Fi Crankcase Pressure
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Has anyone read the 350Z Q&A article in the new issue of Nissan Sport yet?
Part of the article says:
"While the VQ series engine is great at making power and torque and is very reliable, when FI is applied to it, the PCV system may not handle the increased crankcase pressure. After speaking with Nissan North America about this concern, I learned that there may not be sufficient flow through the PCV valve to handle the increase in crankcase pressure. What was recommended to me was to use a PCV valve with Nissan part number 11810-F0511. This is a valve that was used in the older L-series of engine in the original Z car lineup....This will help to make sure the pressure in the crankcase stays low."
Also says you will need to use a larger threaded fitting to adapt the valve to fit.
Has anyone else heard of this?
Sounds pretty interesting. I'm not a mechanic but I wonder if that is what could be causing bent rods and such.
Part of the article says:
"While the VQ series engine is great at making power and torque and is very reliable, when FI is applied to it, the PCV system may not handle the increased crankcase pressure. After speaking with Nissan North America about this concern, I learned that there may not be sufficient flow through the PCV valve to handle the increase in crankcase pressure. What was recommended to me was to use a PCV valve with Nissan part number 11810-F0511. This is a valve that was used in the older L-series of engine in the original Z car lineup....This will help to make sure the pressure in the crankcase stays low."
Also says you will need to use a larger threaded fitting to adapt the valve to fit.
Has anyone else heard of this?
Sounds pretty interesting. I'm not a mechanic but I wonder if that is what could be causing bent rods and such.
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Always a good idea to CONTINUOUSLY measure the WOT crankcase psi to watch the rings as the blowby increases and increases and increases with each stress cycle.
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Originally Posted by Q45tech
Always a good idea to CONTINUOUSLY measure the WOT crankcase psi to watch the rings as the blowby increases and increases and increases with each stress cycle.
I just drilled holes in the case to help equalize the pressure.
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While I was putting my engine back in after the TT install one of the engine straps broke my PCV valve so I used one my friend had laying around from an older Q45. I wounder if this one is bigger then the Q45 one.
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necrobump..
i have a built engine w a single pt6266.. im having issues w what i believe is crankcase pressure.. i get oil leaks out of my dipstick ( sounds like the clap lol) when i get into high boost.. and the oil burns and smells ..
initially we found that the dipstick seal was compromised and oil was overfilled..
but i think im still getting some smell and leak when i get on it and bet up into real boost.. and my pump gas map peaks out at like 24 psi.
anything to add on this? Hoping someone will pick this up in the todays post section..
i have a built engine w a single pt6266.. im having issues w what i believe is crankcase pressure.. i get oil leaks out of my dipstick ( sounds like the clap lol) when i get into high boost.. and the oil burns and smells ..
initially we found that the dipstick seal was compromised and oil was overfilled..
but i think im still getting some smell and leak when i get on it and bet up into real boost.. and my pump gas map peaks out at like 24 psi.
anything to add on this? Hoping someone will pick this up in the todays post section..
Last edited by bmccann101; 05-14-2013 at 03:15 PM.
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i thought most in the FI community were drilling out the PCV valve and driver side valve cover and either A. routing them both to a catch can with a breather or drilling out both PCV valve and driver side valve cover and just installing large breathers on both? my motor let go before i could test either options. more info would be great. ive always felt that this topic was 1 that is left unclear alot. most threads started on this leave no "this is the way to do it correctly"
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I concur..
I dont really want to vent to atmosphere unless its heading out the back of my car..smells bad enuff already Lol. so i steered away from a vented catch can..i actually dont even have a catch can yet..i ran out of time and room..
I dont really want to vent to atmosphere unless its heading out the back of my car..smells bad enuff already Lol. so i steered away from a vented catch can..i actually dont even have a catch can yet..i ran out of time and room..
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Saw some pics of it, and it really came together AWESOME so cheers to that!
BUT back on topic.
All you need to do is run lines from your vents (IE the driver side rear, and the drilled out PCV) and use a special kind of check valve. I believe the valve my friend used on his car is for catalytic converters... I had it favorited on my other computer, but that thing died when I spilled water on it (sad day).
Take a look around the supra forums, they typically are the ones who do it. I personally kind of like the smell of oil, and don't mind venting to atmosphere.
Ill pm you with a thread that shows the kind of fitting you put in your exhaust. Real simple and easy to do, works great.
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Ya, they make those weld in vents that go in the exhaust.
You are probably still pushing oil out of the dipstick. I would vent the valve covers asap if it was me before your front seal blows out of the car like mine did when I had a kink in the vent hoses. I always have that smell from my breathers and I do get some oil residue coming out of my dipstick even with proper venting. The seal on the dipstick just isn't that great.
You are probably still pushing oil out of the dipstick. I would vent the valve covers asap if it was me before your front seal blows out of the car like mine did when I had a kink in the vent hoses. I always have that smell from my breathers and I do get some oil residue coming out of my dipstick even with proper venting. The seal on the dipstick just isn't that great.
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Ill take a moment and compliment how gorgeous your rear end is... on your car...
Saw some pics of it, and it really came together AWESOME so cheers to that!
BUT back on topic.
All you need to do is run lines from your vents (IE the driver side rear, and the drilled out PCV) and use a special kind of check valve. I believe the valve my friend used on his car is for catalytic converters... I had it favorited on my other computer, but that thing died when I spilled water on it (sad day).
Take a look around the supra forums, they typically are the ones who do it. I personally kind of like the smell of oil, and don't mind venting to atmosphere.
Ill pm you with a thread that shows the kind of fitting you put in your exhaust. Real simple and easy to do, works great.
Saw some pics of it, and it really came together AWESOME so cheers to that!
BUT back on topic.
All you need to do is run lines from your vents (IE the driver side rear, and the drilled out PCV) and use a special kind of check valve. I believe the valve my friend used on his car is for catalytic converters... I had it favorited on my other computer, but that thing died when I spilled water on it (sad day).
Take a look around the supra forums, they typically are the ones who do it. I personally kind of like the smell of oil, and don't mind venting to atmosphere.
Ill pm you with a thread that shows the kind of fitting you put in your exhaust. Real simple and easy to do, works great.
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Besides that, I think there is some kind of vapor that actually directly robs hp, can't remember what the name is but I'm pretty sure it comes from the crank case. Someone correct me if they know.