PCV Valve threads

[Silky_Johnson]

Does anybody know what the thread size is on the L-series (4 cylinder) PCV valves? I compared it with 1/4 pipe thread, and while the diameter is good, it seems like the PCV valve has fewer threads per inch, that is, slightly bigger threads. Going into a female 1/4 NPT, it binds up after maybe two full turns. At the local hardware store, they don't have anything in the same diameter with small enough threads for me to compare it with.

 

Just in case your wondering, I'm trying to setup the PCV system to work with my Mikuni manifold. I want to use the stock PCV valve and then run lines after the PCV to the runners on the manifold.

 

Thanks for your help!

[datsunaholic]

I think they're BSP, which is a British pipe thread. Size I'm not sure.

[ggzilla]

Same as all Datsun (L/A/VG/U/R/CA/Z/E/J), many Nissan (including GA) and Subaru 1998-2002 2.5L.

[Silky_Johnson]

Thanks for the responses. I'm not putting the PCV valve into the manifold. I'm just trying to find out the thread size so I know what to buy to thread it into. I'll just assume that it's BSP.

[ggzilla]

It is NPTF -- National pipe thread Fine (1/4-18)

[datsunaholic]

OK, well, BSP (JIS) has MORE threads per inch than NPTF. BSP is 19tpi. whereas NPTF is 18tpi. Maybe it's a taper/non taper issue?

[Silky_Johnson]

Well, I ended up getting a 1/4 NPT fitting, as well as a BSP adapter just in case. I'm waiting for the hardware from McMaster-Carr. I'll report with my findings.

[ggzilla]

1/4 NPT Fine? or 1/4 NPT regular?

[metalmonkey47]

Well, I ended up getting a 1/4 NPT fitting, as well as a BSP adapter just in case. I'm waiting for the hardware from McMaster-Carr. I'll report with my findings.

 

McMaster- Carr is great.

 

Funny thing, their warehouse that they ship orders from is about 30 minuets from my house. I get parts I ordered next day.

[DanielC]

The threads are British Standard Pipe.

There is a chart on this page.

http://pipeandhose.com/node/2

[banzai510(hainz)]

wHY BOTHER

Open vent with Mikunis or use a catch can.

 

I have a Toyota20R manifold set up this way with each runner ported and uses a inline hose PCV valave.

 

I guess it might help keeping the stink down. But as witrh any sidedraft set up gas smell is the usuall

[Silky_Johnson]

wHY BOTHER

Open vent with Mikunis or use a catch can.

 

I have a Toyota20R manifold set up this way with each runner ported and uses a inline hose PCV valave.

 

I guess it might help keeping the stink down. But as witrh any sidedraft set up gas smell is the usuall

 

wHY BOTHER? Datsunmike made me a believer in the PCV system, and I appear to be all set up for it -- just need to slap it all together.

 

My car was REALLY stinky. It has actually gotten better since I made the pilot circuit richer, but it's still not ideal. People used to pull up along side me and say, "Man, smells like your running rich!" And then I'd say, "No, it's an open crankcase..." I've got a hippy sister-in-law, and I need to at least make it appear that I'm not making every effort to destroy the planet. Haha! She's already hacked off about not having a catalytic converter.

[Silky_Johnson]

The threads are British Standard Pipe.

There is a chart on this page.

http://pipeandhose.com/node/2

 

Thanks for the chart DanielC. I used to live in West Linn, but we just bought a house in Gladstone. Still, not too far away...

[banzai510(hainz)]

Whne it comes to down drfats I also use them(PCV) as its already right there so why no use them.

 

But sidedrafts I open vent it

[Silky_Johnson]

Findings:

 

Threads are British Standard Pipe.

 

Here's a comparison of the two -- Datsun PCV and NPT male threads.

 

 

Pretty close, but not quite.

 

Here's the PCV threading into a British pipe adapter:

 

 

 

And here's the PCV threading into NPT female: