Here I go again....PCV
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Well, here's my $0.02 worth of new thoughts. Some of these may sound stupid but please don't be offended; I want to grasp at as many straws as possible since you guys have already investigated most of the obvious stuff 
. First, I don't think the PCV is sucking up liquid oil, I think it's sucking up oil mist that is coalescing into liquid once it hits the throttle body. Like someone else posted, to suck up liquid would require a huge puddle on top of the valley pan. The question is "What's causing that mist"? The people with the worst problems seem to have new rebuilds. Even though the compression is good, have you done a leakdown test? With the pcv disconnected/capped off and the oil fill spout on the driver's valve cover removed, how much "smoke" is there with the engine idling or revved up to maybe 2500 rpm? If there's as much as say the curl of smoke from a just-blown-out candle then I think you have a blow-by problem putting a much greater volume of air into the crankcase than the pcv circuit can handle, and the leakdown test should prove that. If it's not blow-by then the other choices seem to be froth from the turbo drain line (and I have no knowledge of how frothy that is ), excess oil loss around the lifters and camshaft, perhaps somthing in the timing cover like windage off the timing chain or maybe the oil pump bypass, and windage from the crankshaft. In kind of reverse order, how much oil do you add after an oil change? Any chance the dipstick and/or tube was replaced with incorrect parts and you have the crank partly submerged? Was the oil pan replaced with a non-turbo one, without the baffle? If you pull the dipstick with the engine idling, is the oil foamy or bubble free? I guess if you have a huge fog in the valley pan area it's not unreasonable to see bubbles on the dipstick, but lots of foam may mean too much oil in the crankcase. Were the mains and rods set up really loose so lots of oil is spraying out of them? I don't know if it's possible for the oil pump bypass to cause a fog (I can't remember how it drains or returns so this part may be all nonsense), but did you put in a high volume oil pump setup or do you have the stock front cover and pump gears? Are you sure you have the right lifters? Do they bleed down really fast when you turn off the engine so you hear a brief rattle on a warm restart? If the turbo were getting lots of excess oil I think the seals would be weeping and you would either have blue smoke in the exhaust or oil in the intercooler pipe, or both. For brief testing you could unhook the drain line at the block end and use some of that cheap clear PVC hose from Home Depot to extend the drain into a pan on the ground. Run the engine at idle or fast idle and see what comes out - just make sure you have the engine full of oil and only drain out 1 or 2 quarts. Do this with the pcv connected and see how much you get in your oil mist separator, to see if this is the source.
Well, that's all I can come up with. If I had to bet, without ever actually seeing your motor, I'd suspect blow-by past the rings since I've seen a couple of motors where that was the problem.
Good luck with the detective work.
. First, I don't think the PCV is sucking up liquid oil, I think it's sucking up oil mist that is coalescing into liquid once it hits the throttle body. Like someone else posted, to suck up liquid would require a huge puddle on top of the valley pan. The question is "What's causing that mist"? The people with the worst problems seem to have new rebuilds. Even though the compression is good, have you done a leakdown test? With the pcv disconnected/capped off and the oil fill spout on the driver's valve cover removed, how much "smoke" is there with the engine idling or revved up to maybe 2500 rpm? If there's as much as say the curl of smoke from a just-blown-out candle then I think you have a blow-by problem putting a much greater volume of air into the crankcase than the pcv circuit can handle, and the leakdown test should prove that. If it's not blow-by then the other choices seem to be froth from the turbo drain line (and I have no knowledge of how frothy that is ), excess oil loss around the lifters and camshaft, perhaps somthing in the timing cover like windage off the timing chain or maybe the oil pump bypass, and windage from the crankshaft. In kind of reverse order, how much oil do you add after an oil change? Any chance the dipstick and/or tube was replaced with incorrect parts and you have the crank partly submerged? Was the oil pan replaced with a non-turbo one, without the baffle? If you pull the dipstick with the engine idling, is the oil foamy or bubble free? I guess if you have a huge fog in the valley pan area it's not unreasonable to see bubbles on the dipstick, but lots of foam may mean too much oil in the crankcase. Were the mains and rods set up really loose so lots of oil is spraying out of them? I don't know if it's possible for the oil pump bypass to cause a fog (I can't remember how it drains or returns so this part may be all nonsense), but did you put in a high volume oil pump setup or do you have the stock front cover and pump gears? Are you sure you have the right lifters? Do they bleed down really fast when you turn off the engine so you hear a brief rattle on a warm restart? If the turbo were getting lots of excess oil I think the seals would be weeping and you would either have blue smoke in the exhaust or oil in the intercooler pipe, or both. For brief testing you could unhook the drain line at the block end and use some of that cheap clear PVC hose from Home Depot to extend the drain into a pan on the ground. Run the engine at idle or fast idle and see what comes out - just make sure you have the engine full of oil and only drain out 1 or 2 quarts. Do this with the pcv connected and see how much you get in your oil mist separator, to see if this is the source.Well, that's all I can come up with. If I had to bet, without ever actually seeing your motor
, I'd suspect blow-by past the rings since I've seen a couple of motors where that was the problem.Good luck with the detective work.
blackbuick87
Senior Member
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I think the obvious way to tell if the valley pan is the problem would be for the next guy with an oil problem to use Fel Pro 1200's without the pan next time he puts his intake back on. That will determine if it is a mist or puddled oil. I subscribe to the mist theory.
Get you engine hot one time, pull the breathers and watch the oily "mist/smoke" come out. It wont be long before oil condenses on the outside of the valve covers.
And most guys say they are sucking the most oil at idle, which would make sense since the engine is not moving enough air to clear the intake of the oil buildup
Get you engine hot one time, pull the breathers and watch the oily "mist/smoke" come out. It wont be long before oil condenses on the outside of the valve covers.
And most guys say they are sucking the most oil at idle, which would make sense since the engine is not moving enough air to clear the intake of the oil buildup
Man you guys are all having problems with this?
1st, the oil return goes under the valley pan.
2nd, your pcv valve is only there for emissions. To burn off fumes in the crank case. Instead of venting into the air.
3rd, All you have to do is block off the pcv. If you have somke or pressure coming out of the oil fill you have blow by. Do a leak down test! A compression test will show fine because you may have oil on the rings.
Also you guys with new motors. What kind of oil are you using? If you are putting synthetic in the rings may not seat.
4th, Race cars dont have pcv valves. They have breathers. Also pcv valves can be trouble on turbo motors. If you can blow back through a pcv then under boost you are pressurizing the crank case and you will get oil leaks.
The guy asking about the felpro 1200s. With no valley pan you can suck oil at idle until you get boost. On motors I have done with 1200s I block off the pcv. Realy no need for 1200s unless you are going low 10s or faster.
Also if you have a stock oil pan,and you fill the oil up to the top line on the stick you are overfilling it. The GN and TTA motors hold 5 quarts. That will bring the oil up to the bottom of the cross hatch pattern.
maybe this can help. Steve K.
1st, the oil return goes under the valley pan.
2nd, your pcv valve is only there for emissions. To burn off fumes in the crank case. Instead of venting into the air.
3rd, All you have to do is block off the pcv. If you have somke or pressure coming out of the oil fill you have blow by. Do a leak down test! A compression test will show fine because you may have oil on the rings.
Also you guys with new motors. What kind of oil are you using? If you are putting synthetic in the rings may not seat.
4th, Race cars dont have pcv valves. They have breathers. Also pcv valves can be trouble on turbo motors. If you can blow back through a pcv then under boost you are pressurizing the crank case and you will get oil leaks.
The guy asking about the felpro 1200s. With no valley pan you can suck oil at idle until you get boost. On motors I have done with 1200s I block off the pcv. Realy no need for 1200s unless you are going low 10s or faster.
Also if you have a stock oil pan,and you fill the oil up to the top line on the stick you are overfilling it. The GN and TTA motors hold 5 quarts. That will bring the oil up to the bottom of the cross hatch pattern.
maybe this can help. Steve K.
What I've always understood is that people without the valley pan have worse problems with oil accumulation in the intake than those with the valley pan. And with no valley pan, the turbo oil return line should not be affecting things... hmmm...
I remember one guy that ditched the valley pan, welded an enclosure on the underside of the intake around the PCV so it only drew vapors in from the back of the engine, and he had problems sucking oil. Putting the right intake gasket in it solved that problem for him.
Anyway, did an experiment this evening. Plugged the pass side valve cover breather hole completely and plugged the drivers side valve cover breather with a fitting that I hooked up to a vacuum gauge. This gauge says I pull about 17" Hg at idle.
Fired up the car, and it pulled the crankcase (as read at the drivers side valve cover) down to 6-7" Hg. Wow! I had no idea the PCV pulled that much. I don't think I have ever cleaned my breathers, I never thought of much air being pulled through them into the engine, but it obviously does. Shut the engine down, and it has been holding 1.5" Hg for a few hours now.
Anyway, ponder that for a while, there's some implications there. While breathers are great when you're at WOT, are they hurting us around town? I'll tell you one thing: there is a lot less flow through the PCV when the crankcase is at 7" HG than when the crankcase is at atmospheric pressure! I think I'm going to try and get some miles on the car in this configuration (and keep my foot out of it to stay out of the boost), and see how much oil collects in the filter I've got inline with the PCV valve.
John
I remember one guy that ditched the valley pan, welded an enclosure on the underside of the intake around the PCV so it only drew vapors in from the back of the engine, and he had problems sucking oil. Putting the right intake gasket in it solved that problem for him.
Anyway, did an experiment this evening. Plugged the pass side valve cover breather hole completely and plugged the drivers side valve cover breather with a fitting that I hooked up to a vacuum gauge. This gauge says I pull about 17" Hg at idle.
Fired up the car, and it pulled the crankcase (as read at the drivers side valve cover) down to 6-7" Hg. Wow! I had no idea the PCV pulled that much. I don't think I have ever cleaned my breathers, I never thought of much air being pulled through them into the engine, but it obviously does. Shut the engine down, and it has been holding 1.5" Hg for a few hours now.
Anyway, ponder that for a while, there's some implications there. While breathers are great when you're at WOT, are they hurting us around town? I'll tell you one thing: there is a lot less flow through the PCV when the crankcase is at 7" HG than when the crankcase is at atmospheric pressure! I think I'm going to try and get some miles on the car in this configuration (and keep my foot out of it to stay out of the boost), and see how much oil collects in the filter I've got inline with the PCV valve.
John
SKturbo-
If race cars don't use any type of PCV system then why do serious racers waist all that money on vac pumps
? If breathers work so great, there wouldn't be a NEED for them! Anyone who knows anything should know that pulling a vacume on the crankcase is a good thing,,helps rings seal and=less blow by=more power!
Lets also keep in mind that as many of the cars owned by members here are very fast,they are still driven on the street a lot! So there is a need for the PCV. If a car is only used at the track than a evac system should be used to get the most out of what thay have.
If race cars don't use any type of PCV system then why do serious racers waist all that money on vac pumps
? If breathers work so great, there wouldn't be a NEED for them! Anyone who knows anything should know that pulling a vacume on the crankcase is a good thing,,helps rings seal and=less blow by=more power!Lets also keep in mind that as many of the cars owned by members here are very fast,they are still driven on the street a lot! So there is a need for the PCV. If a car is only used at the track than a evac system should be used to get the most out of what thay have.
Chris Taylor
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The PCV valve is very important in our engines. When you tear down an engine that has not ran a PCV valve and see the mess you will see my point. The gasses and condition are not evacuated when a PCV valve is not used. This will cause a tremendous amount of sludge in a motor over time.
I have done a leak down test on my motor and it is OK with no blow by. I used Fel Pro 1200,s at first and changed to a valley pan thinking this would stop the oiling problem, it did not. My motor has 2,050 miles on it at this time. I used file fit rings and they are seated. I have a Fram G3 filter inline along with a check valve. It is useless and fills up with oil after one mile of driving.
A vacuum pump is the ideal way to render this problem, keeping positive pressure in the crankcase. The only problem is the cost of a vacuum pump and mounting the pump with the factory accessories. The electric pumps are very expensive but would be the best bet.
I blocked off my PCV line and this problem stopped so I know this is the source of oil in my plenum and smoke at start up. I connected my PCV knowing the long term damage that is caused by not using a PCV valve. I am working on an oil separator at this time to fix this problem.
I have done a leak down test on my motor and it is OK with no blow by. I used Fel Pro 1200,s at first and changed to a valley pan thinking this would stop the oiling problem, it did not. My motor has 2,050 miles on it at this time. I used file fit rings and they are seated. I have a Fram G3 filter inline along with a check valve. It is useless and fills up with oil after one mile of driving.
A vacuum pump is the ideal way to render this problem, keeping positive pressure in the crankcase. The only problem is the cost of a vacuum pump and mounting the pump with the factory accessories. The electric pumps are very expensive but would be the best bet.
I blocked off my PCV line and this problem stopped so I know this is the source of oil in my plenum and smoke at start up. I connected my PCV knowing the long term damage that is caused by not using a PCV valve. I am working on an oil separator at this time to fix this problem.
When my engine was stock, the tube that connected the right side valve cover to the turbo inlet fed oil into the intake tract. The solution to this problem was valve cover breathers(so I was told). Now it appears I have redirected the oil through the pcv valve. I guess I could run the tube from the intake manifold to the bottom of the car(like they did in the 60's). I already have the valve cover breathers. No more oil in the intake and the crankcase is vented.
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My $.02 worth
I'm doing some tests on the "pvc" deal. I have an elec vac pump off of a mid 90's Camaro. [They, and Caddys, use this pump.]
Their systems are sealed.. NO pvc on them.
I am also looking at the info on what is the "norm" for vac pump performance on various types of engines.
Per the guys at STEF'S, the following is offered.
Pro stock 20 to 23 in vac.
Comp elim. 17 to19.
Stock type [us] 8 to 12.
I asked WJ at one of his TnT sessions how he gauged the engine condition. He replied, "I watch the crank case vac level. If it drops from a specific value, it's time to freshen up".
I haven't taken this pump apart yet, but suspect it has a relief valve in it to prevent pulling too much vac or overloading the motor. [The pro systems have adj relief valves in the kits]
I am going to plug the engine breathers, add a fitting to the VC, run the hose to a JAZ overflow tank, then pull the vac on the tank.
I have orderd one of the Areospace relief valves to put in the V/C.
We'll see.. I may be able to pull enuf vac to turn the engine inside out!!
That is one thing to consider tho.. too much vac and you could pull $hit thru the T/C seal and other places too. It can also pull so much oil off the cyl walls, that the rings scuff. I have seen a PVC pull so much vac on an engine that had no breather gromment cut out, that it pulled the T/C into the timing chain!! [SBC]
Oh well, so many problems and so little time!!
I'm doing some tests on the "pvc" deal. I have an elec vac pump off of a mid 90's Camaro. [They, and Caddys, use this pump.]
Their systems are sealed.. NO pvc on them.
I am also looking at the info on what is the "norm" for vac pump performance on various types of engines.
Per the guys at STEF'S, the following is offered.
Pro stock 20 to 23 in vac.
Comp elim. 17 to19.
Stock type [us] 8 to 12.
I asked WJ at one of his TnT sessions how he gauged the engine condition. He replied, "I watch the crank case vac level. If it drops from a specific value, it's time to freshen up".
I haven't taken this pump apart yet, but suspect it has a relief valve in it to prevent pulling too much vac or overloading the motor. [The pro systems have adj relief valves in the kits]
I am going to plug the engine breathers, add a fitting to the VC, run the hose to a JAZ overflow tank, then pull the vac on the tank.
I have orderd one of the Areospace relief valves to put in the V/C.
We'll see.. I may be able to pull enuf vac to turn the engine inside out!!
That is one thing to consider tho.. too much vac and you could pull $hit thru the T/C seal and other places too. It can also pull so much oil off the cyl walls, that the rings scuff. I have seen a PVC pull so much vac on an engine that had no breather gromment cut out, that it pulled the T/C into the timing chain!! [SBC]
Oh well, so many problems and so little time!!
CLEAN86,
I can see you dont understand the purpose of a pcv
The purpose of the pcv on your car and a crankcase evacuation system on a race car are two differant things. Your pcv is only pulling vac. untill you reach 0"of vac. When you are in boost your pcv shuts off.
Your pcv is there to burn off fumes in the crankcase instead of venting into the air!
And if you think your pcv is helping your rings seal and giving you less blow. You are misstaken.
Steve K.
I can see you dont understand the purpose of a pcv
The purpose of the pcv on your car and a crankcase evacuation system on a race car are two differant things. Your pcv is only pulling vac. untill you reach 0"of vac. When you are in boost your pcv shuts off.
Your pcv is there to burn off fumes in the crankcase instead of venting into the air!
And if you think your pcv is helping your rings seal and giving you less blow. You are misstaken.
Steve K.
Chris,
If you ever tore down a engine and it was full of sludge it was not due to not having a pcv valve.
I have been building these Buicks since '86. I've been in this field since '74
I'm not a beginner in this field. What are your leak down readings, what oil are you using and what oil did you use when you built the engine?
Steve K.
If you ever tore down a engine and it was full of sludge it was not due to not having a pcv valve.
I have been building these Buicks since '86. I've been in this field since '74
I'm not a beginner in this field. What are your leak down readings, what oil are you using and what oil did you use when you built the engine?
Steve K.
So now you are saying that on a street driven car as well as race cars no PCV is needed?
Look I have been involved with racing since I was able to drive. I have built many fast cars with the last running bottom 8's@ over 160. I didn't fall off the truck yesterday.
PCV is needed on street driven cars.
I never said the PCV pulled a vac under boost.
I said that an evac system did and it DOES help keep rings seeled!
The first post was asking a solution to this problem. The PCV isn't the problem, somthing is causing it to suck oil or mist or what the hell ever ends up in peoples upper intakes.
Scrapping the whole system isn't the answer.
Look I have been involved with racing since I was able to drive. I have built many fast cars with the last running bottom 8's@ over 160. I didn't fall off the truck yesterday.
PCV is needed on street driven cars.
I never said the PCV pulled a vac under boost.
I said that an evac system did and it DOES help keep rings seeled!
The first post was asking a solution to this problem. The PCV isn't the problem, somthing is causing it to suck oil or mist or what the hell ever ends up in peoples upper intakes.
Scrapping the whole system isn't the answer.
Chris Taylor
Got 6?
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Steve K,
The leak down results was less that 1% leak down on all six cylinders on the above mentioned engine. This is not bad considering a fresh street engine should have around 5-8% leak down. I have a race engine at this time that has two seasons on it with less than 2% leak down per cylinder.
There is a difference in dirty oil sludge and the sludge caused by crank case gasses and condensation. I am talking about the mess in the engine that is caused when the crank case gases and condition are not removed via the PCV valve. This in not to be mistaken for oil deposits, coke, improper oil temperatures, paraffin deposits etc.. I don’t use PCV valves on all of my race engines but due to daily condition changes, I think it is wise to use a PCV valve in a daily or seasonal driver.
The oil I am using in the above mentioned engine is Mobil 10w30. I will be changing to Mobil 1 around 5,000 miles. For what it is worth I also use Kendal racing oil, Union 76 racing oil, Royal Purple and others. HTH
The leak down results was less that 1% leak down on all six cylinders on the above mentioned engine. This is not bad considering a fresh street engine should have around 5-8% leak down. I have a race engine at this time that has two seasons on it with less than 2% leak down per cylinder.
There is a difference in dirty oil sludge and the sludge caused by crank case gasses and condensation. I am talking about the mess in the engine that is caused when the crank case gases and condition are not removed via the PCV valve. This in not to be mistaken for oil deposits, coke, improper oil temperatures, paraffin deposits etc.. I don’t use PCV valves on all of my race engines but due to daily condition changes, I think it is wise to use a PCV valve in a daily or seasonal driver.
The oil I am using in the above mentioned engine is Mobil 10w30. I will be changing to Mobil 1 around 5,000 miles. For what it is worth I also use Kendal racing oil, Union 76 racing oil, Royal Purple and others. HTH
_______________________________________________
Precisely! Great work thus far!
Gotta find the cause(s)...then the "cure" reveals itself!
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Steady on the case, guys...let's keep the thread active & alive until it's whipped and in the reference file!
CLEAN86,
What race car do you know of that has a pcv valve?
Why is a pcv valve needed on a street driven car?
What did they do before pcv valves? Pre 1974
Why is a pcv valve on a engine?
I know the pcv is not the problem with these cars. But I see all the responces and I think they are looking at the wrong thing.
There are many reasons why someone could get oil in the intake. Each motor could have a differant problem, from oil seeping past the compressor wheel to a bad engine to using synthetic oil in a fresh rebuild etc.....
Steve K.
What race car do you know of that has a pcv valve?
Why is a pcv valve needed on a street driven car?
What did they do before pcv valves? Pre 1974
Why is a pcv valve on a engine?
I know the pcv is not the problem with these cars. But I see all the responces and I think they are looking at the wrong thing.
There are many reasons why someone could get oil in the intake. Each motor could have a differant problem, from oil seeping past the compressor wheel to a bad engine to using synthetic oil in a fresh rebuild etc.....
Steve K.
Mease Performance
Performance Fabrication/Supporting Vendor
- Joined
- Nov 22, 2002
- Messages
- 688
wow, I'm stayin out of this one!
tell him how its done in Jersey steve
Keith Mease
Owner, MPE Racing Fabrication
tell him how its done in Jersey steve
Keith Mease
Owner, MPE Racing Fabrication
Chris,
Your leak down looks good. But to realy check it you should remove the rockers. Start the leak down w/piston at top then rotate the engine to bring the piston to the bottom and check readings.
As for sludge and stuff I have pulled Buicks apart with 180,000+ on them and they are still very clean for their age. Trust me I have bad memories of pulling motors apart in the '70s scraping crud for hours. I dont like to think of that!
Steve K.
Your leak down looks good. But to realy check it you should remove the rockers. Start the leak down w/piston at top then rotate the engine to bring the piston to the bottom and check readings.
As for sludge and stuff I have pulled Buicks apart with 180,000+ on them and they are still very clean for their age. Trust me I have bad memories of pulling motors apart in the '70s scraping crud for hours. I dont like to think of that!
Steve K.
I'm not blameing the pcv valve, as I know it works correctly, I'm just trying to find out why this happens. Obviously, with so many people experiencing this problem there is likely root cause.
In my case, I know that the only oil that enters my intake comes from the pcv. Period. I'm just trying to find out exactly how this happens, becase understanding this will lead to a cure.
In my case, I know that the only oil that enters my intake comes from the pcv. Period. I'm just trying to find out exactly how this happens, becase understanding this will lead to a cure.
