PCV valve

[JST A 6]

I remember reading quite a while ago (probably on a different board since I can't find it here) that there were certain brands of PCV valves to stay away from. What are the good ones to use?

 

[russgoodman]

the only good ones i know of are the delcos, maybe someone else can add more.

 

[gossamer]

+2 I have only used A/C Delco with no problems. I've never tried a different brand though. I'm sure more opinions will come.

 

[87NAT]

You can take 10 PCV's from your local parts store and maybe 3 will actually work. Get a GM PCV and a check valve if you want to stop boost from entering your engine.

 

[JayC]

I posted the part number to a check valve I used to sell that you can put inline with any PCV and it works great. Im sure its just a matter of time before a vendor takes the part number and starts selling it as their own great idea.... not like that hasnt happened before.

 

[JST A 6]

I posted the part number to a check valve I used to sell that you can put inline with any PCV and it works great. Im sure its just a matter of time before a vendor takes the part number and starts selling it as their own great idea.... not like that hasnt happened before.

What's the check valve for? Isn't that essentially what a PCV valve is, or is it just so you have double-valve protection against boost? Where is the part # posted and where can I get one since you don't sell them any more?

Thanks Jay, and I'm sorry you got a rise out of me on that other thread...

 

[JayC]

PCV's really dont seal well under boost. A lot of people sold inline check valves to fix that but the problem with all the valves is that they wont open correctly under vacuum. The valve I sold could be modified to open under all vacuum conditions.

Do a search for clippard on here and see if it returns any results. If not, Ill dig the part number up. I know Ive posted it here before. It's a Clippard valve.. really cheap (Like $6.00 I think) and works great.

 

[BlackMetal]

PCV's really dont seal well under boost. A lot of people sold inline check valves to fix that but the problem with all the valves is that they wont open correctly under vacuum. The valve I sold could be modified to open under all vacuum conditions.

Do a search for clippard on here and see if it returns any results. If not, Ill dig the part number up. I know Ive posted it here before. It's a Clippard valve.. really cheap (Like $6.00 I think) and works great.

http://www.clippard.com/store/display_details.asp?sku=MJCV-1

Found your old link. Just not sure about how you modify them. I understand "open it up and cut the spring", but not sure how a check valve works with a cut spring.

 

[JayC]

The spring is what holds it open. Cutting some of the spring allows it to open and close easier. It still seals completely under pressure and cracks with even a small amount of vacuum. I guess you need to open one up to understand but once you do, it makes perfect sense.

 

[JST A 6]

http://www.clippard.com/store/display_details.asp?sku=MJCV-1

Found your old link. Just not sure about how you modify them. I understand "open it up and cut the spring", but not sure how a check valve works with a cut spring.

Vacuum sucks it open; boost pushes it shut. At least that much I understand.:biggrin:

Now for the part I'm not clear on: by "cut the spring" do you mean removing it completely?

 

[JST A 6]

The spring is what holds it open. Cutting some of the spring allows it to open and close easier. It still seals completely under pressure and cracks with even a small amount of vacuum. I guess you need to open one up to understand but once you do, it makes perfect sense.

Vacuum sucks it open; boost pushes it shut. At least that much I understand.:biggrin:

Now for the part I'm not clear on: by "cut the spring" do you mean removing it completely?

Guess you answered my question as I was typing it...

 

[Chevman2448]

The spring is what holds it open. Cutting some of the spring allows it to open and close easier. It still seals completely under pressure and cracks with even a small amount of vacuum. I guess you need to open one up to understand but once you do, it makes perfect sense.

This is an OLD thread...but I was wondering how much spring you cut off that check valve. I havent searched it yet but will after posting. Thanks

Edit: I searched and didnt find it.

 

[earlbrown]

You want it to have just enough spring pressure to barely keep it closed. The reason for the mod is because the cracking pressure is usually greater than the amount of vacuum the engine makes. When that happens you basically have a plug instead of a line.


Measure your vacuum at idle and cruise. Cut that number in half and that's roughly how many pounds you need to be below.

 

[Chevman2448]

You want it to have just enough spring pressure to barely keep it closed. The reason for the mod is because the cracking pressure is usually greater than the amount of vacuum the engine makes. When that happens you basically have a plug instead of a line.


Measure your vacuum at idle and cruise. Cut that number in half and that's roughly how many pounds you need to be below.

Crap cant exactly measure vacuum at cruise. Damn Winter!

Did you ever get that 4.2 up and running?

 

[3.8L V-8 eater]

I'm going to use another PVC from RJC....Had one on my other Buick and it actually worked like it was suppose to.....

 

[TurboBuRick]

I like the one from RJC. It has a higher crack pressure and a lower volume than stock style.
Less volume has less chance of vacuuming up oil.

RL

 

[Chevman2448]

I have a PCV from Kirbans but I am still getting oil in the TB so I thought I would try this. I also picked up an AC delco PCV and I can blow air through it the way you are not supposed to.

 

[JayC]

I cut the spring in half. I've even removed them completely and it works fine in that regards too. The Clippard stuff is great and well made.


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[ITSAV6]

Check valve is the way to go. Made a brass one and installed it above the pcv. I still had to restrict the vac some due to it sucking up oil. If I have to take the intake back off I will make something to keep oil away from the pcv.

 

[Chevman2448]

I cut the spring in half. I've even removed them completely and it works fine in that regards too. The Clippard stuff is great and well made.


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I took the Kirbans PCV off and found that is was stuck(its working now) but I have the clippard valve.

Edit