breather cap

**JayTA98** · 05-17-2011, 07:54 PM

I'm looking for someone to elaborate some about this topic.
Will this mod help with oil leaks since is reducing pressure?
Is this a plug and play mod? or does the PCM needs to be tuned or something?

Will this mess up my idle?

does the PCV system needs to be deleted?
Any pros and cons of doing this?

Thanks.

**oldmano2z** · 05-17-2011, 08:13 PM

I just put an ls6 in my 02 and vented my oil cap also its out in the atmosphere now i think cali emissions dont allow this.some people also state that it effects the tuning of the fresh air tuning at the throttle body but my tuner says its a moot point and the more the venting of the crankcase the better i dont know the science involved i just know it works. i have less blow by. and less preasure which means less stress on seals old school on new tech

**oldmano2z** · 05-17-2011, 08:17 PM

i also run a cheap air/oil separater on my pcv lines and still run pcv.

**JayTA98** · 05-18-2011, 01:42 PM

I think I was able to fabricate what you explained Oldmao2z.

I bought a small breather filter.

I marked the center of my oil cap and drilled a small pilot hole.

I used a step bit to make the hole big enough to fit the breather grommet. I drilled from top and bottom of the oil cap to keep it even.

I measure the fitment of the grommet. I did made to the top hole slightly bigger than the bottom one so the breather filter sits flush with the top of the oil cap and fits more tight.

oil breather installed.

I have to give Oldmano2z credit for this one. thanks for the idea.

**98maro** · 05-18-2011, 01:51 PM

i always wanted to do that.. good job man.. but i cabt do it cuz the strut tower brace is on the way

so is that a benefit for the motor??

**JayTA98** · 05-18-2011, 01:52 PM

Originally Posted by 98maro

i always wanted to do that.. good job man.. but i cabt do it cuz the strut tower brace is on the way

so is that a benefit for the motor??

I guess i got lucky with mine. I was explained that this might help some with my oil leaks because it lowers the pressure.
I heard that you can delete the PCV but im not sure in all the details.

**98maro** · 05-18-2011, 03:03 PM

I'll see if I can do it to mine.
The Pcv gas to be deleted?? Or with putting the breather on won't mess up anything??
I notice my car burns oil. Doesn't leak. I wonder if that would help lol.

That makes the engine run cooler right?

I found those at the store for like $15 I should get one.
It Looks good IMO

**JayTA98** · 05-18-2011, 04:29 PM

Originally Posted by 98maro

I'll see if I can do it to mine.
The Pcv gas to be deleted?? Or with putting the breather on won't mess up anything??
I notice my car burns oil. Doesn't leak. I wonder if that would help lol.

That makes the engine run cooler right?

I found those at the store for like $15 I should get one.
It Looks good IMO

I haven't deleted the PCV. not sure if it will help your case. I dont think it will keep the engine cooler.

**Firebirdjones** · 05-18-2011, 05:04 PM

I bought a breather setup that is made to screw into the valve cover and replace the factory oil cap. Wasn't that expensive.

Yes it does help to eleviate crank case pressures, and you can still keep the factory PCV setup. Actually I recommend you keep it, because it actually has a small vacuum pull on it to help with crank case pressures. If you want to eliminate it,,,then I would recommend you run a breather there as well that could be "T"d into the factory PCV hoses. Because without the PCV, one breather on one cover wouldn't be enough.

Like oldman says, it's old technoligy on a new car.

**JayTA98** · 05-18-2011, 05:11 PM

Originally Posted by Firebirdjones

I bought a breather setup that is made to screw into the valve cover and replace the factory oil cap. Wasn't that expensive.

Yes it does help to eleviate crank case pressures, and you can still keep the factory PCV setup. Actually I recommend you keep it, because it actually has a small vacuum pull on it to help with crank case pressures. If you want to eliminate it,,,then I would recommend you run a breather there as well that could be "T"d into the factory PCV hoses. Because without the PCV, one breather on one cover wouldn't be enough.

Like oldman says, it's old technoligy on a new car.

thanks for the input FBJ. So the main thing is that each valve cover would need a breather? so i will just need to put the "T" were the PCV valve is? does the hoses still connect to the same locations? like from the "T" to the catch can and from catch can to TB? Will the breather on the PCV setup side get oily?(thats why I have the catch can). Will my idle stay the same?

**Firebirdjones** · 05-18-2011, 05:34 PM

Originally Posted by JayTA98

thanks for the input FBJ. So the main thing is that each valve cover would need a breather? so i will just need to put the "T" were the PCV valve is? does the hoses still connect to the same locations? like from the "T" to the catch can and from catch can to TB? Will the breather on the PCV setup side get oily?(thats why I have the catch can). Will my idle stay the same?

Lets see, I'll answer this best I can,,

I would only do a second breather if you wanted to eliminate the PCV all together. Meaning I wouldn't simply cap off the PCV holes at the back of the valve covers. I would at least use one (probably driver side) and run a hose with a remote breather mounted somewhere, since you'll already have a breather on the pass side cover at the oil fill.

If you follow your PCV system, (and this may have changed during production) you'll probably find it's just like both of mine. The PCV actually runs from both rear valve covers, then comes into a "T". Then that single line runs up the passenger side of the engine to your "inline" PCV valve right before it plugs in behind the throttle body.

The catch can is used to catch the oil from the PCV setup,,,because the engine is drawing a vacuum on it. If you eliminate the PCV completely and just run a pair of breathers,,,then there is no need for a catch can. You are venting to atmostphere so oil vapor in the engine is no longer a concern.
Something the EPA doesn't like, which is why PCV's were incorporated as early as 68 on GM cars. Before that it was breathers and a dump tube that came out of the crank case,,,right to atmosphere. Easy and simple.

None of this should affect your idle. I had my 4th gens both ways back and forth experimenting, I never noticed any changes in my idle trims while scanning, and my idle is rock solid. Some claim it may skew AFR's, but I've never seen it myself on my own cars.

**JayTA98** · 05-18-2011, 05:44 PM

Originally Posted by Firebirdjones

Lets see, I'll answer this best I can,,

I would only do a second breather if you wanted to eliminate the PCV all together. Meaning I wouldn't simply cap off the PCV holes at the back of the valve covers. I would at least use one (probably driver side) and run a hose with a remote breather mounted somewhere, since you'll already have a breather on the pass side cover at the oil fill.

If you follow your PCV system, (and this may have changed during production) you'll probably find it's just like both of mine. The PCV actually runs from both rear valve covers, then comes into a "T". Then that single line runs up the passenger side of the engine to your "inline" PCV valve right before it plugs in behind the throttle body.

The catch can is used to catch the oil from the PCV setup,,,because the engine is drawing a vacuum on it. If you eliminate the PCV completely and just run a pair of breathers,,,then there is no need for a catch can. You are venting to atmostphere so oil vapor in the engine is no longer a concern.
Something the EPA doesn't like, which is why PCV's were incorporated as early as 68 on GM cars. Before that it was breathers and a dump tube that came out of the crank case,,,right to atmosphere. Easy and simple.

None of this should affect your idle. I had my 4th gens both ways back and forth experimenting, I never noticed any changes in my idle trims while scanning, and my idle is rock solid. Some claim it may skew AFR's, but I've never seen it myself on my own cars.

wow thanks for the history lesson in the PCV setups. So if i decide to run 2 breathers then could just eliminate the PCV system. i will need to run a hose from the drivers side valve cover with a "T with breather" to the TB, correct? or no connection to TB? I will not need to Y off to the rear of the passenger side no more, correct? or can I just put the breather on the driver's side valve cover grommet?

Sorry for the questions but this seems very interesting subject.

**Firebirdjones** · 05-18-2011, 05:54 PM

Originally Posted by JayTA98

wow thanks for the history lesson in the PCV setups. So if i decide to run 2 breathers then could just eliminate the PCV system. i will need to run a hose from the drivers side valve cover with a "T with breather" to the TB, correct? or no connection to TB? I will not need to Y off to the rear of the passenger side no more, correct?

Sorry for the questions but this seems very interesting subject.

If you want to run 2 breathers and eliminate the PCV, you can run a hose from the driver side valve cover and just stick a remote breather in the end of the hose and mount it somewhere. You wouldn't run it to the throttle body connection anymore, just cap that off. You won't need the Y connection anymore either, just make sure you cap off the passenger side rear cover hole where that "T" hose also comes from.

If you want to get fancy, since you are now venting to atmosphere, you can put a small oil catch system on the hose of the rear driver side cover to catch any oil vapor that might escape, to keep the engine bay cleaner. Most times that's not a problem though unless you have alot of blowby.

**JayTA98** · 05-18-2011, 05:58 PM

Originally Posted by Firebirdjones

If you want to run 2 breathers and eliminate the PCV, you can run a hose from the driver side valve cover and just stick a remote breather in the end of the hose and mount it somewhere. You wouldn't run it to the throttle body connection anymore, just cap that off. You won't need the Y connection anymore either, just make sure you cap off the passenger side rear cover hole where that "T" hose also comes from.

If you want to get fancy, since you are now venting to atmosphere, you can put a small oil catch system on the hose of the rear driver side cover to catch any oil vapor that might escape, to keep the engine bay cleaner. Most times that's not a problem though unless you have alot of blowby.

thank you. I might look into getting this done next week. I might still use my catch can with that setup you mentioned. I will need to modify it.

**Firebirdjones** · 05-18-2011, 06:04 PM

Originally Posted by JayTA98

thank you. I might look into getting this done next week. I might still use my catch can with that setup you mentioned. I will need to modify it.

Ya if it's a large catch can, you may have to run a pretty long hose off the back of the driver side valve cover just to get it to a place where you can mount it easily.

**TA98** · 05-18-2011, 07:03 PM

[IMG]

[/IMG] Couldve done that too. Simple and very clean looking. I did it just for looks.

**Firebirdjones** · 05-18-2011, 07:27 PM

Yep that's what we are talking about, one there,,,and then eliminate the PCV and run another breather off the other cover.

I have one like you are showing but mine came with a machined aluminum piece that actually screws into the cover like the factory oil cap. Then the breather pops into the top of it.

**TA98** · 05-18-2011, 07:32 PM

that one there outta the package would just fall out. I had to add a large o-ring to the top to make it stay in.

**Frost** · 05-19-2011, 06:46 AM

I don't like a breather for a street car without a good strong vacuum pulling from several other places because it makes your A/C stink like burnt oil. With a good enough draw on the crankcase, this is minimized and relegated to just after a WOT pull.

**JayTA98** · 05-19-2011, 06:57 AM

Originally Posted by Firebirdjones

Yep that's what we are talking about, one there,,,and then eliminate the PCV and run another breather off the other cover.

I have one like you are showing but mine came with a machined aluminum piece that actually screws into the cover like the factory oil cap. Then the breather pops into the top of it.

no clearance issues with the hood on yours?