Thread: LIM PCV mod vs breather

I've searched around but I can't find any hard facts to point to.

What is the actual disadvantage of using a valve cover breather vs keeping stock pcv working or coming up with a fix yourself? I know the MAF needs a slight retune, but I'm wondering if I should have my LIM modded for use with stock pcv or just run the damn breather. I'm new to the 3800, and s/c motors, so I'm pretty confused. Any help would be appreciated.

Long-term reliability is high priority for me so I'm assuming I'd want the pcv working how it should?

you dont need a breather unless your turbo or have a ic thats blocking off the pcv passage ways

Originally Posted by Scottydoggs

you dont need a breather unless your turbo or have a ic thats blocking off the pcv passage ways

Ok thanks. I picked up the ZZP IC on their black friday sale and it says stock pcv function only with their revised LIM. That caveat really confused me...

if you got their lim your set, or make your own little groove in the lim.

do you happen to know what the difference between their two LIM options? is it this groove?

I did get their LIM but I didn't order the option for full stack only. I got the regular gen3 ported. at the time I didn't think I would be getting IC so quickly

thanks again man

from what ive seen they just grind a groove from the pcv hole in the lim to the hole in the ic.

Originally Posted by SgtMarshal

the only other thing they might do in addition to the groove is open up the inlet more. with an intercooler sitting on top of the lim, the lim inlet can be opened up more than normal because it will have something to seal the vacuum.

Pretty sure that zzp Tig welds some aluminum in on the gen 5 version so there is room to run the small groove. Also have to drill the hole in the back because it doesn't line up with Intercooler hole.

I assume there is still a post on how to get the PCV to function I did several years back.

Yup it's a sticky, was just reading it the other day.

Can you just drill a hole in the lim like the rear?

Originally Posted by Swiggles

Yup it's a sticky, was just reading it the other day.

Can you just drill a hole in the lim like the rear?

Can't drill a hole in the front, the intercooler core is in the way.

But with the zzp ic isn't the front functional with the groove cut in the lim? If so why can't you just drill a small hole in the lim where the hole in the zzp core is?

The groove takes the vacuum out where it can go through the intercooler without hitting the core.

There isn't vacuum available under the groove, your above intake air cylinder 1 at that point.

Or you can tap the manifold and run a hose to the tb on the inside of the butterfly that's what I did with my fs ic setup works great. But my rear pcv was already functional,

Note: WBStore & ZZP's Intercoolers don't line up with the rear port for PCV. You have to drill an hole in LIM to get it to work. Front port doesn't line up at all and you need zzp's grooved manifold or an external port.

Lots of pictures and details here.

http://www.grandprixforums.net/threa...cover-breather!

I Also have an adapter that has the PCV port and fitting in it.

https://www.ebay.com/itm/111478776645

Originally Posted by sseilmnop

The groove takes the vacuum out where it can go through the intercooler without hitting the core.

There isn't vacuum available under the groove, your above intake air cylinder 1 at that point.

Thank you that's what I was wondering.

So the wbs ic front pcv will work with a zzp groved lim? Or the wbs core is too big for it to work?

Originally Posted by Swiggles

Thank you that's what I was wondering.

So the wbs ic front pcv will work with a zzp groved lim? Or the wbs core is too big for it to work?

WBStore Intercooler won't work with ZZP groove manifold. You can't make it work with it either. You most go external route.

Both Intercoolers use the same core! They are probable machined on the same machine.

the rear hole (near cyl 6 port runner) that is added outboard of the OEM PCV hole is for the supply of the crankcase air, to the PCV "tower" then to the blower inlet (only see's atmospheric and vac-never boost)
this keeps "PCV valve function" but does not keep 100% PCV SYSTEM function.

this means you have to provide a clean, air supply to the crankcase, since the front bank portion of the PCV passage is blocked off (this passage feeds fresh metered air from behind the OE maf but before the TB blade, through the TB/blower flange, through the blower case casting voids to direct it into the crankcase near cyl 1/3. from there the fresh clean metered (so it can calculate for the additional air/fuel) air circulates through the crankcase to the rear bank where it can then have all that oil laden air feed into the pcv tower and into the blower inlet.

zzp fixed the fresh air side by adding a small groove in the LIM as well as a fresh air passage through the core plates. this usually requires a welded/machined LIM with both the PCV valve hole (rear bank) as well as the front channel.

the problem is tthat the small channel is not large enough to feed the proper volume of air required, so partial crankcase vac can and still does happen, accelerating the oil contamination due to blowby/seal sucking anytime the PCV valve tries to go to its "high flow" position at steady cruise.

on top of that problem is the folks who use too much rtv and plug the passage before they ever even start the engine.

and on top of that is that mare than half the full function zzp cores ive pulled apart have had multiple internal crankcase to manifold/breather vac leaks from improper rtv application to the core plates upon assembly.

for a std PCV valve function core, I just run a hose to the front VC from behind the maf but in front of the TB blade for a metered fresh air supply.
a breather is really the only option when going turbo

Ok thanks, I'll be putting a barb in the lim then

Originally Posted by Turbocharged400sbc

the rear hole (near cyl 6 port runner) that is added outboard of the OEM PCV hole is for the supply of the crankcase air, to the PCV "tower" then to the blower inlet (only see's atmospheric and vac-never boost)
this keeps "PCV valve function" but does not keep 100% PCV SYSTEM function.

this means you have to provide a clean, air supply to the crankcase, since the front bank portion of the PCV passage is blocked off (this passage feeds fresh metered air from behind the OE maf but before the TB blade, through the TB/blower flange, through the blower case casting voids to direct it into the crankcase near cyl 1/3. from there the fresh clean metered (so it can calculate for the additional air/fuel) air circulates through the crankcase to the rear bank where it can then have all that oil laden air feed into the pcv tower and into the blower inlet.

zzp fixed the fresh air side by adding a small groove in the LIM as well as a fresh air passage through the core plates. this usually requires a welded/machined LIM with both the PCV valve hole (rear bank) as well as the front channel.

the problem is tthat the small channel is not large enough to feed the proper volume of air required, so partial crankcase vac can and still does happen, accelerating the oil contamination due to blowby/seal sucking anytime the PCV valve tries to go to its "high flow" position at steady cruise.

on top of that problem is the folks who use too much rtv and plug the passage before they ever even start the engine.

and on top of that is that mare than half the full function zzp cores ive pulled apart have had multiple internal crankcase to manifold/breather vac leaks from improper rtv application to the core plates upon assembly.

for a std PCV valve function core, I just run a hose to the front VC from behind the maf but in front of the TB blade for a metered fresh air supply.
a breather is really the only option when going turbo

Wow, that is 100% accurate.

My Intercoolers have same size 0.343" holes front and back through the intercooler and work in stock manifolds.

the old ford probe cores allowed for more room than the newer mazda millennia cores.

also any of you reading this running the zzp cores that are bolted together, pull your **** apart and reseal it asap, especially if you have lots of oddities to the tuning esp with idle/PT data