mmcilroy

I spoke with Cliff last week, similar advice, made a WORLD of difference. I bet you have the same results, the guy knows his stuff. I was struggling with the same problem all last year.

defiant1

Good to know. Did you install brand new idle tubes and down channel restrictions? Or did you just drill them out to the new size?

mmcilroy

Just drilled them out, my neighbor did it with this small, pin vise type of drill that you just twist with your finger tips. He laughed when I asked if I should bring the cordless drill over. I was amazed how a few thousands of an inch could change things, I really had my doubts. I have been trying to get this thing running right for almost a year. Was sure I had a vacuum leak, different intakes, different gaskets, on and off again. Tried everything. Rebuilt carbs, 4 different ones, one of them we went through 4 times. Even pulled everything off and made sure we degreed the cam right. And all I had to do was open 4 stinking tubes a few thousands of an inch, I can tear down my motor in 2 minutes now with my eyes closed LOL

Still a little tuning left to tweak it all in but at least I'm driving it.

defiant1

Great, I will give it a shot. I still need to get a new air horn gasket and new screws (allen head type this time) as I have mangled both items taking the carb apart so many times.

defiant1

Ok- based on recommendations from Cliff Ruggles, the Idle tubes were replaced w/.039 Idle channel restriction opened to .059 and Idle Bypass air was drilled out to .110"

I am still having the same problem. Engine runs great at fast idle (great vacuum, etc.) as soon as I kick it off of the choke circuit it starts spurting fuel out of the nozzles.

Backing off the mixtures screws starts to decrease the nozzle drip, but it does not stop it completely. I still have to screw in the throttle screw almost 2 turns to get it to idle decently (750 rpm) without dieing. I know I am out of the idle circuit but I can't seem to find the sweet spot where the throttle flaps are closed enough to keep the fuel from dripping out and still have them motor run.

I might have to borrow another carb and see what happens.

oldcutlass

Whether you are in the idle circuit or not, the carb should not drip fuel.

defiant1

I was just going to ask that question. I just came from the garage. I double checked my float height (15/32") and tried again.

Got it to run ok at 880-900 rpm @ 19* BTDC. It is not dripping fuel at a rapid rate like before, it is just barely weeping out, if you weren't using a flashlight you would not be able to see it.

But, if no fuel is suppose to be coming out at all, then not sure what is left. I guess I could open up the idle tubes more??

I bought another SBO 350 the other day and it has a Edelbrock 1406 on it. I think I will clean up the Edelbrock and give it a shot. I got nothing else to lose, I guess (other than more friggin' time I should be driving the car instead of wrenching on it.)

oldcutlass

The Edelbrock carb may need an adaptor plate if your running a spread bore manifold.

defiant1

OK- I took a suggestion from a Q-jet enthusiast. I plugged up the port on the carb that goes to the PCV valve. Ran the motor to operating temp. Timing was set at 14* at 850 and was pulling 14-15" of vacuum. Motor ran really consistent and was not shuddering (very very minor shuddering if at all).

I hooked up the PCV valve to the carb and valve cover, leaving the timing and RPMs the same and it ran like ***. Shuddered horribly and the vacuum dropped to 11"

Soooooo, since I replaced the PCV valve twice. 1. Why is this happening? 2. Is there another way to achieve crankcase ventilation so I don't hurt the motor? 3. Are there custom PCV valves? 4. Can I install a breather on the oil fill tube, similar to the Olds 425 motor I received recently which does not have any PCV valve or breather on the valve covers, only a vented oil fill cap.

Thanks for sticking with me on this.

d1

Indy_68_S

I don't have any advice or guidance, d1...but this may be a common problem....Somehow there's too much 'draw' thru the PCV ???

Here's mine as pulled. Note the vac line is disconnected and a previous owner cleverly installed an big black 'Marks-A-Lot' magic marker cap on the carb...!


click for big

defiant1

Yeah that marker cap is custom! I have been reading that some people use a PCV valve off a V6 motor to help rectify this problem. Still looking for a better answer and hopefully I am not masking another symptom...

Indy_68_S

I figured on mine the vac problem was the result of brittle hose, grommet, & VC gasket....but since yours is all fresh...I don't know...

defiant1

Anyone have any ideas for an alternative to the PCV valve that allows me to keep the high vacuum but removes the vapors from the crankcase?

d1

oldcutlass

How much blowby are you encountering without the PCV?? If your not getting any or minimal, you can discontinue using a PCV and just run a vent line to your Air cleaner from one of your valve covers. This will give you a minimal amount of crankcase ventilation!

My concern is still your dripping carb. Did you rectify that issue?

defiant1

I guess I haven't been able to drive the car more than a few blocks since I installed the motor. And I really only run the motor around 20 minutes or so each time I try to adjust the timing/fuel mixture. So, not sure on the blowby, where will I notice it the most? My valve covers have the baffles, as well.

If I run a vent tube I will have to modify my RAMAIR air cleaner to accept the tube.

When I plugged the PCV port on the carb, the nozzle drip went away as well.

d1

defiant1

Someone relayed that I might have the wrong "sandwich" gasket installed in between the base plate and main body of carb. And that may be causing the carb to pull vacuum from where it is not suppose to (or at least something to that effect).

oldcutlass

You would notice it at the valvecover where the pcv goes, the other valvecover where a vent would go, and coming out the oil fill tube. It will look like smoke.

You can modify your stock breather to run a vent either out the back or on the bottom.

defiant1

Well I tried just installing 2 breathers and I had a lot of blow by. So, I installed 1 breather passenger side and one breather with a tube on the drivers side. I installed the PCV valve in line between base of carb and breather w/tube.

Instead of focusing on initial timing I set the timing based on mechanical advance. I set it at 33 degress all in before 3100 rpm. I checked my initial timing at this point and was at 13* @ 1100 rpm. It did not want to idle well at this point. So, I increased the timing to 15* and adjusted the fast idle and idle mixtures screw accordingly. So now I am at 35* all in before 3100 rpm. The only thing I don't know is the vacuum reading at this setting (still working on installing a permanent vacuum gauge).

Oh, and I wound up using the stock mechanical advance springs (sort of heavy-but not as heavy as the after market ones) and the aftermarket mechanical weights.

It runs the best at this setting, I still have an erratic idle while in drive with brake depressed and also while going reverse at slow speed. It idles around 750 rpm while in drive or reverse.

So I will keep tinkering with idle mixture screws and the throttle flaps.

d1

Rickman48

Is #1 plug still black? That'd tell me a bad manifold seal, bad intake guide/valve seal.
Keep in mind the '80's carb you're using is set up for a pollution motor with a convertor, so is probably lean throughout every aspect. Is it from a 350 or 305?
Obviously, the 305 is made leaner throughout the rpm range.
Fixing the idle circuit won't help the other circiuts very much -
Try to borrow a carb from another 350 - I think you'll feel the difference!
FYI - back -in-the-day of leaded premium gas, my pure stock '69 442 with 97k miles, pulled 26 inches of vacuum after a rebuilt correct carb, shimmed valve springs and new valve seals. Ran away from a few BB Chevys, too!
Did you ever check the primary throttle shafts? Notorious for wearing out quickly!

defiant1

Haven't checked yet, I will tonight after a 100 mile round trip. Intake guides/seals were replaced during rebuild of heads.

Carb is from a 350. I changed jets, metering rods, etc. I basically changed everything I could to eliminate the emission aspect of the carb.
Yes, primary throttle shaft rebuilt as well.

I do need to verify the vacuum I am pulling for sure.

defiant1

Checked my plugs. Looked at all of them and regapped them to .036 from .042.

No black soot or carbon build up on #1 or any of them for that matter.

If fact they were really clean and white. Which is too lean, correct? Granted they have only been ran a few hundred miles.

d1

Rickman48

Yeah - white is lean, should be tan.
With everything you've mentioned, I'd say that carb is AFU!
Sounds like someone could've assembled it with spare parts and nothing matches!
In all my years of messing with them, I've never had the problems you're having, and that's probably close to 200 units!
Borrow/buy another running carb and see the difference, doesn't seem this one is worth the hassle!

MDchanic

Even after a few hundred miles they should be light coffee colored.

Not to sound lie a broken record on every thread I post on, but if you post a picture, it would be very helpful.

- Eric

Rickman48

Are you sure this Q-jet hasn't a STD?
Drippy and all that!
Could that saturated gasket be coming apart?

defiant1

I will go take a picture of the plugs and get it posted. I just got done reading that today's gas does not affect the porcelain of the plugs like it used to. Making reading plugs hard to decipher...


Maybe I should give the carb a shot of penicillin?
I had already installed brand a new gasket, so I think I am good there.

defiant1

Pics:

MDchanic

Those are TOO CLEAN for several hundred miles.

I think I see a bit of whitish deposit on the positive electrodes of some of them, but I'm not really sure.
The porcelain insulators look unusually white - I would expect them to have at least a tiny bit of a light brownish color.

I'm under the impression you've had the heads gone over - how many miles on the pistons, rings, and cylinders? If they aren't tight and close to new, I'd say you're running lean across the board and that you may also benefit from cooler plugs.

Also, I like the idea of installing a known-good carb from somewhere, just to see if it still does it. If the problem goes away, then you know where you need to look.

- Eric

defiant1

I thought the same thing. The electrodes do have a little grayish deposit on them.

Bottom end is stock and to my knowledge has not been rebuilt. So for cooler plugs, what do you recommend vs. R45 or R46(which is what I am using now)?

I picked up a Edelbrock 1406, and am in the process of cleaning it up before I install it on the engine. Supposedly it worked well before I got it, but you never know. I will throw a rebuild kit in it and go from there.

defiant1

Ok- installed the Edelbrock 1406. This was a bigger pain than I thought it would be.

I got the carb from a motor and transmission set I bought recently. Unfortunately the shed the previous owner stored it in leaked water and the carb took the brunt of it. So after 3 days of soaking, cleaning, soaking, cleaning and a rebuild kit later I am in business. I set up the carb as if it came from the factory.

Needed a spacer (due to 3711/need to clear EGR--which I had to do with the Q-jet as well). Needed to modify my throttle cable bracket and cobble up a return spring bracket. I used my 4 BBL throttle cable and "ghettofied" a connector to the linkage. It works pretty well, I got full travel in both directions (closed to full open secondaries).

Ran a longer gas line, double checked everything and gave 'er hell. The choke was not quite right but it ran just long enough for me to get up to the throttle and manually operate it to keep it running and adjust fast idle.

After the choke fully opened the carb had good throttle response and no bogging after idle. I waited for it to warm up and tried setting the idle to achieve the highest vacuum possible (14 Hg). After that I set the timing I set it initially at 750 rpm (idle) and 17* (@1100 rpm). The motor was not liking this and still bucked and shuddered like the Q-jet. I put my hand over the primaries and it started to die, so no massive vacuum leak either.

Now, I am annoyed, either my cam is toast or I have a super secret squirrel vacuum leak. I let the motor cool down ( 85* today and I am in the garage). I pull the plugs and notice the spark plugs 1, 3, 2, 4 are completely black and 5,7,6,8 are not far behind. So, the carb is putting out a rich condition. I knew from reading that Edelbrock riches up the carb from the factory to prevent folks from running lean and potentially causing damage (read: CYA). So, I changed the rods and jets to a leaner condition.
***It should be known the Q-jet ran lean, real lean, no matter how I adjusted it, so I was actually glad to see some color on the spark plugs, even though it was on the other end of the spectrum***

After the motor cooled, I fired it back up and set the idle and timing again. I ended up with 19* (@1100) and 800 rpm for the idle. The motor was not running smooth as I was hoping, but at least it was consistent (I might just have to video tape it so you guys know what I am try to explain). Vacuum still holding strong at 14" Hg. My timing is all in before 3100 rpm and reads 39*. I think I will have to recurve the timing to get it more in the 34-36* range.

I took it for a spin. Ran pretty good, still fighting idle in drive while stopped or going in reverse, but not bad enough where I thought it would stall out. No pinging and no dieseling when I turned it off. I pulled the plugs and they were the glorious color of light brown/tan. It was actually nice to see a positive result from a making an adjustment to the carb. The only issue (other than less than perfect idle) was it stumbled a little at part throttle. I changed the jet and rod and will find out tomorrow if richening up the that circuit will eliminate that little stumble.

I am not sold on the Edlebrock. But I made more headway in one afternoon then I did with the Q-jet in two months and soliciting the help of those on this forum and Cliff Ruggles to boot. Basically, I know the motor is not running how I want it to be, but with the 1406 it is running a hair better then with the Q-jet and I don't have that evil lean condition either that I was having with the Q-jet.

It is definitely frustrating. I have over $300 and God knows how many man hours into the Q-jet and having nothing to show for it but a paper weight. I took a free, rusted out Edelbrock and in a few days had it performing better than the Q-jet.

I know that there are those who cautioned me to go with a year specific carb. But, I thought I was being prudent by asking the opinion of an expert and got the green light from him to go with a later manufactured carb. Live and learn I guess. I would like to send the carb to Sparky's etc. to see if the carb is junk or just set up wrong for my motor.

At any rate, the Edel 1406 was brought back from the dead and is holding its own. I will continue tweeking it and maybe I will get lucky (I am due).

d1