How does PCV system work?

[rrubel]

I'm pretty sure I've got too much pressure under the passenger-side valve cover because even with my new oil cap, I'm still pushing out oil at high RPMs (now it's coming from around the breather hose and/or the valve cover). It was suggested to me that I run either a K&N filter breather and close the port on the throttle body, or perhaps enlarge the line to the TB (which might be difficult if that port is the narrowest part). I'm also thinking that I've got a smaller-than-stock hose on the PCV valve on the driver's side...

Is this all connected, the PCV and the passenger breather? If I use a breather filter, will that mess with the PCV setup? Will it make a mess under the hood, or are they (as I was told) a one-way valve as well? What is the direction of travel for the air in the crankcase? plenum->PCV->crank case-> TB? Or the other way around? If I run larger-ID tubing, will that help? Is Jupiter aligned with Mars? Does your chewing gum lose its flavor on the bedpost overnight?

Thanks.
[RICHR]

 

[G Winter]

I assume your saying the oil comes out around the hose at the valve cover and not between valve cover and head. Do you have original vaulve covers? I have seen some valve covers that didn't have deflactors on the opening for the pvc or breather openings. The only other time I have seen something like that is either the drain holes in the heads are plugged and filling the valve cover with oil or there is excesive blow by on the cylinders.But usually is both sides. Make sure the ID of the hose is big enough. Just some rambling thoughts on it.


Chewing gum on the bedpost??? I didn't think anyone else new about that song. Dang but you must be old ,,,,, no wait that would make me old too, lets say your dated.


PS I think I have the MP3 of that song on my computer ......

 

[Mad-Mic]

Rich i think you should try one of these if it will work.



http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=77265&prmenbr=361

this one is alot cheaper.

720-2054

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=993&prmenbr=361

sorta like a catch can. whats happening is your motor is "Puking" oil due to the high pressure. if you have a hi pressure hi volume pump thats the cause. i think one of these is your ticket.

 

[rrubel]

Mic, I bought one of those today at AutoZone (the cheaper one). Does that go on the PCV side or the TB breather side? Can I just run two breather elements and cap off the rest of the PCV system?

FWIW, I've got HV but not HP pump.

G Winter, I spent my youth listening to novelty songs and occasionally spew forth something from one of them Glad you caught the reference (but I think you missed the other one?).

The engine is essentially brand new - everything has less than 1500 miles on it except for the block, so I'd be surprised if the cyls or valves were getting a lot of blowby.

Thanks.
[RICHR]

 

[G Winter]

Yep. Missed the other one till you mentioned it , but really don't remember the piece of music it came from. Mad Mic is right, higher cyl presure would cause more preasure inside the engine. Have you notice any oil getting into the pcv hose? If so you may want to do something with that too.

 

[G Winter]

Not to highjack the thread but with two people who have worked on the intakes here I have to ask. I have the plentum completely unbolted. Naturally the gaskets are stuck. How to I break the plentum lose without damaging anything.

 

[NT Vettman]

Use a stiff scraper between the runners and the plenuem and tap it with a rubber malet. That what I did when I took my apart. But the gaskets stuck to both the plenuem and the runners after they came apart. Took a bit of scraping to get em clean for reassembly.

 

[rrubel]

G, the other reference is from "Age of Aquarius" (from _HAIR_).

The stock plenum gaskets have plastic tabs holding them into the runners and plenum. One thing you can do is loosen the runners at the manifold (BE AWARE - one bolt on each side comes from the OPPOSITE side of the runner!). Another is just to lay a block of wood on the plenum and smack it with a rubber mallet until the tabs break. That's what I had to do.

Haven't checked the PCV setup; I used to get some oil into that even with the stock engine.

BTW - the airflow is apparently plenum->PCV->crankcase->breather->TB. If I put a breather on BOTH sides and capped things off then I'd probably be OK. Not sure how much oil would get shoved out the element, though. I'm going to try the one breather that Mic suggested, plus larger ID hose on the PCV side, and see what happens.

Also got a bunch of A/C o-rings; with pretty much zero freon in my system I feel OK about taking it apart to re-do things. This weekend should be busy.

[RICHR]

 

[G Winter]

Thanks for the help on the plenum. I got it lose using both ideas. Now my next problem is the fuel rails. Do I have to take the crossovers out to get them off the injectors ? I have two bad injector coils and a leaking valley gasket. So this week is dedicated to removing and replacing intake. With 78k on it, appears the top has never been off. What really bites is the $80 each for the new injectors.

Does your chewing gum lose it's flavor song was played on the radio a lot when I was somewhere around 6 yrs old. No TV at the time only radio in our house. Early 50s . Age of Aquarius that comes back to me now.

I looked real close at my pcv valve and it is damp around it so I think anytime you run them hard to high rpm you get crankcase presure. I hope the breather takes care of it for you. Have you replaced the PCV valve ?

Glenn

 

[NT Vettman]

You pull the fuel rail off as one piece with the injectors. It will be a little tough to pull it, work sections at a time. After this many years, the O rings will be stuck. When the rail is off flip it upside down the injectors are held in with rotating clips that hold in injectors in place. You should think of replacing the O rings in the fuel rail assembly also..
Did you take the runners off the intake manifold. The fuel rail wont come out unless you do.

 

[rrubel]

I used a pry bar (gently) to remove the fuel rail and injectors as one unit (as mentioned above). If you've got time, consider sending ALL the injectors to Rich at Cruzin' Performance and have him clean/rebuild them. Not sure about the coils, but he'll clean, flow-match, and replace the o-rings and pintle caps for about $90/the set. He also swapped one of my injectors for one of his spares because he couldn't get it to flow with the rest. Well worth the $$. I think he's got about a 2-week turnaround.
[RICHR]

 

[tigmaned]

Rich

i have edelbrock value covers on my 86, with the same air filter you just got, mine is on the passenger side (RT) value cover.

 

[Hrtbeat1]

Does that go on the PCV side or the TB breather side? Can I just run two breather elements and cap off the rest of the PCV system?

Rich, this is similar to what I did. I replaced my original valve covers with Moroso alum centerbolt type. They did not have holes in them but did have bosses on the underside for drilling. One thing that WON'T work is just bolting these on ... I tried :nono ... Oil blew out the dipstick tube all over everything. I removed the valve covers and installed two Mr. Gasket breathers, one with a PVC tube one without. I put a pipe fitting in the actual PVC inlet on the manifold, drivers side got the regular breather, passenger side got the PVC one. I ran the PVC fitting to the TB. This seems to work alright, I still get just a drop of oil on the bottom side of the breathers (I think it 'cos they were the cheap ones ... only ones I could find locally and in a rush.) In retrospect I should have plugged the TB inlet and connected the PVC fitting to the breather with the PVC valve. I still may try this but can't seem to find time ... plus its too durn hot outside now.

On my motor buildup I think I am going to use the K&N type breathers, maybe one with and one without the PVC tube. The valve covers I got for the AFR heads are the raised letter CHEVROLET type, again without holes but they have the bosses for them to be drilled.

 

[G Winter]

Thanks NT Vettman took the runners off and used a large screwdriver. The injectors came right out. I also have the intake ready to take off, all bolts removed and dist. removed. I would like to have a talk with the guy that decided the dist. hookup should be down behind the intake :eyerole and did they hire spider monkeys to put these things together ?

Glenn

 

[rrubel]

And if you ever planned on doing the MAT sensor relocation mod, now would be a good time to do it... that connector is also down behind the intake.
[RICHR]

 

[NT Vettman]

Glad to hear it work with no problems. I had replaced my injectors with a set of Bosh I got from a friend who purchased them from TPIS and put a 1000 miles on them. He is now building a 383 stroker. This addition along with an adjustable fuel regulator, 52mm throttle body, a Y pipe with no pre cats and a high flow cat converter, just woke the L98 right up! Motor has 89k on it.

[font=&quot]PS if you go with an adj reg ( which is just the cap with an adj screw) also by the regulator which is the rubber membrane and spring, I got mine from Advanced Auto for about $25[/font]

 

[G Winter]

As of now I am ready to reinstall the manifold. What a chore getting the 15 yr old original gaskets cleaned off. My replacement injectors may not be here till Monday.That should give me time to replace the fuel rail and injector O rings. I hope I don't have to pull the fuel rail again anytime soon. I would rather drive then work on it.

 

[maxrevs85]

The less expensive crome is what I use and works well. That moroso one looks pretty trick though, but $80, whew.:eyerole

Rich i think you should try one of these if it will work.



http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=77265&prmenbr=361

this one is alot cheaper.

720-2054

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=993&prmenbr=361

sorta like a catch can. whats happening is your motor is "Puking" oil due to the high pressure. if you have a hi pressure hi volume pump thats the cause. i think one of these is your ticket.