guys not using the PCV

[kidglok]

But it seems to me that adding a check valve would change the way that the PCV is designed to operate. I mean, the PCV is a check valve. It allows vacuum to suck out the blow-by gases so that they get directed into the TB and burned. Under boost, it keeps the boost from entering the intake.

My main concern is keeping the LIQUID oil out of the intake. Does installing the catch-can keep liquid oil out of the throttle body? If so, I would plan to install, but if it doesn't it seems that it's a waste of money. My concern is not the water vapor, but is the fact that the liquid oil would enter the TB and combustion chamber.

To answer your question- yes, a catch can will prevent oil from entering the intake

i was giving my personal experience with pcv setups. the intake was coated with oil and it was coming out of the exhaust, when i added a second check valve it stopped. I came to the conclusion that the pcv i was using let too much vacuum be drawn into the intake system thus sucking up oil, when i restricted the amount of vacuum it was allowed to pull it wouldnt suck oil anymore, just alleviate any pressure and moisture that was trapped into the system.

i couldve just used a catch can but the less junk in my engine bay the better

 

[87-WE2]

OK - thanks for the info. I'll probably eventually get one in there. I was admiring Rick's setup that he has pictured a couple of pages back. It took me about 30 seconds of looking at the pics to find where his can is located. Over there by the AC dryer looks like a good, clean, factory-looking spot.

 

[bison]

So I go to empty my catch can over the weekend and you're not going to believe what I found. Full of water and white creame. I wondered where the coolant was going. Luckily I don't run antifreeze in my car.

So back to the pcv and it's importance. When a problem like this shows up the pcv vacuums out the moisture that would otherwise stay inside and make a big mess. The catch can did a great job at capturing the contaminants. You would not believe it. It was full of clear water. I knew right away what was up. I cleaned the catch and went for a short ride to confirm. When I came back the catch had about 1" of clear water and more creame.

So I take the intake off and make up some block of plates. Pressurize the the system and low and behold, the passenger hg is seeping. Not real bad so I decide to pop the intake back on and run some sealing tabs. So far so good. Took a long ride last night. No more water in the catch. Just a little creamy. The last of the moisture that getting vacuumed out.

If no pcv was being used there would no doubt be a big mess inside the motor. It does a very important job and does it well.
I changed the oil it showed no signs of water. I was surprised given the amount of water in the catch.

RL

My black car leaks a lot of water into the crankcase. I never ran a pcv valve and i never hurt it. The water vaporizes when the engine gets up to temp. Prior to hitting the temp where the vapor pressure is equal to atmospheric pressure evaporization still occurs. The pcv if the right one won't pull a enough of a vacuum on the crank case to drop the boiling point of the water any significant amount. Therefore most of the moisture must exit the crankcase as invisible water vapor from evaporization. The higher the oil temp is and the higher the airflow through the crankcase is the more likely more the water will evaporate out. The pcv will increase the airflow through the crankcase under vacuum conditions which aids in evaporation and will slightly drop the boiling point vs a no pcv setup but It's not going to protect the engine from damage if there is a big enough leak and especially if anti freeze enters the crankcase. The visible water in everyones catch cans is the condensation from the vapor that normally exits the breathers invisibly. Catch cans usually have a lot of surface area and they are usually considerably cooler than the engine so the water that was in the engine is visible because it condenses once again instead of blowing away with the ambient air.

 

[Ttype6]

My main concern is keeping the LIQUID oil out of the intake. Does installing the catch-can keep liquid oil out of the throttle body? IMy concern is not the water vapor, but is the fact that the liquid oil would enter the TB and combustion chamber.

This is my concern also.

 

[TurboBuRick]

My black car leaks a lot of water into the crankcase. I never ran a pcv valve and i never hurt it. The water vaporizes when the engine gets up to temp. Prior to hitting the temp where the vapor pressure is equal to atmospheric pressure evaporization still occurs. The pcv if the right one won't pull a enough of a vacuum on the crank case to drop the boiling point of the water any significant amount. Therefore most of the moisture must exit the crankcase as invisible water vapor from evaporization. The higher the oil temp is and the higher the airflow through the crankcase is the more likely more the water will evaporate out. The pcv will increase the airflow through the crankcase under vacuum conditions which aids in evaporation and will slightly drop the boiling point vs a no pcv setup but It's not going to protect the engine from damage if there is a big enough leak and especially if anti freeze enters the crankcase. The visible water in everyones catch cans is the condensation from the vapor that normally exits the breathers invisibly. Catch cans usually have a lot of surface area and they are usually considerably cooler than the engine so the water that was in the engine is visible because it condenses once again instead of blowing away with the ambient air.

Been running this catch for a long time. This was the first time ever it captured clear water. I mean full to the rim with crystal clear water.(like my coolant) Even after I cleaned the can and took it out for another short ride it pulled more clear water. I have never seen water or condensation in the can until there was a problem. It's usually just some raunchy smelling dark oil.

 

[longball]

recently, Bobby (RPE) built me a new stroker. No PCV or catch can on the motor. When I asked him why, he said: "You don't need it".
He's gotta know as much about these motor's as anyone..........

 

[Pronto]

My black car leaks a lot of water into the crankcase. I never ran a pcv valve and i never hurt it. The water vaporizes when the engine gets up to temp. Prior to hitting the temp where the vapor pressure is equal to atmospheric pressure evaporization still occurs. The pcv if the right one won't pull a enough of a vacuum on the crank case to drop the boiling point of the water any significant amount. Therefore most of the moisture must exit the crankcase as invisible water vapor from evaporization. The higher the oil temp is and the higher the airflow through the crankcase is the more likely more the water will evaporate out. The pcv will increase the airflow through the crankcase under vacuum conditions which aids in evaporation and will slightly drop the boiling point vs a no pcv setup but It's not going to protect the engine from damage if there is a big enough leak and especially if anti freeze enters the crankcase. The visible water in everyones catch cans is the condensation from the vapor that normally exits the breathers invisibly. Catch cans usually have a lot of surface area and they are usually considerably cooler than the engine so the water that was in the engine is visible because it condenses once again instead of blowing away with the ambient air.

What engine or oil temp do you like to see? Do you run an oil cooler?

 

[MNwe4]

Glad this thread is still going as I thought I had made up my mind years ago, but now I'm not so sure anymore. On my previous build I ran two breathers and replaced the pcv with a draft tube that runs down the tranny and dumps on the ground. At the time I was running gas and alky and essentially never saw any smoking/puffing coming from the breathers or draft tube. I was very happy as it eliminated a possible vacuum leak and the potential for sucking oil into the intake.

Now on the new engine I'm running e85 and higher compression. With the same venting setup there is constant smoke/steam coming from the breathers and draft tube. Coolant level hasn't changed so it's hopefully only from blow by. I'm hoping that some of it's just due to the nature of e85 and the other is from maybe the rings not being seated yet. However, if it doesn't get significantly better I will probably go back to using a pcv.

I've had a few people recommend running the stock pcv and the rjc valve in line with it. Seems similar setups have been mentioned in this thread. Maybe the lesson to be learned is that like many other things it varies from car to car. I'm trying to get some miles on it and decide before the snow shows up.

 

[bison]

Been running this catch for a long time. This was the first time ever it captured clear water. I mean full to the rim with crystal clear water.(like my coolant) Even after I cleaned the can and took it out for another short ride it pulled more clear water. I have never seen water or condensation in the can until there was a problem. It's usually just some raunchy smelling dark oil.

That indicates you have a lot of water getting into the crankcase that you didnt before. Just like i do. Ill be pulling the heads since i have to add thread inserts to the passenger side. At that point i can address the water in crankcase problem.

 

[Garycar]

I have a breather on each valve cover and placed a piece of copper pipe in the rubber hole where the PCV valve once resided. Placed a small breather filter on the pipe so yhat it provides an additional vent similar to the valve cover breathers.

 

[dvernst]

I have a breather on each valve cover and placed a piece of copper pipe in the rubber hole where the PCV valve once resided. Placed a small breather filter on the pipe so yhat it provides an additional vent similar to the valve cover breathers.

I blocked my pcv opening off, but get oil on my driver side valve cover from the breather. Maybe an additional breather where the pcv was will help? For some reason no oil comes out the passenger breather.

 

[TurboBuRick]

That indicates you have a lot of water getting into the crankcase that you didnt before. Just like i do.

In my case the passenger hg is seeping into the valley. It just floors me how good the pcv pulls the water out.

I put 4 sealing tabs in the coolant. Catch can contents is looking much better now.

A pcv with a catch seems a great way to monitor what's going on inside. The voodoo around it's use is unfortunate considering it has no real downside. The pros outweigh the cons IMO.

RL