Anybody have any photos? Seems like it is somewhat of an illusive setup but I have one and an Offy intake. Trying to set it up this winter and not having much luck finding any info. Here are some photos I have found and some relative questions below. Note the vacuum line inserted directly below carb, is this ok to simply be inserted/ jammed in, or should I connect with threaded insert? Why did they connect this vacuum on the manifold? Any photos or advice, constructive input would be greatly appreciated. Sent from my iPad using The H.A.M.B. mobile app
Positive Crankcase Ventilation. ('PCV') Once considered a California pain, it has since relieved many of pesky oil leaks, resultant from excessive crankcase pressure. Lots of threads on this, look up 'PCV Valve'.
Kind of humorous to me I guess because a breather is right behind it. Isn't it a bit of a mute point with a breather? Sent from my iPad using The H.A.M.B. mobile app
Uhhh... Any time a PCV is utilized, the filler 'breather' is either 'valved' one way or actually plugged. If this filler cap is 'open', it's incorrect. Humorous to me is a 'bit of a mute point'. The term is moot. Moot point. Point that is 'mute' would be unheard.
Yes you are correct on both points and my comment wasn’t derogatory towards you- more that it looked to me that the utilization in the photo was just unnecessary. Please don’t take the comment about my very poor sense of humor personally I was merely stating that with a breather I did not believe the PCV was necessary. Thanks for the corrections! I will site mute (not moot) and see if I can get any help in regards to the original intent of my post. I humbly apologize for the egregious error and poor ability to annotate my thoughts; I will make an effort to proofread in the future. Sent from my iPhone using The H.A.M.B. mobile app
The Vacuum line that just plugs into the center of the intake is for a the hot air choke. The stainless tubing connects to a chamber that is warmed by exhaust heat, that warms the manifold to aid in cold drivability and keep the air fuel mixture from freezing up the manifold. Not as big a deal with a V8 but with an inline 6 you can get frost on the intake if it is not warmed up from the exhaust.
The vacuum line for the choke should be sealed at the manifold. You have an open vacuum leak there. Agreed. Both your breathers need to be closed for a PCV to operate correctly.
Pcv system has to have an air inlet... It is not supposed to create a vacuum in the engine. Most factory setups allow air in with a fresh air hose coming off of the air cleaner. Venting with a breather cap is another way to do it and is correct. Sent from my Moto G Play using The H.A.M.B. mobile app
The above intake is designed for the later '48-'53 8RT/8BA engines, with the angled carb pad, road draft port (where the pcv is positioned) and fresh air intake/oil fill. On a late engine, the road draft port leads directly to a vertical stand pipe coming up from the crank case, while the fresh air/oil fill flows down and to the rear. The '35-'48 crank case ventilation is completely different. The late intake will work OK on the earlier engines if the air intake/oil fill is plugged and moved to the rear, using a stock 59 fuel pump stand, and removing the front vertical stand pipe and plugging the hole, or the oil pan vent. The pcv vacuum line should be hard plumbed into the intake with a solid connection to prevent a vacuum leak.
There is NO vacuum on that line. It is only an air source to warm the Temp sensitive spring in the choke pot that opens the choke after a period of time that is set by tension on the choke spring by rotating the choke pot cover for the desired opening time.
I have been running a WCFB 4 bbl on an Offenhauser intake with the same choke heat tube and also a PCV valve on an 8BA 284 flatty for many years. Works great. Dave
I had good luck running ford's 2 barrels from the late '60's on the flatty, some of the 1" carb spacers had a PCV inlet [nipple] cast in it...
Found the base was cracked. So that sucks. I am bailing on it and running dual quads until i can find a reasonable replacement. Sent from my iPhone using The H.A.M.B. mobile app
Been running this setup for a couple years now, no issues. BTW I think the original pics you posted are of my setup that I bought from Dick's.
I wish I could have used it. Looking for a new base. Poor packaging cause the base to crack slightly on its way home. Kind of got tired chasing for now so running two two barrels until I get it all figured out.
Actually there is vacuum on that tube. It comes from the carb and sucks the warmed air into the choke spring chamber to heat the spring. Any carb with a heat tube sucks the hot air into the choke spring chamber. If you don't believe me hook a vacuum gauge to where the tube threads onto the choke.
As stated by BJR, the vacuum source is the throttle area of the carburetor. A passage through the carburetor enters the choke housing behind the internal choke pull-off, and is allowed to bleed into the complete choke housing, and thence into the tube pulling hot air from the manifold. The hot air warms the bi-metallic spring, allowing it to relax, and the internal choke pull-off pulls the choke butterfly open. No vacuum - no choke operation. Jon.