Has anyone ever had a bad CDR valve?

[poolguy]

If so, how do you tell? I'm blowing what looks to be light blue smoke over half the time I'm driving. Runs good, power seems normal, idles ok but seems to be a lot of blowby out of the 1" hose from the CDR valve to the air filter box when I take the hose loose. Also seems to have oil dripping from the air filter box onto the drivers side of the valley, but I haven't verified this yet.
Whats wierd is that sometimes it smokes, and sometimes it doesn't.
Could this be the CDR valve?
Chuck
94 CC Dually 7.3 IDI turbo 123k miles

 

[zigg]

Chuck

I personally believe that the CDR valve is overrated. I have opened one of them up(pics to follow) and there is not much inside. Essentially, the blow-by from the crank/valley/valves is routed via the CDR up into the intake to be reburned. The internal diameter of the opening through the CDR is approximately 3/4". There is no restriction to the flow through the thing, and intake vacuum, although small, is all that is required to maintain "negative" pressure in the crank area.

There is a diaphram, and a soft spring, which holds the diaphram open. It appears in the event of a huge obstruction to the intake, that this diaphram might be able to be sucked shut to prevent the engine from ingesting crank vapours/oil and continue to run itself to death. I hooked a shop vac to the intake side of this unit, and I couldn't get the diaphram to snap shut, so it'd take a huge volume of air to move it.

Any oil that collects in the thing is allowed to drain back down into the valley, but obviously some manages to find it's way into the intake.

There is no service that'll make any difference, nothing will change the oil burning, the CDR itself is in no way responsible. The blow-by is a sign of overall engine condition, and is quite normal in our engines, especially older high mileage ones. You can replace it, but it'll just mean you made a $50 donation to Ford. Won't change how your engine runs at all.

Obviously, this is one of my pet peeves....

 

[payableondeath6]

For blocking off the CDR hole in the intake manifold what kind of plug is used? I know most use the Banks part but wondered if there was another way. How much is the Banks block off? Maybe I should just order that. Anyone have any pictures of their RDT setup?

 

[bradrob82]

I too would like to see pics of RDT setups, i am thinking about doing that mod.

Mel, i cleaned off the valley pan last nite and watched it run for a while and fuel started leaking out of the middle bottom of the pump, all the lines are good and tight, no leaks. so it looks like i will be giving ken a call and getting me a IP

 

[poolguy]

Thanks Zigg, What would be considered normal for blowby? I accidently left the hose from the CDR to intake off during an air filter change, and the smoke that came out from under the hood at 55mph was very noticable.
What is RDT?
Chuck

 

[payableondeath6]

What is RDT?

Road Draft Tube it's in FAQ #1

 

[zigg]

Thanks Zigg, What would be considered normal for blowby? I accidently left the hose from the CDR to intake off during an air filter change, and the smoke that came out from under the hood at 55mph was very noticable.
What is RDT?
Chuck

Chuck

Normal is hard to define for the 6.9. On my '86, if you block off the CDR and then open the oil fill hole, the amount of blowby would cause a neighbour to call the fire department, but it runs fine, just consumes vast quantities of oil.


On my newly completely rebuilt '93 with a 6.9, I have a RDT, and it's barely noticeable most of the time except occasionally at a light, I see a hint of smoke coming out from under the hood.

I've heard, that mostly if it is just simmering up like a simmering kettle, then it's fine, if it's huge amounts like my '86 and gulping oil, and/or puffing in tune to one cylinder, then likely the engine probably is getting pretty worn, and needs valve/ring work.

You really do have to block off the CDR hole though, 'cause otherwise, it will continue to be sucked into the intake while you have the oil fill cap off, and give you a false impression of how much there really is.

Zigg

 

[poolguy]

Thanks for the response!!
Unfortunately I found my problem today. The turbo is so worn out it has 3/8" play on the impeller on the intake side!!!! The little oil leak I had on top of the motor is coming out of the turbo on the waste gate side. I found a used unit in Fl. today for $450. . It will be here Thursday. Man!!! Brakes, trans , rediator, and turbo in 3 weeks!!! I just have ALL the luck!!!!!

 

[zigg]

The turbo is so worn out it has 3/8" play on the impeller on the intake side!!!! QUOTE]

Ah, that'll do it for sure....

Zigg

 

[93_E_350]

Just a side note to the operation of the CDR valve, It is not supposed to close until 2000 rpm so I’m thinking if you have real good air flow between the filter and where the CDR connects it may never close… I put a new one on my van awhile ago. Both the old one and new one closed when a vacuum was put close to the exhaust side of the valve. To be honest it seemed the old valve closed easier than the new one! Don’t be fooled by blow-by a lot of times it’s just oil vapor that looks like smoke at the connection points. Don’t get me wrong it shouldn’t look like a fire !

93

 

[typ4]

Thanks for the response!!
Unfortunately I found my problem today. The turbo is so worn out it has 3/8" play on the impeller on the intake side!!!! The little oil leak I had on top of the motor is coming out of the turbo on the waste gate side. I found a used unit in Fl. today for $450. . It will be here Thursday. Man!!! Brakes, trans , rediator, and turbo in 3 weeks!!! I just have ALL the luck!!!!!

Dont lose the other one I have all the parts and some rebuild kits to fix it. If you wanna ship it here I can do it for you, or tell you if its really junk, The intake housing is a prime candidate for machining a bigger compressor wheel.

 

[poolguy]

Russ,
That sounds good!
By the way, did you get the check for the other part?
Chuck