Ok, I have what I beleive to be a mid '60's 327... I have that CAN in my lifter valley... but I can't figure out where the breather comes out in the back of the block.(its in the truck still.) Or, whewre it may have been plugged up... Could someone post a PIC of what this thing looks like so I can figure my crap out? I really wanna run some old script valve covers I've got, without the aftermarket breathers cut into 'em. (yes, the intake going on has a filler.) Thanks, Jason
it should come out right along the right side of the distributor to the rear a little if i can remember correctly. look closely of feel around there, you should find it. jerry
if u are going to use a intake with a filler neck. u can use the breather on the stock filler neck cap it has a beather in it . if there aint one on the driver side of the dist.
Speedy3, good to know, thanks, I didn't think that would be ENOUGH ventilation. Ok, so I've been poking around on the wrong side of the block. If I have the CAN, does it mean the tube/opening is DEFINATELY there? Thanks, J
Yes. Sometimes guys will put a freeze plug in there... sometimes there's a road draft tube... and sometimes there's a tube that leads up to the air cleaner... I've taken a freeze plug, popped a hole in it for a Chevy PCV valve grommit... then popped the PCV Valve in it and drove it in the hole... works slick. Sam.
I was thinking the same thing.. is that gonna be enough ventilation? I was thinking about putting some Moon breathers in the VC but I'd like to avoid it if I can.
yup, sounds good. But if anybody could snap a pic of this elusive thingy, or just where it lives, it'd be much appreciated! Thanks,
AHA! its on top.... ok, I got a freeze plug where that should be... whats the best way to re-establish that? Get another freeze plug, drill and tap it? does it vent to the ground, does it need anything put on the end? For some reason, I like NOT venting anythiing back into the carb, I'd rather just smell it. If I had an aircleaner that would accept something like that, I'd do that, but I dont, and I really wouldn't be fond of the extra hose.... whattya reccomend? Thanks, J
I think the reason they're called "road draft tubes" is because a rubber hose leads down to the road to dump the stuff. I'm not sure if it's secured to the firewall or bellhousing somehow or if it just dangles. I have a '68 327 without that provision and one with (or it did before the rebuild). It makes me wonder when they stopped it.
What BigCheese said. Just a hose to the ground. I'm wondering if a guy could use a PCV valve in a line to the carb instead ?
A road tube engine will have a metal tube pointing to the ground. That engine has a nipple for a rubber line back up to a PCV valve. I think 68 was the first year for a pcv valve. A rubber hose will work for venting.
Another way to do it is to weld a angled pipe into one of the exhaust pipes and connect it to the breather. Cut the end of the pipe at a 45 degree and put the long end to the front. As the exhaust passes over the end of the pipe it will creat a vacumn and suck the fumes out of the engine. This keeps the bottom of yer car a lot cleaner. I used one on a 327 in a 32 5W coupe and it worked just fine.
you know,harley motors have a crank case vent that they run to the air filter via a rubber hose.the problem with that was,it always made a mess of the air cleaner and if you didnt keep e'm clean[most people don't]it made a mess down the side of the bike.what most guys did was reroute the hose to dump below the bike.the only thing i did beyond that was mount a little breather filter[it's about the size of an erosole lid]to the hose.i was always told that not only do they push out air,but suck as well,and i did'nt want it to suck road dirt and maybe plug.you could always think about something similar for your car,that way you could keep it clean underneath..
Ok..... the way I handled this on my old vw bus... a kludge in of itself... I looped a lond piece of vinyl hose from the breather outlet up to the top of the engine cpt down to the road... figuring the oilyness is gonna go all the way out, but the incoming particulates A) either wouldn't get pulled all the way in, or B) if they did, they would eventually stick to the oily sides of the tube... ? whatever. I'll just pop one of my old chrome breathers on the end of a hose and attach it.... somewhere. Thanks!
A "road draft breather" works on the same principle as a carburetor. It's a metal tube that extends down below the motor into the "draft" of air as the car is MOVING down the "road". It's usually cut off on an angle. As the air passes over the end of the tube it forms a negative pressure(vacuum). The vacuum pulls the blowby gasses and moisture out of the crankcase <font color="red">IF </font> there is another breather (usually the oil fill cap) to let freash air into the crank case. This is a Chevy V8 road draft tube. 58-62 it goes in the same hole in the block behind the dist. Pre-PCV valve cars idleing will sometimes have oil vapors coming out of the breather when they aren't moving. (no vacuum) PCV valves work when parked and when moving. Pulling a vacuum on a motor without another breather wont pull any air through the motor. Put your finger over the end of a drinking straw and suck. . It's the same principle for either a PCV or a road draft system. Bad air out good air in. A hose running from the fitting in SJFAST's block picture above to a PCV valve continuing on to the intake will pull the vapors out through the "can" under the intake. The oil fill tube breather will let freash air into the front of the valley. Bad air out ...good air in
i had that thing hooked up to the carb on my 283 and it puffed smoke every time i shifted gears(4 speed). so i blocked it off. no problems. but now i know why, i changed to an aluminum intake with no filler tube. so i guess it was the sucking on the straw theory.
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