Cleaned up my fuel and vacuum lines...

[Jet Wrench]

and the engine really runs well considering how long it sat. No smoke and very smooth! I haven't done a thing to the Weber other than run some carb cleaner through it and check for any vacuum leaks. I do have a question about the valve cover, is the larger hole just an oil breather and escape to the atmosphere? I have a rectangular air filter assy. (Redline), with no pick up port to accept the hose from the PCV. Thanks in advance.

Jet Wrech

[namba209]

Actually, the large hole is for air to go in to the valve cover, from the air cleaner housing and the smaller hole is for a metered oriface to the intake manifold. HTH.

[tekenaar]

Originally Posted by Jet Wrench and the engine really runs well considering how long it sat. No smoke and very smooth! I haven't done a thing to the Weber other than run some carb cleaner through it and check for any vacuum leaks. I do have a question about the valve cover, is the larger hole just an oil breather and escape to the atmosphere? I have a rectangular air filter assy. (Redline), with no pick up port to accept the hose from the PCV. Thanks in advance. Jet Wrench

. . . they used to supply a 90° plastic "adapter" fitting that mounted in the bottom plate of that little air cleaner that sits on top of your Weber. I'll look and see if I have one . . .

[opelnut10]

Originally Posted by Jet Wrench and the engine really runs well considering how long it sat. No smoke and very smooth! I haven't done a thing to the Weber other than run some carb cleaner through it and check for any vacuum leaks. I do have a question about the valve cover, is the larger hole just an oil breather and escape to the atmosphere? I have a rectangular air filter assy. (Redline), with no pick up port to accept the hose from the PCV. Thanks in advance. Jet Wrech

The large hole in the valve cover is a vent, to allow blow by to not build up crank case pressure, they ran it thuough the bottom of the air cleaner to burn the fumes (blow by) back into the engine. While it helps emmission to have it hooked to the air cleaner as long as you have some kind of vent over or in the hole to vent the valve cover you will be all right.

[kwilford]

Originally Posted by opelnut10 The large hole in the valve cover is a vent, to allow blow by to not build up crank case pressure, they ran it through the bottom of the air cleaner to burn the fumes (blow by) back into the engine. While it helps emission to have it hooked to the air cleaner as long as you have some kind of vent over or in the hole to vent the valve cover you will be all right.

That is correct part of the time. When the engine has more blowby than the small PCV hose that is connected to the metered orifice can inhale (and/or at higher throttle settings when there is more blowby and less vacuum to suck the blowby gases into the metered orifice), the big hose allows crankcase vapours to be exhaled from the valve cover and ingested into the carb intake.

But when the engine is at an idle, and if there are less crankcase vapours being created than the vacuum PCV is pulling out of the valve cover, the large hose actually lets filtered air INTO the valve cover, preventing the crankcase from being pulled into a vacuum. Exactly the same function as a "breather" oil filler cap, but ensures that air entering the engine has passed through the air filter before it is circulated through the valve cover on the way to the PCV metered orifice

[Dale .D]

Just a question to put out there.I didn't think we used a pcv valve in our cars. At least not in my 71.With that hose off the car stalls all the time & just doesn't run that well.Had to JB weld a proper fitting to the cover to get the hose to stay in properly.

[Jet Wrench]

Redline air filter (probably an aftermarket cleaner assy) I could modify the air cleaner to accept the line from the valve cover, but I would rather not to keep it original. Thanks again for the input! The website is a valuable source of information!

Jet Wrench

[kwilford]

Originally Posted by Dale .D Just a question to put out there.I didn't think we used a pcv valve in our cars. At least not in my 71.With that hose off the car stalls all the time & just doesn't run that well.Had to JB weld a proper fitting to the cover to get the hose to stay in properly.

Dale, there is NEVER an PCV valve in this era of Opel. Instead of a PCV valve, Opel used this funky metered orifice on the intake for low speed operation, and the big hose for high speed.
HTH

[Dale .D]

I thought so.Got confused when jetwrench was talking about his pcv valve on his gt.Was in a car show up at Qualicum up Island here last weekend.Incredible ,Around 600 cars.I was the only Opel.Lots of interest & stories.

[wrench459]

From a performance stand point..the last place that you want oil vapors is in the intake tract.
Vent the blow hole to atmosphere or better yet the exhaust.

[Bill Hoffmann]

For years I ran a hose from the large opening to the ground with no adverse effects. However, if you do that keep an eye on the possibility of sludge buildup in the engine. One primary function of the PCV system is to purge water vapor from the engine, and without it the oil will become contaminated. You can see the milky emulsion if you remove the oil filler cap. Be sure to follow good oil maintenance schedules.

Venting to the atmosphere is not the environmentally responsible thing to do, and now my Opels are properly vented to the air cleaner. No, it's not the ideal situation for performance, but most of us probably won't notice the difference.

One side benefit of venting the PCV hose to the air cleaner is that maintaining a partial vacuum in the engine will reduce oil leaks!

Bill

[sawdust]

If you can't feed it back into the carb you can find a breather filter at NAPA.

[flippinbruce]

In sawdust's photo on the 6-17-08 thread on the napa air breather, where does the breather vent to, and also it is hard to see where the smaller hose also leads to. It looks as though it T's to another line. I have a 69 gt and am still trying to finish up all the vacuum lines among other things. thanks for any help you can provide. Bruce

[sawdust]

The red breather vents to atmosphere.
The small vacuum line does 'T' to another line going to the base of the carb.

fwiw..

[crliwa]

I'd like to hook up both valve cover hoses on the Targa properly.. they currently vent to nowhere.. I guess a T for the large hose and running the small hose to the intake manifold where I found a place for it that is currently capped.
Any reasons why I should not do the above?

[sawdust]

You can always undo it if it does not work