Too much crank case psi! Any ideas?
Apr 25, 2010, 03:45 PM
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Too much crank case psi! Any ideas?
Well Just got the project done and tuned making 520whp on 93 oct. But I started to get an oil leak and by mistake did not tie down the dip stick and it shot out along with a quart of oil. Im just wondering if this is normal or is the pcv valve bad or what? this motor is brand new and fully built! So everything is mostly new. I just dont think its normal. Thanks, Mike
Apr 25, 2010, 03:59 PM
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which hose the one on the back left of valve cover or the one front right on valve cover? I have a filter on the front right one cause its actually sucking in air....
Apr 25, 2010, 04:01 PM
#4
positive crankcase pressure is due to blow by from the cylinders/piston rings.
somhow recirculate your system with a catch can, make sure if you still have PVC valves ensur they are working and if you eliminated them ensure the system is being recirculated.
somhow recirculate your system with a catch can, make sure if you still have PVC valves ensur they are working and if you eliminated them ensure the system is being recirculated.
Apr 25, 2010, 04:04 PM
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If you shot your dipstick out along with 1qt of oil something is very wrong, that's a LOT of crankcase pressure. So something is presurizing your crankcase, there are two things that build pressure in your engine:
Combustion Chambers
Turbo
Since the shortblock is new you probably aren't getting excessive blowby on your rings, cause it would need to be a lot of blowby to cause your problem. However if you re-used your PCV valve that could be the issue. The PCV valve could be stuck and allowing the turbo to pressurize your crankcase.
PCV valve is easy to check, take off the vacumme hose, unscrew the valve, hold it next to your ear and shake it. You should hear the check ball bouncing around in there. If not, then it's broke, get another one. If you do hear the ball do one more check (have a beer ready to wash your mouth out after this. Put the PCV valve to your mouth and blow into it where the vacumme hose goes. You shouldn't be able to blow at all, it should be like tring to blow through a clogged hose. If you can blow through it, it's broke, get another.
If the PCV valve checks out then you need to look elsewhere, something is leaking pressurized air into your crankcase. If you have a compression gauge I would do a full compression test (plus it's good to have baseline numbers on a new motor anyhow).
Lastly, you didn't overfill your engine with too much oil did you? Cause that will cause issues...
Combustion Chambers
Turbo
Since the shortblock is new you probably aren't getting excessive blowby on your rings, cause it would need to be a lot of blowby to cause your problem. However if you re-used your PCV valve that could be the issue. The PCV valve could be stuck and allowing the turbo to pressurize your crankcase.
PCV valve is easy to check, take off the vacumme hose, unscrew the valve, hold it next to your ear and shake it. You should hear the check ball bouncing around in there. If not, then it's broke, get another one. If you do hear the ball do one more check (have a beer ready to wash your mouth out after this. Put the PCV valve to your mouth and blow into it where the vacumme hose goes. You shouldn't be able to blow at all, it should be like tring to blow through a clogged hose. If you can blow through it, it's broke, get another.
If the PCV valve checks out then you need to look elsewhere, something is leaking pressurized air into your crankcase. If you have a compression gauge I would do a full compression test (plus it's good to have baseline numbers on a new motor anyhow).
Lastly, you didn't overfill your engine with too much oil did you? Cause that will cause issues...
Apr 25, 2010, 04:08 PM
#7
you dont have to go through all that to check to PVC valve, ,,, 1, start the engine 2, pull the vacume hose from the intake mani side 3, plug the intake side with a rubber cap so the car doesnt stall 4, and put your finger on the hose on and off you should hear the valve clicking
i think the OP built his engine, so there could be ring allignment issues, and what not,,, not being negative BUT !!
i think the OP built his engine, so there could be ring allignment issues, and what not,,, not being negative BUT !!
If you shot your dipstick out along with 1qt of oil something is very wrong, that's a LOT of crankcase pressure. So something is presurizing your crankcase, there are two things that build pressure in your engine:
Combustion Chambers
Turbo
Since the shortblock is new you probably aren't getting excessive blowby on your rings, cause it would need to be a lot of blowby to cause your problem. However if you re-used your PCV valve that could be the issue. The PCV valve could be stuck and allowing the turbo to pressurize your crankcase.
PCV valve is easy to check, take off the vacumme hose, unscrew the valve, hold it next to your ear and shake it. You should hear the check ball bouncing around in there. If not, then it's broke, get another one. If you do hear the ball do one more check (have a beer ready to wash your mouth out after this. Put the PCV valve to your mouth and blow into it where the vacumme hose goes. You shouldn't be able to blow at all, it should be like tring to blow through a clogged hose. If you can blow through it, it's broke, get another.
If the PCV valve checks out then you need to look elsewhere, something is leaking pressurized air into your crankcase. If you have a compression gauge I would do a full compression test (plus it's good to have baseline numbers on a new motor anyhow).
Lastly, you didn't overfill your engine with too much oil did you? Cause that will cause issues...
Combustion Chambers
Turbo
Since the shortblock is new you probably aren't getting excessive blowby on your rings, cause it would need to be a lot of blowby to cause your problem. However if you re-used your PCV valve that could be the issue. The PCV valve could be stuck and allowing the turbo to pressurize your crankcase.
PCV valve is easy to check, take off the vacumme hose, unscrew the valve, hold it next to your ear and shake it. You should hear the check ball bouncing around in there. If not, then it's broke, get another one. If you do hear the ball do one more check (have a beer ready to wash your mouth out after this. Put the PCV valve to your mouth and blow into it where the vacumme hose goes. You shouldn't be able to blow at all, it should be like tring to blow through a clogged hose. If you can blow through it, it's broke, get another.
If the PCV valve checks out then you need to look elsewhere, something is leaking pressurized air into your crankcase. If you have a compression gauge I would do a full compression test (plus it's good to have baseline numbers on a new motor anyhow).
Lastly, you didn't overfill your engine with too much oil did you? Cause that will cause issues...
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Apr 25, 2010, 04:44 PM
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you dont have to go through all that to check to PVC valve, ,,, 1, start the engine 2, pull the vacume hose from the intake mani side 3, plug the intake side with a rubber cap so the car doesnt stall 4, and put your finger on the hose on and off you should hear the valve clicking
i think the OP built his engine, so there could be ring allignment issues, and what not,,, not being negative BUT !!
i think the OP built his engine, so there could be ring allignment issues, and what not,,, not being negative BUT !!
) *might* do this.I personally had this issue on one of my stock shortblocks right after I cracked the ringlands but before the piston let go. If I put it on the 2 step with the hood up I could have shot the dipstick out like a mortor
. But I don't think it's his shortblock, unless it was tuned poorly and has been detonating and cracked the ringlands on one piston like mine did.Just get a new PCV valve, $14 is cheap and you don't want to run a gummed up one anyhow.
Apr 25, 2010, 05:09 PM
#13
Just recirulate your breather hose as mentioned, if your PCV valve is still OK.
Under boost, the only vent the valve cover has is the breather hose. If connected to the intake pipe (or through a catch can to the intake pipe), the vacuum created by the turbo helps scavenge the excess pressure built up in the crankcase due to loose fitting pistons, etc.
Otherwise, if you don't want to recirc your breather hose, then you need bigger vents on your crankcase.
Under boost, the only vent the valve cover has is the breather hose. If connected to the intake pipe (or through a catch can to the intake pipe), the vacuum created by the turbo helps scavenge the excess pressure built up in the crankcase due to loose fitting pistons, etc.
Otherwise, if you don't want to recirc your breather hose, then you need bigger vents on your crankcase.
Apr 25, 2010, 06:15 PM
#14
Even on a brand spanking new EVO if you pinch the hose that runs from the VC to the intake pipe you will probably blow the DS out.
If you put a filter on the VC breather and left it like that odds are its not enough of a vent for your system. Running a hose from there back to the intake pipe will sucks the pressure out of the system just as it was designed to do.
If you put a filter on the VC breather and left it like that odds are its not enough of a vent for your system. Running a hose from there back to the intake pipe will sucks the pressure out of the system just as it was designed to do.
Apr 25, 2010, 06:28 PM
#15
Evolving Member
whan i bought my evo i was told that the dipstick would blow out when i had the meth on but it shouldnt with out the meth ...not sure why, a big *** zip tie stopped it.