The diaphragm in the Crankcase Depression Regulator is acted upon by the spring on the crankcase side, and atmospheric pressure on the other side. There's a small vent hole to atmosphere on the back side of the case.

Think about the conditions that would have to exist for a runaway to happen. There would have to be enough oil in the crankcase vapors for the engine to runaway even with the injection pump shut down. Very unlikely, but possible... Extreme blow-by could do it, as could an extremely high engine oil level. Think about a ruptured lift pump diaphragm pumping fuel into the crankcase... In such an event, the engine starts revving up, the driver shuts off the ignition switch, but there's enough oil in the crankcase vapors to fuel the engine...
In such an event, there'd be enough of a pressure differential between the intake and the atmosphere to close the CDR.

If the CDR is modified to require crankcase pressure to open, it'd probably start blowing oil through the crank seals & valve guides.
Engineers first did road draft tubes to create a slight vacuum in the crankcase to stop seal leakage...

 

Phy is right on this one. Woth out a place for the gasses to go you will have oil coming out all over the place. A road draft tube will make a mess every where park and a real mess under the truck. I tried that idea when I first put the old girl on the road. I went back to the cdr. When the proper maintance is done on it it works well. The only reason I am deleteing it is due to the placement of my future turbo and needing the spot for the oil drain tube. Our trucks are not the only ones useing these things. I know that gm used them on caddies as well.

 

Well it seems gm used them on there diesels as well. They seem to be similar to ours and could be modded to work with a little skill. I think they would be a good match for the turbo guys with the cdr in the valve cover. They are also alot cheaper than the one for ours http://www.ssdieselsupply.com/produc...tor_Valve.html

 

Phy, please explain this a little better basicly is what you had just said is blah blah blah with the blah blah so that the pressure can blah blah. hahahaha im just kidding. So in other words all the basic functionality of this diaprham is to allow gasses in at a certain time and to stop them when not correct. if so then how is it if i had modified the cdr that the crankcase pressure would be spewing gasses everywhere else when in turn in the crank case only oil should be flowing threw there? and if this was designed correctly then when it is removed for turbos to be placed in its place then how is it that these gasses are not blocked or pushed else where via the pressure of the oil from the turbo?

I am not a specialist or anything as i had said before, im just trying to get a understanding of exactly how the heck this over priced high tech "tube" is supposed to be acting as a pressure valve if it is always open?

i mean unless this spring that sits in the center is contracted via the air comin into the the intake and closes the diaphram then would you need less suction comin from the intake and more comin from that part of the motor to close it as for in my experiecne it took about 2lbs or so to push that spring around. and concidering that there is quite the amount of suction threw the intake just on the air cleaner side i dont believe it would be able to create such vacum to close it off for the air is just rushing to the cyliders to act with the fuel.

again as i have said im not a specialist or anything on these motors i just LOVE THEM i have killed two but just cant seem to get away from them they are just too much fun and i will continue to own them till the government breaks down my front door and beats the livin **** outta me for them to come take them away from me!

 

The spring side of the diaphragm is exposed to the crankcase and the intake. Normally, the spring pushes the diaphragm to the open position, and crankcase vapors are sucked into the intake. The other side of the diaphragm is exposed to atmospheric pressure, through the small vent hole on the back side of the CDR. (the vent hole is easy to miss. It's only about 1/16") If the engine over-revs, it creates enough intake vacuum to overcome the spring and close the CDR. If the engine was over-revving because of a run-away situation due to sucking enough oil from the crankcase, this will stop it.
So, under normal operation, the CDR remains open, and the crankcase is exposed to the slight vacuum of the intake. This vacuum insures that pressure can't build up in the crankcase and blow oil through the seals.

On a turbo motor, the CDR isn't deleted, it's relocated. On the factory and ATS turbo set-ups, the CDR is on the driver's side valve cover.

 

It doesn't really take a whole lot of vacuum to close the CDR. The diaphragm is about 3' in diameter. That's about 7 square inches. You said it took about 2 pounds to close the spring, so less than 1/3 PSI of vacuum on the intake side of the diaphragm would close it...

 

okay thanks for that but one more question how is it that if it was shut and allowed to much gas to build up that the oil would and or gasses would be blowing out of the seals and shouldnt the seals be built to deal with this amount of pressure to ensure little amount of leakage? like i said in one of my earlier post i ended up redoin it my way and it couldnt built enough pressue to open so instead of takin it apart again i just drilled some holes on the inner tube of it.

also where the hell do you get one of these things at cause i went to checker and spent a good hour in there system looking for one and have not a freakin clue as to what it is listed under

 

Way back when, engines only had crankcase breathers. If the breather got clogged up, the crankcase built up pressure and pushed air out the dipstick tube, and oil out the seals.
Engineers then put on a road draft tube. A RDT replaces the breather, and plumbs a large tube from the oil filler or valve cover down to a tube that ends down under the vehicle, with the end down in the wind when the vehicle is moving. This air moving across the end of the tube creates a slight vacuum in the tube, like a perfume atomizer, sucking the crankcase vapors out. With a slight vacuum applied to the crankcase, the seals worked better.
When emissions started to become a big deal, they plumbed the crankcase to the intake to burn the vapors, instead of dumping them into the atmosphere. On a gasser, they used a PCV (Positive Crankcase Ventilation) valve to control this. On a diesel, because of the small amount of intake vacuum available, they needed a valve that would be much more sensitive to vacuum: the CDR.

I've only had to buy one CDR, but I could only find it at the stealership...
It seems there was a guy here, partsguyed I think, that could get them...

 

I did an internet search for these part #'s E3TZ-6A665-A this is the Ford part # and 1805319C1 is the IH part # and found several place that still had them.

 

Price ? or is that a no-no ?

 

E3TZ-6A665-A - Ford ADAPTOR this one is $50.00

E3TZ-6A665-A | RearCounter.com | 2 found at 2 dealers this one you have to as for a quote.

E3TZ6A665A: - Other Parts - Ford/FD. E3TZ-6A665-A, E3TZ6A665A. this one is $57.00

Sorry bout that.

 

Thanks Ken ! IT seems like most of the parts for our trucks are 20 to 100 dollars. Mine apparently needs a bunch of them. It adds up quick.

 

Yes it does. But it is usaully due to lack of maintanace by the po that makes it expensive at first. Once you get them up to snuff they don't take much love and give you all they have with out any compaint. So keep at it and she will treat you right for it.

 

hahaha well said! not to fear.you are not alone.
kenpobuck's so right though.the more old things you replace,the more and more you enjoy the truck.so worth it.it really is.
the problem is,it just doesn't ever seem to end lol.good old trucks!! as to be expected though due to age alone.

think of this one;
in a couple years now, in 2014.all IDI diesel trucks will be considered as classics according to the Classic Car Club of America.
(as far as age goes only i mean of course.)

 

CDR Part #’s

Rubber tube from CDR to pan - E8TZ-6A892A $7.35
Grommet from CDR to intake - E3TZ-6A892A $3.08
CDR (Adapter Assembly) - E3TZ-6A665A $62.57