Pvc Valve - Too Much Pressure In Crankcase

[zayd687]

Hi Guys,

ive got an issue with my modded ba xt turbo. when under boost the dipstick comes out and squirts oil.

I re routed the air breather on the rocket cover to a catch can and ATM its venting to atmosphere till I find the problem.

The pcv valve is located on the back of the rocket cover which has a hose that goes into the intake manifold.

im not sure what to do, ive cleaned out the pcv valve with wd40 so theres no sticky buildup and put it back in yet under boost ( sump pressurising )

the dipstick still comes out. im not sure whether the pcv valve is working properly or not, I have cleaned it and tested both ways by blowing in the valve and air comes out on one way which is the way it gets vacummned into the intake manifold.

is there anyway I can re-route or perhaps change the pcv or something so I can decrease pressure in the crankcase?.

I took the hose from the intake manifold to the pcv off, blocked it and the car shut down.

I want to know what is a possible way of venting the crankcase pressure as im guessing theres too much or maybe the pcv valve is shot im not too sure.

any ideas what I can do or re route?

im stuck with ideas :(

p.s the dipstick was pretty loose, my fathers Expensive Daewoo had a better seal on it on his dipstick then my one, its so flimsy any pressure could pop it up. O ring is in take. I might buy a new dipstick. any ideas really appreciated

Edited 16/02/11 03:23 PM by zayd687

[YOB POM]

Does the pcv valve rattle? If it does it should be ok.

Cheap enough to replace any way, however that amount of crankcase pressure sounds like a more serious problem.Do a compression test as it sounds like it could be blowby pass your rings,it doesn't take much wear with forced induction.

John.

[GOLDIE]

that's +1 for rings that is the way it could be biulding up that much pressure.

Ian

[zayd687]

nah rings, it would be blowing out smoke on all speeds, more oil consumed etc,

not sure, the pvc valve rattles. onli thing I can think of is putting a bigger one or replacing the stock one, if that's not it, leave it and drive it till it dies lol

not sure .. if all else fails ill do a compression test on her and see what she comes back with?

do mechanics do this or can I do this test at home?

Edited 17/02/11 10:30 AM by RHR
No need to quote above post. USE FAST REPLY

[GOLDIE]

it may not burn oil if the compression rings are gone.to blow the dipstick out there has to be alot of pressure in the crank case that must come from the cylinders some where.

I would be doing a compression test.

Unlessthe breather for the crankcase is fitted after the turbo and is being pressurised by the turbo it should be before the the turbo.

The pcv goes after the throttle body so it has vacum on it to drew the crank case fumes out.

Ian

[zayd687]

hi Ian

thankyou for the reply.

I will be doing a compression test on saturday, do you have an idea what the original specs or what the compression of the cylinders should be so I can compare when I get the readings?.

I've attached a pic of the xt engine of what ive done its not my engine but similiar. I havent done anything with the pvc yet.

its not the exact pic.. but the front breather is the one I vented to atmosphere through a catchcan.

I havent touched the pvc valve at the back yet, I thought id replace it just incase that's the problem and do a compression test and see what I come up with.

Edited 17/02/11 10:31 AM by RHR
No need to quote above post. USE FAST REPLY

[GOLDIE]

at least 150 psi.

looking at the pic the hose will be ok so that is not the issue.

Ian

[turbotrana]

You can do a compression test but probably a leak down test would give you more of an idea of ring condition.

You are barking up the wrong tree with the PCV valve. THis only operates under vacumn. Its the other breather on the back of the rocker that leads into the inlet that vents crankcase pressure under load.

When the engine is worn a bit, the small hole cant cope with the blowby so it pushes the dipstick out. What I have down in the past is Tig weld a 1" fitting on the nonpcv breather and then connect this to the inlet tract. Inbetween this I have also built an oil/air seperator to stop any oil getting into the inlet.

Main thing is to leave the PCV in place. THis is not your problem.

Although your engine is worn, as long as it is not blowing smoke when warmed up or fouling the plugs it will still go on forever. But you will have to modify the breather system to cope with more blowby.

[IBOO57]

Why do people say rocket cover

[zayd687]

You can do a compression test but probably a leak down test would give you more of an idea of ring condition.

You are barking up the wrong tree with the PCV valve. THis only operates under vacumn. Its the other breather on the back of the rocker that leads into the inlet that vents crankcase pressure under load.

When the engine is worn a bit, the small hole cant cope with the blowby so it pushes the dipstick out. What I have down in the past is Tig weld a 1" fitting on the nonpcv breather and then connect this to the inlet tract. Inbetween this I have also built an oil/air seperator to stop any oil getting into the inlet.

Main thing is to leave the PCV in place. THis is not your problem.

Although your engine is worn, as long as it is not blowing smoke when warmed up or fouling the plugs it will still go on forever. But you will have to modify the breather system to cope with more blowby.

so refering to the picture I posted there is another breather on the back of the rocket cover??????

would you by chance have any pictures of the setup of what you've done it'd be great to get a better understanding of it as it could solve the problem.

so should I do the compression test and post the results? or look into how to do a leak test which I have no clue what it is without further investigating it

pictures of your setup would be great!