Ama83
New Member
So could the tunacan be removed and fumes routed with hose under car or does it need to be there?
-
Welcome to The Truck Stop! We see you haven't REGISTERED yet.
Your truck knowledge is missing!
- Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
- We have tons of knowledge here for your diesel truck!
- Post your own topics and reply to existing threads to help others out!
- NO ADS! The site is fully functional and ad free!
Problems registering? Click here to contact us!
Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!
About deleting PCV in 6.5TD
- Thread starter Ama83
- Start date
That was explored years ago by one who swore by it... later returned with hat in hand and said, that he should not have done it. That's called the CDR (Crankcase Depression Regulator)
That little do-hicky helps provide reduced pressure in the crankcase (more vacuum, more power can be produced). It scavenges the oil vapors, etc and runs them into the intake. The amount of vacuum it can be provided is predicated on a) how much blowby and b) how much pressure drop is available across the air filter. It also helps in some degree to keep oil from weeping more out the seals etc. You really probably don't want as slobbering mess of oil on the underside of the truck either. The CDR's main function is to limit the amount of vacuum. You can also have too much too in the minds of the engineers. Have a read now with "CDR" term, and see what comes up.
That little do-hicky helps provide reduced pressure in the crankcase (more vacuum, more power can be produced). It scavenges the oil vapors, etc and runs them into the intake. The amount of vacuum it can be provided is predicated on a) how much blowby and b) how much pressure drop is available across the air filter. It also helps in some degree to keep oil from weeping more out the seals etc. You really probably don't want as slobbering mess of oil on the underside of the truck either. The CDR's main function is to limit the amount of vacuum. You can also have too much too in the minds of the engineers. Have a read now with "CDR" term, and see what comes up.
bison
Well-Known Member
It's only there cause the tree huggers wanted it there.
The 95 in my sig has high blowby and has been without it for the last 80 thou km.No leaks observed as of today.
Oil use has nearly disapeared.Was using a ltr oil in 3-400 km,now 3 ltr between oil changes
If your crank seals start leaking after,then you got bad seals to start with.
my 2c
The 95 in my sig has high blowby and has been without it for the last 80 thou km.No leaks observed as of today.
Oil use has nearly disapeared.Was using a ltr oil in 3-400 km,now 3 ltr between oil changes
If your crank seals start leaking after,then you got bad seals to start with.
my 2c
Ama83
New Member
Did you just put hose to valve cover and lead that down to chassis or?
bison
Well-Known Member
I disconnected the elbow at the turbo from the tube ,swung it aside and put a plug in it.
I hooked the exit hose to the tube.I used an old washing machine drain hose for it(has the curve in it allready)
I hooked the exit hose to the tube.I used an old washing machine drain hose for it(has the curve in it allready)
buddy
Active Member
Its probably the #1 emissions item on a vehicle, its a simple thing but cuts the emissions in half, compared to all that other fancy stuff like EGR and catalytic converters and DPF and what not. The fuel vapors out of the hot oil is an emisions thing like Bison said. Now, it also helps maintain Postive Crankcase Ventilation (PCV), which is in fact negative pressure, or a vacuum in the crankcase. That also helps seals from leaking by reducing pressure on them. However, if you are venting it with a road draft tube there would be minimal buildup of pressure. Sealing the valve cover could be disasterous, but just venting it will not be so harmful, except maybe to your children's children, if emissions are actually harmful. Thats another debate, how the Earth itself produces more of these harmful emissions in a year than a man could in a 100 years. However, it has done a lot of good in big cities to improve roadways and air quality, where draft tubes put so much oil in the road when every car was that way, and it cut smog in LA considerably.
Like was also mentioned the CDR minimizes the vacuum, it regulates it so there very little vacuum, but how well it regulates I don't know. The turbo causes a large vacuum and will suck oil out of the valve cover, so if the CDR doesnt seal thats what you get. We start turning up the boost and fueling amounts on older engines and all of a sudden the system doesnt work as designed, even when it is functional.
Like was also mentioned the CDR minimizes the vacuum, it regulates it so there very little vacuum, but how well it regulates I don't know. The turbo causes a large vacuum and will suck oil out of the valve cover, so if the CDR doesnt seal thats what you get. We start turning up the boost and fueling amounts on older engines and all of a sudden the system doesnt work as designed, even when it is functional.
Ama83
New Member
Suspecting that is stuck open, quite a lot oil at turbo and oil is disappearing somewhere from engine. I really wouldn´t like to pay 100$ for that item...
bison
Well-Known Member
They are easy to test.
Its open most of the time anyway and only close at high boost.
Clogged air filter makes it worse,its got to get the air somewhere.
Oil into the turbo would be normal... Stuck open can only be determined by vacuum level within the crankcase while running and best tested on the roadway. You could use a magnehelic manometer, or fashion your own U-Tube manometer to verify operation. It regulates in inches of water column of vacuum, (not PSI, or InHg.)
If you have no vacuum, it could be that you have either a) excessive blowby b) no pressure drop across your intake air filter c) CDR stuck closed.
If you have excessive vacuum, then it would be stuck open. The CDR regulates to 4-6"wc.
I wouldn't condemn it based on oil though... that's a natural byproduct of it working, even with a new one.
If you have no vacuum, it could be that you have either a) excessive blowby b) no pressure drop across your intake air filter c) CDR stuck closed.
If you have excessive vacuum, then it would be stuck open. The CDR regulates to 4-6"wc.
I wouldn't condemn it based on oil though... that's a natural byproduct of it working, even with a new one.
bison
Well-Known Member
Stuck open or faulty can also be determined by a simpler test.
Take the thing off the cover,hold the cover side tube closed with one hand and apply vacuum with you mouth to the other,you should feel/hear it "pop" closed.
There is a tiny bleed hole on the round cover.(make sure it is open).
Put a finger over this pin hole while you have the CDR under full vac as in above,release vac,the membrane should hold in the closed position.
Now uncover the pin hole, the membrane should snap back to open.
If you can't make it move,the membrane valve is either seized or has a tear in it.Washing in diesel may restore it if seized.(keep fluid from entering the pin hole.)
Take the thing off the cover,hold the cover side tube closed with one hand and apply vacuum with you mouth to the other,you should feel/hear it "pop" closed.
There is a tiny bleed hole on the round cover.(make sure it is open).
Put a finger over this pin hole while you have the CDR under full vac as in above,release vac,the membrane should hold in the closed position.
Now uncover the pin hole, the membrane should snap back to open.
If you can't make it move,the membrane valve is either seized or has a tear in it.Washing in diesel may restore it if seized.(keep fluid from entering the pin hole.)
buddy
Active Member
PCV valve, $8, CDR $80, little bit of a difference when it really doesnt help all that much, especially when youre thinking its really needed at high RPM, well the 6.2/6.5 doesnt go to high RPM, but even if it did the CDR is pulled shut from the vacuum of the turbo boost, so its not doing anything under a high load scenario. Which is safer then, a closed crankcase allowed to build pressure while youre hauling 10k lbs up a grade for 20 minutes or one venting pressure, like a breather on classic cars?
Stuck shut and pressurizing the crankcase under load? If I understand it right, it regulates the vacuum level in the crankcase. If it's shutting back... it's regulating the amount of "vacuum" in crankcase by throttling it to it's max set level of 6"wc. It just has to do with the side that is sensing and regulating....
I think you are looking at it from the stand point of regulating based on vacuum source... not the crankcase. I've watched mine in the past operate under load @ WOT. The vacuum rises and goes just above setpoint, and then you can see it start to "regulate" just below that 6"wc rating. It also operates in modulation, rather than an on/off position from my observation at least. So it never went shut and went pressurized...
Dat's my story at least
I think you are looking at it from the stand point of regulating based on vacuum source... not the crankcase. I've watched mine in the past operate under load @ WOT. The vacuum rises and goes just above setpoint, and then you can see it start to "regulate" just below that 6"wc rating. It also operates in modulation, rather than an on/off position from my observation at least. So it never went shut and went pressurized...
Dat's my story at least
buddy
Active Member
So you were observing vacuum in the crankcase? Or vaccum from preturbo intake?
You are thinking when the CDR is as shut as it can get from vacuum from the turbo it is regulating to 6"? How much boost were you running?
Its a spring and diaphragm that gets sucked closed by vacuum to prevent too much vacuum from the turbo, its fully open at idle when there is very little vacuum.
You are thinking when the CDR is as shut as it can get from vacuum from the turbo it is regulating to 6"? How much boost were you running?
Its a spring and diaphragm that gets sucked closed by vacuum to prevent too much vacuum from the turbo, its fully open at idle when there is very little vacuum.
bison
Well-Known Member
Knreb is right with the CDR regulating crankcase vacuum to a set point.But it also means oil pullover is constant and worse on a high blowby engine.
Not much alternative in such a situation but rebuild the engine or vent to the world, unless one don't mind buying oil by the pail full and burning it.
I opted for venting.It was the cheaper of the options.
Not much alternative in such a situation but rebuild the engine or vent to the world, unless one don't mind buying oil by the pail full and burning it.
I opted for venting.It was the cheaper of the options.
buddy
Active Member
So when the CDR is fully closed does it still allow air to pass? If thats true it could not regulate how much vacuum is there. Boosting to 18psi would make a lot more vacuum than 9psi would, if the CDR got to its fully closed point at the vacuum created by 6psi of boost.
You are correct in thinking of construction... but the operational end is just a wittle bit off. There is two ways are regulator can regulate. Based on inlet conditions, or outlet conditions. The construction of the CDR is concerned about crankcase pressure. Yes, it does go more closed to nearly shut as the outlet of the CDR into the turbo vacuum increases. The "fully closed" position is not really fully closed. It's not a binary on/off. It's modulating. It may be 95% closed against very high vacuum available at the turbo. That 5% opening maybe all the more it needs to be open to provide that 6"WC setpoint.
As for my conditions, I did not measure the turbo boost pressure during that test. I knew historically that the engine could pull 7 psi at 65, and full boost of 12 psi was never a problem at WOT. Vacuum was measured at oil dipstick while driving down the road.
There is two ways are regulator can regulate. Based on inlet conditions, or outlet conditions. The construction of the CDR is concerned about crankcase pressure. Yes, it does go more closed to nearly shut as the outlet of the CDR into the turbo vacuum increases. The "fully closed" position is not really fully closed. It's not a binary on/off. It's modulating. It may be 95% closed against very high vacuum available at the turbo. That 5% opening maybe all the more it needs to be open to provide that 6"WC setpoint.As for my conditions, I did not measure the turbo boost pressure during that test. I knew historically that the engine could pull 7 psi at 65, and full boost of 12 psi was never a problem at WOT. Vacuum was measured at oil dipstick while driving down the road.
nobby
Old Timey Diesel Guy
Personally I like a bit of vacuum on my base end!
Cheers
Nobby
Cheers
Nobby
Last edited:
buddy
Active Member
When I sucked mine closed I thought it was closed, but I'll check it again. It could always be one of ours is not operating correctly.
nobby
Old Timey Diesel Guy
KnKreb is on the mark in that it modulates to maintain a set vacuum rather than be a binary control. As Buddy noted makes no sense that it fully closes.
As Bison noted the ability of the CDR to keep oil mist from the intake is questionable at best especially once the miles pile on. Even after a new CDR I still see some oil getting by. Truth is better systems have come along such as the Walker Airsep Crankcase ventilation systems (Racor has them to) that go a step further in separating the oil out and return it to the base.
Whilst it is another cost, with what it is trying to achieve and the fact that they get oiled and gunked possible spring weakening etc I view them as a maintenance item. Personally as I joked earlier I like a little vacuum on the base and in the larger marine applications that I work on it is normally the case to maintain a vacuum and a manometer is on the engine as standard to monitor it. Whilst it may be considered a recent concept for on land diesels, some of the pre 1950's marine units that I work on breathe back into the intake. Separate to discussions of reducing oil mist in the base if nothing else it makes for a much less messy enclosed space such as a marine engine room.
As an FYI my manual states 3-4 in/hg and with the water tube test under full load one should be looking for 3-4" of water.
Cheers
Nobby
As Bison noted the ability of the CDR to keep oil mist from the intake is questionable at best especially once the miles pile on. Even after a new CDR I still see some oil getting by. Truth is better systems have come along such as the Walker Airsep Crankcase ventilation systems (Racor has them to) that go a step further in separating the oil out and return it to the base.
Whilst it is another cost, with what it is trying to achieve and the fact that they get oiled and gunked possible spring weakening etc I view them as a maintenance item. Personally as I joked earlier I like a little vacuum on the base and in the larger marine applications that I work on it is normally the case to maintain a vacuum and a manometer is on the engine as standard to monitor it. Whilst it may be considered a recent concept for on land diesels, some of the pre 1950's marine units that I work on breathe back into the intake. Separate to discussions of reducing oil mist in the base if nothing else it makes for a much less messy enclosed space such as a marine engine room.
As an FYI my manual states 3-4 in/hg and with the water tube test under full load one should be looking for 3-4" of water.
Cheers
Nobby