Crankcase vent connections questions - no rats
 

For starters thank you to everyone that has done work on taking out the rats nest. RX7Carl and everyone else :dubs: After reading about adding a Fram FV333 PCV valve I modded this pic (sorry didn't catch who author was). 84 12a.

I am a bit confused and need a connect the dots. Tell me what's wrong with
this picture. :wallbash:
http://www.noobgames.com/images/elraton03.jpg

I just ran a hose from the nipple on the oil fill tube to the base of the carb. Worked for me. Lots of people say you need a pcv valve though...

http://i44.photobucket.com/albums/f1.../elraton03.jpg




Sorry, can't help ya on the AC soleniod... but I'd like to know the answer to that tooo since my AC is DEFINATLY going back in this spring.

We should archive this...

If you're using a PCV valve the stock purge valve gets removed entirely.

It's a hell of a lot simpler than these diagrams... give me a bit and I'll draw one up tonight

Jon

Even better

Here, this should tide you over until I have enough time to MSPaint up a diagram

https://www.rx7club.com/showthread.p...&highlight=PCV

Jon

Yea thanks, if you see there I added the same valve you used the FV333 well the zone's cross of it and moved the dizzy vac adv to that first hole. From reading the various posts. Then got lost from there...

I'm glad to see this came up as I'm currently in the process of sorting out the vacuum lines on my car after they previous owner screwed up trying to remove the emissions.

That sounds like all we may need, if the line from the intermediate houseing goes to the charcoal canister. But where does your carb bowl vent go?

You have to like the simplicty of Wackyracer's setup, though I wonder if his car smells like gas. ;)

Jon, the way you have yours ran has one less line than my drawing, 3 instead of 4, thats a "little" simpler, and from what I could see you have no way to purge the charcoal canister.

Maybe if the carb bowl vent and the charcoal can were tee'd together like Jon's, but the third leg of the tee went to a pcv valve then to the intermediate houseing. The pcv would keep the fumes from the engine unless it was running. (I think I remember trochoid saying something about gas fumes saturating the oil).
Then run the filler neck line to a carb vac source, 3rd hole from the front on the spacer.

I connected the dots by going off the way my unmolested 12A straight from the factory is.

The only difference with the drawing and my 12A is the PCV valve, which in series with the crankventsolenoid isn't going to effect a thing since it's just a check valve anyways... but sure no need for both.

I used a Fram FV333. I'll try a different Fram PCV valve next because the 333 has a 3/8" and 5/16". the other (can't remember the number) has 5/16 and 1/4 (but with an NPT threaded end if you need it to fit in a 3/8" hose, which is will). It is more compatible hose wise. I'll have to get one and let everyone know how it works out.

My 12A has massive yukky inside the filler tube... and I'd like to hook up a vent.

The above has worked well for me on my 13B w/yaw nikki... and now I'd like to do the same to my 12A w/Mikuni except the Mikuni doesn't have all the ports on the manifold and spacer like the nikki does.

I believe the Mikuni has a vacuum sorce right on top of itself from my prior postings, but then where / how would I dump the condensation / yukky back into the intake...? If i'm right in assuming that's what is even supposed to happen...?

ur not dumping anything back into the intake. keeping a slight vac draw in the crankcase keeps the condensation from forming in the first place. i'm using a holley setup so there's no vac source other than for the brake booster. i T'd into the line to the booster from the nipple on the center housing and no, nothing gets into the booster. the vac draw is towards the engine. nipple from the filler neck goes into the air cleaner. i'll take pix if needed.

I did T or actually more like Y'ed off the brake booster line kinda close to where it comes off the intake. After talkin to my pops he thought the brake booster would be fine too...

Nipple from the filler neck I attached to the big nipple on the bottom of the purge vavle like the picture above...

Nipple below it / off the center housing, I attached to the charcoal canister like the pic above...

Small nipple on top of the purge valve got vacuum off the mikuni...

And small nipple on the bottom of the purge valve got Y'ed into the brake booster line closer to the intake.

It seems to be working fine.

I thought the purge valve was to prevent you from having basicly a vacuum leak by connecting say... the brake booster vacuum source straight to the oil fill nipple.

I just ran a fuel line from the intermediate housing bung to a bung on my carb hat. It's an RB hat, but you can do the same thing with a Mazda hat. It just needs suction from the carburetor pulling the vapors out. No lung mustard and no problems after 5000 miles.

You do not NEED a PCV valve. It's just a good idea. The purpose of the valve is simply to keep the moisture from returning through the hose back into the crankcase. It has a one way check valve inside and can only flow one direction. I'm using one from a 1990 Dodge Caravan 3.0L.

Ok resurrecting this thread for clarification.

here are pic of what I have now( I know dirty nasty engine) and my revised interpretation of the diagram from this thread and the one that vipernicus42 posted.

What did I do wrong? whats wrong with my diagram interpretation. thanks.

http://i328.photobucket.com/albums/l...7/DSCF1867.jpghttp://i328.photobucket.com/albums/l...7/DSCF1864.jpghttp://i328.photobucket.com/albums/l...DEMISSIONS.jpg

I think your float bowl vent line should be separate from the oil case vent. If it can't breath at all times with the PCV connected to it to vent it will back up and cause problems. I would run the bowl vent straight to the canister or just dangle it loose to dribble.

Red hose is to the top of the stock valve, the green hose is to the bottom of the stock valve.
Question now is when using the new PCV part # fv333 what hose goes where? only one can connect to the new PCV.

http://i328.photobucket.com/albums/l...7/DSCF1868.jpg

EDIT: I noticed I had the filler vent & crank case vent reversed in the previous post.