JayShadow

I did a search for a "how to" on eliminating the pcv valve. i found this thread below but the link doesnt work. Is his site down?
https://www.rx7club.com/showthread.p...valve+location

and yes i did search
https://www.rx7club.com/search.php?searchid=237835

My question is should i do the elimination or just buy a new one from mazda. And If i Do the Elimination is there someone that can show me a write on how to do the mod?

Thanks,
Jay

EpitrochoidMan

IMO, it shouldn't be eliminated. Just buy a new one from mazda.

rotoboy661

Dont!!!

JayShadow

Would malloy Mazda have the Part I need?

scotty305

iTrader: (2)

PCV is positive crankcase ventilation. How exactly would that work, since we don't have a crank? Is the eccentric shaft / output shaft similar enough in it's function that the same concept applies?

-s-

xb2002

Why did Mazda eliminate it in 95? Just did a rebuild on a 93 and I eliminated it. No big deal the crank case now breathes to the turbo inlet thru a oil catch can.

IMO, i think mazda eliminated it to prevent positive crankcase pressure(boost) caused by a sticky pcv valve.

If you want to eliminate it : remove the hose off the uim, plug the uim, remove hose off oil filler neck, plug the nipple on the oil filler neck, route the other hose on the oil filler neck thru a oil catch can. Pretty simple actually

JayShadow

PCV = Purge Control Valve

Location: https://www.rx7club.com/showthread.p...+valve+location

https://www.rx7club.com/showthread.p...+valve+location

Thanks,
Jay

xb2002

The pcv valve is in the system to reburn excess blow by and eliminate pressure in the crankcase to prevent oil seals...gaskets...etc from blowing out. If it were a sealed system the oil pan / valve covers(on piston engines) would blow off.
I really dont know about a comparison to a rotary engine as I dont think that any rotor movement would affect crankcase pressure as the rotors are contained in their housings. I think that the rotary is mainly vented for blow by.

xb2002

Never heard it called that!!

Positive Crankcase Ventilation = PCV

the_glass_man

iTrader: (2)

It's not on the 95+ vehicles. Just purchase an oil catch can, hook one end up to the filler neck and the other the intake vacuum and call it a day.

Sonny

You can eliminate it. The crankcase is "vented" by the oil filler neck which has 2 nipples on it:

1) PCV valve
2) Line going to the inlet of the primary turbo

If you cap off the PCV, you aren't sealing anything. There is still the line going to the compressor housing. I eliminated mine because it was leaking and I didn't want to pay the Mazda price for a new one. As stated above, it was eliminated (along with the EGR) on the '95 car.

Sonny

xb2002

dont hook it to intake vacum ... hook it to the turbo inlet

the_glass_man

iTrader: (2)

My turbo didn't come with one?

JayShadow

im hoping this will eliminate my boost issues.

xb2002

I used port "A" in this pic:


you can just plug off the uim and go run it to see if it helps boost issues. shouldnt hurt to let it vent from the filler neck for a couple of pulls.

the_glass_man

iTrader: (2)

Mine looks a lot like this one.

JayShadow

gotham has a oil catch can for 49.00. would that help like glass man said instead of eliminating it?

xb2002

Must be nice with a single!!! Which one you got? If you plumbed the catch can to the intake you would again need a pcv/checkvalve because you would be boosting into your catch can/crankcase and possibly blow some seals.

JayShadow

lol so i should just cap it?

xb2002

If you are only concerned about the pcv valve because of a boost issue , I would just plug the uim, and the oil filler neck and go run it. You will still have ventilation from the oil filler neck(crankcase) to the turbo inlet...which has constant vacum.(assuming its a stock fd)

the_glass_man

iTrader: (2)

GT35R, so would it be better to just tap the turbo housing and put the line there?

JayShadow

Thanks for all the help guys.

Thanks,
Jay

xb2002

lol I thought you were being sarcastic at first when you said yours doesnt have one

I f I were in your shoes I would just run two lines from the oil filler neck to the catch can and eliminate the vacum to it, and just plug it at the vacum source. Boosted crankcase is not good. Have you had it this way for a while? Has it caused any oil leaks? Nice choice on turbo! I'm jealous

Dont tap it!!

One more thing while Im thinking about it... Are you running the blue line in your picture? You should just vent it to the atmosphere. You wouldnt want to boost to the fuel tank either!

jeremyb

just get a new one from mazda. it never did anything to hurt you so dont kill it =). and plus it helps your motor breathe. You have more than one but you might as well just replace it rather than eliminate it. And wusup with the oil catch can thing guys? Isn't better to have a little oil go into your ROTARY motor to help lubrication?

xb2002

The oil gets all in your intercooler and air pipes never makes it to the internal parts... thats what the metering oil pump is for