Carb questions

[sleepychallenger]

I know this might be a dumb question but

1. Is there a way to get the same performance that I am getting now but better gas mileage. 10 miles to a gal is killing me,

2. I get a loud whistle from the carb when I am on low speed accel? any ideas?

 

[MyMopar]

Well it would depend on what carb first of all and the specs of the motor/drivetrain? 
Low whistle could indicate vaccum leak like a brake booster or the vac lines for a/c & heater controls or you are pulling in massive amounts of air by a throttle plate that is really close to being closed?

Leaning out the jets and retarding the timing could help, also running a vac. advanced is good for mileage.  If you have vac. secondaries on the carb, use a heavier spring to be sure they aren't opening or tighten the spring on the thermoquad. 

Not having much info about the engine makes it tough to determine what to do.  I'm sure once you post up Chryco may have tips. 

[Chryco Psycho]

running an engine lean usually decreases milage 7 increases heat , neither are good , having it jetted correctly & timed right with help milage ......tuning is evrything though

[sleepychallenger]

all righty. I am running pretty hot I belive because the passenger side valve cover gasket keeps burning out right by the exhaust manifold. Possibly timing. what should the timing be. How do I know if I am running lean? the plugs show no signs of running lean? what is the carb vaccum suppoesed to be? I should be getting better than 10 MPG right?

Specs:
383 Magnum
.030 bigger than stock comp cam (dont remember the exact specs)
Engine is bored .030 over
Carter AVS carburetor w/ vaccum secondaries.
There is a vaccum advance on the distributer.
Auto Trans
No A/C
Cant think of anything else.
Oh... yes im keeping my foot out of it.

[MEK-Dangerfield]

I'm just curious, what gears you have in the rear end? That could be hurting your gas mileage too.


  Mike

[Chryco Psycho]

if the exhaust amnifolds are excessively hot the timing is too far retarded
 What stall converter do you have ?

[sleepychallenger]

MEK -  323 gears

Chryco -  Stock converter. I was told that my rockers were riding to tight and I needed adjustable rockers and that is why it is running that hot. I have never heard of that but does it make sence?

[Chryco Psycho]

if the seats are recessed in the heads & the valve tips were nto trimmed down the preload in the lifter could be excessive which could potentially pump up at higher rpm & hold the valve open slightly , this would cause misfiring or back firing , but as long as the valve fully closes it should not run hotter

[sleepychallenger]

there is no backfiring. the only thing that we did was change the cam. dont know if that would make a difference?

[moper]

You could have put in the cam or dist drive retarded when you did the cam. Did you degree it? Do you know what the real timing curve is on it? That means how much initial timing (set by turning the dist.), plus the centrifical (mechanical advance under the cap) plus the vaccum advance (the vaccum can).  If you have a basic timing light, and a timing tape ($#), you can figure all this stuff out easy. Also, what is the cylinder pressure readings with the new cam? (a compression test, with all the plugs removed from the engine, and the throttle blocked wide open...)

[sleepychallenger]

i am unsure. let me check and i will let you know

The cam was dialed in to exact specs. In other words it isn't advanced or retarded but double checked to be exact. The cam scec sheet gives you the information on valve timing, overlap, and degree of advance.

message from the guy that put it in.

[falcon50flier]

whistling noise is certainly vacuum related and could be doing extraordinary harm (burned valves and top rings). beware continuing to drive it until you isolate the real trouble. 10 mpg is poor for your motor too, and confirmed cam timing and your carb setup need attention after the vacuum issue.

[sleepychallenger]

it only whistles when my foot is in one spot on low accel (30 mph) or if I stay at that speed while the whistle is happening. any ideas on where to check?

[Chryco Psycho]

under the intake manifold & carb are the usual suspects for vacuum leaks

[MEK-Dangerfield]

under the intake manifold & carb are the usual suspects for vacuum leaks

      

Yep,

  Just make sure the carb is on tight. The bolts on the intake should be checked once in a while too.


  Mike