The PCV valve keeps blowing out of the block and the motor sprays oil everywhere. This always happens after going for a ride and I decide to boost more than 2 psi. Is that normal??? home made JYTT setup that I just got running.

 

i would have to say that is not normal:jawdrop:


of course it could be a lot of things. glue the bitch in and see if you blow out the rear main seal

 

got breathers? i dunno?

 

ttt for some tips. this is a home made turbo setup btw.

 

1) what are you using for valve cover breather(s)??

2) If you still have the stock line that goes from oil fill tube to TB, you need to remove that. Block the TB end, and add a small filter to the valve cover end, or vent to air filter.

or,
3) Get a screw on filter that replaces the oil filler cap.

crankcase has to breathe, and can't be pressurized.

ALSO, Make sure the PCV will still block airflow past it.

Take a brand new one, you can suck through it (normal) but you can't blow through it. Make sure yours will do that!!

You can get a PCV for a supercharged T Bird. Get it from ford, the parts store ones are crap.

 

Thanx, thats exactly what I needed to know. Yep, I still have that stock TB to oil filler line connected, I'll disconnect that tommorow.

 

pcv and boost don't mix.

no forced induction car should still have a pcv valve


the point to the pcv valve is to draw vacume into the engine under part throttle aceleration to help rign seal and gasket seal.

here is your problem.

with boost in your intake under full throttle the pcv is held shut by that boost as it is basicly a one way vacume check valve.

there for when under boost you have no place for the blow by in your engine to go and this builds crank case preasure until either the pcv blows out your dipstick blows out or you blow out one of the seals in the engine

IE valve cover oil pan timeing cover gasket etc.

The only way to avert this is to run a valve cover breather so that under boost the preasure has some place to go.
Or to run a vacume pump instead of a pcv as the 03 cobra and almost all factory force induction cars do..

well guess what

If you keep your pcv and put in breathers that pcv just became a vacume leak under part throttle operation beacause it can no longer build vacume in the engine because it is just sucking fresh air into the crank case through the valve cover breather.

since the crank case is not sealed you are sucking air same as if you have just left the pcv hanging out off the side of the intake you are just suckign it through your engine and putting un needed oil into your intake air charge ..
Wich is a bad thing as oil in the air charge helps induce detonation.

so in plain english .
on any forced induction car you should be running valve cover breathers and no pcv at all..

 

OOPS! Yeah, look at everything that is attached to the intake. Make sure you aren't sending boost anywhere it isn't supposed to go.

 

Re: pcv and boost don't mix.

Dean, I don't think you are being 100% realistic. How many people out there run a PCV with no problems?? - - -
I don't have any exact numbers, but I am sure there are quite a few, and I am going to *assume* that more people run a PCV than those who don't.

A PCV is really helpful for a daily driver to keep water vapor out of the crankcase. Race cars don't need them, but if it is a daily ride I think it is a good dea to keep it.

That is 100% incorrect. The PCV was deigned to ventilate the crankcase, not improve ring seal. PCV stands for "positive crankcase ventilation"

EVERY car equipped with a PCV has some form of crankcase breather filter/fresh air supply which allows atmospheric air to enter the engine. On 5.0 engines it is the tube from oil fill to TB that supplies this fresh air supply.
Older cars used a breather in the valve cover, often ducted up into the air cleaner. I can pull that hose off of my '79 F-250 and place my thumb over the hole, and it takes a few seconds for crankcase vacuum to build because I just shut off the fresh air supply. As soon as I take my thumb away, fresh air flows into the engine and any crankcase vacuum that was there goes away.

You will not build crankcase vacuum at any time if a PCV system is working properly like it was designed to.

 

my PCV valve is removed and a hose is routed from that hole to a catch can.

my oil cap is in place but the nipple on the filler is hooked up to cobra electric air pump that is activated by a 1-psi hobbs switch.

 

Can you give me some more details on the cobra air pump? Price, p/n, pictures maybe?

 

Re: Re: pcv and boost don't mix.

sorry wrong answer and yes i know what pcv stands for
I think you are confusing my saying it uses engine vacume to help ring seal and gasket seal with the idea of it actualy causeing high vacume in the crank case.


wator vapor is realy a non issue once the engine reaches operating temperature the vapor will evaporate there is not enough vapor colected in the engine to be a issue to its operation.

the only thing this will cause is slight milky deposits at the valve cover breather etc but the internal engine oil will not break down or froth from the slight amount of vapor you are refering to.

positive crankcase ventilation
yes to vent the ring seal blow by there by useing engine vacume to pull the blow by gasses out of the crankcase in order to keep the preasures from building in the crankcase and cause a gasket failure and if allowed to build YES IT DOES upset the ring seal. capping off a engines pcv with no breathers would cause excesive crank case preasure to upset the ring seal and cause the gaskets to leak from the preasure.

trust me that is WHY the pcv is there ..


the air cleaner hose you are refering to does not alow air into the crancase unles you have your air cleaner disconected or that hose unconected.

the hose actualy has some VACUME on it via the air flowing past it into the engine in the air cleaner assembly

this is the sam principle that header tube evacuation systems work on .. even though there is preasure in the header and exhaust pipes you get vacume on the fitting due to the dynamics of air passing over a open hole.

if you have a open hose and pull air pased it or even blow air passed it at a 90 degree angle in relation tot he hose you will have vacume placed in that hose it will SUCK through that hose into the closed container not leak out that hose.

here is a simple real world test for you to show this effect blow across the top of a straw in a soda and watch the soda RISE up the straw as a result of the low preasure caused at the opening of the straw by the air passing it.

that hose is there for times where you are at FULL THROTTLE and there is no real engine vacume the air rushing passed that hose into the engine will STILL pull some of crank case gases out and stop them from building in the crank case and upseting ring and gasket seal

this is the same function the hose from the oil filler neck to the throttle body on a 5.0 serves.

and just because half the world does it wrong does not make it right PERIOD

you SHOULD NOT have a pcv hooked up to any vehicle running a valve cover breather as it has just become a simple vacume leak.

 

You guys have confused the hell out of me.

I have the stock PCV with the little hole on the filler neck vented to atmosphere. Whats the problem with that? Also, i notice after shutting of the car i get a whistle sound, vaccum/pressure?

I've not had problems with either the dipstick or the pcv blowing out.

 

Okay, I can't believe I just registered on this forum just to put my two cents in, but here goes...

Many years ago (before most of us were even born) there were drive ways that had concrete only where the tires of the car went. In other words there was dirt or gravel in the middle and you straddled it when you parked your car. Why was this? Well, because of the engines. They were called "road oilers" and that is what they did...they leaked oil...a lot of it!

You could reseal an engine only to have it leak again in a year or so!

The engines had a hole in the rear of the block with a "down tube" that allowed the blow-by gasses to exit and run down past the transmission so crank case pressure was not the issue.

The problem was the blow-by gasses! They would swirl around in the crank case and mix with the oil and become very acidic which in turn caused premature failure of the seals!

When some genious finally came up with a system (PCV) to positively remove these gasses, he not only improved the life of the seals, he also increased the life of the bearings and rings and pistons etc. (He also reduced harmfull emissions by burning the blow-by gasses but that is another story!)

Prior to the PCV System, the average lift span of an engine was about 12,000 miles between overhauls.

Yes, there are some draw backs. I mean, who wants blow by gasses entering their intake manifold and causing carbon build up on their valves & throttles & runners & such, but it is a cheap system to build and it works.

The gasses are drawn into the intake manifold via the PCV Valve at one location, and fresh air is drawn in at another location through a hose or filter. The cross flow is what scavenges the gasses from the crank case!

At full throttle or under boost, the PCV Valve is closed and the crank case pressures are forced out through the fresh air source and either goes to atmosphere through your oil filler cap/filter, or is drawn into the engine via the air filter housing.

The problem that twinturbowannabe91 is having seems simple--he has his fresh air supply hose, (the hose from the oil filler location), attached to the intake pipe and is turbocharging his crank case with boost pressure.

Personally, I recommend capping the hose and installing a filler/filter or running the hose to a location where it can get fresh air without being affected by boost.

 

or he could install these in his pcv line and the outlet on the filler neck -- honda check valves

 

More info please

I dont think installing one in both would be good, under boost you have the system completely blocked... right?

 

Yes you are correct. If you have both of these check valves installed on both of the valve cover pcv lines it will completely block off the crank case under boost. However you only boost for about 15 seconds tops so i don't think you would build up to much pressure.

Now if you had one of these check valves installed thats bad also. B/c when you build boost boost will enter the crankcase making more pressure which is bad.

Basically you don't need check valves

 

What? dont you mean you DO need one, otherwise pressure is going to enter the crankcase soon as you hit boost and for the length of that time too. unless you dont have a PCV of anything like that...

 

Okay let me teach some of you noobs a lesson in the correct way to run a pcv system with a turbo car in plain simple english.

There are 4 ways to run a pcv system correctly with boost.

#1 correct way. Use one breather for the valve cover and for the other valve cover use a one way check valve attach to your pcv which is attach to your intake manifold source for vacume.

Only problem with this method is that when your boosting the crank case never has a good ring seal since fumes have to exit thru your breather.

Also I think you might get a vacume leak b/c the engine will suck from the crankcase and also thru the breather as well drawing in fresh unmetered air past the maf.

You may correct this by instead of routing the pcv valve and check vavle to intake manifold you route it before the maf meter.

#2 correct way. Put valve cover breathers better yet run a tank with a filter on it to catch the oil.

Only problem with this method is you never have a vacume source to get the better ring seal but at least your not putting pressure in the crank case.

However if your a super pimp you would run an electric air pump at all times to suck away the crankcase however the electric air pump is not strong enough to create good ring seal.

#3 correcty way. Instead of using the intake manifold as a vacume source for your two pvc lines route them to the air filter of your turbo. Your air filter is always under engine vacume and when your boosting heck your turbo is helping suck more out of the crankcase.

Only problem with this method is that your intercooler and maf will get oily over time due to crank case vapor.

#4 Super pimp correct way. Run a mechanical vacume pump. Hardcore drag cars do this to create better ring seal and yes they do gain hp.

 

Yes I meant don't run a pcv system.

And if you did run a pcv system and you had one check valve your the other pcv will build boost up and put boost in the crank case.

Unless you ran a combo of using one breather for one valve cover and also a 1 way check valve for another valve cover. But yes thats the only way the system can work with a pcv system.

As I stated earlier this method will cause the engine to suck air from the crank case as well as the breather drawing unmetered air into the engine at idle and crusing conditions. However once your boosting it does not matter since the 1 way check valve closes when you boost and you will no longer have vacume leak. To make sure you never get a vaume leak at idle and cruising conditions , instead of routing the pcv line to the intake manifold you route it before the maf to get the metered air readings.