cdr questions and thoughts...

[turbonator]

hey guys, i have been thinking a bit about the crap that the OEM cdr system dumps into the intake and i have been wondering if anyone has ever thought to install a nipple in the exhaust after the muffler, entering the stream parallel with the flow, and running the vapour from the crank-case into it, i have tried collector-cans of all types with un-satisfactory results..... now one question i have is will the exhaust back up into the hose and cause pressure in the crankcase, or will it create a suction effect because the exhaust is bigger than the nipple? i am tired of seeing the oil in the turbo inlet piping, and inside the intake...:mad2:.... anyways this is an interesting topic, and all input is welcome....:agreed:

 

[3500GMC]

This topic has been discussed to the point of almost being 'taboo'..

Sound logic you have.. but you'd have to run the 'vent' all the way back to the exhaust exit (with a venturi) and 45 it in post 'venturi' to have any real negative pressure on the crank-case.. There are valve deals that are used with open headers in drag racing.. But open headers are short... and loud.

I vent to the atmosphere, the trick is to not 'pressurize the crankcase' IMO:

 

[deejaaa]

my thoughts,,,,,,,,still doing it the same way, still getting oil.......
http://www.thetruckstop.us/forum/showthread.php?30762-CDR-valve-relocated-to-stop-oil-suction

 

[turbonator]

This topic has been discussed to the point of almost being 'taboo'..

Sound logic you have.. but you'd have to run the 'vent' all the way back to the exhaust exit (with a venturi) and 45 it in post 'venturi' to have any real negative pressure on the crank-case.. There are valve deals that are used with open headers in drag racing.. But open headers are short... and loud.

I vent to the atmosphere, the trick is to not 'pressurize the crankcase' IMO:

View attachment 32596

whats that unit? is it pushed into the CDR grommet in the valve cover? when you say vented to the atmosphere, how did you do it? roadraft tube? i see your 2 lines go towards the driverside.... looks to be a nice setup.... do you notice any SOTP power increase, being that the motor is not sucking in the hotter air....am i making sense?

 

[ak diesel driver]

I'm toying with making a larger coaleser to seperate the oil. Problem is finding cheap materials

 

[turbonator]

I'm toying with making a larger coaleser to seperate the oil. Problem is finding cheap materials

i have built 3 different styles, and all still pulled oil.... anybody that vents to the atmo. do you notice any fumes at idle coming from under the hood? i guess a motor with a crapload of miles would be worse than a fresher motor....

 

[ak diesel driver]

i have built 3 different styles, and all still pulled oil.... anybody that vents to the atmo. do you notice any fumes at idle coming from under the hood? i guess a motor with a crapload of miles would be worse than a fresher motor....

So tell me about the 3 diff designs

 

[Cumminsfever]

i have built 3 different styles, and all still pulled oil.... anybody that vents to the atmo. do you notice any fumes at idle coming from under the hood? i guess a motor with a crapload of miles would be worse than a fresher motor....

I just have a hose going down over the side of the engine. I refuse to crap up the intake and turbo with oil.
Sadly, with 266k miles of abuse, you can literally follow my trail of blowby down the road. A constant cloud behind me. When I stop, I am surrounded by what appears to be steam. It is blowby. On the other hand, I get lots of attention and people pointing and laughing!

There is a way to keep oil out of the system. It involves NO air filter restriction, and a second CDR in the other valvecover...

 

[3500GMC]

whats that unit? is it pushed into the CDR grommet in the valve cover? when you say vented to the atmosphere, how did you do it? roadraft tube? i see your 2 lines go towards the driverside.... looks to be a nice setup.... do you notice any SOTP power increase, being that the motor is not sucking in the hotter air....am i making sense?

I'm toying with making a larger coaleser to seperate the oil. Problem is finding cheap materials

It's an adapted 'vent box' that the turbo ricer boys use.. I found it in a bargain bin locally, took it home and gave it some dignity. The two clear tubes are in fact 'road tubes' that vent just below the frame on the driver side. I did this to get away from the hot side and to give the vapors time to settle down. Yes there is a small amount of smoke- but NO SLOBBER. The 6.2 is in decent shape- SOTP feel I couldn't tell ya- had this device ever since the build of this truck...

 

[turbonator]

So tell me about the 3 diff designs

the first one i built was with ABS 4", i filled it with steel wool, and made the 2 inlets different legnths, it sucked oil.... the second i made longer with 4" exhaust, with a seperator welded in between the 2 inlets, with steelwool in the bottom, this time with a drain.... made this one too air tight, it pulled even worse.... the last one i made with a piece of 5" fire extinguisher, baffle, drain and it pulled oil as well.....

 

[racedaymechanic]

If you guys are pulling that much oil out of the engine, You have bigger issues than the CDR

 

[turbonator]

If you guys are pulling that much oil out of the engine, You have bigger issues than the CDR

it is because the OEM system is flawed, how can we not pull oil when the cdr is 1" from the oil in the valve cover with just steel wool seperating the 2? same thing using the oil fill, the oil is flung up and collected with the vacuum, the old 6.2l had a steel baffle inside which helped... if you feel to aid in the discussion, pull off your intake on your CKO-40 and snap a pic of what it looks like inside, is there any oil accumulation? i am not talking about 1 liter a day or anything, but we have oil in there... every 2 weeks i pull off the air inlet and it has a small puddle in the turbo inlet(the turbo is in great shape, i rebuilt it myself, and dissmantled it to verify it was not leaking) and the intake manifold has the greasy film inside... if left un attended it will build up, and looks like crap... the motor is only 3 years old from a refresh, and has a minimal amount of blow-by.....

 

[racedaymechanic]

I just pulled mine off about 2 weeks ago There was No oil in the Turbo inlet Thats after about 3k of running

 

[ak diesel driver]

My thought was to go 8-10" in diameter with the coarse steel wool. I think that the problem is there's too much speed in the air not giving the oil a chance to coalesce (sp?) I think that along with my adjustable CDR might do it. And yes I have tons of blowby 250k worth. Still runs good tho

 

[turbonator]

My thought was to go 8-10" in diameter with the coarse steel wool. I think that the problem is there's too much speed in the air not giving the oil a chance to coalesce (sp?) I think that along with my adjustable CDR might do it. And yes I have tons of blowby 250k worth. Still runs good tho

yeah, x-2 on blow-by and still running good... not all enthuisists can afford to go out and buy a new motor, even some find it hard to buy a questionable used motor from mil. surplus, so we work with what we got... our old 6.2l with the cracked pistons(8) had massive blow by, pull off the cdr, and it would create a huge noxious cloud all around the front of the truck....

we are going to try a venturi into the exhaust just after the down pipe flange..... my question here is this... does anyone thing that the exhaust will back up the tube, or because the exhaust is bigger it will follow the path of least resistance? i think that it will draw good...

 

[ak diesel driver]

did you read about NMB2's setup?

 

[buddy]

The only problem with a long road draft tube is that you can build more pressure the longer the tube is, so maybe having two tubes helps that. And the object is to have atmospheric pressure or a slight, very slight vacuum. I just vented my CDR for a while, under the hood, and yeah, noticeable blowby puffing out even at idle. And then that side of the engine bay gets a little oil film all over it. I put my CDR on top of the oil fill tube, plumbed into the intake, and did have less oil in the intake, but still had some and it barely fit under the hood, pushed the heat/noise pad in and may not fit once I get the new motor mounts in.

The problem is we are making too much vacuum with more boost. The CDR doesnt regulate down enough, doesnt close it off enough when it hits its limit of closing. Just finding a better vacuum regulator would be awesome. Maybe a large PCV valve would be better. They work under the same concept. High vacuum at idle on a gas engine closes them off mostly, and then low vacuum at high throttle opens them up so there can still be some vacuum in the crankcase. Although they are smaller, so maybe they wont allow as much vacuum when closed off.

One way to lower the vacuum would be to place the CDR input into the intake closer to the filter, after the bend. There will be less vacuum pull there, than right at the opening to the turbo. If I had a manometer I might test what the difference is all along the intake pipe. I know some of you guys have them.

 

[tanman_2006]

did you read about NMB2's setup?

he started with a bung in the down pipe didnt he?

 

[ak diesel driver]

problem witha pcv valve is it works opposite of what a cdr does. we have higher vacuum with more boost/rpm and less at low rpm/idle. I adjusted my cdr with a digital manometer and still use lots of oil. I think the speed of the air coming out of the engine is too fast and can't let the oil drop out of it. If you want to borrow my manometer Buddy email me.

NMB2 abandoned his exhaust setup because of too much oil in the exhaust.

 

[buddy]

The gas engine works opposite, but doesnt the PCV valve still work the same way? high idle vacuum pulls against some spring tension to restrict the flow and low vacuum at high throttle allows full flow through the valve. Just reverse engine operation and the PCV would be wide open at idle for us, with low vacuum and fully restricted when the turbo pulls the vacuum at high throttle. Thats what my head is telling me anyway. But untested as to whether any valve would shut it off any more than the CDR does. And maybe diesel fuel vapor would eat at the materials.