I'm wanting to raplace my cdr valve they are way to expensive to replace every 25000 miles so i want to replace it with an RDT. Can someone can tell me how to do this?

 

Why a cdr valve? - Diesel Place : Chevrolet and GMC Diesel Truck Forums

 

that didnt tell me how to run the rdt.

 

I don't understand why you would do that when they got away from them in the early 60's. And for a very good reason - pollution.

 

Polution would be very low on my list for the good reason for the draft tubes going away. Think more of the lines of a more efficient way of removing combustion blow by out of your engine when you do city driving.

The draft tube was useless sitting still and at speeds below 25 - 30 mph. This is why cars of the 1950`s had a 2,000 mile oil change interval. The oil would just become to saturated with combustion blow by that it had to be replaced.

 

i know but like i said cdr valves are too expensive to replace and theyre hard to come by down here. besides it'd probably be a temporary thing until i can get a cdr valve or 2.

 

if i run the rdt how can i get enough vacuum to get the blow by out

 

Road draft tubes do not use vacuum engine vacuum. The blow-by comes out due to the crankcase being a higher pressure than the atmosphere, and then the slight vacuum created by driving.

 

I think you are looking for something like this http://www.summitracing.com/parts/vpe-11189
It uses exhaust flow to create a venture and pull crankcase blowby out of engine into exhaust.

 

Road draft tubes do use vacuum. Not engine vacuum how ever. I never said they used engine vacuum either.

When you drive down the road the air blowing across the draft tube creates a low pressure suction on the end of the tube. This is the same effect on carburetors and how fuel is pulled from the carb.

Now as far as higher pressure forcing its way out through the draft tube, thats not how it always works. There has been numerous issues with draft tube equipped cars of the 1950`s that were blowing oil out past seals due to crank case pressure building up. As a combustion engine is running it is putting blow by pressure into the crank case, this is happening faster than it can find its own away out through the draft tube or the breather cap.

The main reason for PCV to come out and replace draft tubes was not entirely emission based. Chevrolet started using PCV setups on their engines starting in 1961/62 for example.

But if you want to believe that it was brought out for emission reasons then please, be my guest. I do not see it as the reason as the PCV had more benefits being more efficient than the draft tube over the emission point of view.

 

to do it, I would be more interested in where you could actually get lower-crankcase relief with adequate breathing to make it practical. Your adaptation options will vary based on what engine you have. (Now if you used an electric fuel pump in place of the usual manual one, THAT spot may actually be a big enuf hole to get some breathing)...that being said,

The above race-option of scavenging to the exhaust is used a lot...but a lot will depend on which engine you have, how well it returns oil to the pan, what rpms, and whether or not you need a catch-can setup....(another study)..

kudos for thinking outside the box though, for these obviously older engine designs we seem to like.

 

There is another diesel forum I am a member of, and they sure have tried everything over there. Some guys just run a hose from the fitting on the top and let it hang down underneath. Works well enough, but it spits oil all over the bottom of the truck and when they were at a stoplight people would start waving at them thinking their truck was on fire. There is a lot of smoke that comes out.

Some guys tried the exhaust thing, but then they had terrible amounts of smoke coming out of the tailpipe, enough to be embarrassed about it and take it back off.

Some used the hose in combination with a homemade catch can for the oil. Worked ok but still smoked like a freight train.

Then they had a guy cut one of the CDR's apart, and found out how it really worked, and they then figured out these things by their design can rarely go bad and really never need replacing. The only downside to them is the back two cylinders can run a little hotter,, since they are burning some of the blowby oil from the cdr.

 

Genuine PCV systems (on gas engines) are a lot older than some people realize.

I have a 1942 6x4 GMC truck; these have the same 270 GMC engines as the 6x6.
Part-way through the war GM began sending PCV kits into the field to update the engines with, as trucks were serviced.......along with other ongoing upgrades over the production period.

The kit was just like a modern system, with a valve & the necessary piping (steel, not rubber) to plumb into the inlet manifold & rocker cover.

 

You don't want a RDT on a 6.9, the smoke will have people telling you your truck is catching fire. Been there, done that, have the t-shirt.
Why are you replacing the CDR valve every 25,000 miles?
All they ever need is a cleaning, they never wear out.

On the other hand, my 12V has a RDT, and you would never know it does with how little comes out of it.