Valve cover breather thread

[Onion]

From what i understand in my searches, the thread for the valve cover breather is a bilok 1/2 NPT. Does anyone know where to source fittings for this? I'm looking to obtain a right-angle to 8AN fitting.

Thanks!

[Mark Maras]

 McMaster-Carr would be a good place to look.

[zKars]

It would be easier to have an aluminum AN fitting welded to the end of the stock elbow than to source a Bi-lok fitting.

I've also discovered that you can run a 1/4NPT tap into the end of the stock elbow (not too far, it will split!) then get a $2 1/4NPTM to 8AN adapter. 

[Onion]

Mark- I did try McMaster-Carr and this sadly was one of the times that that amazing site has let me down...and I say that because I've lost hours perusing that place!

ZKars- I was considering actually drilling/tapping a proper NPT fitting but was hoping for the necessary elbow already in existence before going down that road. I would rather not weld or tap onto the stock elbow. I appreciate the suggestion though!

[Mike W]

I've actually been through this as I wanted to install a catch can directly from the breather port and wanted to also us AN fittings.

I can tell you for sure that the original threads are not 1/2 NPT.  I purchased a 1/2 NPT right angle AN fitting and it was too big.  I ended up purchasing a 1/2 NPT tap and retapped the hole.  Was not a super hard effort and made for a nice solution in the end.

Since then I have actually had the breather hole welded over and smoothed out to the contours of the valve cover and welded in a 1/2 NPT bung in the very back of the valve cover and have attached my catch can there.  Makes for a cleaner and fairly unique installation.

 

[zKars]

I'm willing to bet the Bi-lok thread that is used is the tubing compression nut thread end. I searched a bit once trying to track down what that thread is, and about all I can remember it is a straight thread, and nothing common. 

Doing the usual Bi-lok google thing did reveal several suppliers.

[Onion]

zKars- It did illuminate several suppliers but nothing with a conversion to an AN-fitting. This site in particular seems to offer a female bilok to male AN - opposite of what I need...which disheartened me:

http://www.tubefittings.biz

They do have a male bilok to NPT that I was seriously considering which is on this page on that site:

http://www.tubefittings.biz/dlf.shtml

I actually fired off an email to them earlier this morning inquiring about options...and may end up giving them a call later once I have a few minutes. I'll update the thread with anything I find.

Mike W- lol, it's funny that you responded on this thread (thanks btw)!  I didn't realize you didn't know my nick on here!  Anyhow, the 1/2 NPT tap and drill is what I may end up doing. I do really like the rear relocation though...those pictures don't do it justice. Seeing it in person is pretty schweet. I do still want to pursue the relocation but was thinking about saving that for another iteration...either way, that solution is my end goal at some point...it's just too clean.

 

[gundee]

Is this supplier any help?

https://www.pegasusautoracing.com/productselection.asp?Product=3253

[Chickenman]

Not sure how I feel about the rear location for a breather vent. The stock location has a VERY effective baffle plate underneath the top breather vent. A heck of a lot of oil spray gets flung about from the Camshaft under there. 

Edited July 10, 2017 by Chickenman

[Mike W]

I agree with you on the baffle plate and so we designed something that I believe will be more than sufficient in terms of preventing a significant amount of oil from being slung around and ultimately ending up in the catch can. 

 

I removed the old baffle as it was no longer needed.  There are 2 bosses cast into the cover at the very end of the cover.  I drilled and tapped these so I had something to mount the new baffle to.  I fabricated a very simple L bracket out of some 3/32 aluminum stock and this new bracket actually "covers" the hole made by the newly welded in bung.  I then drilled about a dozen small holes in the bracket right around the area of the hole so it makes sort of a mesh filter.  I mounted the new baffle and secured it in the cover with red loctite.

So far so good.  No significant flow of oil from the cover into the catch can and everything else seems to be running fine.

Mike.

 

[Onion]

Lumens- Great supplier...but nothing in the way of bilok adapters unfortunately...

FYI, I usually sort my AN fittings/hosing from one of these places (in no particular order)-

• http://www.anfittingsdirect.com/
• https://www.anplumbing.com/
• JEGs
• Summit Racing
• Amazon
• Local (Austin) speed shop

Usually atleast one of them has what I need with the exception of this bilok conundrum.  I'm sure there are many other great suppliers...I've just been using these for my two Z project cars.

[wheee!]

I used the existing baffle and tapped the side of the valve cover.