Silky_Johnson Posted July 23, 2012 Report Share Posted July 23, 2012 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! Quote Link to comment
datsunaholic Posted July 23, 2012 Report Share Posted July 23, 2012 I think they're BSP, which is a British pipe thread. Size I'm not sure. Quote Link to comment
ggzilla Posted July 23, 2012 Report Share Posted July 23, 2012 Same as all Datsun (L/A/VG/U/R/CA/Z/E/J), many Nissan (including GA) and Subaru 1998-2002 2.5L. Quote Link to comment
Silky_Johnson Posted July 23, 2012 Author Report Share Posted July 23, 2012 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. Quote Link to comment
ggzilla Posted July 23, 2012 Report Share Posted July 23, 2012 It is NPTF -- National pipe thread Fine (1/4-18) Quote Link to comment
datsunaholic Posted July 23, 2012 Report Share Posted July 23, 2012 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? Quote Link to comment
Silky_Johnson Posted July 24, 2012 Author Report Share Posted July 24, 2012 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. Quote Link to comment
ggzilla Posted July 24, 2012 Report Share Posted July 24, 2012 1/4 NPT Fine? or 1/4 NPT regular? Quote Link to comment
metalmonkey47 Posted July 24, 2012 Report Share Posted July 24, 2012 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. Quote Link to comment
DanielC Posted July 24, 2012 Report Share Posted July 24, 2012 The threads are British Standard Pipe. There is a chart on this page. http://pipeandhose.com/node/2 Quote Link to comment
banzai510(hainz) Posted July 24, 2012 Report Share Posted July 24, 2012 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 Quote Link to comment
Silky_Johnson Posted July 24, 2012 Author Report Share Posted July 24, 2012 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. Quote Link to comment
Silky_Johnson Posted July 24, 2012 Author Report Share Posted July 24, 2012 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... Quote Link to comment
banzai510(hainz) Posted July 24, 2012 Report Share Posted July 24, 2012 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 Quote Link to comment
Silky_Johnson Posted August 18, 2012 Author Report Share Posted August 18, 2012 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: Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.