The Stovebolt Site Forums The Shop Area Engine Shop PCV on a 216.......again

Hello, I wanna get rid of my draft tube and put a PCV on my original 216. I only have one vacuum port on my intake manifold that's being used for my original wiper motors. I'm keeping the vacuum wiper motors as well as my original fuel pump. Can I Tee off of that same vacuum port on the intake manifold for a PCV valve AND the wiper motors? :rolleyes:

I'm skeptical you can Tee in and have any performance on the vacuum wiper motor but no harm to try it. If it fails ur either gonna have to drill the manifold, go to thru the air filter or reverse the crankcase flow and get a fuel pump that provides vacuum--Chevs of the 40's has such a glass bowl fuel pump for the 216 -- I think.

Although not a huge deal I would think that adding PCV to a manifold source on an engine that it (carb metering) wasn't originally designed for would cause a lean condition that would have to be compensated for? Jim.

You'll need to seal the valve cover top if you're 216 is like mine. There are vents on the top of mine.

Why are you wanting to kill the downdraft tube?

If you're getting a lot of smoke or blowby the PCV won't fix the situation. Mine doesn't give me any headaches.

A PCV system is a good addition, keeps the motor free of water vapor and reduces emissions too.PCV was an option on those old trucks, the manual mentions that the PCV shouldn't affect carburation ,but if it does, install one jet size larger,.001 of an inch.

Shane--

When a pcv is added, the downdraft tube is typically removed and replaced with a filter to draw clean air into the engine and crankcase fumes are drawn out usually thru the valve cover to the intake manifold where they are burned and exhaused.

The first time I became aware of it was when I was a kid haulin hay. My little AD jimmi did fine be driven to school and around town but when it spent all day crawling around a hayfield it would turn a crankcase full of oil to sludge literally in a day--speed was too slow to allow the draft tube to evacuate crankcase blowby and of course the rings on these engines never were much and were typically worn out anyway. Back then--in the mid sixties--they sold what were called ventilation valves. Run a tube from valve cover or valve cap to intake manifold with ventilation valve in line--and put a filter in the draft tube bung. I've seen em run both ways--exhaust to intake or exhaust to fuel pump. Lotta folks also ran exhaust to air filter--but I never wanted to run that nasty crap thru a carb.

I suppose as long as ur truck is always run at speed--draft tube will get u by but pcv will keep ur oil cleaner--my 2 cents.

I did exactly that on my 235, made up a tee and came off the intake manafold, no problems,If you think that you will not have enough vacuum ,go to most late model chevys they use asmall vacuum canister made of plastic shaped like a ball . you can put that in line and that will increse your vacuum. old navy 51................

I mentioned the valve cover needing to be sealed <the vents at the top> Because a PCV valve will only open when the crankase builds enough pressure to overcome your engine vacuum. The check valve inside it would always be closed if the valve cover vents were not sealed.

Since around '94 I've driven no cars newer than '62 and only had a complaint on the downdraft tube from one which had worn out valve guides which caused an oil consumption problem and subsequently a little smoke out the downdraft tube on startup and when sitting still at idle. I would add a pcv system to an engine that didn't have the valve cover vent myself, but probably wouldn't go out and invest in another cover <unless i already had one around the garage>

I drive my '42 to and from work <which is 45 miles roudntrip> and don't mind mine.

On the 'improved' emissions - That is a bit of a hoax. the only thing that will improve slightly is the hydrocarbons that slowly leak off of the oil <instead they will be adding themselvs back through the tailpipe..If the intake manifold were more efficiant it might make a negligable difference, but as it stands the cylinders don't really burn evenly and you have a rich/lean variation which throughs the emissions of by a whack> I checked mine with a gas analyzer i use at work and it's not horrible, but i tune my carb up with the analyzer regularly.

anyhow, my two cent.

Thats an intresting point. But when I remember the 57 (or so) Assembly manual right they route a hose from the crank case right to the airfilter. But on the valve cover there is a breather. Is this a valve to?

As I`m looking forward to convert to a PCV to I found some intresting stuff on my Google tour.

Any experience with this kind of devices?
http://www.condensator.com/

http://www.wyominginstruments.com/gas_home.htm

http://www.geocities.com/davevandrunen/ind3.html

there will still be vacuum if it was connected to the air filter - the carb is sucking a lot of air. It just won't be the same ammount of vacuum as the manifold.

i checked out the links in your post. I'm a mechanic so my experience is only with your usual oem or high performance equipment. One of the links looked great - if it works. I'm skeptical since a lot of sales peolpe make all kinds of claims that rarely turn otu to be true. Let us know if you install one

What I ment was the valve cover breather.
It would leave air into the engine down to the crank case right?

So if I connect the PCV hose to that crankcase and the intake, would `nt I get to much air into the intake and cause a lean condition?

I heard that - even with new rings - you get some of the unburned gases into the crank case.
It woud be a good thing to burn that gases instead of dump them to the enviroment by the vent tube.

I can imagine that those gases are verry light, so they should go upwards to the valve cover. I think this would be the best location to suck them back into the engine.

My plan:

1. Seal the draft tube
2. close all ventholes in the valve cover
3. put a hose at the valvecover to collect the gases and route them back in to the engine.

what would be the better bet? Use the intake with big vacuum (is the rest of the engine really thight?) ore go the saver route and connenct the hose to the airfilters?

Thanks, Frank