Four Carbs, all loading fuel at bottom of intake

IMG_2833.jpg
Ok, here's where I am at today. Put the Edelbrock 1411 back on. Timing was at about 14 and 16 HG vacuum. Increased the timing as per suggestion to 25, raised vacuum to about 17-18. Ran for about 5 minutes, ran rough. Next pics show front and rear of intake.
IMG_2833.jpg


After running for about five minutes, removed the carb and white gaseous vapor inside intake.
Then tried to take pictures of raw fuel at bottom of intake. Spark plug wasn't bad this time. Has been soaked other times.
Checked voltage at "+" side of coil running. It is 14.07 volts. This excess fuel looks like, according to where the gasket is damp, seems to be coming from the secondary's, but from all 5 carbs?

Exhaust is a new flex coil and new Dynomax to get it to the paint booth. So don't think an blockage there. The Preview is hard to follow so not sure how this will end up on the site.

IMG_2834.jpg


IMG_2838.jpg


IMG_2841.jpg


IMG_2844.jpg


IMG_2848.jpg


IMG_2852.jpg
 
Could your intermediate Shaft gear be off by 1 tooth ? That would cause all sorts of issues including timing.
B5DA5243-5F3A-430A-BB27-7D99E4A245D5.jpeg
 
Spark plug confirms you're running rich.
Can't blame the carbs because several have done the same thing.
Can't blame the distributor because you've used 2 different distributors.
Engine is running way rich. Timing retarded engines run rich unless the fuel mixture is leaned out (like modern cars are for better gas mileage.)
Fuel puddles in the carb plenum. Like the intake valves are open during compression stroke.
Timing Chain/gears: did you degree the cam?
Damper/Harmonic Balancer: did you reuse the old balancer? If not, are you sure #1 piston is at TDC when timing mark is at 0° on the timing chain cover grid? Harmonic Balancer has a rubber divider between the inner and outer sections. That divider can dry up allowing the outer section to slip in timing retarded direction, such that the timing mark is retarded from where it should be.
 
That "gas" in the intake plenum is just vaporized fuel, which should be very explosive in nature.

Something's out of whack, somewhere. Which makes things harder to diagnose with the engine in the car. Things like the hopefully perfect relationship of the marks on the timing chain sprokets to each other (easy to be "one tooth off", sometimes), how accurate the timing mark on the balancer is to actual TDC, and how the distributor drive is indexed. Hope it's someting simple to do!

Just some thoughts,
CBODY67
 
Could your intermediate Shaft gear be off by 1 tooth ? That would cause all sorts of issues including timing. View attachment 501127
The only issue that would cause is ignition timing, and not if you pay attention to where the rotor is pointing when wiring your distributor. While there is a recommended orientation for the slot, it can really be anywhere and still work fine. If your distributor cap has a cast-in "1" on it, the #1 plug wire may not line-up with that tower when putting everything together. If later you don't like how the distributor is oriented, you can always "walk" the wires 1 tower clockwise or counterclockwise and turn the distributor 1 tower (45*) in the opposite direction. Repeat as necessary.

On a related note, you checked that the distributor is wired so the firing order is correct, and that the rotor is not 180* off from where it should be?
 
Just for giggles, I would take the fuel pump completely out of the picture. You need to know for sure if your pump is forcing fuel past the floats in the carbs.

Pull and cap the suction line to the pump so it can't pump any fuel with the engine running and run the engine to use up the remaining fuel in the line.

Disconnect the line at the carb and rig up a gravity feed container to the carb. It doesn't need to be fancy. I use an upside down gear oil jug. Run the engine and see if it improves anything.

I'll see if I can post a photo of my gravity feed rig later today.

Jeff
 
Here's a quick and simple fuel rig.

It won't run a big block for long, but you can pour in more fuel while the engine is running. I hook it to the bottom of the hood. If your hood is still off the car, you'll need to improvise.

IMG_0997.JPG


fuel iv.JPG


Jeff
 
Looking at your pictures that is not where vacuum advance connects, lol. You should connect it if you are driving it, although it should have no effect on what your doing it could improve a stumble.
 
Looking at your pictures that is not where vacuum advance connects, lol. You should connect it if you are driving it, although it should have no effect on what your doing it could improve a stumble.
Vacuum advance tube is not connected to anything. I had put it on to see if there would be a difference once connected, wasn’t so plugged the carb port for it and it’s dangling.
 
Just for giggles, I would take the fuel pump completely out of the picture. You need to know for sure if your pump is forcing fuel past the floats in the carbs.

Pull and cap the suction line to the pump so it can't pump any fuel with the engine running and run the engine to use up the remaining fuel in the line.

Disconnect the line at the carb and rig up a gravity feed container to the carb. It doesn't need to be fancy. I use an upside down gear oil jug. Run the engine and see if it improves anything.

I'll see if I can post a photo of my gravity feed rig later today.

Jeff
I bench tested this carb after putting new parts in from rebuild kit. Electric pump at 6-7 psi showed no signs of leakage.
 
Just for giggles, I would take the fuel pump completely out of the picture. You need to know for sure if your pump is forcing fuel past the floats in the carbs.

Pull and cap the suction line to the pump so it can't pump any fuel with the engine running and run the engine to use up the remaining fuel in the line.

Disconnect the line at the carb and rig up a gravity feed container to the carb. It doesn't need to be fancy. I use an upside down gear oil jug. Run the engine and see if it improves anything.

I'll see if I can post a photo of my gravity feed rig later today.

Jeff
I see what you mean now. Took me a couple reads. This would eliminate the pump. Agree.
 
The only issue that would cause is ignition timing, and not if you pay attention to where the rotor is pointing when wiring your distributor. While there is a recommended orientation for the slot, it can really be anywhere and still work fine. If your distributor cap has a cast-in "1" on it, the #1 plug wire may not line-up with that tower when putting everything together. If later you don't like how the distributor is oriented, you can always "walk" the wires 1 tower clockwise or counterclockwise and turn the distributor 1 tower (45*) in the opposite direction. Repeat as necessary.

On a related note, you checked that the distributor is wired so the firing order is correct, and that the rotor is not 180* off from where it should be?
 
I did get into fight with myself on this one. With the timing marks at TSTC and piston confirmed at tdc, I marked where number should be on distributor cap. My thinking was that “tdc” should be firing on number 1. It backfired on that setup. If I placed wires 180 from tdc, it starts and runs but rough like it is now. Now I’m thinking maybe I was too far off from number one and gave up too soon.
 
The only issue that would cause is ignition timing, and not if you pay attention to where the rotor is pointing when wiring your distributor. While there is a recommended orientation for the slot, it can really be anywhere and still work fine. If your distributor cap has a cast-in "1" on it, the #1 plug wire may not line-up with that tower when putting everything together. If later you don't like how the distributor is oriented, you can always "walk" the wires 1 tower clockwise or counterclockwise and turn the distributor 1 tower (45*) in the opposite direction. Repeat as necessary.

On a related note, you checked that the distributor is wired so the firing order is correct, and that the rotor is not 180* off from where it should be?
Post #35 addresses my wiring issue.
 
Spark plug confirms you're running rich.
Can't blame the carbs because several have done the same thing.
Can't blame the distributor because you've used 2 different distributors.
Engine is running way rich. Timing retarded engines run rich unless the fuel mixture is leaned out (like modern cars are for better gas mileage.)
Fuel puddles in the carb plenum. Like the intake valves are open during compression stroke.
Timing Chain/gears: did you degree the cam?
Damper/Harmonic Balancer: did you reuse the old balancer? If not, are you sure #1 piston is at TDC when timing mark is at 0° on the timing chain cover grid? Harmonic Balancer has a rubber divider between the inner and outer sections. That divider can dry up allowing the outer section to slip in timing retarded direction, such that the timing mark is retarded from where it should be.
Here is a pic of the cam gear timing. My understanding is the square and triangle are 4 degree advance and retard. I place it on the “0” which I believe would be neutral zone.

6A36AD9C-6B79-4C26-AF7E-AA009A6EF003.jpeg
 
That "gas" in the intake plenum is just vaporized fuel, which should be very explosive in nature.

Something's out of whack, somewhere. Which makes things harder to diagnose with the engine in the car. Things like the hopefully perfect relationship of the marks on the timing chain sprokets to each other (easy to be "one tooth off", sometimes), how accurate the timing mark on the balancer is to actual TDC, and how the distributor drive is indexed. Hope it's someting simple to do!

Just some thoughts,
CBODY67
Post 36 is the timing marks. I’m wondering now if I should be 4 degrees advanced. I did not degree the cam on installation.
 
You're way off on that timing chain. It's surprising that it runs at all.

Yellow circle is the correct mark.
timing mark.JPG


The keyway is around 1 o'clock at TDC.

Jeff
 
Keyway should be parallel to the #1 connecting rod with #1 @ TDC, i.e., pointing at the centerline of the piston pin. IIRC
 
Back
Top