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Discussion Starter #1 (Edited)
Holley 3310-2

Runs really well at idle (13" plus vacuum) but pulls fuel in a big way on full throttle AND deceleration.
Engine smokes like start up after flooding. 72/80 jets. 6.5 PV. Its so rich the pipes turn black in 1 hour and may be causing high oil consumption?????????

Where could the fuel be coming from and how? Would a bump in fuel pressure cause something like that or is there somewhere between the metering block/body or body and throttle plate that could cause something to go rich?????
 

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3310-2 has a secondary plate not jets -stock(F)72,(R)plate 134-21.
What plate are you using?
You've checked the obvious ?
Fuel pressure
Float level
Plugged idle bleeds
etc.
This just start or what changes have been done?
 

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Discussion Starter #3
Hi Mike.
we have a block on the secondary side of this 3310-2

Fuel Pressure is between 6-9 lbs. Gauge fluctuates.
Floats are right at the bottom of the sight holes and we have the plastic plugs in at the moment to watch the level.

We blew out the idle bleeds/mains as well. This car idles really well. If you plug them with your finger, the engine dies (idle).

I'm trying to see where to look next.

This may have been going on for a long time as the engine has been smoking on decel and the exhaust is SOOTY black. The water on the floor under the muffler drains is black/sooty when it dries.
 

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Suggest checking that the plate on the secondary side is tight, with new gaskets. The older style with the metering plate, gasket, and flat plate, that seals against the rear of the main body can leak. If the gaskets compress or get saturated, the void in the main body will fill up, and eventually fuel will leak into the secondarys, dripping out the idle feed, transfer slot, and the main feeds. Sometimes just tightening the wonderful clutch head screws will temporarily fix it, and give you time to find the gasket. Newer ones don't have the void in the main body and seem to seal much better.

Mine have show up first at idle, but eventually it will smoke all the time.

A failed power valve can also let fuel leak by.
 

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13" at idle(must be in gear with auto trans when taking idle vac reading because it will be lower like 9"-10" idle vac in gear with 13" in park) .

If the 13" vac is with auto in gear thats fine,but if you have auto trans that was in park then a 5.0-5.5 would be a better choice but just as long as the current 6.5 your running is ok/not blown-defective.

It should not go pig rich on you because the 6.5 p/vlave your running is not that far off where you need to be,it has to be something else as long as your current p/valve is ok.

They are so cheap if i had your problem and had the carb appart i would replace it or at least test it to be safe.

Anyway, your rich situation could be a Blown /defective power valve,incorrect float lvl,bad float taking on fuel-too heavy,worn needle & seat or dirt in them,fuel pressure too high ,cracked -warped metering block allowing too much fuel in when off /out of idle circut,bad metering block gaskets.

If you pull carb appart and dont find any issues that would cause an over-rich situtatuon use a strong light and magnifying glass to lookvery closely at the metering blocks and main carb body looking for cracks.

Scott
 

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One word.....Edelbrock ! ! ! Switched over a year and never looked back.... Cross over to the dark side....If you lived closer i would pull it off for ya.....
 

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Discussion Starter #7
Ok I get the idea but I still cannot understand how a needle/seat would leak but not show up on the sight glass? Same with a float. BTW these are brass in this car.

I'll pull a known good 3310 from a friend and see what happens next year as the race car is now in the nest and the Chevelle put away.

BTW Part 2. I am sure its not the primary block as I have had 2 in there and no change. However the secondaries?????


Scott this is a 4 speed car FYI.
 

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You may have the timing retarded. This will cause the idle adjustment set to high. This will expose the transfer slot making the carb to run rich. My question is does run rich during idle? If it does, your idle circiut may be running rich. You may have to open to idle air bleeds. If it run rich while driving. Then the jets need to be change to a smaller size. The jets will come not to play until your 1800 to 2000 rpm. Below that it's the idle circuit doing the work. Check the power valve, too. Also lower the fuel pressure to 5-6 PSI. Hope this helps:thumbsup:
 

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As stated above, What rpm is your idle set at. Make sure the transfer slot is not being exposed. You can advance your timing and that will raise the idle speed, letting you back off the idle speed screw and get the carb running off the idle circuit.
 

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I have nothing against the edelbrock carbs, I run a Holley. I do believe a properly set up holley will out perform a eddy though. Open the hood of a nascar, and you'll find a holley bolted on the intake.
 

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Discussion Starter #11
As stated above, What rpm is your idle set at. Make sure the transfer slot is not being exposed. You can advance your timing and that will raise the idle speed, letting you back off the idle speed screw and get the carb running off the idle circuit.
All of this is OK. Idle 900; timing 28* with 18 mech/10 vac at idle, timing 38 mech /48 with vac at 2500 up.

I'll have to check the rear block/gaskets etc. as there is always a steady fuel pressure fluctuation (rapid movement of gauge) from idle up as soon as the car warms a bit.
 
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