Road draft tube

[Selahdoor]

I made that change a couple years ago. Stuck a pipe in the intake, stuck a hose on that, and hung the hose down the back of the engine.

There's so much blowby after she has been run to town, that it sometimes looks like the truck is on fire.

I get dirty looks, I get alarmed looks, I smell the blowby...

Tired of it, I pulled that hose up, ran it across the top of the engine, put an elbow in it, and extended it so that it blows right into the intake.


Before I get attacked about the engine running out of control...

I did it in such a way that if that started happening, I could quickly pop the hood, get out the truck, and yank that sucker out of there. And I paid very careful attention to just that...

It's been absolutely no problem. And if it ever does happen, it is still just as easily yanked out of there. I see no reason to change it.



It has also helped to smooth the engine out.

Lately it has developed an "unbalanced" run. Like there is no balancer.

I have a hunch it is an injector or two clogging up. I'll remove the filter, fill it with trans fluid, run it for long enough to fill the injectors with fluid, and let it sit for a week or two. However long it takes me to feel the need to go to town again. (I put a whopping 250 miles per month on it.)

But in the meantime, like I said, this seems to have helped at least a bit, with that.


I'm also curious if this is going to affect my fuel mileage. I'll find that out after two more fillups.

 

[Big Bart]

Selahdoor,

My jeep has pretty good blow by and caused my valve cover accessories to leak oil out. (PVC valve gromet, air breather valve gromet, and even the oil fill cap.) The blow by is more than the PVC and breather can deal with, so the air pushed out of the seals. Got tired of that so I added a big T in replacement of the skinny air breather. (1/4" to 3/8") Also no screened material to slow down when oil soaked like the breather had. I ran from the T to the air cleaner but ran the tube up high and then down. I wanted to avoid oil from easily rolling down to the air cleaner. Then on the other side of the T I am going down to one of these catch cans, so the oil can drain off to that side more easily than going up and over to the air cleaner. I wanted to catch the oil but not in my air box. So far it is working. At somepoint will do a rebuilt long block and fix the issue all together.

Perhaps to avoid run away, you install a recovery can like this in the middle of your line. Let it catch any oil and you burn up any fumes or mist. That could help you avoid a run away situation. As I recall you are very handy so you could make something out of scrap to save some money.

https://www.amazon.com/Mishimoto-MMOCC-RB-Black-Oil-Catch/dp/B004CFY60E

Food for thought.

 

[Selahdoor]

Yup.

I already have plans and parts for making my own. This is just 'temporary' until I have the opportunity to actually make it.

I had intended to make the catch can, run the hose to that, and then to the intake. Just got tired of all the hassle, and did this because it is what I had time for.

I'll post up some pictures and descriptions when I actually make it.

 

[Laine D]

So here’s my take on the draft tube thing. I have never tested it or anything. I had a draft tube for about 2 months. I noticed that my truck had more blow by. I also noticed a difference in idle. I think that an engine needs at least some sort of vacuum on the crank case to keep everything happy and even with a draft tube there is positive pressure. I think that it may in a small way effect how the rings seal. Mine was going through oil until I hooked the tube back up to my intake. It’s very happy now.

 

[u2slow]

Tired of it, I pulled that hose up, ran it across the top of the engine, put an elbow in it, and extended it so that it blows right into the intake.

I did exactly that on my 6.2L diesel for the 3-4 years I had it. Wasn't an issue.

Many stationary engines run a tube up near the intake or turbo, but leave an air-gap. Usually the tube is vertical, and features a chamber of sorts with a metallic mesh-screen/scrubby type thing inside for extra surface-collection, and it just drains back to the crankcase.

EDIT: The 1stgen Dodge/Cummins uses a road-draft tube factory.

 

[homelessduck]

Been there , had one for over 2 years , finally had enough! Immediately after installing it the engine started seeping oil from places that use to be dry. I had several people tell me my truck was on fire. The dirty looks and guilt when you're stopped in traffic , on a hot day , and you're blowing smoke in to the car beside you with an elderly couple that has no AC and has to have their windows down...That was the final straw for me. Finally decided to just put a new $60 cdr on it. Immediately the leaks stopped and zero smoke!

 

[IDIBRONCO]

I think that an engine needs at least some sort of vacuum on the crank case to keep everything happy and even with a draft tube there is positive pressure.

It absolutely does. I read about this in Hot Rod magazine years ago. One trick to get a little bit more power for free was to increase the amount of vacuum inside the crankcase. Not a lot, but more than a PCV valve puts in. When I put a wore out 302 in my 1984 Mustang years ago, it had a pretty good oil leak until I hooked up a vacuum line to the crankcase. Then it barely leaked any oil and it ran better.

 

[subway]

I don't think you are going to have issues with the engine running away on you. I do remember reading that the rear two cylinders on our engines can run a little hotter due to the CDR on the back of the intake feeding the oil gasses back into the engine. On the list of "things I need to worry about" I would not rank that one very high up.

 

[subway]

Been there , had one for over 2 years , finally had enough! Immediately after installing it the engine started seeping oil from places that use to be dry. I had several people tell me my truck was on fire. The dirty looks and guilt when you're stopped in traffic , on a hot day , and you're blowing smoke in to the car beside you with an elderly couple that has no AC and has to have their windows down...That was the final straw for me. Finally decided to just put a new $60 cdr on it. Immediately the leaks stopped and zero smoke!

I can understand, I try not to be the obnoxious one in the crowd anymore

 

[u2slow]

If anyone cares, here's the crankcase breather on one of our 13.5L John deere gensets. I'm 90% sure it's a Parker/racor with the label stripped off.

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