Cascade Crew

Quasi-Traction · Posted: Fri Nov 17, 2006 4:02 pm Post subject: We got a Bleeder!!

Since it was nice today, I decided to take the berlinetta for a short spin.

Got about 5 blocks from my house, shifting out of third into neutral to come to a stop...car stalls...very strange.

I start the car back up and take off. Seems to be bogging pretty bad. I come to a stop, open the hood, found a vaccum line loose...so I plug it back in...I look down and notice a suspicous dark brown liquid rolling out from in front of the wheel.

Sure enough, its oil....I look all around, entire K memeber, spring, shock, motor mount, sway bar..etc..is soaked in it. I stick my fingers in it, and oddly enough it smells like Gas, and has a thinner consistancy than old oil.

I drive it home, and suprisingly smoother. oil pressure is consistant....doesn't seem to have any seemingly compression related problems and acceleration/deceleration seems crisp.

I get under it and start checking every nook and cranny whith the engine running. Turns out its the fuel pump leaking gas out the side of the housing but the substance squirting out was a gas/oil mixture. I've seen a fuel pump leak gas like this before, what I can't figure is, where the oil is coming from.

I take the pump out and I look at the arm for the pump.. seems to have a pretty good dimple, and some scoring on the very tip. there's a "groove" where I assume the rod is supposed to sit... looks like it'd never been touched. I take the rod out too....it seems to be ok, just one little tiny imprerfection on it..you almost can't see it.

anyone want to insert any knolege where the oil might be coming from? I know I'll definately need a new fuel pump...but if there's a greater problem at hand (like a blown oil passage inside the block..) I won't bother

Also...the PVC and oil fill cap had oil rolling out on the valve cover....and both were seated tightly. dipstick was also out of postion.

Twilightoptics · Posted: Fri Nov 17, 2006 6:59 pm Post subject:

There are two bolts on the front of the block near where the fuel pump is. It's where the smog pump bolts. One of those bolts threads it the oiling area of the block. Make sure it's sealed too.

Twilightoptics · Posted: Fri Nov 17, 2006 7:01 pm Post subject:

Could also be running lean.

Is this new oil or bobby oil?

chevymad · Posted: Fri Nov 17, 2006 7:02 pm Post subject:

The fuel pump can pump oil out of the block and out through the bleed holes above the diaphram when the internal seal goes bad. Nothing too unusual there. Make sure you don't have alot of gas in the oil pan though. If it smells strong change it. Just replacing the pump should be good to go.

Quasi-Traction · Posted: Sat Nov 18, 2006 2:21 am Post subject:

Good to know about the pump.....I've never done a pump on a Small Block Chevy...any trick to getting the arm of the pump to seat on the rod where its supposed to?

either way...my motor isn't ruined Rock on!

Quasi-Traction · Posted: Sat Nov 18, 2006 2:24 am Post subject:

Xophertony · Posted: Sat Nov 18, 2006 3:27 am Post subject:

Twilightoptics · Posted: Sat Nov 18, 2006 7:52 am Post subject:

No, you need to change the jets or rods. A qjet on a 350 is perfect. I had one on a 305 and it was stellar... with proper primaries.

The rod seats itself. That screw that feeds into the oilway, you can get a longer bolt, and screw it in with the pump on... and it holds the rod up in place so you don't have to fight it when putting the pump on.

chevymad · Posted: Sat Nov 18, 2006 9:52 am Post subject:

GM has used qjets all the way down to the 4.3 and even the inline pontiac OHC six. The nice thing about them is that the secondaries are variable in size. The upper flap will only open as much as the engine demands.

So I'd start by checking the float level in yours. If thats ok then see about doing a primary rod/jet change.

Is it only at idle that its so rich? If so that has nothing to do with the rod/jet combo. All idle mixture is set with the screws in front. If this is the case i'd try setting the float a little lower.

Quasi-Traction · Posted: Sat Nov 18, 2006 6:36 pm Post subject:

Its Much leaner at Idle than it is at half or Wide open throttle....does that mean it should have a rod/jet change? What does the float level have to do with the amount of fuel that actually is injected into the venturis?

Quasi-Traction · Posted: Sat Nov 18, 2006 6:41 pm Post subject:

Twilightoptics · Posted: Sat Nov 18, 2006 6:50 pm Post subject:

The bolt holds the rod in place from where it was on the lobe. It's easy to compress the pump into the flange even if the rod is downward position. This way you aren't fighting the rod falling down etc.

chevymad · Posted: Sun Nov 19, 2006 1:19 pm Post subject:

Since the jets are in the bottom of the carb, the level of the fuel above them causes pressure. The higher the fuel level the more pressure, thus more fuel is allowed into the venturi's. That's why in a rebuild kit, there are different float settings for different size motors. You can play with this a little bit. If you're rich everywhere you can try adjusting the float to a slightly lower level.

To really get the carb set right, you'll need to lock the secondaries out. Either wire them shut, or adjust the air door spring too tight. Then just work on the primary side. There are several settings on the primaries you can mess with. First you'll need to open the carb and see what is actually in there. Should be letters on the rods, and #s on the jets, and then maybe a color of the spring. Each rod has at least 2 stages, most have 3. Theres a wot tip size, then a part throttle taper, and then at the top a larger stage for cruise. These all vary depending on what/when your motor needs fuel. These are the fine tuning areas. For a gross change you can also change the jets themselves. To change the actual timing of the mixture changes you change the primary spring.

Once the primaries are set you can play with the secondaries. These are easier and don't require taking the carb apart, unless a jet change is needed. Here you can change metering rods, and the hanger holding them. The hanger is what determines how far the metering rods will be pulled out of the jet. To speed or slow the opening there is a spring tension on the top air door. You mainly want to adjust this until it opens as fast as possible without bogging.

I would do some studying on the web to find out good rod/jet combos to try for your combo.

I like to set my primaries to the lean side. On a quad the primary barrels are only 1.5" in diameter, the secondaries are 2.25 each. So if you set the primaries lean and the secondaries rich, you can overcome the primaries and end up with a good performance afr ratio. Yet you'll be cruising around with good mileage on the primaries.

Edlebrock should still be selling all the rod/jet combos for their quads. They did quit making the carbs though. I've found close enough combo's out of junkers though myself.

Quasi-Traction · Posted: Sun Nov 19, 2006 6:40 pm Post subject:

*nod*

I'll have to wait until finals are over and tear into it on my Christmas Break.

The hangers I pulled out of the old CC Q-jet off my LG4 were lettered D. they seemed to be in good shape, could I reuse those? Will that be too lean on the primary side for the 350? When locking out the secondaries the car will have to be tested under load, correct? (correct me if I'm wrong, the secondaries won't open when you free rev the thing?)

I'll probably start a new thread with questions as I tear into it. Thanks for the help so far Brandon (and paul). I'll search some on TGO about the endless questions people have about Q-jets.