<VV> PCV system on the Corvair

moonpie8n at comcast.net moonpie8n at comcast.net
Sun Dec 19 12:11:22 EST 2010

HI Guys, 

For those of you who are interested in installing a PCV system on your Corvair [instead of "talking it to death"], I found a kit I had made up from the "OLD DAYS". Remember , these are old part numbers , but , a good parts man can find them in the <"PARTS HISTORY", and convert to the new numbers. 
One of the PCV valves I used was a CV607 AC. IT is for 5/16 hose on one end & 1/2 hose on the other, ... with an outside diameter of 5/8 inch. This gives you a lot of options for hooking it up [you can install it to suit yourself]. The other PCV valve I used was for a '63 - '64 327 Impala or Corvette [don't have the AC #]. IT has 1/4 inch pipe threads on one end and 3/8 hose on the other. I used a 90 degree bypass hose from V8s to connect from the road/vent tube to the PCV valve. Remember to cut off the road/vent tube so it doesn't connect to the air cleaner anymore. There are several hoses that will do the job , but just take your cut/off road/vent tube with you to the parts store. 
A good hose to start with is the CH-1 Dayco bypass hose [old #], ... this is for a "smallblock ford V8. This hose should slide tightly over your cut/off. IF you are not happy with the fit, you can use a CH-3 [OLD #]. I know this is for a Chtysler V8. Not sure if it was "BIG BLOCK" 383 , or "Small Block" 273-318. This allows you to do a little "engineering" on your own to get exactly what you want. From the PCV valve to the "balance tube" is just straight hose. 
IF you are a ,"PURIST" ,this is probably not the "easy fix" you are looking for, but , this simple system has worked many times for me and my father [ Anderson Chevy Corvair Specialist], in the past.... 
----- Original Message ----- 
From: "Chris & Bill Strickland" <lechevrier at earthlink.net> 
To: "VirtualVairs" <virtualvairs at corvair.org> 
Sent: Thursday, December 16, 2010 8:22:26 PM 
Subject: Re: <VV> PCV system on the Corvair 

> The system, unless it gets completely plugged, should always keep 
> pressures from building up and causing oil leaks. 

I fully agree, Seth, one does not want pressure building up. But with 
the good running engine with normal combustion bypass, in addition to 
sucking up such vapors, one wants to provide fresh air inlet to purge 
those crankcase vapors, including the water vapor portion of the 
combustion bypass -- without the "ventilation" part, that moisture can 
get trapped in the crankcase. 

> the orifice in the PCV tee is supplying main engine vacuum to the 
crankcase - well, a bit of it anyway, through the tee 

Heh, heh -- not really. It is more like holding a vacuum source out to 
the open atmosphere and thinking that it is sucking your crankcase -- no 
way! (unless maybe your air cleaner(s) is(are) plugged -- the balance 
tube only will get what is forced out of the crankcase into the air 
cleaner tube, where it mixes with the air cleaner air. 

> It would be interesting to place an extremely sensitive vacuum gauge 
on, say, the oil filler cap, 

That was one of the early PVC testers -- little round flat thing with a 
ball in it that was sucked up a ramp, when it worked. better than a 
gauge, you could set up a manometer tube, or the U-shaped version to 
compare vacuums here and there, but assuming the air cleaner has a good 
system, it should be at atmospheric pressure internally. Likewise, the 
air cleaner tube, meaning there is atmospheric pressure at the PVC / 
orifice -- please explain where the "crankcase suction" comes from ... 
however much your orifice or PVC sucks, it will still be at atmospheric 
pressure on the air cleaner side, and thus, so will the crankcase -- no 

And I think we all know what happens when you take the oil fill cap off 
a running stock Vair -- it may as well be on an overhead cam valve cover. 

Bill Strickland 
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