Catch can fittings for valve cover

[Gamble97]

I want to add a catch can to the pcv and the breather side of the valve cover but want to avoid welding because my cover is already powdercoated.
Who makes a fitting that will thread into the pcv side and come out 6an?
Also I saw local that had the same fitting THREADED into the valve cover on the breather side. So maybe they cut off the nipple and threaded it in. Anyone done this with success? Also what fitting?
Only looking for a 6an outlet on each.

 

[Calan]

You're going to have to tap and drill, no matter what fitting you use. You could go with something like a 1/4" NPT to -6AN adapter, but that's a fairly large hole to drill and tap in the VC, and there isn't much room to do it.

EDIT:

In reference to what Brian posted below, you may be able to get by with a 1/8" NPT fitting but you'd probably need to drill out the ID, depending on the brand and style of it. If you do, be sure to not get the wall too thin or it will twist off in the VC.

Here is one from Summit for $2.75

 

[snowborder714]

You should be able to tap the breather fitting to 1/8" NPT. Then you can buy an adapter from 1/8" to -6 from ANPlumbing.
AN PLUMBING.COM Earls performance products, Hose ends Hose,Adapters, fittings

Just keep in mind the adapter will be a restriction if you go with a 1/8" size.

 

[99gst_racer]

^^^ Bingo. You can run a 1/8" NPT tap through the PCV valve hole too, and just run an AN adapter fitting. But you're not really benefiting from anything at that point, because it's just as much of a restriction as the factory setup at that point. The true benefit to adding fittings to the VC, is increasing the the diameter to help with evacuation.

 

[Calan]

Be sure to hold a shop vac nozzle next to your work while tapping and/or drilling and it will keep aluminum out of the VC

 

[Gamble97]

^^^ Bingo. You can run a 1/8" NPT tap through the PCV valve hole too, and just run an AN adapter fitting. But you're not really benefiting from anything at that point, because it's just as much of a restriction as the factory setup at that point. The true benefit to adding fittings to the VC, is increasing the the diameter to help with evacuation.

So I gain nothing from doing 6an fittings then and I should just weld 8an fittings on it?
Problem is nobody will do it for a good price and my cover is already powdercoated so I would have to pay someone to sand blast it, then pay for fittings, welding and then powdercoat again. I was looking for an easier solution.

 

[Calan]

Depending on the welder's skills, PC color, etc....you may get away with only having to repair the PC job around the fittings, rather than redoing the whole thing. You'll need to keep the heat localized to the area around the fittings as much as possible though. But... I don't know how economical that would be. It may end up costing as much as just recoating the whole thing depending on how much special prep work there would be.

In any case, it really isn't worth going to AN lines unless you are welding on larger fittings.

 

[greengoblin]

So I gain nothing from doing 6an fittings then and I should just weld 8an fittings on it?
Problem is nobody will do it for a good price and my cover is already powdercoated so I would have to pay someone to sand blast it, then pay for fittings, welding and then powdercoat again. I was looking for an easier solution.

Buy an used uncoated VC. Have fitting welded on then sell yours that is coated. It will be cheaper that way. Stripping powder is not cheap.

Kevin

 

[badas93tsi]

FWIW, I drilled and tapped both factory holes in mine to accept 3/8 to -8 adapters. You have to step down with the hole a little bit, but it works fine.

 

[greengoblin]

Depending on the welder's skills, PC color, etc....you may get away with only having to repair the PC job around the fittings, rather than redoing the whole thing. You'll need to keep the heat localized to the area around the fittings as much as possible though. But... I don't know how economical that would be. It may end up costing as much as just recoating the whole thing depending on how much special prep work there would be.

In any case, it really isn't worth going to AN lines unless you are welding on larger fittings.

Doing patch work to powder coating is next to impossible and welding will damage the powder a good distance away from the actual weld zone.

 

[99gst_racer]

Buy an used uncoated VC. have fitting welded on then sell yours that is coated. It will be cheaper that way. Stripping powder is not cheap.

This is exactly what I would do too. Start from scratch and sell the existing VC to help recoop costs.

 

[4g63Powered]

What would the recommended AN fitting size be? -10? -12?

There's a fairly long thread on Honda-tech about them, but with everything on that site, it's hard to filter the bullshit from the good stuff. There's people running anything from one -12 line to four -10 lines.

My gut says two -10 lines would suffice? Is that a bad guess?

 

[snowborder714]

Two -10's would be enough for almost any car. There's some people who run with just one -8 line and the stock PCV. My brother and I have pretty much decided on using one -10 fitting with the stock PCV, partially because we can't fit two -10 fittings off the top of a valve cover in a 2g with the stock hood.

 

[4g63Powered]

Ah yes, that gives me another question.

Is there an optimal placement for them? IE, sides vs. top? Again, I've seen them both ways.

The VC I have is shaved but still bare metal, so there's no finish to ruin or letters in the way.

 

[snowborder714]

If you plan on keeping the baffles (which most people would recommend), you need to keep the fittings above the baffles. Placing them on the top is the easiest way to do so. That's the only real advantage for top vs. sides, other than fitment issues on a stock 2g with them off the top. 1g's I don't believe have that problem and can put them wherever.

 

[Gamble97]

FWIW, I drilled and tapped both factory holes in mine to accept 3/8 to -8 adapters. You have to step down with the hole a little bit, but it works fine.

Pics? What fittings did you use?

Buy an used uncoated VC. Have fitting welded on then sell yours that is coated. It will be cheaper that way. Stripping powder is not cheap.

Kevin

The only issue here is mine is a candy color which costs more to have done and it's going to be hard to sell a candy purple valve cover. It's not a common color people have done.

 

[jpmxrider489]

How many people on here have tapped the valve cover for the fittings. Im thinking tapping 1/4 for the pvc and breather. Would that make the walls to thin?

 

[romeen]

How many people on here have tapped the valve cover for the fittings. Im thinking tapping 1/4 for the pvc and breather. Would that make the walls to thin?

I actually did tap the breather hole for a 1/4 NPT fitting. It gets awfully thin on top but the tapping part went fine. When I screwed in the fitting it caused a small crack in the thinned out part. I was able to save it with some JB Weld over the crack and it's held up fine. BUT, even though I did manage to screw in a 1/4 NPT fitting I WOULDN'T recommend it in your case since your VC has cosmetic value. I can take pics tomorrow if you like.

IF you decide to try this don't run the tap all of the way in. Only go as far as absolutely necessary. Same with the fitting.

 

[jpmxrider489]

Ya pics would be great. What's the next step down for a tap. Big enough I can tap with no worries and still be close to 8an?

 

[romeen]

Ya pics would be great. What's the next step down for a tap. Big enough I can tap with no worries and still be close to 8an?

To reiterate, I'm not recommending this but rather just saying that it can be done.

 

[jpmxrider489]

Would 3/8 be the next step down?

 

[romeen]

Would 3/8 be the next step down?

No, 3/8 NPT is actually larger than 1/4 NPT. To go smaller than 1/4 I believe you might have to go down to 1/8 NPT which won't give you much benefit. But I'm not certain about that.

 

[Calan]

To go smaller than 1/4 I believe you might have to go down to 1/8 NPT which won't give you much benefit.

True story ^.

 

[jpmxrider489]

Ha calan I knew you would chime in sooner or later. The one guy said he did 3/8. I'll probably give 1/4 a go. What about 1/2 since thats the same a 8an?

 

[Calan]

Most 1/2 NPT fittings have an ID that is closer to -10AN or even -12AN (and bigger is better), but it varies a lot. You would have a really hard time getting a 1/2 NPT fitting worked into the stock ports, and it would take a lot of drilling and filling.