[Miss89baron]

The 2.5 build up page with Gus says that the PCV valve will leak under high boost pressures. He recommends to intall a check valve in the line from the intake manifold to the PCV. Has anybody had experience if this is necessary or actually seen benefits?

 

[oklamopar]

PT-Performance.com

I use one and Yes it keeps boost from entering the crankcase. most pcv valves will not completely close causing pressurization of the crankcase.
i also use a catch can between the check valve and the pcv valve.

 

[Miss89baron]

PT-Performance.com

I use one and Yes it keeps boost from entering the crankcase. most pcv valves will not completely close causing pressurization of the crankcase.
i also use a catch can between the check valve and the pcv valve.

I'll go down to a parts shop and pick a one way valve and install. Seems like an inexpensive fix or insurance. Is the catch can just there to catch any blow back oil from the crank case?

 

[19omni87]

yes a friend of mine recommended this too me alsoit definetly works. you need a low pressure shut check valve there adjustable i believe his closes at like less then 1 psi

 

[speeduphoria]

yes a friend of mine recommended this too me alsoit definetly works. you need a low pressure shut check valve there adjustable i believe his closes at like less then 1 psi

Exactly, low cracking pressure check valve. I have one from McMasterCarr, costs a couple $. I also read a thread on neons.org a while back that said the replacement stock Supra Turbo pcv valve is a god one to lok for at the parts store.

 

[Miss89baron]

Exactly, low cracking pressure check valve. I have one from McMasterCarr, costs a couple $. I also read a thread on neons.org a while back that said the replacement stock Supra Turbo pcv valve is a god one to lok for at the parts store.

I checked at the basic Pep Boys and car stores down the road and they don't seem to have a low pressure crack one way that fits in the hose size to the PCV. Do you know where to find the type check valve we need. If the Supra pcv valve fits and is a good replacement that secures the crank vacuum when under boost without leakage, then that seems the way to go versus an in-line check.

 

[speeduphoria]

I dont remember all the details on the supra pcv, i would try to look at one at the parts store. They fully close against boost, and AFAIk the mopar ones were supposed to be good also, but i never tested one. On neons.org they used it and said it was good, but I dont know how it looks or if its easily adaptable. I have an SRT4 one on my 2.4 but also use a checkvalve like I said(many SRT4 guys do because they can leak a little). If you get a generic one way valve make sure it has low cracking pressure. The one from McMasterCarr has different sized and you need to buy the hose barbs to thread into it for what ever hose size you want to use.

McMaster-Carr
"Brass Medium-Pressure Spring-Loaded Piston Check Valves" on page 462

 

[Miss89baron]

I dont remember all the details on the supra pcv, i would try to look at one at the parts store. They fully close against boost, and AFAIk the mopar ones were supposed to be good also, but i never tested one. On neons.org they used it and said it was good, but I dont know how it looks or if its easily adaptable. I have an SRT4 one on my 2.4 but also use a checkvalve like I said(many SRT4 guys do because they can leak a little). If you get a generic one way valve make sure it has low cracking pressure. The one from McMasterCarr has different sized and you need to buy the hose barbs to thread into it for what ever hose size you want to use.

McMaster-Carr
"Brass Medium-Pressure Spring-Loaded Piston Check Valves" on page 462

I would imagine the stock PCVs work well for stock or slightly over boost, but when you hit 25 lbs with the new hybrids and FMICs, what do they do? I read you want the crank case to maintain some vacuum to keep the rings sealed. So adding a little pressure can't be good. I ran across this site which is for techno-geeks, but is very comprehensive on the pcv and breather system workings.

http://www.106rallye.co.uk/members/dynofiend/breathersystems.pdf

 

[85lebaront2]

Here is the one I used. It came from a local supplier, Hampton Rubber

 

[Miss89baron]

Here is the one I used. It came from a local supplier, Hampton Rubber

Nice Pic, and a good idea. Thx

 

[SUPER60omni]

I run a stock mopar one from like 86 probly, 30+psi with no crackcase pressure problems. Car went 11's and made 340 with no problems.