Runs crappy with the air cleaner on

[Kerplunk]

Hey guys,
I have a mildly warm 440 in my 67 belvedere doesn't like it's air cleaner for some reason. I had a 14x3 K&N with the Xstream top, so I swapped it out for a regular 14x3 chrome air cleaner and the same thing happens. Without the air cleaner off in neutral or driving it seems to rev free, with the air cleaner on it falls on its face. Its a 750 Holley (70 primary, 77 secondary), the linkage isnt binding etc.

Could it be tuned too rich and adding the Air Cleaner puts it over the top?

Any suggestions would be great.
Thanks!

 

[Garys1969RR]

Sounds strange to me. I always run with an air filter, and never saw thet kind of problem. I would start by checking spark plug color. A good free flowing air filter should have little to none air flow reduction.

 

[RustyRatRod]

Try a taller element. The lid might be stopping up the float bowl vents.



....and throw the K&N in the trash. They are worthless as filters. They let more air in....and more dirt.

 

[67 coronet]

like rusy said,if it is a drop base lower section your lid may be too close to the air horn of your carb.had this prob on a 68 charger.

 

[RustyRatRod]

Also too, I've run into where some air cleaners interfere with the choke and actually close it up.

 

[bigmanjbmopar]

Choke bind

 

[daredevil]

Try a taller element. The lid might be stopping up the float bowl vents.



....and throw the K&N in the trash. They are worthless as filters. They let more air in....and more dirt.

I,m with Rusty on this one.

 

[Dako]

He currently has a 3" tall filter element...and NEEDS a taller one? Just doesn't pass the sniff test for me...even if it is on a 1.5" dropped base there should be ample airflow...especially with the X-Stream top.

I would be looking at clearance issues with the base plate, or as you mentioned, mixture being too lean. On my 1.5" dropped base (Spectre) I had to add a 1/2" spacer to the carb throat and dimple two spots from underneath to ensure proper clearance of the Edelbrock 650. In my case it hit the elecrtic choke solenoid and put a slight kink in the rubber fuel line (maybe the latter is your problem?). Spectre makes an air cleaner adapter and riser kit(Autozone...$9) that comes with 1/2" & 1" spacers to raise the filter base up off the carb a bit.

Maybe this will help?

 

[RustyRatRod]

He currently has a 3" tall filter element...and NEEDS a taller one?

If he has a deep drop base it is possible. It's either the air cleaner stopping up the float bowl bowl vents or the choke binding. One of the two.

 

[Kerplunk]

Thanks for all the suggestions,
I checked the choke and it seems OK, it is a drop base, I have probably an inch of clearance between the top of the vents, and the air cleaner top, Im not sure if that is enough or not. A taller element would be tough to do as Im running an RO23 scoop, but only have the center between the bracing cut. I can get an 11 inch or 9 inch cleaner and it would fit through the hole, maybe that is the way to go. Im just not particularily a fan of the look of a small air cleaner. If I could Id really have preferred more of a stock look.

Its a pretty tight fit on the base and the holley, so it might not be sealing 100%, would this cause it to run crappy? I'll try the spacer, sounds like a good suggestion.

Thanks again guys!

 

[440roadrunner]

1" is plenty of vent clearance

Examine the base carefully, for contacting/ hitting part of the choke. Wire the choke open or remove the butterfly

Does it contact the (if used) rubber fuel hose?

Does the rim hit anything electrical, coil wire, other ignition wires?

Is there some way to temporarily remove the element from the equation? Maybe cut three scrap wood spacer blocks the same height as the element, and try it with NO element?

(Years ago, with a big 4bbl filter on my 440, the element had gotten wet in the rain. Took me over a week to figure out why the engine was "flat" until I took a little drive with the filter OFF)

Also, a dropped base filter may not flow as much as you think. Without seeing yours, it's hard to figure, but look in the carb hole with the top/ filter assembled. See how much space is between the top/ bottom of the filter.

 

[rev.ronnie]

Make sure it isn't disrupting airflow to the air bleeds somehow. Just a thought.

 

[Photon440]

Does it exibit the same problem with the air cleaner base in place, but no filter or top?