Here is my setup. B20 (injection ports plugged), with two SUs mounted on the combination cast iron manifold (secondary butterflies removed and plugged). Using the B18 PCV system: Crankcase breather box on side of engine through PCV valve to what looks like a large orrifice nipple on the manifold. Oil cap hose goes to air filter.

Problem is that the PCV valve (less than a year old) rattles like crazy clickty clickty clickty. The valve seems to be functional as I can suck through the hose but can't blow into it (mmmm yummy oil flavor).

Other things I noticed. The engine dies rather quickly when the hose is pulled off of the manifold (duh), and from a subjective feel it seems to suck pretty steadily when I put my finger over it. I looked in the archives and all I could find is that someone else had the problem so they just removed the PCV valve from the system.

What is the deal?

Am I using the wrong nipple on my manifold? Should it have a more restrictive orrifice? Does it sound like a bad PCV valve? Is this pointing to another problem? I really want to avoid going to the B20 pcv route since that would involve going over the whole thing again and trying to find the right size hoses and everything.

thanks,

mario m.

Check the cap to see if all is well there as the hose should lead to a pin-hole in the cap that admits air to the crankcase. Excess air will just be sucked through the system.
Also, try getting a new PCV valve. I went down to Kragen/Shucks/Checker and looked over the selection with the old one in my hand and found one that fit and it worked like a champ (right way round!)

Mike!

There's no pinhole (a.k.a. "metered orifice") used with a PCV valve. Airflow is from the air cleaner -> oil cap -> crankcase -> oil trap -> PCV valve -> intake manifold.

Therefore, PCV valve is defunct as the spring is not strong enough. If it is clattering, it is open A LOT which allows large volumes of air into the intake manifold after the carbs.

Mike!

Any thoughts as to what could cause this incessant clicking??

I've never heard one make any sound at all. Joaquin's idea of an air leak may have merit.

Obviously you do have the valve in the right way, with the fatter part nearest the oil trap teardrop, yes?

Is the hose between the valve and the intake manifold teed into a brake booster?

Are you positive it's the valve? If you remove it and plug the hose to the manifold, does the sound go away? Leaks can make very mechanical sounds that'll fool you...

My cap does not seem to have a pin hole. My oil cap has a large hole in it that goes into that metal fiber stuff that is in the cap. I have tried taking my cap apart numerous times to clean it out but there was no budging that cylinder apart.

You have a air leak. I has the same trouble some months ago (I adapt the PCV system to my B18A engine). In my case was the tube from the valve to the oil breather have leaks on the union with the breather. I change it with a ... rubber spark plug cover. Now it work ok (some weird the view a orange spark plug rubber on that position, but...). A old local technitian say that leaks can be detected on any part of the pcv setup. or on the servo air tubes (for detect it, I use a plastic flexible tube - from a IV blood kit - one extreme on my ear with some cotton, the other, going around the suspect areas - seeking by ear for a hissing sound.

Joaquin
Rojo 121 Amazon
Lima Peru

Could someone run through the theory of why a small airleak on the engine side of the PCV valve would cause this clicking??
From what I can figure the crankcase side of the PCV valve is connected to atmospheric pressure due to the oil cap being connected to the air cleaner.

Am I getting this wrong?

I take the clue from the section "PCV valve" on http://www.automecanico.com/auto2002/mantenimiento.html
(a web site on Los Angeles, but on spanish). Also, in my case the leak was half of a dime size (hose with a big crack on the side facing the engine- this type of hose was not for use on hot places).
J.

Also check if the spring into the pcv are ok (press it with a small stretch screwdriver, carefully).
J.