Why isn't this PCV/Vent setup working!
 

I'm tired of driving the car and smelling like oil, so therefor I want a working PCV system again.

If I leave the system attached as is I get pressure in my crank case that blows oil out the rear vent when i'm on higher boost (12+ psi). I've done a leakdown on the car and get anywhere between 3-5% and the compression is even (190) across the board.

When in boost the front PCV is snapped shut (pressure tested to 20+psi, no problem, no leakage) and pressure just builds so fast that I have to have more than just that rear vent for it to escape. It seems no matter what the throttle there is NO vacuum on the turbo intake hose. In fact it seems to trap the combustion gasses and compound the problem.

I want to know why there is no vacuum on that rear vent hose when I'm on the throttle....

http://www.powersquirt.com/pcv.gif

Re: Why isn't this PCV/Vent setup working!
 

Since you have no vacumn between the turbo and air filter then congrates you have free enough flowing air filter.
As vor the pcv valve you may need a catch can setup, vacumn pump, or the to supra tt pcv setups.
The latter setups were discussed in this thread https://www.homemadeturbo.com/forum/...?topic=96426.0 the supra tt pcv was towards the end of this link.
For the catch can setup https://www.homemadeturbo.com/forum/...opic=41175.100 but the pictures are gone until you get to page 3.
Good look what is your setup?
What engine in what car?

Re: Why isn't this PCV/Vent setup working!
 

The engine is a 2.5L V6 fully built Mazda KL engine with a 60-1 Turbo.

My old KLZE didn't have this problem, but I also didn't give a ---- about that motor.

I had a CDM catch can on the car for a moment but took it off because I needed to drill out the opening as it was like a 1/4 in!!! I eleminated it for now until I could solve the current issue and then it'll be restored. For now I have the rear vent going into a Gatorade bottle with some duct tape so I can keep tabs on how much oil actually blows out.

Last time I had the system connected as shown above except the rear valve cover was just vented I manged to splooge oil all over the firewall after too pulls at 14psi. So that leads me to believe pressure just wasn't escaping fast enough.

EDIT:

I've already read that smog pump thread and it definitely is on my to do list....

Re: Why isn't this PCV/Vent setup working!
 

Do you have any info on the TT Supra PCV...I just see it mentioned, but nothing more.

Re: Why isn't this PCV/Vent setup working!
 

No not completely I have not done any research on that yet.
But I'm leaning towards that setup for my twincharge d16z6 in eg setup.

Re: Why isn't this PCV/Vent setup working!
 

some people put another check valve in line with the pcv or go to a pcv from a forced induction car.
On my setup (5.0 mustang), I just vent both valve covers and the place where the pcv goes to oil separators and then to the turbo inlets.
Erich

Re: Why isn't this PCV/Vent setup working!
 

the PCV is from a boosted car...actually the Millenia S (miller cycle) so I know it can withstand the pressure and flow enough. The valve has also been pressure tested and doesn't leak.

Re: Why isn't this PCV/Vent setup working!
 

just dump all of your crank case from the valve covers into a catch can and call it a day. No use in over complicating things.

Re: Why isn't this PCV/Vent setup working!
 

I'd like to daily drive the car some more and I can't smell like an oil change when I get to work which is the reason i'm looking into this.

I could always just vent them to air, but even with it routed under the car, the vacuum created by the windows being open (no a/c) will just suck the fumes back in.

Re: Why isn't this PCV/Vent setup working!
 

no reason it shouldnt work. Maybe oil is coming from another place?

Re: Why isn't this PCV/Vent setup working!
 

That is what I was thinking, but pressure is still building up in the crank.

I double checked everywhere and its definitely oil coming out the rear vent on higher boost....

This is annoying because I'm headed to the rollers tomorrow and would like to break the 540whp record for a KL engine....

Re: Why isn't this PCV/Vent setup working!
 

Well at 15psi the car made 400.8 whp and 407ft/lb of torque which I'm happy with, but there is still a major crankcase venting issue. All day on the dyno for 30ish pulls never head a drop of oil in my waterbottle of a catchcan. Each run on the dyno was done in 4th gear though....

As soon as I pulled off the rollers and drove it on the street, it spit oil. A 15psi pull from 3rd-4th gear a few times = about a 1/2 pint of oil in the bottle :(

I'm really at a loss at this point. The leakdown came back great, compression was nice and even, valveseals are BRAND NEW...the machine shop said maybe it was the seal on the compressor from the center section leaking into the drain line of the turbo causing pressure there....that sounds retarded to me. The turbo is a year or two old (very low miles) from Garret via Full Race and I've been its only owner.

Since the entire block is completely vented....any ideas?

Re: Why isn't this PCV/Vent setup working!
 

Try moving the PCV off the valve cover, like put a fitting in, and run a 5inch tube to the PCV from the valve cover. You might be getting a bit of splash on the valve causing it to fill up and spit when it closes.

Re: Why isn't this PCV/Vent setup working!
 

No, on my setup the pcv is about 7" from the black box on the side of my engine block. And when boost gets to about 8 psig and WOT around 2.5k rpms or higher my engine starts using oil. I have the fresh crankcase air coming from the air inlet to my supercharger.

Re: Why isn't this PCV/Vent setup working!
 

ummm, slash cut exhaust anyone?

either that or just run the ---- to the ground, ---- a catchcan. and ---- complicating things, slash cut is proven to be effective and is simple to set up. also you wont be sucking nasty ---- fumes into your intake

Re: Why isn't this PCV/Vent setup working!
 

Because it's full of crankcase blowby gasses, like any normal turbo or high CR NA car. If those are stock vent lines... fail, dude. Your engine hates you and ring seal is being degraded by crankcase pressure.


Not all engines blowby as much as others. Having your car on the dyno where you can induce load without air rushing past the car dissipating exhaust emissions will give you a very good idea of how well your crankcase breather is working. This being primarily a Honda site, and me being primarily a Honda guy, I'll give you a nice turbo D16 example. They typically smoke a little under boost and/or on decel - nothing you notice unless you stand next to the tailpipe during a dyno pull or start pushing past 250 whp, but it *is* noticeable. I tuned a somewhat ragged D16 setup last week that had a -10 and a -12 AN vents tapped into the valvecover, vented through a catchcan to atmosphere. If you aren't up on AN sizes, -x/16" or 10/16 (5/8") and 12/16 (3/4") lines. At 281 whp the car smoked not at all.

I have two 700+ whp drag cars I babysit. One has four -10 AN lines from the valvecover with a single -10 return to the back of the block as an oil drain. The other car's owner refuses to vent his block correctly, and after a pull on the dyno or the dragstrip the pistons are wet with oil due to crankcase pressure degrading ring seal and feeding oil across the rings. It won't last long. :1

FYI:

http://i256.photobucket.com/albums/h...c/Photo_11.jpg

Re: Why isn't this PCV/Vent setup working!
 

BTW, your solution doesn't have to be the baller braided stainless route... after all, this is HMT, bitches! Just get the job done. ;)

Re: Why isn't this PCV/Vent setup working!
 

electrical tape does this job

Attachment 12542

Re: Why isn't this PCV/Vent setup working!
 

If you didnt have any issues on the dyno, but once you were back on the street, it could be the way you have tapped your head. Acceleration could cause the oil to puddle up around where you have tapped it, and when the pressure escapes, it spits oil.

Re: Why isn't this PCV/Vent setup working!
 

Thanks for the advice JD. I'm aware of what crankcase pressure can do which is why i'm trying to fix this POS.

As for the rear vent hose vacuum question....I was referring actually to the side that is connected to the turbo inlet. Obviously there won't be vacuum on the block side of the rear vent due to the pressure buildup. Physics escape me on the other side though. If I pull the hose from the vent and just leave it to atmosphere, I can't feel any suction on the hose when I open the throttle....

Why is the inlet of the turbo not creating a negative pressure area? Too close to the filter I suppose?

A another forum member has done this: Attachment 12150 to his drag only car....

Looking at it, the ID of the hose he's planning to use isn't much bigger than what I have no on the stock front PCV line AND he capped the vent on the rear valve cover (center/top of picture). Doesn't appear to be much more venting than stock :-/

I'm going to add another port to vent the front valve cover further and see how it goes.

btw....

I'm very familiar with the HMT way....here was the old car/engine bay http://www.turboklze.com/getajob/broke.jpg

Megasquirt FTW ;D

You can also see by comparing the two above pics, my old engine/valve cover had a 2nd vent on the front valve cover that Mazda deemed unnecessary in later years....probably trying to save $ on the fititng, rubber hose, and pipe :3

Re: Why isn't this PCV/Vent setup working!
 

It doesn't look much bigger, but that other guy's vent setup is a lot bigger. Keeping the stock PCV is a big restriction and that hose is easily twice the diameter with results in more than twice the volume/crossectional area. Still not big enough, IMO. I'd run that much to a 300 whp Honda engine... but as I stated how much the engine wants to breathe is particular to the specific model, and I know less than nothing about yours so I'm going to waffle and say the other setup you posted might be enough.


You aren't getting any real vacuum to speak of at the turbo inlet, not if your intake tract is set up correctly. I definitely wouldn't run one as there's oil vapor in the crankcase, regardless of how well baffled, and that will collect in your intake tract. Oil has an octane of about 70, and once it lights it stays on fire... Some of the internal combustion engine theory books (the ones actual automotive engineers read) have pictures of oil or oil-related carbon buildup that hotspots and ignites, and it keeps burning pretty fiecely all through the combustion cycle and causes pre-ignition. This is one of the major reasons incorrectly vented engines don't last as long as they should, especially non-turbo platforms that (built or not) get turbos strapped to them.

I'd vent to a catchcan mounted high up as possible, with a drain at the bottom run back to the oil pan or block so oil can gravity feed back, vented to the atmosphere. This will do away with crankcase vacuum at idle, and that's going to cause oil to lay against your valvecover gaskets and cam seals so if they are shitty the engine will pour... I'm sure you've owned an old beater with a shitty valvecover gasket that was fine when driving, but as soon as you shut the engine off all sorts of oil ran out onto the exhaust manifold and she started smoking underhood. Well, with this setup you will lose oil all the time if your seals aren't top notch, hint hint a thin layer of RTV on some VC gaskets can make a world of difference.

There are ways to vent to atmosphere under boost and retain PCV function at idle/cruise, but it's complex. If you put together a setup based on, and grasp the concepts, I've put forth here you'll be able to construct such a setup if you feel it's worth spending the time on. I'd rather go to the track and try to make my soggy ass car hook, which can be a real chore - no sense (from my perspective) to create more work. :P

Re: Why isn't this PCV/Vent setup working!
 

Grey RTV is good stuff.....Napa also has some ---- called "the right stuff" that works really well.


I was looking at my mazdaspeed3 (daily driver) to see how the OEM setup was done and its basically the same as mine, with the vent to the turbo inlet and all....which is leading to lovely carbon build up on the inside of the intake manifold per my last inspection at it....whatever, warranty is king on that...

Like I said, gonna add some extra venting, throw on a couple of water bottles to catch the oil vapor (held together with electrical tape) and see if it pukes any more oil. If it stops pressurizing the block then I can start investigating some other options (really liking the slash cut idea) to remove the oil vapor smell so I can drive it somewhere else besides the track and the dyno.

Before I can do anything though....I need to change the oil AGAIN as its diluted with fuel from blowbye gasses....

Hey JD...

On a side topic, how well do the honda trannies hold up to power? I know I can easily shatter my trans with moderate sized slicks and about 4-500whp within 1-2 passes...the car now is on trans number 3 or 4 as it stands...just curious...

Re: Why isn't this PCV/Vent setup working!
 

B-series:

I was taking 804 whp and 501-503 wtq passes on a stock B-series 5th gear the day before yesterday because it was the only way we were getting traction, they like to let go at 850... well, they (5th gear) really likes to go at less than that but there's a difference between doing it all the time and doing it ten times for tuning reasons. Stock B-series gearsets, 1-4th gear, are better supported than 5th gear so they deal with power better. You can campagin a 4-600 whp drag car off of a stock gear B-series transmission with good results, they only catch a gear if you miss a shift but the whole thing doesn't scatter so you are left with an easy rebuild. Every so often you will shell the main shaft's pinion and/or the ring gear, if your driver is good and doesn't bog the car, on 24.5" slicks they will take 400+ passes before fatigue sets in - that's quite a lot. If you aren't a dedicated track car you can get away with more power as it doesn't get hammered on as much due to there being less traction on the street. There are more and more affordable gearsets for Hondas out there all the time, you can get in an out of what you "need" to build a reliable 9 second car for under a grand up to $3-4K for a Liberty(win)/Quaife(fail) setup. Past 900 the stock case is known to be weak and let go, there are billet cases on the market or you can reinforce the stocker a variety of ways.

D-series:

If you get rid of the stock diff, and don't start with a high mileage un-maintained unit, they are supposedly stock for stock stronger than B-series. There are a lot less big power D-series than B-series so information isn't as fluent. You can get inexpensive FDs and gears from places like MFactory/etc that sell for about what the cheaper B-series stuff goes for, and a lot of the big name drag guys (Bisi) mention that the gear design of the D-series box is superior as they are "stubbier," but whether or not they are made of comparable quality to B-series I do not know. I'm really happy with the ZC/Si hybrid gearbox I had built for my beater, some polishing of the gears and replacing the case bearings really makes it shift smooth. The #1 problem with the D-series trans is people thought they weren't worth as much or as good as B-series so they haven't been maintained, resulting in notchy shifting, etc.

CG trans:

This is the family of gearboxes that came in 86-89 Integra, brown top ZC, and 86-89 Integra. Bisi runs one in his F-series powered Insight, swears by them as being superior to even D-series. Meh, good luck finding one with less than a million miles on it.

All the newer K-series transmissions are junk and fall apart in stock vehicles owned by middle aged women who go everywhere at ten under the speed limit.



If you are considering a transmission swap you can't run any of the "good" Honda transmissions as they spin the wrong direction. You really need to look into the turbo or blower MR2. They both share the same internals, stout as ----, the cases(bellhousings) are a little different as the turbo boxes are for 3S-GTE and the blower units are for 4A-GZE. There are definitely others you can and should consider, but those leap to mind as they are easily as strong or stronger than Honduh boxes, stock for stock.

Do you have multiple carnage pics of your exploded gearboxes? There's a good chance the basic parts are pretty stout but the case is flexing causing main and lay shafts to hammer against each other and shear off gears, or something like that.

Re: Why isn't this PCV/Vent setup working!
 

I'd have to look, but I have some pics laying around at home and there are plenty on probetalk.com....

Our most common failure point is blowin up 3rd gear...its actually physically smaller than the rest of them ???

The whole G series mazda transmission was designed for 4cyl econbox applications. It's the same gearset (short of final drive ratios) found in Ford Escort ZX2s, and 4cyl base probe, mx6 and 626s. Those cars put about about 115hp at best on a cold day...and mazda in all their infinite wisdom decided lets attach that same ecobox transmission to an engine that makes up to 100hp MORE stock. Take that and go up another 300hp and tranny soup (gross) is available on demand.

Some Protege people swap in the 3rd and 4th gears from the Mazda 323 GTX (AWD 1.6L Turbo) as they are a little beefier, but still break them. As far as I've been able to find, our only serious option are gears from PAR...a gearset from them runs more than my entire car is worth filled with hookers and blow.

I've given the yota transmission some thought, its cable shifted too IRC, so that would make it an adapter plate and axles away. We were also breifly discussing the SRT4 transmission, but I don't think it would come close to clearing the frame rail on the side of the engine bay.

Re: Why isn't this PCV/Vent setup working!
 

Frame rails can be modified. It's not uncommon to cut holes in 88-91 chassis to pass charge pipe through. I wouldn't think twice if the rest of the unit can be made to fit. At the rate SRT4s get wrecked you can find one easy as pie, the MR2 stuff is starting to command a bit of money IIRC.

---- adapter plates. What you need to do is have a shaft made that rides in the main journals of an empty block and in the bearing recesses of a hollowed out transmission. This will align the two so that you can weld the trans bellhousing so it bolts to the engine, don't forget two alignment dowels for precise location. You find a local clutch rebuilder (or approach ACT, etc) to mate a friction disc of the correct diameter to a friction disc hub that mates with the transmission. Pilot bearings can be looked up in generic catalogs (make sure of the rpm ratings) or made out of oil impregnated brass. Pretty easy if you can weld and have patience, it's mostly slow align/measure/think sort of work and the guys who like to plow through bolt-together jobs and see rapid progress really hate doing it.