Yes you will see the bubbles popping as they are being sucked in. There isn't enough soap / water to cause any issues other than telling you where the vacuum leak is.

Like I said, worked great for me, cost me nothing.

Good luck with it

 

I know the dist. Is in and timed correctly, and I may be wrong, but I just can't see that it's a vacuum leak, at least not between the heads & manifold. I went to great pains getting it right, checked & rechecked.
I got tired messing with this old carb so this morning ordered a new one from Summit. Supposed to be here tomorrow.
Expecting great things...

 

plug it, tape it, shove a bolt in the pcv line with, are you serious? : )

you must be messing with us

 

Of course I know how to plug a line, or do away with it! The question is how do I have a PCV system and not have it act like a vacuum leak. This whole thing started with trying to use original Corvette valve covers and do away with my valve covers with breathers.

 

That is kind of important information. Would have been nice to know that at the beginning of this conversation.

It sounds like you are now in the "throw parts at it until it is fixed" mode.

Good luck with your car.

 

You could very well bolt that new carb on and have the same issues if your PCV valve is the issue, but, at least you'll have 'unfrozen' mixture screws. If somebody cranked down on the old carb's screws so hard they're jammed up that would be your lean condition but your the mixture screw tips are already ruined in that case.... If you somehow had a '75 Quadrajet on there then you may well have an old emissions carb with the sealed adjustments (my '75 Pontiac LeMans had that setuo).

 

Dont know if u bought a electric choke qjet or a divorced choke qjet from summit 59. Im still questioning the choke operation and ya know FYI the choke is very easy to remove on the qjet. Then all it takes in warm weather is a couple of pump shots to start - needs some feathering in cold weather though. To late now but i have a divorced qjet w/o the choke blade i could have sent u as a loner - rebuilt and not run since. Also have a rebuilt late model qjet w/electric choke and APT i could have loaned u for testing.

Really the best deal on the planet is to have lars rebuild a good core qjet and he will test run it in for u also so u know its in tune. Well it sounds like u bought a remaining stock new Edelbrock qjet from summit and should be in good hands.

Hope things work out with the new carb.

 

Well, throwing parts at it is not helping either. Got the rebuilt carb from Summit this morning, same thing. Took the PCV out of the equation and it runs slightly better but still will not idle. Engine sounds bad, acts like a vacuum leak. A friend is coming over to look at it tomorrow but I'm ready to start over.
Not sure I don't want to go back to my original intake & CalCustom valve covers with breathers and say to hell with it!

 

If your Manifold has an Oil Fill Tube installed and a PVC Mounting Hole, what kind of Cap is on the Oil Fill. My 67 OEM, 327/350 has a Cap that Seals the Fill so that the Vaccuum for PVC operates correctly. I'd try Sealing the Oil Fill and remove that from the equation. Air may be entering the Crankase and into the Intake Base of the Carb. I may be reaching, but something strange is going on here. Al W.

 

I could offer a myriad of choices for my stupidity, not enough sleep thinking about this problem, old age, beginnings of Alzheimer's, etc. All offered for not plugging a hard to see underneath the carb vacuum tube. I'm tired, and embarrassed.
Anyway, it idles fine now with the rebuilt carb. I reset the timing at 8 deg. and test drove it. After a few blocks, it acted like it was missing and I think it is the PCV. Tomorrow I will test drive it again without a PCV and see what happens. Thanks to all for your help and guidance.

 

Other than a switched wire it only made sense to be a Air entering after the Butterfly's. Al W.

 

Try to fix one thing at a time, too many variables makes it much harder. As you fix or confirm the non- problems you can begin to narrow down your problem area.

You say it does not idle. But does it seem to run smoothly above about 1500 rpm?

Have you confirmed the timing, sounds like you have.

I would eliminate the question of vacuum leaks, since there is a tie to the valve cover, intake, and carb swap.

Like Franks says, get an UNLIT propane torch (the kind used to braze copper piping). First turn it on (did I mention unlit?), and point it down the carb primary throat, and listen to the engine speeding up - it's burning propane with the carb gas.

Now slowly pass the torch end, unlit, over the body of the carb, the carb to intake gasket interface, all hoses and fittings associated with the PCV system, and the intake to head interface. If the engine speeds up, you have pinpointed your leak. This method will reveal leaks too small to otherwise be seen, including hard to reach and see areas. If it does not speed up, you have eliminated any leaks (the only oddball being the area of the intake to head interface that is open to the valley; however, any leaks here will result in a suction, instead of a slight pressure in your crankcase, which the propane torch should reveal when you expose it to the PCV system). Did I mention the torch should be used unlit?

 

Exactly right. Far and away the easiest means to pinpoint even the smallest vacuum leaks....unlike other methods (like soap bubbles) its not just visual - you can hear the effects of the propane gas at the leak point...the gas is also under pressure so it is forced into the leak areas...

 

Too much oil is being sucked up thru the PCV valve. Need to tear it back down and add a metal baffle to the manifold, besides the Moroso. Not looking forward to that!

Also, I installed the Corvette script valve covers using the new FelPro Dry gaskets. One side sealed well but the other side leaks like a sieve. Is it feasible to fix this with red silicone adhesive?

 

Just a thought since your set up isn't 100% OEM. The rubber grommet for a PCV is close to the OD of 1/2" copper fittings. A fresh grommet should seal it well enough. You could experiment with a couple home made copper tubing baffles and an inline PCV before tearing the manifold off.

 

Well really NO liquid oil should come into the PCV valve. You may have the wrong valve; the amount of 'draw' they allow varies -- too much and you'll pull oil through. On a non OEM setup that might require some experimentation. Some have added an oil 'catch can' prior to the PCV valve to separate the oil and vapor IF ITS NOT TOO EXCESSIVE. It works...but may require more plumbing than you want to deal with.

Valve cover gaskets leak over the top where oil is splashed...that is where they must seal.... Regular cork FelPro with ultra-gray RTV where the cover meets the gasket is all I ever use - leak free...

I guess I won't even ask why you swapped out good parts on an engine you yourself state was running great

 

Because it looks bad. My engine is about un-corvette as you can get, corporate blue on a C1? I wasn't winning any awards at car shows and my friends told me the engine bay is what is holding me back.
So, I started cleaning it up. Removed and painted the wiper motor, hood hinges, firewall, fender wells, had the splash shields powder coated. Painted the exhaust manifolds gray & engine orange.
As you know, in order to use Corvette script valve covers you have to have a manifold with the fill tube. I wanted to keep the quadrajet (my preference) so I could either use a cast iron or aluminum manifold. The Performer 2101 had provisions for the fill tube, could drill it for a rear PCV, looks kinda like the 2x4 setup, and drops a lot of weight off the engine.

Fixing our cars or making them look or perform better while keeping a stock look is what it's all about, right?



Before



Almost done
I would sure like to know more about this PCV valve you mention. Anybody have a part # for this?

 

Good to read u figured it out and thx for sharing it helps us all. Im wondering if that PCV hole was covered with the original splash guard on the bottom of the intake it would still work while keeping oil out? I cant even see the PCV or tubing connection in your pic. Looks like u got it plugged. But wow, that would be alot of oil to make it run rough - check/clean your plugs too (and oil lvl).

 

Yes, it's plugged right now but here is what it would look like.




Intake w/PCV

 

WOW! I can't believe how good your engine looks now.