thread size for PCV valve

Post by **Legacy777** » Tue Oct 07, 2003 2:25 pm

Anyone know the thread sizing for the PCV valve. I want to feed the engine some cleaner, and that location is the best spot, but I need to put something in place of the PCV valve.

Any ideas?

vrg3 · Post by **vrg3** » Tue Oct 07, 2003 3:19 pm

I seem to remember it being 1/4" BSPP last time I bought a valve.

British pipe fittings are hard to find, though. You might be best off taking a stock PCV valve and "gutting" it somehow... like maybe with a drill. You'd just have to be careful to get all the debris out of it. Or maybe cut it (between the threaded part and the hose nipple) with a Dremel or something so everything falls out and epoxy in your own tubing.

entirelyturbo · Post by **entirelyturbo** » Tue Oct 07, 2003 8:48 pm

Why not just feed some cleaner through the CPV hose on the TB? That's what I do...

Post by **Legacy777** » Tue Oct 07, 2003 11:30 pm

because i don't really want to go through what I went through last time with the black goo going away. Water I don't mind, but a petrolium based cleaner.....nah...

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 12:24 am

The PCV fitting is a good central-ish place on the manifold, but you might be able to get good results using the brake booster vacuum nipple too. It's kind of biased towards the rear driver side cylinder, but it still may work.

entirelyturbo · Post by **entirelyturbo** » Wed Oct 08, 2003 2:45 am

vrg3, I've tried running an engine cleaner through the brake booster hose, and was not pleased with the results. The engine barely bogged down, which seems to me like the #4 cylinder was sucking it all down.

And, I'm not trying to sound arrogant here, but you cannot possibly tell me that the #2 intake runner can possibly gather any cleaner from that #4 intake runner... Air is simply too lazy to go around a corner like that...

I was much happier with the CPV hose and I did not cause any TB leaks... But if you can devise a way to do it through the PCV opening, then go for it. I see no disadvantages there...

Hey Josh, I wonder, is there a way to thread a female coupling into the manifold which will accept a hose with a male coupling, much like attaching an air tool to a compressor?

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 3:14 am

I guess you're right... The booster nipple is too far away from the center. I was just guessing it might work, since the IAC valve is also off-center, but your experience shows it's not the same.

If I'm right about the pipe thread in the manifold, you could use a 1/4" male BSPP-to-whatever coupling. 1/4" NPT is common on air tools.

I just went to http://www.napaonline.com/ and searched for a PCV valve for our cars. The Echlin application, part number CRB29254, is described as follows:

Item#: CRB29254

Price: $ 4.69
tax and shipping not included

Usually ships in 24 hours.

Attributes:
Attributes: PCV Valve
# of Hose Connectors: 1 Connector
Hose Size: .65''
Thread Size: 1/4'' - 19'' British Standard
Type of Packaging: Blister Pack

1/4" - 19" isn't really a specification, but it may be a typo. 1/4" BSPT and 1/4" BSPP both have a pitch of 19 threads per inch.

It doesn't say whether it's tapered or parallel (BSPT or BSPP), though. But it looks pretty certain that it's either 1/4" BSPT or 1/4" BSPP.

Josh, If you don't care about perfect sealing, you may be able to use a nylon 1/4" NPT fitting (easily available at any hardware store in the USA). The nylon probably shouldn't damage the aluminum manifold's threads even though NPT has a slightly different pitch (18 TPI).

Post by **Legacy777** » Thu Oct 09, 2003 2:17 am

The nylon idea is a good one. I may just go that route. I don't really care if it seals super well......I just want it to suck down chemicals

vrg3 · Post by **vrg3** » Thu Oct 09, 2003 2:31 am

Yeah, I bet the nylon NPT fitting will work well enough. Let us know how that goes.

As luck would have it, though, a friend asked me to help him do a tuneup on his car tomorrow, including changing the PCV valve. I'll play around some with the old valve and see how hard it is to take the "valve" part out of it.

Post by **Legacy777** » Thu Oct 09, 2003 2:34 am

the problem with drilling the old valve out is that the spring valve inside is not held solid so it's just going to rotate with the drill bit, and piss ya off

vrg3 · Post by **vrg3** » Thu Oct 09, 2003 2:41 am

But it's not a big deal to have the spring in there. The ball is what's the problem.

Post by **Legacy777** » Thu Oct 09, 2003 2:42 am

It's a little plunger type thing with the spring behind it. that plunger is what needs to be drilled out, and it spins freely.

vrg3 · Post by **vrg3** » Thu Oct 09, 2003 2:46 am

Oh.

Maybe I could fill the whole thing with epoxy, let it set, and then drill it.

Post by **Legacy777** » Thu Oct 09, 2003 2:48 am

that might be an option.......

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 12:05 am

I just tried it. A nylon 1/4" NPT fitting with teflon tape on it will thread in about half-way. It won't damage the aluminum threads and will seal successfully against manifold vacuum.

ciper · Post by **ciper** » Wed Feb 18, 2004 1:56 am

Why not use the purge valve line?

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 2:01 am

Legacy777 wrote:because i don't really want to go through what I went through last time with the black goo going away. Water I don't mind, but a petrolium based cleaner.....nah...

ciper · Post by **ciper** » Wed Feb 18, 2004 5:12 am

I thought the purge valve was AFTER the throttle plate.

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 5:28 am

The port is just barely before the plate.

If you connect a vacuum gauge to that port, you'll measure roughly atmospheric pressure when the throttle is closed. But when the throttle is opened just a little you'll measure roughly the same pressure as in the rest of the manifold.

ciper · Post by **ciper** » Wed Feb 18, 2004 5:35 am

Learnt something new today.

Guess the PCV valve is the best location. Why not just get another PCV valve from the parts store, cut your original one in half, and reinstall the new one when you are done?

I bet it would be cheaper that way, and no guessing if it will fit or not!

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 5:40 am

What do you mean by cutting the original PCV valve in half?

The nylon fitting cost me $0.79 at my local hardware store, and fits.

ciper · Post by **ciper** » Wed Feb 18, 2004 5:46 am

Take a saw and cut the top of the valve off so the internals can be removed. Didnt realize the nylon part was so cheap, still my method gives you a new PCV valve so the car automatically runs better

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 5:55 am

Then you'd glue, solder, braze, or weld it back together?

It's all pretty much moot anyway, since long ago Josh just fed the Sea Foam in through his PCV valve with the throttle wedged open slightly and it worked fine.

I just thought I'd let people know in case they had another need.

ciper · Post by **ciper** » Wed Feb 18, 2004 5:57 am

No, let it stay cut in half. It would be an open top smooth cylinder.

Can someone suggest an online place to purchase the cleaner?

vrg3 · Post by **vrg3** » Wed Feb 18, 2004 6:13 am

ciper wrote:No, let it stay cut in half. It would be an open top smooth cylinder.

How do you attach a hose to it then? How is that better than just removing the valve entirely?

Can someone suggest an online place to purchase the cleaner?

http://www.partsamerica.com/PartDetails ... umber=SF16

Parts America is the online version of Kragen, Checkers, Shucks, and Advance Auto Parts, so you could probably order it locally at one of those shops and not have to pay shipping.

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thread size for PCV valve

thread size for PCV valve