Performance & Maintenance Engine, forced induction, intakes, exhausts, torque converters, transmissions, etc.

2JZGTE Strangest boost leak ever. Is this bad?

Thread Tools
 
Search this Thread
 
Old 10-15-10, 02:16 PM
  #16  
slappy96
Lead Lap
Thread Starter
 
slappy96's Avatar
 
Join Date: Oct 2006
Location: Nebraska
Posts: 468
Likes: 0
Received 1 Like on 1 Post
Default

Same results with valve cover and PCV hose disconnected and plugged. I'm going to do a compression test next. If compression comes back good then it's got to be somewhat normal. Right? Ali, I get what you are saying I'm just having a hard time understanding how it could hold boost perfectly if air can escape through the oil return. Will this not happen when it's running, but only at rest?
Old 10-15-10, 02:32 PM
  #17  
stockhatch
Lexus Champion
iTrader: (12)
 
stockhatch's Avatar
 
Join Date: May 2009
Location: Raleigh NC
Posts: 2,544
Received 5 Likes on 5 Posts
Default

No, it doesn't behave the same way when running. When its running, there will be vacuum, or "0" at the hose running from the valve cover to the turbo intake piping. The PCV will be shut in boost conditions, so no boost will feed in from there. At that point, it is pretty much just ring blowby getting to the crankcase, but that vc hose will allow the pressure a place to escape and equalize.
Old 10-15-10, 06:14 PM
  #18  
Ali SC3
Lexus Champion

iTrader: (10)
 
Ali SC3's Avatar
 
Join Date: Oct 2007
Location: CO
Posts: 10,761
Received 438 Likes on 368 Posts
Default

Originally Posted by slappy96
Same results with valve cover and PCV hose disconnected and plugged. I'm going to do a compression test next. If compression comes back good then it's got to be somewhat normal. Right? Ali, I get what you are saying I'm just having a hard time understanding how it could hold boost perfectly if air can escape through the oil return. Will this not happen when it's running, but only at rest?
A compression test could be helpful at this point, with the pcv and cc disconnected i don't see why any boost is getting in there. Ive never done this test you are doing so a little unsure if its normal, where exactly are you feeding in the pressure again?

normally the crank case should be run to the turbo intake pipe which never sees boost, so pressure can't build up in the crank case from the turbo boosting and even if it does (internally past rings/ turbo seals? etc.) it will escape through that cc fitting. you should never plug the cc fitting on the valvecover, if you do even the slightest leak could allow pressure to build up in the crank case and give your symptoms.

the problem is with your can method is you may be putting in the psi before the turbo, so the crank case fitting will now see boost which it isn't supposed to do before the turbo.
so ideally, you need to remove the crank case hose and plug the intake side, but leave the valvecover side open to the air to vent off any pressure. you can also leave the pcv connected to the intake manifold, it will shut under boost 100%. this way if you are still experiencing any leaks at the return with the crank case open, something is leaking significantly.

If the engine is running fine I wouldn't be concerned if its not leaking anything while running. if the crank case was pressurized while running it will 100% leak oil out of the return line fitting you are saying leaks when you pressure test the system.
Old 10-16-10, 10:48 AM
  #19  
slappy96
Lead Lap
Thread Starter
 
slappy96's Avatar
 
Join Date: Oct 2006
Location: Nebraska
Posts: 468
Likes: 0
Received 1 Like on 1 Post
Default

Thank you everyone for your help. I've got good compression across all cylinders and have finally gotten sequential operating. Car feels really good with a minor caveat (starting a new thread on this).

I don't think the "boost leak" I found is an issue on a running engine.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
CircuitMS
Maintenance
2
06-17-14 01:34 PM
mindf
Wheels, Tires & Brakes Forum
2
07-31-13 11:05 PM
1NSIGHT
Performance & Maintenance
1
06-07-13 12:19 PM
SuicidnS13
Suspension and Brakes
2
09-29-11 11:55 PM
indypwr
Performance & Maintenance
8
03-30-05 02:31 PM



Quick Reply: 2JZGTE Strangest boost leak ever. Is this bad?



All times are GMT -7. The time now is 03:02 PM.