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how can we measure it? i know the pressure is barely positive, id love to get a reading on it. any ideas?
CCV Pressure
- Thread starter bigrpowr
- Start date
White_monster
Active member
Use a manometer. It's a tube with water. For a reference point.. 4" of Water = .15 PSI... thats POINT ONE FIVE PSI.. less than a quarter of one PSI.. which makes sense as there is a 3/4 hole in the head which vents air to the atmosphere. This information is from the aviation industry and on high hp turbo engines. There should be no more than .15psi at high rpm.
Building a manometer is simple just look it up on the Internet. Hope this helps.
Building a manometer is simple just look it up on the Internet. Hope this helps.
redx
New member
What your looking for like Shane mentioned is a "slack tube" manometer. The one we have is made by Dwyer and was less than $50 or so.
kevin
New member
Caterpillar actually has a tool for this, its a clear tube with markings on the side with a ball in it.. more pressure the higher the ball goes..
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i dont have a means to record this onfo as i dont have a truck, its just one of those things kinda bugging me lately.
powr2stroke
Active member
you and me both buddy
Wayne
Active member
I lifted my dipstick on xtreme street the other day before I got the 1"heater hose venting to atmosphere :lookaround
ower balance is perfect, and relative compression is within 1%. Runs really smooth too so go figure. Bone stock '09 with 10k miles I was working on the other day was blowing a haze visible for about 10" high with the cap removed fwiw.
ower balance is perfect, and relative compression is within 1%. Runs really smooth too so go figure. Bone stock '09 with 10k miles I was working on the other day was blowing a haze visible for about 10" high with the cap removed fwiw.
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my concern is with the aftermarket twin kits.
White_monster
Active member
This is why the gas performance world uses small vacuum pumps to have zero pressure in the crank case. Who wants to build a kit? Just need a small electric vacuum pump. The gas world has gone through these growing pains and we should learn from them cause it applies.
HD F250
Active member
You guys are some smart Mo Fo's and I greatly appreciate the knowledge......subscribed!!!!
Tree Trimmer
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on our demolition derby cars with roller 383's, we use header pointed straight up. to these headers, is a tube running from the top of the header to the valve cover. as the exhaust flows out the header, it creates a suction on the tube, this relieving any pressure in the crank case.
its the same thing as the chimney on your house. air blows across the top, and sucks the smoke out.
we have found, that if the angle of your bung is any greater than 30*, it will literally suck the oil out of the motor and spray it all over the car. we use about 15*. the manometer verified that this worked, as we ended up with about .12 psi of negative pressure in the case. we have since corrected this to have zero psi even.
could the same thing be done on a turbo charged truck? the principle is there, but the additional flow through the exhaust from the turbo's is what i dont know. just throwing that out. carry on.
its the same thing as the chimney on your house. air blows across the top, and sucks the smoke out.
we have found, that if the angle of your bung is any greater than 30*, it will literally suck the oil out of the motor and spray it all over the car. we use about 15*. the manometer verified that this worked, as we ended up with about .12 psi of negative pressure in the case. we have since corrected this to have zero psi even.
could the same thing be done on a turbo charged truck? the principle is there, but the additional flow through the exhaust from the turbo's is what i dont know. just throwing that out. carry on.
We were talking about this a while back so i will just quote what I said back then.
"I have been thinking about this for a few days. This was all like 8 years ago so please forgive me it I do not recall everything. Back when we were racing EVOs and Eclipses in Hawaii, we kept blowing the dipstick out of holder. This was happening after we took off the Hose going to the intake coming from the valvecover. I went and drilled and tapped in two -8 lines on the valvecover and had no more issues. I was going to goto a vacuum pump but never got around to it.
Fast Fwd to today, I searched the internet and could only fine a atrical that was sometime close to what we were going to do.
"For every cubic inch above a piston, there's an equal amount below it. Your basic crankcase ventilation system is a simple PCV valve which sucks that air back into the engine to be reburnt. The downside is that you're sucking oil and water vapour back into the cylinders.
Racers have used other ways of keeping the crankcase clean and reducing pressure inside it. Exhaust evac systems have been around for years. They use a check valve similar to the AIR valve on your exhaust manifolds. When hooked into the exhaust system down at the end of the headers, the exhaust gasses can create enough vacuum to keep the crankcase pressure low. They pull very little from the crankcase at high rpms though.
In the last 30 years or so when the car manufacturers started using air pumps (smog pump) to inject air into the exhaust to reduce emissions, racers found that these pumps can also suck a lot of air out of the crankcase with a few modifications. Smog pumps are still used today but there are now better vacuum pumps available to do the job. Moroso makes a very good but expensive belt driven pump. GM produces an electric AIR pump for the exhaust on late model F-bodies that's supposed to work just as good for pulling the crankcase down into a vacuum.
The theory is that when the crankcase is in a vacuum, the pistons are not trying to compress air below them. This means some HP is free'd up. Having lower crankcase pressure also allows the rings to seat tighter against the cylinder walls. You'll also eliminate any oil leaks from the engine.
There are some drawbacks from running a crankcase in a vacuum. The rear main seal is designed to keep oil from going out. If the crankcase is in a vacuum, it can easily draw dirty air into the crankcase through the rear main seal. The common way to correct it is to install the seal backwards.
Too much vacuum can be hazardous. No more that 14-15" of vacuum should be used. A vacuum pump of any kind in a well sealed engine can pull 28" of vacuum. This is enough to pull the oil out of the wrist pins and bearings. The best way to limit the amount of vacuum is with a vacuum relief valve. It's preset to open if the vacuum become too great. Think of it as a controlled vacuum leak.
Dyno results vary but a 2-5% increase in HP can be expected."
http://www.camaroz28.com/forums/showthread.php?t=82357
I hope this helps out some.
Luke
"I have been thinking about this for a few days. This was all like 8 years ago so please forgive me it I do not recall everything. Back when we were racing EVOs and Eclipses in Hawaii, we kept blowing the dipstick out of holder. This was happening after we took off the Hose going to the intake coming from the valvecover. I went and drilled and tapped in two -8 lines on the valvecover and had no more issues. I was going to goto a vacuum pump but never got around to it.
Fast Fwd to today, I searched the internet and could only fine a atrical that was sometime close to what we were going to do.
"For every cubic inch above a piston, there's an equal amount below it. Your basic crankcase ventilation system is a simple PCV valve which sucks that air back into the engine to be reburnt. The downside is that you're sucking oil and water vapour back into the cylinders.
Racers have used other ways of keeping the crankcase clean and reducing pressure inside it. Exhaust evac systems have been around for years. They use a check valve similar to the AIR valve on your exhaust manifolds. When hooked into the exhaust system down at the end of the headers, the exhaust gasses can create enough vacuum to keep the crankcase pressure low. They pull very little from the crankcase at high rpms though.
In the last 30 years or so when the car manufacturers started using air pumps (smog pump) to inject air into the exhaust to reduce emissions, racers found that these pumps can also suck a lot of air out of the crankcase with a few modifications. Smog pumps are still used today but there are now better vacuum pumps available to do the job. Moroso makes a very good but expensive belt driven pump. GM produces an electric AIR pump for the exhaust on late model F-bodies that's supposed to work just as good for pulling the crankcase down into a vacuum.
The theory is that when the crankcase is in a vacuum, the pistons are not trying to compress air below them. This means some HP is free'd up. Having lower crankcase pressure also allows the rings to seat tighter against the cylinder walls. You'll also eliminate any oil leaks from the engine.
There are some drawbacks from running a crankcase in a vacuum. The rear main seal is designed to keep oil from going out. If the crankcase is in a vacuum, it can easily draw dirty air into the crankcase through the rear main seal. The common way to correct it is to install the seal backwards.
Too much vacuum can be hazardous. No more that 14-15" of vacuum should be used. A vacuum pump of any kind in a well sealed engine can pull 28" of vacuum. This is enough to pull the oil out of the wrist pins and bearings. The best way to limit the amount of vacuum is with a vacuum relief valve. It's preset to open if the vacuum become too great. Think of it as a controlled vacuum leak.
Dyno results vary but a 2-5% increase in HP can be expected."
http://www.camaroz28.com/forums/showthread.php?t=82357
I hope this helps out some.
Luke
I went to two 1 inch hoses out of my vent just to be sure I didn't have issues
Didn't want to flood q Turbo because too much crank case pressure.
Caterpillar also measures blowby by HP rating
Ill see what I can dig up at work today.
Didn't want to flood q Turbo because too much crank case pressure.
Caterpillar also measures blowby by HP rating
Ill see what I can dig up at work today.
Wayne
Active member
I plan on plumbing my ccv hose to my exhaust pipe with a venturi and tweak with it to achieve proper ccp. I'll let you guys know if it works.
I also went with 2 1'' hoses for the CC vent. I dont need it now but I am planning for the future.
75312[/ATTACH]"]
Attachments
Erikclaw
Active member
Well I got Rudy's new ccv on my truck when rebuilt. On my drive home it pukes oil all over the frame, exhaust etc. Now I had an issue with excess oil before my motor blew. We thought maybe it was hurt long ago but with it still doing it with an completely new motor I am now ???????? Their kit uses two 5/8" lines from a line connected to the valve cover located so it doesn't suck oil out of the motor. I think baffling is needed. But not sure.
White_monster
Active member
Of course baffling is needed guys. Oil vapor is inside the engine and that's what is being pushed out the vents. Without a baffle there's no way for the oil to be captured and the air inside the engine to escape. I've. Sen looking for a way to build a baffle that looks good but so far no luck on my part.
Erikclaw
Active member
I was told that where they connected the hose to the valve cover baffling wasn't needed. I asked about it when I finally saw the finished product.
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