I have a 235 that the draft tube was removed and capped with a freeze plug. I ran a cap from the valve cover with a ½” hose to the port on the intake (see pic). Is this enough for the engine to breath? Pros, Cons?? Thanks for the help & info in advance!! Pros, Cons??
You've kind of posted this in the wrong thread for this kind of question. One of the moderators will probably move it to the appropriate place for you, so keep an eye on it. But until then, here goes. You don't want the crankcase completely sealed off and you don't want it under too much vacuum either. If your fill cap is vented you're probably doing no harm, but you're also not doing the best job of venting the crankcase. If it were me I'd route the vacuum hose to where the draft tube was previously attached and get a PCV valve of some sort in the hose. Then make sure the fill cap is vented and filtered so that clean outside air can be drawn thru the crankcase and into the intake manifold. Welcome to the HAMB. And you'll get a better reception here if you fill in some more of your personal details and at least the general location of where you are in the world.
I moved this to the Main board for ya. Man if there is just a hose going from the breather to intake vacuum with no pcv valve, you must have a tremendous vacuum loss..... do as Claymart says and adapt a pcv to the place the draft tube went and have a breather cap on the valve cover. or just put a draft tube on it.
If you need a 235 draft tube, I'm pretty sure I have one I'll never use - yours for the postage. PM me.
On the 235’s and 261’s used in truck you could get a factory pcv system It went in place of the road draft tube it used a threaded pcv valve and went in to the intake and you oil cap was vented. Easy enough to make one up, you could even drill out the frost plug in the block use a grommet and a modern push in style pcv And a vented oil cap.
You have to be a bit careful with these things. the road draft tube was simply a vent for the crankcase to relieve any excess pressure built up there. But it was minimal pressure. It was almost a passive vent. If you look at the bottom of the road draft tube it was cut at an angle and places so that the air that went by it created a slight vacuum to suck the vapors and relieve the pressure. No problem with leaving it there - it worked OK but not so good for mother nature (or the underneath of the car). If you decide to go the route of a PCV, just size it right and plumb it correctly with appropriate parts. I put mine to the bottom of the back air cleaner. works OK and is sort of out of sight
Very comprehensive article for just what you are wanting to do. I am going to be doing this myself. http://devestechnet.com/Home/PCVInstall
I found a draft tube hole canister that is set up for a PCV valve. Must be for one of the last 235s ever made!! That of course is by GM; They sold the molds for that great engine to Toyota who made 235s for the Land Cruiser up at least thru the '80s. As I understand it, Toyota didn't even change the various casting numbers and GM symbols in the patterns.
I hate dumping anything but air, fuel, and accelerant into the top of an engine. Internal combustion engine are not supposed to eat their own sh!t
Ditto. Exhaust gas recirculation is a dumb idea gone bad. But I sort of like PCV valves. They recirculate gas vapors they have blown by and that have some BTU value. Actually increase fuel use efficiency probably 0.00000000054123%
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