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3L turbo final round

BAD SVT said:
when that hose pops off, the motor sucks in a bunch of air that is unregistered by the maf, allowing it to become lean. unfortunately when it popped off, i was in full boost. triple digits if that helps u;). nuthn could save it.
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once again I must ask you to forgive my ignorance in regards to the configuration of your setup, but how did you manage to connect the lines in such a manner that boost pops them off, but results in sucking air in instead of blowing it out?

I suppose I am also curious what failed in that engine?
 
Pope said:
once again I must ask you to forgive my ignorance in regards to the configuration of your setup, but how did you manage to connect the lines in such a manner that boost pops them off, but results in sucking air in instead of blowing it out?

I suppose I am also curious what failed in that engine?
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sure. the 2.5 motor was old, and so was the vent hose. the hose i speak of is the one that covers the open nipple on the rear valvecover. it connects to the intake accordian tube. there's one as well on the front valvecover. the nipple and hose become visible when u take off the front plastic piece that has the words "2.5L DURATEC V6" on it. the hose was all swollen and stuff, and so it loosely sat on the nipple. somehow it came off while in boost, loosing all engine vacuum. and pop! smoke everywhere. after doing a compression check, i found out i chipped a piston. i'll find the thread and post it here.
***EDIT- heres the thread- http://www.contour.org/ceg-vb/showthread.php?t=14109
 
im still not sure how that would cause the engine to fail either. the valve cover breathers are routed to the turbo intake pre turbo. if the pcv is sealing correctly they engine isn't getting pressureized and it isn't going to be pulling air from the crank case through the pcv to the intake. and if I recall how the pcv system works it actuall takes air in from the valve covers and it exits through the pcv into the intake.
 
BrApple said:
im still not sure how that would cause the engine to fail either. the valve cover breathers are routed to the turbo intake pre turbo. if the pcv is sealing correctly they engine isn't getting pressureized and it isn't going to be pulling air from the crank case through the pcv to the intake. and if I recall how the pcv system works it actuall takes air in from the valve covers and it exits through the pcv into the intake.
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i dunno brian. that was my only explanation. it was the only thing amiss as i looked over the motor. if u guys think it it couldve been sumthn else, i'd luv to know.
 
BAD SVT said:
sure. the 2.5 motor was old, and so was the vent hose. the hose i speak of is the one that covers the open nipple on the rear valvecover. it connects to the intake accordian tube. there's one as well on the front valvecover. the nipple and hose become visible when u take off the front plastic piece that has the words "2.5L DURATEC V6" on it. the hose was all swollen and stuff, and so it loosely sat on the nipple. somehow it came off while in boost, loosing all engine vacuum. and pop! smoke everywhere. after doing a compression check, i found out i chipped a piston. i'll find the thread and post it here.
***EDIT- heres the thread- http://www.contour.org/ceg-vb/showthread.php?t=14109
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this is the problem I am having:

if you left the hoses connected in the factory locations, the accordion tube is pressurized during boost, therefore the vent hoses are pressurized and thereby the crankcase, which is the exact opposite of what is desired. If one of these hoses pops off during boost, the pressure would vent out of the intake resulting in less metered air entering the engine and a rich condition. Off boost, the open intake port would result in unmetered air entering the system and the possibility of a lean condition, but this should not harm the engine.

The picture links in the other thread appear to be dead, so I am not sure what I am missing by not seeing them.

What caused the engine to smoke? It sounds like only one of the hoses came off, so the other one could have been continuing to pressurize the crank-case. Was the smoke the result of oil being pushed out of the engine and burning on the exhaust? Alternatively, if the smoke was generated inside the engine, it could have been the result of crankcase pressure preventing ring seal resulting in contaminated combustion, oil consumption, and/or detonation.

If the current engine shared enough common features with the old one, your current failure could share contributing factors with the old one.

I am curious to know more.
 
Pope said:
this is the problem I am having:

if you left the hoses connected in the factory locations, the accordion tube is pressurized during boost, therefore the vent hoses are pressurized and thereby the crankcase, which is the exact opposite of what is desired. If one of these hoses pops off during boost, the pressure would vent out of the intake resulting in less metered air entering the engine and a rich condition. Off boost, the open intake port would result in unmetered air entering the system and the possibility of a lean condition, but this should not harm the engine.

The picture links in the other thread appear to be dead, so I am not sure what I am missing by not seeing them.

What caused the engine to smoke? It sounds like only one of the hoses came off, so the other one could have been continuing to pressurize the crank-case. Was the smoke the result of oil being pushed out of the engine and burning on the exhaust? Alternatively, if the smoke was generated inside the engine, it could have been the result of crankcase pressure preventing ring seal resulting in contaminated combustion, oil consumption, and/or detonation.

If the current engine shared enough common features with the old one, your current failure could share contributing factors with the old one.

I am curious to know more.
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hmm... u make good points. i thot it was the other way around. u're not missing much from the pictures in that thread. they were simply pix of the rear vent hose dislodged from the nipple. and the smoke was probably the oil burning off the exhaust, as there was oil all over the motor. honestly, i'm not sure anymore what happened. thanx a lot pope:p jk. the only difference between the last one and this one is the displacement(2.5) & the LIM. heres what one of the pistons looked like when we took it apart... of the last one that is.

DSC02871.jpg


DSC02872.jpg
 
did that piston melt, break, or dent?

based on carbon build up on the adjoining cylinders vs. the bad one, it appears that the piston was that way for some time and not something that happened suddenly, unless you cleaned that piston before the photo. No matter what, a piston in that condition will allow a lot of oil into the chamber to be burned and a lot of combustion gasses into the crankcase.


As for the current motor, how exactly are the vent tubes connected, are they completely stock or modified? What about crankcase pressurization, have you taken any steps to ensure that it is not being pressurized? I have never heard of pressure causing spun bearings, but there is a first time for everything (if nothing else can be identified as the cause).
 
Pope said:
did that piston melt, break, or dent?

based on carbon build up on the adjoining cylinders vs. the bad one, it appears that the piston was that way for some time and not something that happened suddenly, unless you cleaned that piston before the photo. No matter what, a piston in that condition will allow a lot of oil into the chamber to be burned and a lot of combustion gasses into the crankcase.


As for the current motor, how exactly are the vent tubes connected, are they completely stock or modified? What about crankcase pressurization, have you taken any steps to ensure that it is not being pressurized? I have never heard of pressure causing spun bearings, but there is a first time for everything (if nothing else can be identified as the cause).
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i dont recall vividly. but i think it got bent. that would be really really strange if that piston had been like that for a while. and no, i didnt clean it b4 taking the photo. as for the present motor, the vent hose is routed as stock; post MAF/pre-turbo. i'll get a picture. also, i've done nuthn to depressurize the crankcase. i don't think i'm the only one running this setup tho. and no one has taken any steps for that. at least not that i've heard of...:shrug:?

edit***- here's a pic. i dont know how to circle sumthn on a picture and post it. at least using photobucket anyway... its the hose on the curved turbo intake piping right after the MAF. it meets the front vent hose at a 'T' junction.

underhoodpix012.jpg
 
BAD SVT said:
i dont wanna say am getting tired of svt tours yet. cuz i dont think i am. i like these cars. little will change that. however, my luck with these cars is unbelievable. i'm about to embark on my 3rd motor project. i know turbocharged cars have to be looked after always. but dang! this motor had only 30k miles. i've put 5-6k in the last year and a half. and yet, the car has developed a knock:nonono:. this is gonna be the thread i'll be updating as i carry on with this build. this is the last one i swear to GOD! if it pops again, i turn troll. i'm going to be doing this build myself with the help of others hopefully. i've ordered my new 3L. when it gets here, i'll post pix. wish me luck. Lord knows i'll need it:).
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I know what you mean about the contour, I call mine the Detour. i love the car. but damn it has been getting outta hand over the past 4 years I've owned it. So far I've replaced the rack and pinion, installed a 36k 3L (my fault for destroying the 2.5L) while the motor was out I put a new clutch, Alternator, various sensors (nearly all of them) now a new power steering hose and a power steering pump. oh and I've also put in a used but good engine harness.
the car is nearly new. I guess I'll be keeping it for a while now since I have no car payments.
 
I had an issue with smoke out the exhaust when I was getting my turbo running. the pcv wasn't sealing and when I let off the throttle it would smoke out the exhaust. I installed a turbocoupe pcv valve and it stopped. It sealed when pressure was applied where the stock one didn't. my valve cover vents are routed to after the maf and before the turbo so that the pcv system works as it should.


also wouldn't the color of that piston indicate it was running lean? and that is most likely what caused the piston to fail ....
 
one good thing about the new 3L is the pcv is in the valve cover going to the bottom of the intake and is clamped on
 
ok, I get it now, the hose routing the way it is supplies nearly constant suction to the crankcase and pressurization is not a factor.

You original hypothesis that the hose falling off added unmetered air is correct, I was under the impression that the hose was connected post-turbo not pre-turbo.

Any chance you have a vacuum gauge on the crankcase? It is possible that the suction from the turbo inlet generated too much vacuum in the crankcase and actually pulled oil away from the bearings, which is one of the potential downfalls to crank-case vacuum pumps and your turbo is doubling as one (whether you intended it to or not). just a thought.
 
Pope said:
Any chance you have a vacuum gauge on the crankcase? It is possible that the suction from the turbo inlet generated too much vacuum in the crankcase and actually pulled oil away from the bearings, which is one of the potential downfalls to crank-case vacuum pumps and your turbo is doubling as one (whether you intended it to or not). just a thought.
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nah, i doubt it. i think the healthy-working parameters for our motors are very tight. a drift in any direction will cause it's demise.
 
BAD SVT said:
is it advisable i used the water pump on the 3l? dangerous move?
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I would use it over the 2.5, i for one couldn't even use the 2.5 pump because of the size differences in the block's "Pipe input" size. Its seriously like a half inch bigger.
 
Beans said:
I would use it over the 2.5, i for one couldn't even use the 2.5 pump because of the size differences in the block's "Pipe input" size. Its seriously like a half inch bigger.
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icysvt said:
just use the 3l one it will be just fine
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cool, thanx. does it matter tho that this motor sat for a couple years, braving the elements? any effects on the waterpump?
 
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