pull a small vacuum on the crankcase. This will increase your power because the with the vacuum, the pistons are not "pushing" all the vapor out/around when they go down. [ya, I know. One piston goes down, the other goes up, so they should cancel each other out. Well, lets just say that strange things happen in a crankcase at a few grand RPM because they don't 100%] You will see that most drag/race cars have a vacuum pump, or a vent line tapped into a header to take advantage of this power boost from crankcase vacuum. Now where this system will really shine in long term tractor use, is sludge control. Most of the water , and oil vapor hanging around in that crankcase waiting to settle and make sludge, is being sucked out. If any of you have had an older car that was WAY overdue for a PCV valve replacement, you could see the sludge in the motor.

Sorry to ramble on here. As a newbee in the tractor world, I don't have much advice to give. But when it comes to motors, I have a lot of experience. I have been working on cars sense I was about 7 years old. So I help when I can.
/forums/images/graemlins/grin.gif

 

[5030]

Obviously, the tractor has a lot of hours on it. You probably have worn valve guides and the compression rings have lost some of their tension due to wear and heat. That's why the engine is pushing pressure through the breather. The pressure picks up oil mist as the oil splashes around in the crancase. The crankshaft, connecting rods and gears whip the oil around inside like a big set of egg beaters. The oil gets whipped up and the gasses going by the rings and seals poick up the hot mist and vent through the breather. Old barnyard buicks run forever so I'd fab a tube to vent the vapor (down) next to the engine toward the ground. I'd not even think of a closed system, the tractor isn't worth the aggrivation. With that much blowby, you'd probably foul the engine internally if it had to reburn the vapor.

 

[shady1701]

It's a 5020 agco with 270 hours it has been sitting a while.. the problem isn't so much volume of product you can't actualy see any vapors or anything just a oil smell where you can see oil vapors has come out and hasn't used any oil so far since i got it with 220 hrs. I took the oil cap off and no real vapor pressure no more than any of my other diesel's i have.

Most vw diesel's don't have any valves my powerstroke doesn't eather just a hose into the intake which on a turbo engine it can create quite a but of suction volume. I was just inquiring on the likely hood of retro fitting a system as to reduce the oil smell and/or retrofitting a drip tube system on some other vehicles.

I found details of a closed system with a filtering/control piece too on www.tdiclub.com
thanks..

 

[5030]

Your Powerstroke does have a valve of sorts. If you look into the air intake right in front of the compressor wheel, you will see a tube that's cut at an angle. The angle of the cut was computer designed along with restrictors built into the box on the top of your valvecover meters the vapor intake that the engine consumes. That's why if you chip your engine and increase the turbo boost substantially, the intake will get "snotted" up with oil. The restrictors and tube angle are designed for a maximum boost of about 16psi.

I know, I have a Ford too, and it's chipped but I returbo'd it.

I'd put a road draft tube on the tractor. My opinion is, i'm not that enviromentally correct to try and design a closed system for any engine. There is too many parameters involved in that design. Keep it simple and cheap.

 

[Richard]

</font><font color="blue" class="small">( With that much blowby, you'd probably foul the engine internally if it had to reburn the vapor. )</font>

Pardon my swapping the order of your comments, 2 things, I dont want to hijack the thread and second, this is a diesel tractor, so I presume the fouling comment would not apply?


</font><font color="blue" class="small">( Obviously, the tractor has a lot of hours on it. You probably have worn valve guides and the compression rings have lost some of their tension due to wear and heat )</font>

It IS old, it has ?? hours on it, was bought used probably 20/25 years ago...

Presuming your comments above to be accurate (and I suspect they are dead on), that will also help explain why rather than taking 4 revolutins to start the engine cold, it might take 20 (having never counted, just making illustration)...however, when hot, the engine fires right up.

This is the tractor with 5' rotary cutter that has cut roughly 125 acres of fields for the last 2 decades... if this tractor blew up, we'd HAVE to do something... everyone here SURE you dont know any tractor asassins for hire? /forums/images/graemlins/crazy.gif

 

[5030]

If it's a diesel, and she's blowing that much, it most certainly has worn rings and guides. If it's hard to start cold, that means the compression is down because of the worn rings (most likely), the delivery pressure to the injectors is not high enough (maybe), or the pump is out of time (not likely). Older barnyard buicks that i've seen come with either a Rosa Master or Stanadyne rotary pump. They are very expensive to rebuild and if you take the pump off the engine for any reason, mark the position that it came out at and don't turn the engine over. I knew of a guy who had an 806 that took the pump out and then spun the engine over. it took him about 2 days to find the right position to insert the pump in. I don't know if he ever got it right on, but it ran.

Being a diesel and I presume naturally aspirated, I'd not try to recycle the blowby so to speak. Again, the easiest solution is a draft tube. If you park it anywhere and let it idle, just make sure it's on gravel or dirt as the concrete will show an oil puddle.

If you want to get really precise, you could call a dealer or go to the library and research an old shop manual for the tractor. It will list the permissible blowby for that engine. It will probably be listed in inches of mercury. You'd need a manometer to measure that specification.

All engines, modern and ancient have a constant that engineers will list as to permissible blowby. Again, a sure sign of more than permissible blowby is worn rings or guides.